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Occupational science is a discipline dedicated to the study of humans as "doers" or "occupational beings". As used here, the term "occupation" refers to the intentional or goal-directed activities that characterize daily human life as well as the characteristics and patterns of purposeful activity that occur over lifetimes.
== History ==
Occupational science evolved as a loosely organized effort by many scholars in different disciplines to understand human time use. It was named and given additional impetus in 1989 by a team of faculty at the University of Southern California (USC) led by Dr. Elizabeth Yerxa, who had been influenced by the work of graduate students under the supervision of Mary Reilly at the same university. Since its formal beginning at that time, which coincided with the establishment of a Ph.D. program in Occupational Science at USC; occupational science has evolved as an additional source of research to expand empirical knowledge underlying the profession of occupational therapy.
== Links between occupational science and occupational therapy ==
Occupational science was developed by scholars (mainly from the profession of occupational therapy) who drew from original ideas predating the founding of occupational therapy. It may thus be considered as a developing or emerging academic discipline. The substrates (or underlying dimensions) of occupation (form, function, and meaning) are difficult to observe and quantify, and thus require and benefit from a multidisciplinary approach. While both occupational science and occupational therapy are rooted in systems theory and holistic views of human agency, the methods for observing and understanding an occupation's form (how something is done), function (its purpose), and meaning (how it is understood and experienced by the doer) are not always holistic in approach. For instance, disciplines such as biomechanics and psychology inform occupational science but, individually, are not necessarily concerned about how their explanations contribute to an integrated understanding of the factors collectively influencing a person's daily life. Professional practice in occupational therapy can prompt new ideas and spark potential research within the discipline of occupational science; although typically, knowledge from academic disciplines precedes the application of such knowledge in applied fields. Occupational science has the capacity to provide insight into the primary modality of occupational therapy (occupation) through studying the consequences of participation in occupation and its therapeutic benefits. Reciprocally, occupational therapy research may provide insights into how human agency and the factors influencing it change under conditions of illness, disability or therapeutic intervention. Additional viewpoints about these relationships may be found in documents describing relationships between occupational science and occupational therapy that have been published by the World Federation of Occupational Therapists (WFOT) and the Society for the Study of Occupation in the United States (SSO:USA). Research has been reported that begins to delineate key or essential concepts from occupational science as they pertain to the practice of occupational therapy. Further refinement of this work may help focus research initiatives in occupational science to guide educators, scientists, and practitioners to advance the evidence-based use of occupation in occupational therapy practice.
== Relationships between human occupation and health and well-being ==
Beyond the well-documented benefits of regular physical activity, occupations that engender purpose, competence and self esteem may provide psychological benefits related to satisfying needs for meaning. Living sitations that limit or restrict participation in meaningful occupations (such as geographic isolation, refugeeism or incarceration) or lead to participation in harmful occupations, (such as substance abuse, deviant or risky behaviors), can lead to "illness, isolation and despair," or even death. However, participation in occupations shown to be beneficial or restorative can enhance health. Through participation in engaging or restorative occupations, the mental state of individuals can be improved and result in feelings of regeneration. Sleep, an area of occupation, not only regenerates physical and cognitive processes, but also is required for satisfactory occupational functioning. Participating in other relaxing or tension-reducing occupations, such as (for example) reading a book, getting a massage, going for a walk, exercising, or pursuing an engaging hobby; may provide physical, cognitive and mental restoration, and stress reduction.
Empirical research linking the perceived psychological and physiological benefits of participation in different types of daily human occupation is ongoing. Questions about the nature of different dimensions of human occupation and their influences on human identity, behavior and states of being are viewed by occupational scientists as suitable areas of investigation. Developmental theorists have long hypothesized that the occupations of childhood and activity related events characteristic of different stages of adulthood are critical factors in physical, cognitive and psychological growth and maturation.
Similarly, there is ongoing interest in how patterns of daily time use, including habits, routines, and lifestyles, may be related to states of well-being. Adolf Meyer, a prominent early psychiatrist and advocate for occupational therapy in the United States, was among the first to speculate that a regular pattern, rhythm or flow of daily occupations contributed to mental health. Meyer also postulated that the life history of his patients could be used to identify situational conditions and events that helped explain their disorders, thus providing an avenue for prevention through community interventions to promote public health (mental hygiene).
== Academic application ==
The development of occupational science as an academic discipline has been advanced through the creation of several university-based programs of study leading to undergraduate and graduate degrees in the field. Disciplines within which occupational scientists can be found include architecture, engineering, education, marketing, psychology, sociology, anthropology, economics, occupational therapy, public health, and geography. There are several national, regional and international societies dedicated to promoting the evolution of this specialized area of human science. Academic journals containing content directly relevant to occupational science include the Journal of Occupational Science, OTJR: Occupational Therapy Journal of Research, Journal of Happiness Studies, 'Quality of Life Research, Applied Research in Quality of Life, Canadian Journal of Occupational Therapy, The Scandinavian Journal of Occupational Therapy, the American Journal of Occupational Therapy and various other occupational therapy journals.
== See also ==
Occupational therapist
Occupational therapy
Occupational justice
== References ==
== External links ==
Journal of Occupational Science
Society for the Study of Occupation: USA
Occupation UK
Canadian Society of Occupational Scientists
About Occupational Science | Wikipedia/Occupational_science |
Occupational lung diseases comprise a broad group of diseases, including occupational asthma, industrial bronchitis, chronic obstructive pulmonary disease (COPD), bronchiolitis obliterans, inhalation injury, interstitial lung diseases (such as pneumoconiosis, hypersensitivity pneumonitis, lung fibrosis), infections, lung cancer and mesothelioma. These can be caused directly or due to immunological response to an exposure to a variety of dusts, chemicals, proteins or organisms. Occupational cases of interstitial lung disease may be misdiagnosed as COPD, idiopathic pulmonary fibrosis, or a myriad of other diseases; leading to a delay in identification of the causative agent.
== Types ==
=== Asthma ===
Asthma is a respiratory disease that can begin or worsen due to exposure at work and is characterized by episodic narrowing of respiratory airways. Occupational asthma has a variety of causes, including sensitization to a specific substance, causing an allergic response; or a reaction to an irritant that is inhaled in the workplace. Exposure to various substances can also worsen pre-existing asthma. People who work in isocyanate manufacturing, who use latex gloves, or who work in an indoor office environment are at higher risk for occupational asthma than the average US worker. Approximately 2 million people in the US have occupational asthma.
=== Bronchiolitis obliterans ===
Bronchiolitis obliterans, also known as constrictive bronchiolitis or obliterative bronchiolitis is a respiratory disease caused by injury to the smallest airways, called bronchioles. It has been reported to occur from exposure to inhaled toxins and gases including sulfur mustard gas, nitrogen oxides, diacetyl (used in many food and beverage flavorings), 2,3-pentanedione, fly ash and fiberglass.
=== COPD ===
Chronic obstructive pulmonary disease is a respiratory disease that can encompass chronic bronchitis and/or emphysema. 15% of the cases of COPD in the United States can be attributed to occupational exposure, including exposure to silica and coal dust. People who work in mining, construction, manufacturing (specifically textiles, rubber, plastic, and leather), building, and utilities are at higher risk for COPD than the average US worker.
=== Hypersensitivity pneumonitis ===
Hypersensitivity pneumonitis (HP; also called allergic alveolitis, bagpipe lung, or extrinsic allergic alveolitis, EAA) is an inflammation of the alveoli within the lung caused by hypersensitivity to inhaled organic dusts.
=== Lung cancer ===
Numerous categories of ionizing radiation, chemicals and mixtures, occupational exposures, metals, dust and fibers have been linked to occurrence of lung cancer.
=== Mesothelioma ===
Mesothelioma is a cancer of the mesothelium, part of which is the pleura, the lining of the lungs. Mesothelioma is caused by exposure to asbestos.
=== Pneumoconiosis ===
Pneumoconiosis are occupational lung diseases that are caused due to accumulation of dust in the lungs and body's reaction to its presence. Most common pneumoconiosis are silicosis, coal workers’ pneumoconiosis (CWP), and asbestosis. Other examples include minerals (such kaolin, talc, mica), beryllium lung disease, hard metal disease and silicon carbide pneumoconiosis.
== Environmental exposure ==
=== Arsenic ===
Arsenic is classified as an IARC Group 1 carcinogen and is a cause of lung cancer. Workers can be exposed to arsenic through work with some pesticides or in copper smelting.
=== Asbestos ===
Asbestos is a mineral which was extensively used in the United States to fireproof buildings and textiles, among other items, in the 1950s-1980s. Workers are frequently exposed to asbestos during demolition and renovation work, which can cause asbestosis and/or mesothelioma. Asbestos exposure can also cause pleural effusion, diffuse pleural fibrosis, pleural plaques, and non-mesothelioma lung cancer. Smoking greatly increases the lung cancer risk of asbestos exposure.
Residents and workers of asbestos mining centers such as the town of Asbest, Russia experience dangerous exposure to asbestos and asbestos dust.
=== BCME ===
BCME (Bis(chloromethyl) ether) is associated with small cell lung cancer in workers who have been exposed. Exposure can occur via direct manufacture of BCME or its presence as a byproduct.
=== Beryllium ===
Beryllium is classified as an IARC Group 1 carcinogen and can also cause interstitial lung disease. Manufacturing workers, dental technicians, machinists, jewelers, plumbers, electricians, precious metal reclamation workers, and welders are at risk for beryllium exposure.
=== Cadmium ===
Cadmium is classified as an IARC Group 1 carcinogen and it is a cause of several cancers, including lung cancer. Workers can be exposed to cadmium through welding, zinc smelting, copper smelting, lead smelting, electroplating, battery manufacture, plastics manufacture, and in alloying.
=== Chromium ===
Chromium is classified as an IARC Group 1 carcinogen and is linked to lung cancer. Workers can be exposed to chromium via welding, steel manufacturing, pigment/dye manufacturing, and electroplating.
=== Coal dust ===
Exposure to coal dust is the cause of coalworker's pneumoconiosis, also called "black lung disease", is an interstitial lung disease caused by long-term exposure (over 10 years) to coal dust. Symptoms include shortness of breath and lowered pulmonary function. It can be fatal when advanced. Between 1970 and 1974, prevalence of CWP among US coal miners who had worked over 25 years was 32%; the same group saw a prevalence of 9% in 2005–2006. It can also exacerbate or cause COPD.
=== Diesel exhaust ===
Diesel exhaust contains a variety of gaseous and particulate chemicals, including soot, polycyclic aromatic hydrocarbons, and other known carcinogens.
=== Flock ===
Flocking is the technique of adding small pieces of nylon or other material to a backing, usually a textile, to create a contrasting texture. Inhalation of flock can cause flock worker's lung.
=== Indium lung ===
Indium lung is an interstitial lung disease caused by occupational exposure to indium tin oxide.
=== Nanoparticles ===
The high surface area to volume ratio of nanoparticles may make them an inhalation hazard for workers exposed to them. This is a topic of ongoing research as of 2015 and 2023.https://www.frontiersin.org/journals/bioengineering-and-biotechnology/articles/10.3389/fbioe.2023.1199230/full
=== Nickel ===
Nickel is classified by the IARC as a Group 1 carcinogen; nickel compound exposure is associated with nasal cancer as well as lung cancer. Workers may be exposed to nickel in machining/grinding industry, nickel extraction/production, welding, and electroplating.
=== Polycyclic aromatic hydrocarbons ===
Polycyclic aromatic hydrocarbons (PAHs), fused-ring chemicals formed during the combustion of fossil fuels, are metabolized by the cytochrome P450 complex to highly reactive carbocations, which can mutate DNA and cause cancer. Workers may be exposed to PAHs while working in a foundry, in the roofing industry, or due to environmental tobacco smoke.
=== Silica ===
Exposure to silica can cause Silicosis, which is a fibrosing interstitial lung disease caused by inhaling fine particles of silica, most commonly in the form of quartz or cristobalite. Short-term exposures of large amounts of silica or long-term (10 years or more) exposure of lower levels of silica can cause silicosis. In 1968, more than 1060 US workers died of silicosis; this number fell to 170 by 2005.
Besides causing silicosis, inhalation of silica can cause or exacerbate COPD. It can also impair lung function in general and cause cancer by oxidation damage. It is classified as a "known human carcinogen" (Group 1 carcinogen) by the IARC. Exposure is common for people working in tunneling, quarrying, construction, sandblasting, roadway repair, mining, and foundry work.
=== Silo-filler's disease ===
Silo-filler's disease (not to be confused with farmer's lung, associated with inhalation of biologic dusts) results from inhalation of nitrogen dioxide (NO2) gas from fresh silage. The presentation is variable depending on level of exposure. Often the gas penetrates throughout the lung and if severe can manifest as a form of acute respiratory distress syndrome, such as significant pulmonary edema, hyalinized alveolar membranes, congestion and other respiratory illnesses.
=== Tobacco smoke ===
Tobacco smoke is a known carcinogen. Workers in the hospitality industry may be exposed to tobacco smoke in the workplace, especially in environments like casinos and bars/restaurants.
== Infectious exposure ==
=== Influenza ===
Health care professionals are at risk of occupational influenza exposure; during a pandemic influenza, anyone in a close environment is at risk, including those in an office environment.
=== Tuberculosis ===
Tuberculosis is a lung disease endemic in many parts of the world. Health care professionals and prison guards are at high risk for occupational exposure to tuberculosis, since they work with populations with high rates of the disease.
== Others ==
=== World Trade Center lung ===
World Trade Center lung is a cluster of diseases caused by exposure to fallout at Ground Zero of the September 11 attacks in 2001. These diseases include asthma, asthmatic bronchitis, terminal airways disease, sarcoidosis, and acute eosinophilic pneumonia.
== Examples ==
Pneumoconiosis
Asbestosis
Baritosis
Bauxite fibrosis
Berylliosis
Caplan's syndrome
Chalicosis
Coalworker's pneumoconiosis (black lung)
Siderosis
Silicosis
Byssinosis
Hypersensitivity pneumonitis
Bagassosis
Bird fancier's lung
Farmer's lung
== References ==
13. https://www.frontiersin.org/journals/bioengineering-and-biotechnology/articles/10.3389/fbioe.2023.1199230/full | Wikipedia/Silo-filler's_disease |
Hazard controls for COVID-19 in workplaces are the application of occupational safety and health methodologies for hazard controls to the prevention of COVID-19. Multiple layers of controls are recommended, including measures such as remote work and flextime, personal protective equipment (PPE) and face coverings, social distancing, and enhanced cleaning programs. Recently, engineering controls have been emphasized, particularly stressing the importance of HVAC systems meeting a minimum of 5 air changes per hour with ventilation or MERV-13 filters, as well as the installation of UVGI systems in public areas.
== Hazard controls ==
The U.S. Occupational Safety and Health Administration (OSHA) recommends implementing multiple layers of controls, including measures such as remote work and flextime, engineering controls (especially increased ventilation), administrative controls such as vaccination policies, personal protective equipment (PPE), face coverings, social distancing, and enhanced cleaning programs with a focus on high-touch surfaces.
Preliminary evidence suggests that fully vaccinated people can become infectious and can spread the virus to others. The U.S. Centers for Disease Control and Prevention (CDC) recommends that fully vaccinated people can reduce their risk of becoming infected and potentially spreading it to others by:
wearing a mask in public indoor settings in areas of substantial or high transmission;
choosing to wear a mask regardless of level of transmission, particularly if individuals are at risk or have someone in their household who is at increased risk of severe disease or not fully vaccinated; and
getting tested 3–5 days following a known exposure to someone with suspected or confirmed COVID-19 and wearing a mask in public indoor settings for 14 days after exposure or until a negative test result.
Along with vaccination, key controls to help protect unvaccinated and other at-risk workers include removing from the workplace all infected people, all people experiencing COVID symptoms, and any people who are not fully vaccinated who have had close contact with someone with COVID-19 and have not tested negative for COVID-19 immediately if symptoms develop and again at least 5 days after the contact (in which case they may return 7 days after contact). Fully vaccinated people who have had close contact should get tested for COVID-19 3–5 days after exposure and be required to wear face coverings for 14 days after their contact unless they test negative for COVID-19.
Additional fundamental controls that protect unvaccinated and other at-risk workers include maintaining ventilation systems, implementing physical distancing, and properly using face coverings, and proper cleaning. Fully vaccinated people in areas of substantial or high transmission should be required to wear face coverings inside as well. Employees may request reasonable accommodations, absent an undue hardship, if they are unable to comply with safety requirements due to a disability.
There is low quality evidence that supports making improvements or modifications to personal protective equipment in order to help decrease contamination. Examples of modifications include adding tabs to masks or gloves to ease removal and designing protective gowns so that gloves are removed at the same time. In addition, there is weak evidence that the following PPE approaches or techniques may lead to reduced contamination and improved compliance with PPE protocols: Wearing double gloves, following specific doffing (removal) procedures such as those from the CDC, and providing people with spoken instructions while removing PPE.
== Workers' rights ==
In the United States, under the General Duty Clause of the Occupational Safety and Health Act of 1970, employers are responsible for providing a safe and healthy workplace free from recognized hazards likely to cause death or serious physical harm, which includes COVID-19. In addition, OSHA's Emergency Temporary Standard applies required measures to most settings where any employee provides healthcare services or healthcare support services. Section 11(c) of the OSH prohibits employers from retaliating against workers for raising concerns about safety and health conditions, and OSHA encourages workers who suffer such retaliation to submit a complaint to OSHA's Whistleblower Protection Program within the legal time limits.
On July 15, 2020, Virginia adopted binding safety regulations on COVID-19, the first such regulations in the United States. The regulations includes mandates about control measures and prohibits retaliation against workers for expressing concern about infection risk, and provides for fines of up to US$130,000 for companies found in violation. As of July 2020, Oregon adopted a timeline that targets the establishment of COVID-19 regulations for September 1.
== Historical guidance before availability of COVID-19 vaccines ==
COVID-19 outbreaks have been responsible for several effects within the workplace. Workers may be absent from work due to becoming sick, needing to care for others, or from fear of possible exposure. Patterns of commerce may change, both in terms of what goods are demanded, and the means of acquiring these goods (such as shopping at off-peak hours or through delivery or drive-through services). Lastly, shipments of items from geographic areas severely affected by COVID-19 may be interrupted.: 6
An infectious disease preparedness and response plan can be used to guide protective actions. Such plans address the levels of risk associated with various worksites and job tasks, including sources of exposure, risk factors arising from home and community settings, and risk factors of individual workers such as old age or chronic medical conditions. They also outline controls necessary to address those risks, and contingency plans for situations that may arise as a result of outbreaks. Infectious disease preparedness and response plans may be subject to national or subnational recommendations.: 7–8 Objectives for response to an outbreak include reducing transmission among staff, protecting people who are at higher risk for adverse health complications, maintaining business operations, and minimizing adverse effects on other entities in their supply chains. The disease severity in the community where the business is located affects the responses taken.
=== All workplaces ===
In many workplaces, groups share many hours of the day indoors. These conditions can facilitate the transmission of disease, but also control it through workplace practices and policies. Identifying industries or particular jobs that have the highest potential exposure to a specific risk can help in the development of interventions to control or prevent the spread of diseases such as COVID-19.
According to the U.S. Occupational Safety and Health Administration (OSHA), lower exposure risk jobs have minimal occupational contact with the public and other coworkers.: 18–20 Basic infection prevention measures recommended for all workplaces include frequent and thorough hand washing, encouraging workers to use sick leave if they are sick, respiratory etiquette including covering coughs and sneezes, providing tissues and trash receptacles, preparing for remote work or shift work if needed, discouraging workers from using others' tools and equipment, and maintaining routine cleaning and disinfecting of the work environment. Prompt identification and isolation of potentially infectious individuals is a critical step in protecting workers, customers, visitors, and others at a worksite.: 8–9 The U.S. Centers for Disease Control and Prevention (CDC) recommends that employees who have symptoms of acute respiratory illness are to stay home until they are free of fever, signs of a fever, and any other symptoms, and that sick leave policies are flexible, permit employees to stay home to care for a sick family member, and that employees are aware of these policies.
There are also psychosocial hazards arising from anxiety or stress from worries about contracting COVID-19, the illness or death of a relative or friend, changes in work patterns, and financial or interpersonal difficulties arising from the pandemic. Social distancing measures may prevent typical coping mechanisms such as personal space or sharing problems with others. Controls for these hazards include managers checking on workers to ask how they are, facilitating worker interactions, and formal services for employee assistance, coaching, or occupational health.
=== Medium-risk workplaces ===
According to OSHA, medium exposure risk jobs include those that require frequent or close contact within six feet (1.8 m) of people who are not known or suspected COVID-19 patients, but may be infected with SARS-CoV-2 due to ongoing community transmission around the business location, or because the individual has recent international travel to a location with widespread COVID-19 transmission. These include workers who have contact with the general public such as in schools, high-population-density work environments, and some high-volume retail settings.: 18–20
Engineering controls for this and higher risk groups include installing high-efficiency air filters, increasing ventilation rates, installing physical barriers such as clear plastic sneeze guards, and installing a drive-through window for customer service.: 12–13
Administrative controls for this and higher risk groups include encouraging sick workers to stay at home, replacing face-to-face meetings with virtual communications, establishing staggered shifts, discontinuing nonessential travel to locations with ongoing COVID-19 outbreaks, developing emergency communications plans including a forum for answering workers’ concerns, providing workers with up-to-date education and training on COVID-19 risk factors and protective behaviors, training workers who need to use protecting clothing and equipment how to use it, providing resources and a work environment that promotes personal hygiene, requiring regular hand washing, limiting customers' and the public's access to the worksite, and posting signage about hand washing and other COVID-19 protective measures.: 13–14, 21–22
Depending on the work task, workers with at least medium exposure risk may need to wear personal protective equipment including some combination of gloves, a gown, a face shield or face mask, or goggles. Workers in this risk group rarely require use of respirators.: 22
For retail workers in food and grocery businesses, CDC and OSHA recommend encouraging touchless payment options and minimizing handling of cash and credit cards, placing cash on the counter rather than passing it directly by hand, and routinely disinfecting frequently touched surfaces such as workstations, cash registers, payment terminals, door handles, tables, and countertops. Employers may place sneeze guards with a pass-through opening at the bottom of the barrier in checkout and customer service locations, use every other check-out lane, move the electronic payment terminal farther from the cashier, place visual cues such as floor decals to indicate where customers should stand during check out, provide remote shopping alternatives, and limit the maximum customer capacity at the door.
Meat and poultry processing facilities have work environments that may contribute substantially to their potential exposures, as they often work close to one another on assembly lines during prolonged work shifts. For engineering controls, CDC and OSHA recommend configuring communal work environments so that workers are spaced at least six feet apart including along processing lines, using physical barriers such as strip curtains or plexiglass to separate workers from each other, and ensuring adequate ventilation that minimizes air from fans blowing from one worker directly at another worker. For administrative controls, they recommend staggering workers' arrival, break, and departure times, cohorting workers so they are always assigned to the same shifts with the same coworkers, encouraging single-file movement through the facility, avoiding carpooling to and from work, and considering a program of screening workers before entry into the workplace and setting criteria for return to work of recovered workers and for exclusion of sick workers. For personal protective equipment, they recommend face shields and considering allowing voluntary use of filtering facepiece respirators such as N95 masks. They also recommend wearing cloth face masks that should be replaced if they become wet, soiled, or otherwise visibly contaminated during the work shift, although cloth face masks are not considered to be personal protective equipment.
If a person becomes sick on an airplane, proper controls to protect workers and other passengers include separating the sick person from others by a distance of 6 feet, designating one crew member to serve the sick person, and offering a face mask to the sick person or asking the sick person to cover their mouth and nose with tissues when coughing or sneezing. Cabin crew should wear disposable medical gloves when tending to a sick traveler or touching body fluids or potentially contaminated surfaces, and possibly additional personal protective equipment if the sick traveler has fever, persistent cough, or difficulty breathing. Gloves and other disposable items should be disposed of in a biohazard bag, and contaminated surfaces should be cleaned and disinfected afterwards.
For commercial shipping, including cruise ships and other passenger vessels, hazard controls include postponing travel when sick, and self-isolating and informing the onboard medical center immediately if one develops a fever or other symptoms while on board. Ideally, medical follow-up should occur in the isolated person's cabin.
For schools and childcare facilities, CDC recommends short-term closure to clean or disinfect if an infected person has been in a school building regardless of community spread. When there is minimal to moderate community transmission, social distancing strategies can be implemented such as canceling field trips, assemblies, and other large gatherings such as physical education or choir classes or meals in a cafeteria, increasing the space between desks, staggering arrival and dismissal times, limiting nonessential visitors, and using a separate health office location for children with flu-like symptoms. When there is substantial transmission in the local community, in addition to social distancing strategies, extended school dismissals may be considered.
For law enforcement personnel performing daily routine activities, the immediate health risk is considered low by CDC. Law enforcement officials who must make contact with individuals confirmed or suspected to have COVID-19 are recommended to follow the same guidelines as emergency medical technicians, including proper personal protective equipment. If close contact occurs during apprehension, workers should clean and disinfect their duty belt and gear prior to reuse using a household cleaning spray or wipe, and follow standard operating procedures for the containment and disposal of used PPE and for containing and laundering clothes.
=== High-risk healthcare and mortuary workplaces ===
OSHA considers certain healthcare and mortuary workers to be at high or very high categories of exposure risk. High exposure risk jobs include healthcare delivery, support, laboratory, and medical transport workers who are exposed to known or suspected COVID-19 patients. These become very high exposure risk if workers perform aerosol-generating procedures on, or collect or handle specimens from, known or suspected COVID-19 patients. Aerosol-generating procedures include intubation, cough induction procedures, bronchoscopies, some dental procedures and exams, or invasive specimen collection. High exposure risk mortuary jobs include workers involved in preparing the bodies of people who had known or suspected cases of COVID-19 at the time of their death; these become very high exposure risk if they perform an autopsy.: 18–20
Additional engineering controls for these risk groups include isolation rooms for patients with known or suspected COVID-19, including when aerosol-generating procedures are performed. Specialized negative pressure ventilation may be appropriate in some healthcare and mortuary settings. Specimens should be handled with Biosafety level 3 precautions.: 13, 23–24 The World Health Organization (WHO) recommends that incoming patients be separated into distinct waiting areas depending on whether they are a suspected COVID-19 case.
In addition to other PPE, OSHA recommends respirators for those who work within 6 feet of patients known to be, or suspected of being, infected with SARS-CoV-2, and those performing aerosol-generating procedures. In the United States, NIOSH-approved N95 filtering facepiece respirators or better must be used in the context of a comprehensive, written respiratory protection program that includes fit-testing, training, and medical exams. Other types of respirators can provide greater protection and improve worker comfort.: 14–16, 25
The WHO does not recommend coveralls, as COVID-19 is a respiratory disease rather than being transmitted through bodily fluids. WHO recommends only a surgical mask for point-of-entry screening personnel. For those who are collecting respiratory specimens from, caring for, or transporting COVID-19 patients without any aerosol-generating procedures, WHO recommends a surgical mask, goggles, or face shield, gown, and gloves. If an aerosol-generating procedure is performed, the surgical mask is replaced with an N95 or FFP2 respirator.
== Guidance after the availability of COVID-19 vaccines ==
=== Noncompliance with guidelines ===
This runs counter to guidelines published in the wake of the 2002–2004 SARS outbreak.
=== General workplace guidelines ===
The CDC suggests that, in non-healthcare settings, building ventilation should be brought up to 5 air changes per hour, along with the use of MERV-13 filters, the use of air purifiers (air cleaners), and upper-room Ultraviolet germicidal irradiation (UVGI) to reduce the odds of infection and people coming down with COVID-19. The UVGI systems are said to be similar to the UVGI systems used against tuberculosis in the past in healthcare facilities. As for ventilation, a survey conducted under 1989 ASHRAE standards showed that, of the buildings constructed in prior years and surveyed, all but one did not meet the recommended 5 ACH.
Corsi–Rosenthal Boxes have been suggested as a viable temporary air cleaner. When tested by NIOSH, the boxes were found to reduce aerosols up to 73%, but most did not operate below noise standards.
== Proposed controls ==
These fixtures have been suggested as forms of "engineering controls" in the Hierarchy of hazard controls:
Instead of the use of UVGI, use of far-UVC lighting to inactivate the virus causing COVID-19.
Use of ceiling fans to aid in the removal of viral aerosols in the air, and support other engineering control measures, particularly ventilation. One paper found that by using ceiling fans to mix the air, the particles involved in short-range transmission could drop significantly, at the cost of a small increase in the amount of particles involved in long-range transmission. However, for ceiling fans to be effective, the authors noted that occupancy in a given ventilated room should generally stay within ASHRAE 241 recommendations, at around 36-154 m3 ventilated air/hr/person.
== See also ==
COVID-19 portal
Biological hazard
Hierarchy of hazard controls
Non-pharmaceutical intervention (epidemiology)
Pandemic
== References ==
This article incorporates public domain material from websites or documents of the Occupational Safety and Health Administration.
This article incorporates public domain material from websites or documents of the Centers for Disease Control and Prevention.
== Further reading ==
Related media at Wikimedia Commons:
Building Air Quality - A Guide for Building Owners and Facility Managers
== External links ==
Listing of international guidance from EU-OSHA
List N: Disinfectants for Use Against SARS-CoV-2 (COVID-19) (United States Environmental Protection Agency)
24th Collegium Ramazzini statement. Prevention of work-related infection in the COVID-19 pandemic May 2020.
European Agency for Safety and Health at Work, Healthy workplaces. Stop the pandemic campaign materials
European Agency for Safety and Health at Work, COVID-19: guidance for the workplace
European Agency for Safety and Health at Work, Back to the workplace: Adapting workplaces and protecting workers
Office for National Statistics, UK, Which occupations have the highest potential exposure to the coronavirus (COVID-19)?
CDC/NIOSH guidance
U.S. National Institute for Occupational Safety and Health website on COVID-19
U.S. Centers for Disease Control and Prevention, Resuming Business Toolkit.
U.S. Centers for Disease Control and Prevention, Toolkit for Worker Safety & Support
Fact Sheet for Food and grocery pick-up and delivery drivers, Centers for Disease Control and Prevention.
Fact Sheet for nail salon employers and employees on measures to protect against COVID-19 while at work.
Fact Sheet for Firefighters and EMS Providers, Centers for Disease Control and Prevention.
Fact Sheet for Grocery and food retail workers, Centers for Disease Control and Prevention.
Fact Sheet for Mail and Parcel delivery drivers, Centers for Disease Control and Prevention.
Fact Sheet for Rideshare and ride-for-hire drivers, Centers for Disease Control and Prevention.
Resources related to Coronavirus Disease 2019 (COVID-19) and Mining, Centers for Disease Control and Prevention.
Guidance for Healthcare settings, Centers for Disease Control and Prevention.
U.S. Occupational Safety and Health Administration website on COVID-19
American Industrial Hygiene Association website on COVID-19
The Synergist, American Industrial Hygiene Association, COVID-19 and the Industrial Hygienist
European Agency for Safety and Health at Work website on COVID-19
UK Health Executive COVID-19 guidance for employees, employers, and businesses
Canadian Centre for Occupational Safety and Health COVID-19 fact sheet
COVID-19 Health Screen Questions | Wikipedia/Workplace_hazard_controls_for_COVID-19 |
Animal-assisted therapy (AAT) is an alternative or complementary type of therapy that includes the use of animals in a treatment. The goal of this animal-assisted intervention is to improve a patient's social, emotional, or cognitive functioning. Studies have documented some positive effects of the therapy on subjective self-rating scales and on objective physiological measures such as blood pressure and hormone levels.
The specific animal-assisted therapy can be classified by the type of animal, the targeted population, and how the animal is incorporated into the therapeutic plan. Various animals have been utilized for animal-assisted therapy, with the most common types being canine-assisted therapy and equine-assisted therapy.
Use of these animals in therapies has shown positives results in many cases, such as post-traumatic stress disorder (PTSD), depression, anxiety, sexual abuse victims, dementia, and autism. It can be used in many different facilities, like hospitals, prisons, and nursing homes, to aid in the therapy provided. Some studies have shown that animal-assisted therapy can improve many aspects of a patient's life, such as improving their overall mood or reducing feelings of isolation.
== Description ==
Animal-assisted therapy is an alternative or complementary type of therapy that includes the use of animals in a treatment. It falls under the realm of animal-assisted intervention, which encompasses any intervention in the studio that includes an animal in a therapeutic context such as emotional support animals, service animals trained to assist with daily activities, and animal-assisted activity.
The goal of animal-assisted therapy is to improve a patient's social, emotional, or cognitive functioning. Literature reviews state that animals can be useful for educational and motivational effectiveness for participants.
== History ==
Research has found that animals can have an overall positive effect on health and improve mood and quality of life. Studies have documented some positive effects of the therapy on subjective self-rating scales and on objective physiological measures such as blood pressure and hormone levels. The positive effect has been linked to the human-animal bond. In a variety of settings, such as prisons, nursing homes, and mental institutions, these animals are used to assist people with different disabilities or disorders. In modern times animals are seen as "agents of socialization" and as providers of "social support and relaxation". The earliest reported use of the therapy for the mentally ill took place in the late 18th century at the York Retreat in England, led by William Tuke. Patients at this facility were allowed to wander the grounds which contained a population of small domestic animals. These were believed to be effective tools for socialization. In 1860, the Bethlem Hospital in England followed the same trend and added animals to the ward, greatly influencing the morale of the patients living there. Other literature refers to animal-assisted therapy being used as early as 1792 at the Quaker Society of Friends York Retreat in England. Velde, Cipriani & Fisher also state "Florence Nightingale appreciated the benefits of pets in the treatment of individuals with illness."
=== Examples of historical uses ===
The US military promoted the use of dogs as a therapeutic intervention with psychiatric patients in 1919 at St Elizabeth's Hospital in Washington, DC.
Sigmund Freud kept many dogs and often had his chow Jofi present during his pioneering sessions of psychoanalysis. He noticed that the presence of the dog was helpful because the patient would find that their speech would not shock or disturb the dog and this reassured them and so encouraged them to relax and confide. This was most effective when the patient was a child or adolescent. Increased recognition of the value of human–pet bonding was noted by Dr. Boris M. Levinson in 1961. Levinson accidentally used animals in therapy with children when he left his dog alone with a nonverbal child, and upon returning, found the child talking to the dog.
== Physiological effects ==
Edward O. Wilson's (1984) biophilia hypothesis is based on the premise that our attachment to and interest in animals stems from the strong possibility that human survival was partly dependent on signals from animals in the environment indicating safety or threat. The biophilia hypothesis suggests that if we see animals at rest or in a peaceful state, this may signal to us safety, security and feelings of well-being which in turn may trigger a state where personal change and healing are possible.
Six neurotransmitters that influence mood have been documented to release after a 15-minute or more interaction with animals. Mirror neuron activity and disease-perception through olfactory (smelling) ability in dogs may also play important roles in helping dogs connect with humans during therapeutic encounters.
Animal-assisted therapy has also been shown to have a positive impact on brain, neurochemical, and cardiovascular function. Interventions involving canines has been shown to decrease blood pressure, the stress hormones epinephrine and norepinephrine, and increase hormones associated with pleasure, like dopamine and oxytocin.
== Medical uses ==
Animals can be integrated into settings such as prisons, nursing homes, mental institutions, and in the home. The techniques used depend on the needs and condition of the patient. Assistance dogs can support certain life activities and help people navigate outside the home.
Assessing whether a program is effective as far as its outcomes are concerned is easier when the goals are clear and are able to be specified. There are a range of goals for animal-assisted therapy programs relevant to children and young people, including enhanced capacity to form positive relationships with others. It is understood that pets provide benefits to those with mental health conditions, but further research is required to test the nature and extent of this relationship with an animal as a pet and how it differs between pets, emotional support animals, service animals, and animal-assisted therapy.
=== Cognitive rehabilitation treatment ===
Acquired brain injury survivors with cognitive impairments can benefit from animal-assisted therapy as part of a comprehensive rehabilitation treatment plan.
=== Pediatric care ===
Animals can be used as a distraction method when it comes to various situations or pain, and animals can also help bring happiness, pleasure, and entertainment to the pediatric population. Animals can also help improve children's moods and reinforce positive behaviors while helping to decrease negative ones.
==== Behavioral health ====
Therapists rely on techniques such as monitoring a child's behavior with the animal, their tone of voice, and indirect interviewing. Animal-assisted therapy can be used in children with mental health problems, as a stand-alone treatment, or along with conventional methods.
==== Hospital setting ====
Animal-assisted therapy (AAT) is used in hospital settings with children to try to improve their overall well-being and mood during their stay. Most commonly reported research results are decreased anxiety and pain within the pediatric population. One area of pediatric hospital care in which the use of AAT has been studied is magnetic resonance imaging procedures which can trigger negative emotions in children, causing them to move and require procedural sedation. After AAT intervention, the anxiety levels of the subjects decreased significantly when compared to controls. Dogs have been shown to increase comfort and decrease pain in pediatric palliative care. Specific tactics have not been researched, but collective reviews of varied techniques displayed similar results of increased comfort reports by children and guardians. Though meta-analysis has determined that children receiving AAT have seen a reduction in pain when compared to control groups, further quantitative research is needed to confirm this conclusion.
==== Potential risks ====
Though AAT has existed and been in practice for decades, the lack of standardization creates potential risks for both the animals and humans involved. As the use among pediatric populations continues to climb, another concern that has been raised about the use of animals in a hospital setting is the spread of germs. Many children in hospital settings have weakened immune systems and are already at risk of contracting hospital-borne infections. It has been found that both the patients and dogs participating in therapy experienced changes to their biome after their sessions. Whether these changes pose a long-term benefit or risk has yet to be proven, and more in-depth studies are needed to make this determination. Additionally researchers are working to find an accurate way to determine the effects of AAT on both the service animal and the human participating in therapy.
=== Prisons ===
Animal-assistance programs, such as cell dog programs, may be useful in prisons to relieve stress of the inmates and workers, or to provide other benefits, but further study is needed to confirm the effectiveness of such programs in these settings. Internal file data reviews, anecdotal stories, and surveys of inmate and staff perceptions have been used to gauge the effectiveness of animal-assisted therapy in prisons, but these methods are limited and have resulted in an inadequate assessment.
Researchers have, however, begun to find methods of gauging the effectiveness of prison animal programs (PAPs) by using Propensity Score Watching. One study using this method found that PAPs positively impact reductions in severe or violent infractions. A reduction in offenses statistically may reduce recidivism rates and increase former inmate job marketability and societal reintegration.
Training and being responsible for an animal can foster empathy, emotional intelligence, communication, and self-control in inmates; however, the results of studies done so far must be taken with caution as the methodological quality of existing studies is limited. PAPs also benefit the animals involved as many come from situations where they faced abuse, neglect or potential euthanasia.
=== Nursing homes ===
The findings offer proof of the concept that canine-assisted therapies are feasible and can elicit positive quality-of-life experiences in institutionalized people with dementia. Researchers and practitioners need to elucidate the theoretical foundations of animal-assisted therapies. The Lived Environment Life Quality Model may serve as a guide for client-centered, occupation-focused, and ecologically valid approaches to animal-assisted occupational therapy beyond people with dementia.
When elderly people are transferred to nursing homes or long-term care facilities, they often become passive, agitated, withdrawn, depressed, and inactive because of the lack of regular visitors or the loss of loved ones. Supporters of animal-assisted therapy say that animals can be helpful in motivating the patients to be active mentally and physically, keeping their minds sharp and bodies healthy. A significant difference has been seen among verbal interactions among nursing home residents with a dog present. Therapists or visitors who bring animals into their sessions at the nursing home are often viewed as less threatening, which increases the relationship between the therapist or visitor and patient.
=== Occupational therapy ===
Occupational therapists can use animal-assisted therapies to work on the child's motivation. Some occupational therapy goals using animal-assisted therapies include improving attention skills, social skills, participation in play, self-esteem, and reducing anxiety, loneliness, and isolation.
== Types ==
Various animal species are used in animal-assisted therapy. Individual animals are evaluated with strict criteria before being used. The criteria include appropriate size, age, aptitude, typical behaviors and the correct level of training. The most commonly used species are dogs and horses. Research has been published on dolphin therapy.
=== Canine-assisted therapy ===
In canine-assisted therapy, therapy dogs interact with patients in animal assisted interventions, to enhance therapeutic activities and well-being including the physical, cognitive, behavioral and socio-emotional functioning of clients. Well-trained therapy dogs exhibit the behavior that human patients construe as friendly and welcoming. They comfort patients via body contact. Therapy dogs are also required to possess a calm temperament for accommodating the contact with unfamiliar clients while they serve as a source of comfort. They promote patients engaging in interactions which can help patient improve motor skills and establish trusting relationship with others. The interaction between patients and therapy dogs also aids reducing stressful and anxious feelings patients have. Due to those benefits, canine-assisted therapy is used as a complement to other therapies to treat diagnosis such as post-traumatic stress disorder, attention deficit hyperactivity disorder, autism spectrum disorder, and dementia.
Canine assistance can also be used in classroom for promoting the development of creative writing and living skills and the participation of children in group activities. There are programs called canine-assisted reading programs which facilitate children with special educational needs. These programs utilize the calm, non-judgmental, happy characteristics of canines to let the process of reading become more meaningful and enjoyable for children. With these benefits, researchers suggest incorporating dogs into assisting learning and educational programs.
=== Dolphin therapy ===
Dolphin-assisted therapy refers to the controversial alternative medicine practice of swimming with dolphins. This form of therapy has been strongly criticized as having no long-term benefit, and being based on flawed observations. Psychologists have cautioned that dolphin-assisted therapy is not known to be effective for any condition and that it presents considerable risks to both human patients and the captive dolphins. The child has a one-on-one session with a therapist in a marine park. An ethical issue with data on dolphin-assisted therapy and the effectiveness of it is that most of the research is done by people who operate the dolphin-assisted therapy programs.
=== Equine-related therapy ===
Equine-assisted therapy encompasses a range of treatments that involve activities with horses and other equines to promote human physical and mental health.
Therapeutic riding is used by disabled individuals who ride horses to relax, and to develop muscle tone, coordination, confidence, and well-being. Equine-assisted psychotherapy (EAP) or Equine Facilitated Psychotherapy (EFP) is the use of equines to treat human psychological problems in and around an equestrian facility.
The existing body of evidence does not justify the promotion and use of equine-related treatments for mental disorders.
=== Pig therapy ===
Pigs have been used in various types of animal-assisted therapy to perform duties in facilities including airports, hospitals, nursing homes, and special-needs schools, or as emotional support animals for individuals with conditions such as autism or anxiety and veterans with PTSD. Two well-known miniature pigs named Thunder and Bolt trained by children to certified animal therapy status have been put to work in a number of nursing homes, schools and a hospital.
=== Therapy with other animals ===
Llamas are also used in therapy.
For patients that have allergies to animals that have fur, snakes have been used to provide emotional support.
== Effectiveness ==
Based on current research, there are many conditions that can benefit from animal-assisted therapy in diverse settings around the world. Those conditions include psychological disorder, developmental disorder, dementia, chronic pain, advanced heart failure, etc. Animal-assisted therapy is commonly used for psychological disorders. Attention deficit hyperactivity disorder, autism spectrum disorder, post-traumatic stress disorder, and major depressive disorder are among the psychological disorders that can benefit from animal-assisted therapy.
In recent decades, an increased amount of research indicates the social, psychological, and physiological benefits of animal-assisted therapy in the fields of health and education. Although the effectiveness of animal-assisted therapy is still unclear due to the lack of clarity regarding the degree to which the animal itself contributes in the recovery process, there is a growing awareness that the therapy may be effective in treating attention deficit hyperactivity disorder, post-traumatic stress disorder, autism spectrum disorder, and dementia.
=== Attention deficit hyperactivity disorder ===
Children with attention deficit hyperactivity disorder (ADHD) may decrease behavioral issues and improve socialization skills with the intervention of animal-assisted therapy. Compared to children who received only cognitive-behavioral therapy, children who received both canine-assisted therapy and cognitive-behavioral therapy had reduced severity of ADHD symptoms. However, the dog-assisted therapy did not relieve symptoms in long-term treatment.
=== Post-traumatic stress disorder ===
Post-traumatic stress disorder (PTSD) is a psychological disorder affects people's mental health and has varying severity and forms. It is often difficult to treat due to high drop-out rates and low responses to traditional psycho-therapeutic approaches and interventions.
Animals have both direct and indirect effects on a mental health spectrum including biological, psychological, and social responses, further targeting marked symptoms of post-traumatic stress disorder (i.e., re-experiencing, avoidance, changes in beliefs/feelings, and hyperarousal). Direct effects of animals include a decrease in anxiety and blood pressure while indirect effects result in increased social interactions and overall participation in everyday activities.
Biologically, specific chemicals are released when observing human and animal interactions. Similarly, dog assistance can potentially mediate oxytocin which effects social and physical well-being and decrease blood pressure. The psychological benefits of animals focus mainly on dog and human interactions, the reduction of anxiety and depressive symptoms, and increased resilience. Animals in this capacity can further provide emotional and psychological assistance and support, addressing several of the disorder's symptoms. The presence of an animal can alleviate intrusion symptoms by providing a reminder that there is no danger present. Animals can further elicit positive emotions, targeting emotional numbing experiences. Animal interactions also provide social benefits, providing companionship and alleviate feelings of loneliness and isolation through everyday routines and increased social interactions in public.
The incorporation and involvement of animals dates back to the earliest forms of organized combat. Dogs, in particular, were utilized in different capacities. Ancient armies employed dogs as soldiers and companions which extended to modern combat including dogs as a crucial asset in communication, detection, and intimidation. While a range of animals can be utilized, dogs and horses have been the principal species studied in practice. Dog-assisted therapy and therapeutic horseback riding are non-invasive methods for treating post-traumatic stress disorder in veterans.
Canines can easily integrate into a multitude of environments, are highly responsive to humans, and are very intelligent. For those reasons, dogs are the species most commonly used in interventions. Dogs are typically categorized according to the level of training received and the specific needs of the individual. A service dog provides relief through specialized support related to a physical, mental, or psychological disability. Emotional support animals solely provide psychological relief and do not require specialized training. Therapy animals often provide additional support in a therapeutic environment by supporting counselors or therapists in their therapeutic duties. While service dogs, emotional support animals, and therapy dogs can support the diverse symptoms that veterans, specifically bred and selected post-traumatic stress disorder service dogs, are trained and assigned to veterans with the disorder to support with daily life activities as well as with emotional and mental health needs.
Dogs provide subjective positive effects to veterans and serve as a compassionate reminder to veterans with post-traumatic stress disorder that danger is not present, creating a safe space for the veteran. They are often sensitive to humans and have the ability to adapt their behavior accordingly by doing tasks such as preventing panic, waking a veteran from a nightmare, and nudging to help the veteran "stay in the present". Dogs provide veterans with a nonjudgmental and safe environment that can help a veteran express feelings and process thoughts without interruption, criticism or advice. Interactions, such as petting, playing and walking, with the dog can increase physical activity, reduce anxiety, and provide encouragement to stay in the present moment. The interaction between dog and veterans supports social interactions for isolated veterans, reduces symptoms associated with the disorder such as depression and anxiety, and increases veterans' calmness.
Similar to dogs, horses have been included in the treatment of veterans with post-traumatic stress disorder by providing an accepting and nonjudgmental environment, which further facilitates a veterans' ability to cope with symptoms. Because horses are social animals, they are capable of creating and responding to relationships based on the veteran's energy, providing an opportunity for veterans to regain the ability to form trusting relationships. Therapeutic work with horses varies from ground-based activities, mounted activities, or a combination of both. In the therapeutic context, horses can promote cognitive reframing as well as an increase in the use of mindfulness practice. While there is limited research and standardized instruments to measure the effects, veterans who have participated in pilot programs have better communication skills, self-awareness, and self-esteem, promoting safety and support during the transition into civilian life. Long-term effects of equine-based interventions with veterans include increased happiness, social support, and better sleep hygiene because they are able to process information regarding their emotions and behaviors in a nonjudgmental space.
While animal-assisted interventions may be effective, it is not yet verified due to limited research. Animal-assisted interventions can be challenging to study. Because of lack of effective resources, most studies are limited to small sample sizes which prevents genralizing results over a larger population. Furthermore, there is often a lack of randomization and a lack of information about sample representativeness that prevents widespread application. Hospital-based animal-assisted therapy programs may present a slight risk of pathogen transmission, but further research is needed.
Post-traumatic stress disorder in sexual assault survivors
The disorder can develop when a person experiences a sexual assault or rape. Sexual assault is the leading cause of post-traumatic stress disorder in women; an estimated 50% of women who were sexually assaulted develop the condition. Animal-assisted therapy can be an effective in treating the trauma for survivors of sexual assault. The presence of dogs have been shown to improve communication between the survivor and the therapist and to decrease survivors' anxiety and fear-responses. Animal-assisted therapy increases social interaction for those with the disorder. Studies show that animal-assisted therapy leads to an overall reduction of symptoms including anger, depression, and dissociation in survivors of sexual assault. Animal-assisted therapy has also been shown to reduce problem behavior and improves overall behavioral functioning for children survivors of sexual assault.
Further research is needed to show the effectiveness of animal-assisted interventions in treating post-traumatic stress disorder for sexual assault survivors across varying demographics. Limitations in current research include small sample sizes and reliance on anecdotal evidence.
=== Autism spectrum disorder ===
Animal-assisted therapy may reduce the symptoms of autism spectrum disorder such as aggressiveness, irritability, difficulty concentrating, and hyperactivity. In one review, five out of nine studies reviewed showed positive effects of therapeutic horseback riding on children with autism spectrum disorder. Canine-assisted intervention provides a calmer environment by reducing the stress, irritation, and anxiety that children with autism spectrum disorder experience. Playing with dogs increases positive mood in children with autism spectrum disorder. Animals also can serve as a social catalyst. In the presence of animals, children with autism spectrum disorder are more likely to engage in social interactions with humans. However, the impact of animal-assisted therapy upon parent–child interaction is not clear.
=== Dementia ===
Animal-assisted therapy encourages expressions of emotions and cognitive stimulation through discussions and reminiscing of memories while the patient bonds with the animal. Studies have found that animal-assisted therapies (particularly using dogs) resulted in measurable quality of life improvements for patients with dementia. Patients with dementia were also found to improve their social interactions and their scores on the Cohen-Mansfield Agitation Inventory. Animal-assisted therapy has been shown to slightly reduce depressive symptoms in people with dementia in a 2019 systematic review.
== Limitations ==
There is limited scientific research on the use of the therapy among adults who have been sexually assaulted. While animals do tend to comfort survivors, animal therapy may not be the catalyst that provides positive success in therapy sessions. As mentioned above, adults tend not to focus as much on having an animal companion, and therefore, animal therapy cannot be attributed as the reason for success in those types of therapy sessions. There are some ethical concerns that arise when applying animal therapy to younger survivors of sexual assault. For example, if a child is introduced to an animal that is not their pet, the application of animal therapy can cause some concerns. First of all, some children may not be comfortable with animals or may be frightened which could be avoided by asking permission to use animals in therapy. Second, a special bond is created between animal and child during animal therapy. Therefore, if the animal in question does not belong to the child, there may be some negative side effects when the child discontinues therapy. The child will have become attached to the animal, which does raise some ethical issues as far as subjecting a child to the disappointment and possible relapse that can occur after therapy discontinues.
It is unclear to what degree the animal itself contributes in the recovery process.
There are some concerns specific to dolphin-assisted therapy: First, it is potentially hazardous to the human patients, and it is harmful to the dolphins themselves; by taking dolphins out of their natural environment and putting them in captivity for therapy can be hazardous to their well-being. Second, dolphin-assisted therapy has been strongly criticized as having no long-term benefit, and being based on flawed observations. Third, psychologists have cautioned that dolphin-assisted therapy is not effective for any known condition.
There are concerns that people may become dependent on the animal and could interfere with the recovery process for PTSD. People may feel as though they cannot do things on their own without the presence of the animal.
== Ethical concerns ==
Though AAT has existed and been in practice for decades, the lack of standardization creates potential risks for both the animals and humans involved. Due to the unclear structural guidelines on the use of animals in therapeutic settings, possible impacts to the animal include stress, injury, and health complications. Research has shown that despite quality guidelines in place to ensure the health of the therapy animal, there are reports of negative interactions between human participant and therapy dogs. These reports include mistreating and teasing the dogs by patients and staff at locations in which therapy is hosted. In studies conducted, people with certain disabilities had to be excluded from the experiment due to increase in the stress of the therapy dog, and ultimately decline in overall well-being. There is a question as to whether bringing animals into AAT settings where the client has a history of violence is ethical, or if the benefit outweighs the risk.
Equine-assisted therapy showed a need for more studies of equine behavior to obtain an understanding of stress signals from horses. Through understanding the stress signals shown by horses, a safe and healthy experience during the therapy session can be held, by allowing handlers to minimize stress. For therapy animals limited time for rest, multiple sessions, and long duration of sessions were linked to higher stress. Assessing animals for signs of fatigue and stress can prevent negative experience for both humans and animals involved. Animals used should be limited to a specific duration and number of sessions, as well as given access to proper environmental conditions, food, water, and rest.
== See also ==
== References ==
== External links ==
Media related to Animal-assisted therapy at Wikimedia Commons
Assistance Animal State Laws - Michigan State University
Disabilities and Medical Conditions - TSA (Transport Security Administration)
Skloot, Rebecca (December 31, 2008) "Creature Comforts", The New York Times
Medicine Horse | Wikipedia/Animal-assisted_therapy |
The Kawa model (kawa (かわ)), named after the Japanese word for river, is a culturally responsive conceptual framework used in occupational therapy to understand and guide the therapeutic process. Developed by Japanese occupational therapists (OTs), the model draws upon the metaphor of a river to describe human occupation, which according to OTs refers to individuals' daily activities that make life meaningful. The overarching goal of the model is to "provide a culturally flexible model to aid occupational therapists to improve communication with clients, to better understand what a client finds meaningful and important, and to design optimal client-centered interventions.": 17
The model incorporates five main elements: water, river banks and space, rocks, and driftwood. In the model, "water (mizu) represents life flow and health, driftwood (ryuboku) represents personal assets and liabilities, rocks (iwa) represent life circumstances and problems, and the river walls (torimaki) represent physical and social environmental factors.": 1 The model emphasizes that each person's river is unique and influenced by cultural, social, and personal factors.
== History ==
Along with a team of Japanese OTs, Dr. Michael Iwama first developed the Kawa model in 1999. Iwama aimed to develop an occupational therapy model that could be easily understood by clients, not just practitioners and scholars. Coming from a Canadian background, Iwama imagined a model that utilized boxes and squares with arrows between them, but his Japanese colleagues envisioned the river, in part due to the popularity of the song "Kawa no nagare no yō ni" ("Like the Flow of the River") by Hibari Misora, which depicted life as a river. Iwama's colleagues believed the metaphor of the river would resonate more deeply with their clients than Iwama's original idea because of their connection with nature, as well as their collectivistic perspective.
The Kawa model is the first in occupational therapy "developed from clinical practice outside of the Western English-speaking world through qualitative research.": 1 Because "Eastern culture emphasizes the harmony between the person and environmental factors, which is believed to enhance health and well-being[,] ... the model focuses heavily on the client's environmental contexts and how that impacts the flow of harmony in life, rather than mainly focusing on the individual client.": 1
In 2006, Iwama published The Kawa Model: Culturally Relevant Occupational Therapy, a textbook that provides an overview of the model. The model is now actively taught in over 500 OT programs and utilized on six continents.: 1
== Core concepts ==
=== Water ===
The concept of "water" represents an individual's life flow and priorities, including their cognition, emotion, physical impairments, occupations, roles, and life experiences. In nature, water often flows from a mountain, which would symbolize a person's birth, and runs into an ocean or other large body of water, which would represent the person's death. Because "water is fluid and ever changing,": 373 it reflects the dynamic nature of occupation and the constant interaction between individuals and their environment. Iwama and other proponents of the model suggest that without water flowing and moving, life is stagnant.: 1 Further, water is impacted by the structural environment, such as rocks and riverbanks, much like how an individual's "life flow can be shaped, enhanced, or diminished" by physical, social, and other environments.: 373 Beyond the water's ability to flow, OTs may ask clients to describe how the river is flowing, such as whether it is choppy or smooth.
According to the model, if the river has a "strong, deep, unimpeded flow,": 1129 the individual should experience optimal well-being.
=== River banks ===
The concept of "river banks" represents external factors that influence a person's life flow, including social and physical environments and contexts, as well as cultural norms, social expectations, family, and environmental conditions. These factors can support or hinder the person's occupational journey. However, in the most ideal circumstances, "these external elements would support and guide the client through difficult times just as the banks of the river support its flow.": 1
=== Rocks ===
The concept of "rocks" represents obstacles, challenges, and life events that may disrupt or impact a person's occupational well-being. They can include physical or mental health conditions, personal difficulties, or environmental barriers. When visually depicting their life journey, individuals may consider the location and size of rocks, which would indicate when the event occurred, as well as how the individual perceives it. If an individual perceives an event or challenge as being highly impactful and disruptive to their life, the rock would be larger, whereas a smaller rock may represent a less significant challenge.
=== Driftwood ===
The concept of "driftwood" represents personal traits and skills individuals can use to navigate their occupational journey. Driftwood can include personal traits (e.g., being optimistic or determined); personal skill sets and experiences (e.g., being trained in carpentry); specific beliefs, values and principles; and/or material/social capital (e.g., financial wealth or strong social networks).: 9 Driftwood can have either a positive or negative impact on the river's flow. It generally flows with the current but may become stuck on a rock and become an impediment; however, it may also unearth rocks to make them less challenging.
=== Spaces ===
The concept of "spaces" represents "opportunities for expanding flow and well-being in accordance with the client's perspective and priorities.": 1 Using the metaphor, the overarching goal of occupational therapy is to increase spaces for water to flow through the river. OTs can work with their clients to decrease the size of rocks, widen the river banks, and/or better utilize driftwood. For the former, clients may find ways to eliminate burdens in their life and/or develop strategies to overcome those barriers. To widen the metaphorical river banks, OTs may work with clients to implement universal design methods into their daily lives and/or find other ways to alter the physical environment to make it less of a barrier. Lastly, OTs can work with clients to better utilize existing skill sets and attributes and/or develop new ones to help address barriers. Through these practices, the client's well-being should be positively impacted.: 10
== Use ==
When utilizing the Kawa model, OTs often begin by requesting their clients create a visual representation of their life using the river metaphor. During and after the client's creation, the OT will ask "open-ended, clarifying questions",: 17 which allow the OT and client "to explore life's problems, to discuss support systems, and to brainstorm effective methods of problem resolution.": 2 This conversation helps ensure the client's drawing accurately portrays how they perceive their life. Importantly, the Kawa model is meant to be used as a flexible guide that can be utilized in multiple ways.
In an interview, Iwama discussed how the model may be used for individuals who may not be able to communicate their life flow for themselves, such as individuals with severe cognitive impairments, young children, or people with dementia. In these cases, Iwama suggested communicating with a group of people close to the individual to collectively discuss the individual's values, barriers, and priorities and thus, as a group, develop their personal Kawa model and collectively problem-solve how to help the individual's river flow.
Some researchers have also suggested using the model for interprofessional discussions regarding clients as a tool to promote team-building collaboration. Importantly, "teambuilding has been positively correlated with job satisfaction, and quality of client care," whereas "a lack of teamwork can lead to decrease morale/job satisfaction, decreased productivity and lost revenue, and decreased client satisfaction and quality of care.": 2
In one study, Lape et al. used the Kawa model within a collaborative care team to facilitate communication about a patient's care needs. Using the model, the care team developed created a Kawa depiction for a client that included perspectives from multiple care providers. Participants in the study found that using the model provided new opportunities for collaboration across the care team; they determined the tool could be effectively used within their profession.
== Strengths ==
Studies utilizing and analyzing the Kawa model have recognized multiple strengths across various domains. The greatest finding across all use cases "was that the Kawa model provides a unique platform for open communication and deeper perspective." Other strengths include its ability to be culturally responsive and client-centered, as well as how it helps develop partnerships and collaboration.
=== Culturally responsive ===
More and more, OTs are recognizing that occupational therapy must be culturally aware and relevant to meet clients' diverse needs. In part, this is because an individual's values, beliefs, ways of thinking and behaving depend upon their cultural backgrounds. Many OTs consider the Kawa model to be culturally responsive. This is, in part, because the model was developed outside the Western world and does not rely upon "Western cultural norms".: 213 For example, occupational therapy models often focus on the future, despite some cultures being more focused on the past and present. Additionally, because the model was developed by Japanese OTs, it has a more collectivistic focus than many Western models. In part, this means the model embraces "interdependence within the social environment": 371 and the importance of relationships. Overall, "the tenets of autonomy, self-sufficiency, and individual control, or superiority of the environment, commonly promoted by traditional models of occupation, do not take precedence within the Kawa model.": 372
=== Client-centered approach ===
More and more, OTs aim to keep their clients at the center of occupational therapy work, focusing on the client's perceived needs and priorities rather than focusing on pathologising clients' bodies. In part, this is because "a person's view on what is meaningful to them is unique".: 222 That is, instead of deciding upon a set of practices considered universally beneficial, OTs focus on what clients personally find valuable in their life. For example, OTs may spend time helping clients meaningfully participate in hobbies they enjoy (e.g., playing guitar) rather than focusing solely on necessary living tasks (e.g., bathing) and work tasks (e.g., typing on a keyboard). Further, OTs are focusing on how they can teach client's skills, as well as how they can modify environments, to address their perceived needs.
Many OTs find that the Kawa model is highly client-centered, which helps OTs understand the client's perspectives and priorities. In part, this is because the model encourages OTs to discuss with clients what they perceive as barriers, strengths, and opportunities. Clients are also actively involved in goal-setting, centers the clients' values and may increase their motivation to participate in therapy.
=== Partnerships and collaboration ===
Many OTs find that the Kawa model helps develop a therapeutic partnership between the client and the clinician. Because the model is client-centered, it requires discussion between the OT and the client, as well as collaboration between them throughout the process, including discussions regarding the client's values and priorities, goal-setting, and more.
Research has also found that the Kawa model helps facilitate interprofessional collaboration.
== Limitations and criticisms ==
Both OTs and clients can find the conceptual framework difficult to understand. Multiple studies have found that OTs who are new to the Kawa model, as well as those new to occupational therapy, may struggle to use the model with clients. In part, this difficulty may result from an OT's lack of understanding regarding the model's foundational concepts. OTs' difficulty with use may also be due to their preconceptions of the model and metaphor. That is, OTs may have a specific belief about how the model should be used, and when a client has a "unique interpretation",: 232 they may find difficulty working with the client. Conversely, clients may struggle with the metaphor and/or be skeptical about its use. Iwama noted that "Westerners looking at the model for the first time may be concerned about where the 'self' is located in the model.": 140 This can be seen in some studies in which a participant described the river as "one big wave hitting me over and over again.": 4
The model's ambiguity may also be cause for criticism and impact ease of use. Individual's ability to connect with the metaphor can impact how well clients communicate their occupational needs. Some researchers have also noted that the model doesn't focus on the individual's inner self, that is, the unique and independent part of them that is separate from their surroundings. They also posit that it doesn't pay enough attention to the idea of belonging, which involves being actively involved in a social group and having specific roles and routines. This ambiguity may also result in the OT imposing their own views and biases.
Further, the Kawa model relies upon in-depth discussions with clients. As such, OTs who do not have practice conversing with clients in-depth may struggle to understand their clients' perspectives and needs. However, OTs with proficient interviewing skills may be "more confident in facilitating and guiding the participants to complete their drawings without fear of errors.": 233
== References == | Wikipedia/Kawa_model |
An occupational disease or industrial disease is any chronic ailment that occurs as a result of work or occupational activity. It is an aspect of occupational safety and health. An occupational disease is typically identified when it is shown that it is more prevalent in a given body of workers than in the general population, or in other worker populations. The first such disease to be recognised, squamous-cell carcinoma of the scrotum, was identified in chimney sweep boys by Sir Percival Pott in 1775. Occupational hazards that are of a traumatic nature (such as falls by roofers) are not considered to be occupational diseases.
Under the law of workers' compensation in many jurisdictions, there is a presumption that specific diseases are caused by the worker being in the work environment and the burden is on the employer or insurer to show that the disease came about from another cause. Diseases compensated by national workers compensation authorities are often termed occupational diseases. However, many countries do not offer compensations for certain diseases like musculoskeletal disorders caused by work (e.g. in Norway). Therefore, the term work-related diseases is utilized to describe diseases of occupational origin. This term however would then include both compensable and non-compensable diseases that have occupational origins.
In a landmark study published by the World Health Organization and the International Labour Organization in 2021, 745,000 fatalities from coronary artery disease and stroke events in 2016 were attributed to exposure to long working hours. With these UN estimates, the global burden of work-related cardiovascular diseases has been quantified for the first time.
Occupational disease is expected to be reported less than actual figure. Neither educational material nor educational meeting increase the report of occupational disease. However, reminders on the legal obligation to report the occupational disease seem to increase physician reporting.
== Types ==
Some well-known occupational diseases include:
=== Lung diseases ===
Occupational lung diseases include asbestosis among asbestos miners and those who work with friable asbestos insulation, as well as black lung (coalworker's pneumoconiosis) among coal miners, silicosis among miners and quarrying and tunnel operators and byssinosis among workers in parts of the cotton textile industry.
Occupational asthma has a vast number of occupations at risk.
Bad indoor air quality may predispose for diseases in the lungs as well as in other parts of the body.
=== Skin diseases ===
Occupational skin diseases are ranked among the top five occupational diseases in many countries.
Occupational skin diseases and conditions are generally caused by chemicals and having wet hands for long periods while at work. Eczema is by far the most common, but urticaria, sunburn and skin cancer are also of concern.
Contact dermatitis due to irritation is inflammation of the skin which results from a contact with an irritant. It has been observed that this type of dermatitis does not require prior sensitization of the immune system. There have been studies to support that past or present atopic dermatitis is a risk factor for this type of dermatitis. Common irritants include detergents, acids, alkalies, oils, organic solvents and reducing agents.
The acute form of this dermatitis develops on exposure of the skin to a strong irritant or caustic chemical. This exposure can occur as a result of accident at a workplace. The irritant reaction starts to increase in its intensity within minutes to hours of exposure to the irritant and reaches its peak quickly. After the reaction has reached its peak level, it starts to heal. This process is known as decrescendo phenomenon. The most frequent potent irritants leading to this type of dermatitis are acids and alkaline solutions. The symptoms include redness and swelling of the skin along with the formation of blisters.
The chronic form occurs as a result of repeated exposure of the skin to weak irritants over long periods of time.
Clinical manifestations of the contact dermatitis are also modified by external factors such as environmental factors (mechanical pressure, temperature, and humidity) and predisposing characteristics of the individual (age, sex, ethnic origin, preexisting skin disease, atopic skin diathesis, and anatomic region exposed.
Another occupational skin disease is Glove related hand urticaria. It has been reported as an occupational problem among the health care workers. This type of hand urticaria is believed to be caused by repeated wearing and removal of the gloves. The reaction is caused by the latex or the nitrile present in the gloves.
High-risk occupations include:
Hairdressing
Catering
Healthcare
Printing
Metal machining
Motor vehicle repair
Construction
=== Other diseases of concern ===
Overuse syndrome among persons who perform repetitive or forceful movements in constrictive postures
Carpal tunnel syndrome among persons who work in the poultry industry and information technology
Computer vision syndrome among persons using information technology for hours
Lead poisoning affecting workers in many industries that processed or employed lead or lead compounds
Infectious diseases transmitted through unsanitary working conditions, such as meningitis, whooping cough, or bloodborne illnesses
The List of Occupational Diseases of the International Labour Organization (ILO) also includes "mental and behavioral disorders associated with exposure to risk factors",
=== Historical ===
Donald Hunter in his classic history of occupational diseases discusses many example of occupational diseases. They include:
Phossy jaw among the London matchgirls
Radiation sickness among some persons who had been working in the nuclear industry
Radium jaw among the Radium Girls
Squamous cell carcinoma of the skin of the scrotum among chimney sweeps (see Chimney sweeps' carcinoma)
Bernardino Ramazzini in his book, dated 1700, De Morbis Artificum Diatriba, outlined the health hazards of chemicals, dust, metals, repetitive or violent motions, odd postures, and other disease-causative agents encountered by workers in more than fifty occupations.
== Prevention ==
Prevention measures include avoidance of the irritant through its removal from the workplace or through technical shielding by the use of potent irritants in closed systems or automation, irritant replacement or removal and personal protection of the workers.
In order to better prevent and control occupational disease, most countries revise and update their related laws, most of them greatly increasing the penalties in case of breaches of the occupational disease laws. Occupational disease prevention, in general legally regulated, is part of good supply chain management and enables companies to design and ensure supply chain social compliance schemes as well as monitor their implementation to identify and prevent occupational disease hazards.
== In popular culture and literature ==
=== In literature ===
The Jungle by Upton Sinclair
Midnight in Chernobyl by Adam Higginbotham
Radium Girls by Kate Moore
=== In film ===
== See also ==
Industrial and organizational psychology
Occupational health psychology
Occupational medicine
Occupational safety and health
== References ==
== External links == | Wikipedia/Occupational_disease |
Substance use disorders (SUD) can have a significant effect on one's function in all areas of occupation. Physical and psychosocial issues due to SUD can impact occupational performance. Unfulfilled life roles and disruption in meaningful activity can result from lack of structure or routine, poor motivation, limited skills, and poor social networks. These deficits may also contribute to stress, affecting the ability to cope with challenges. While SUD can affect a client's participation in therapy and ability to follow recommendations, occupational therapists are trained to facilitate occupational participation and performance.
== Interventions ==
Occupational Therapists (OT) address substance use through focus on self-care, leisure, and productivity, and may encounter SUD in a variety of settings. OTs address substance use by determining occupational needs, executing assessments and interventions, and creating appropriate prevention programs. They evaluate a client's ability to function, help them set short- and long-term goals, and evaluate their likelihood for relapse.
An OT session for SUD may address: development of coping strategies, rebuilding roles, balancing responsibilities, managing money, effectively communicating with others, and developing stress management skills.
With technological advances, occupational therapists can use telehealth services as a way to offer school-based wellness programs such as education on healthy lifestyles, violence prevention and other health programs.
In order to provide health and wellness, habilitation, and rehabilitation services across various practice settings, emerging technologies are poised to be advantageous for occupational therapy practitioners and their patients.
Occupational therapists that work in behavioral health treatment programs can work closely with peer specialists to offer recovery and support services. Collaboration with peer specialists is important in addressing complex issues that surround mental illness and addiction.
Sustaining recovery is addressed through stress and anger management, modifications to social behavior, occupational exploration, and development of life skills. Through improvements in occupational performance, clients with SUD can improve their quality of life and sustain recovery.
== Frames of reference ==
Two frames of reference employed by OTs are Dr. Gary Kielhofner's model of human occupation (MOHO) and cognitive behavioral frame of reference. MOHO focuses on the effects a SUD has on volition, habituation, and performance. Cognitive-behavioral frame of reference focuses on skill building. The client identifies negative thoughts affecting function or skills, finds alternative thoughts for replacement, and rehearses or role plays situations while implementing these alternative thoughts.
== Notes == | Wikipedia/Occupational_therapy_and_substance_use_disorder |
Zaglossus attenboroughi, also known as Attenborough's long-beaked echidna or locally as Payangko, is one of three species from the genus Zaglossus that inhabits the island of New Guinea. It lives in the Cyclops Mountains, which are near the cities of Sentani and Jayapura in the Indonesian province of Papua. It is named in honour of naturalist Sir David Attenborough.
It is currently classified as critically endangered by the IUCN, and there had been no confirmed sightings between its initial collection in 1961 and November 2023, when the first video footage of a living individual was recorded.
== Taxonomy ==
The early taxonomy of Zaglossus saw a number of different specimens described as separate species or subspecies, but by the late 1960s the genus was considered to be monotypic, pending a comprehensive evaluation of collected specimens. Subsequent systematic revision of Zaglossus by Flannery & Groves in 1998 identified three allopatric species and several subspecies present within the island. These authors established a new species, Z. attenboroughi (Attenborough's long-beaked echidna), to describe a single echidna specimen collected in 1961 at 1,600 metres (5,200 ft) near the top of Mount Rara, in the Cyclops Mountains of northern Dutch New Guinea, and named it in recognition of Attenborough's contribution to increased public appreciation of New Guinean flora and fauna through his documentary work.
== Description ==
It is the smallest member of the genus Zaglossus, being closer in size to the short-beaked echidna (Tachyglossus aculeatus). The weight of the type specimen when it was alive was estimated to be 2 to 3 kilograms (4.4 to 6.6 lb). The male is larger than the female, further differentiated by the spurs on its hind legs. The species has five claws on each foot like the eastern long-beaked echidna, and has short, very fine and dense fur, reflecting its mountain-top habitat.
The diet of Attenborough's long-beaked echidna consists primarily of earthworms, in contrast to the termites and ants preferred by the short-beaked echidna.
The long-beaked echidna is not a social animal, and it comes together with its own kind only once a year, in July, to mate. During the reproduction stage, the female lays the eggs after about eight days, with the offspring staying in their mother's pouch for around eight weeks or until their spines develop. The creature is nocturnal; it rolls up into a spiky ball when it feels threatened, resembling the behavior of a hedgehog.
== Conservation status ==
Z. attenboroughi was described from a single damaged specimen collected almost 40 years prior to its identification as a unique species, and no other specimen has been collected since. The ongoing anthropogenic disturbance of the Cyclops Mountain forest habitat is a threat to Z. attenboroughi populations in the area, where the echidna is endangered by hunting and habitat loss. It was thought to be extinct until some of its "nose pokes" were found in the mountains of New Guinea during an expedition in 2007. These "nose pokes" result from the echidna's unique feeding technique.
Z. attenboroughi is classified as critically endangered by the IUCN. An educational campaign was initiated in local communities to educate the Papuan people about the endangered echidnas in an effort to stop the common tradition of hunting and killing the creature to share with rivals as a peace offering.
Researchers from EDGE of Existence programme visiting Papua's Cyclops Mountains discovered burrows and tracks thought to be those of Zaglossus attenboroughi in 2007, and after further communication with locals, it was revealed that the species had possibly been seen as recently as 2005. In 2007, Attenborough's long-beaked echidna was identified as one of the top-10 "focal species" by the Evolutionarily Distinct and Globally Endangered (EDGE) project.
As of 2017, this species of echidna was among the 25 "most wanted lost" species which are the focus of Re:wild's "Search for Lost Species" initiative.
In 2023, during an expedition led by Oxford University scientists to the Cyclops Mountains, the species was spotted on footage retrieved from a trail camera. This was more than 60 years after it was last spotted by scientists.
== See also ==
List of things named after David Attenborough and his works
== References ==
== External links ==
http://news.bbc.co.uk/2/hi/science/nature Archived 2010-07-16 at the Wayback Machine
EDGE of Existence (Zaglossus spp.) – Saving the World's most Evolutionarily Distinct and Globally Endangered (EDGE) species | Wikipedia/Sir_David's_long-beaked_echidna |
Chronoperates (meaning "time wanderer" in Greek) is an extinct genus of mammal whose remains have been found in a late Paleocene deposit in Alberta, Canada. It is represented by the type species Chronoperates paradoxus and known only from a partial left lower jaw. It was first identified in 1992 as a non-mammalian cynodont, implying a ghost lineage of over 100 million years since the previously youngest known record of non-mammalian cynodonts, which at that time was in the Jurassic period (some non-mammalian cynodonts are now known to have persisted until the Early Cretaceous). Subsequent authors have challenged this interpretation, particularly as the teeth do not resemble any known non-mammalian cynodonts. Chronoperates is now generally considered to be more likely to be a late-surviving symmetrodont mammal. This would still infer a ghost lineage for symmetrodonts, but a more plausible one, as symmetrodonts persisted into the Late Cretaceous.
== References ==
http://darrennaish.blogspot.com/2006/05/time-wandering-cynodonts-and-docodonts.html
https://web.archive.org/web/20081219051716/http://www.palaeos.com/Vertebrates/Units/410Cynodontia/410.400.html | Wikipedia/Chronoperates |
The short-beaked echidna (Tachyglossus aculeatus), also called the short-nosed echidna, is one of four living species of echidna, and the only member of the genus Tachyglossus, from Ancient Greek ταχύς (takhús), meaning "fast", and γλῶσσα (glôssa), meaning "tongue". It is covered in fur and spines and has a distinctive snout and a specialised tongue, which it uses to catch its insect prey at a great speed. Like the other extant monotremes, the short-beaked echidna lays eggs; the monotremes are the only living group of mammals to do so.
The short-beaked echidna has extremely strong front limbs and claws, which allow it to burrow quickly with great power. As it needs to be able to survive underground, it has a significant tolerance to high levels of carbon dioxide and low levels of oxygen. It has no weapons or fighting ability but deters predators by curling into a ball and protecting itself with its spines. It cannot sweat or deal well with heat, so it tends to avoid daytime activity in hot weather. It can swim if needed. The snout has mechanoreceptors and electroreceptors that help the echidna to detect its surroundings.
During the Australian winter, it goes into deep torpor and hibernation, reducing its metabolism to save energy. As the temperature increases, it emerges to mate. Female echidnas lay one egg a year and the mating period is the only time the otherwise solitary animals meet one another; the male has no further contact with the female or his offspring after mating. A newborn echidna is the size of a grape but grows rapidly on its mother's milk, which is very rich in nutrients. By seven weeks baby echidnas grow too large and spiky to stay in the pouch and are expelled into the mother's burrow. At around six months they leave and have no more contact with their mothers.
The species is found throughout Australia, where it is the most widespread native mammal, and in coastal and highland regions of eastern New Guinea, where it is known as the mungwe in the Daribi and Chimbu languages. It is not threatened with extinction, but human activities, such as hunting, habitat destruction, and the introduction of foreign predatory species and parasites, have reduced its abundance in Australia.
== Taxonomy and naming ==
The short-beaked echidna was first described by George Shaw in 1792. He named the species Myrmecophaga aculeata, thinking that it might be related to the giant anteater. Since Shaw first described the species, its name has undergone four revisions: from M. aculeata to Ornithorhynchus hystrix, Echidna hystrix, Echidna aculeata and finally, Tachyglossus aculeatus. The name Tachyglossus comes from Ancient Greek ταχύς (takhús), meaning "fast", and γλῶσσα (glôssa), meaning "tongue", and aculeatus means 'spiny' or 'equipped with spines' in Latin.
The short-beaked echidna is the only member of its genus, sharing the family Tachyglossidae with the extant species of the genus Zaglossus that occur in New Guinea. Zaglossus species, which include the western long-beaked, Sir David's long-beaked and eastern long-beaked echidnas, are all significantly larger than T. aculeatus, and their diets consist mostly of worms and grubs rather than ants and termites. Species of the Tachyglossidae are egg-laying mammals; together with the related family Ornithorhynchidae, they are the only extant monotremes in the world.
The five subspecies of the short-beaked echidna are each found in different geographical locations. The subspecies also differ from one another in their hairiness, spine length and width, and the size of the grooming claws on their hind feet.
T. a. acanthion is found in the Northern Territory and Western Australia.
T. a. aculeatus is found in Queensland, New South Wales, South Australia and Victoria.
T. a. lawesii is found in coastal regions and the highlands of New Guinea, and possibly in the rainforests of Northeast Queensland.
T. a. multiaculeatus is found on Kangaroo Island.
T. a. setosus is found on Tasmania and some islands in the Bass Strait.
The earliest fossils of the short-beaked echidna date back around 15 million years ago to the Miocene epoch, and the oldest specimens were found in caves in South Australia, often with fossils of the long-beaked echidna from the same period. The ancient short-beaked echidnas are considered to be identical to their contemporary descendants except the ancestors are around 10% smaller. This "post-Pleistocene dwarfing" affects many Australian mammals. Part of the last radiation of monotreme mammals, echidnas are believed to have evolutionally diverged from the platypus around 66 million years ago, between the Cretaceous and Tertiary periods. However, the echidna's pre-Pleistocene heritage has not been traced yet, and the lack of teeth on the fossils found thus far have made it impossible to use dental evidence.
The short-beaked echidna was commonly called the spiny anteater in older books, though this term has fallen out of fashion since the echidna is only very distantly related to the true anteaters. It has a variety of names in the indigenous languages of the regions where it is found. The Noongar people from southwestern Western Australia call it the nyingarn. In Central Australia southwest of Alice Springs, the Pitjantjatjara term is tjilkamata or tjirili, from the word tjiri for spike of porcupine grass (Triodia irritans). The word can also mean 'slowpoke'. In the Wiradjuri language of Central NSW, it is called wandhayala.
In the central Cape York Peninsula, it is called (minha) kekoywa in Pakanh, where minha is a qualifier meaning 'meat' or 'animal', (inh-)ekorak in Uw Oykangand and (inh-)egorag in Uw Olkola, where inh- is a qualifier meaning 'meat' or 'animal'. In the highland regions of southwestern New Guinea, it is known as the mungwe in the Daribi and Chimbu languages. The short-beaked echidna is called miɣu in the Motu language of Papua New Guinea.
== Description ==
Short-beaked echidnas are typically 30 to 45 cm (12 to 18 in) in length, with 75 mm (3 in) of snout, and weigh between 2 and 7 kg (4.4 and 15.4 lb). However, the Tasmanian subspecies, T. a. setosus, is smaller than its Australian mainland counterparts. Because the neck is not externally visible, the head and body appear to merge. The earholes are on either side of the head, with no external pinnae. The eyes are small, about 9 mm (0.4 in) in diameter and at the base of the wedge-shaped snout. The nostrils and the mouth are at the distal end of the snout; the mouth cannot open wider than 5 mm (0.2 in). The body of the short-beaked echidna is, with the exception of the underside, face and legs, covered with cream-coloured spines. The spines, which may be up to 50 mm (2 in) long, are modified hairs, mostly made of keratin. Insulation is provided by fur between the spines, which ranges in colour from honey to a dark reddish-brown and even black; the underside and short tail are also covered in fur.
The echidna's fur may be infested with what is said to be one of the world's largest fleas, Bradiopsylla echidnae, which is about 4 mm (0.16 in) long.
The limbs of the short-beaked echidna are adapted for rapid digging; they are short and have strong claws. Their strong and stout limbs allow it to tear apart large logs and move paving stones, and one has been recorded moving a 13.5 kg (30 lb) stone; a scientist also reported that a captive echidna moved a refrigerator around the room in his home. The power of the limbs is based on strong musculature, particularly around the shoulder and torso areas. The mechanical advantage of its arm is greater than that of humans, as its biceps connects the shoulder to the forearm at a point further down than for humans, and the chunky humerus allows more muscle to form.
The claws on the hind feet are elongated and curved backward to enable cleaning and grooming between the spines. Like the platypus, the echidna has a low body temperature—between 30–32 °C (86–90 °F)—but, unlike the platypus, which shows no evidence of torpor or hibernation, the body temperature of the echidna may fall as low as 5 °C (41 °F). The echidna does not pant or sweat and normally seeks shelter in hot conditions. Despite their inability to sweat, echidnas still lose water as they exhale. The snout is believed to be crucial in restricting this loss to sustainable levels, through a bony labyrinth that has a refrigerator effect and helps to condense water vapour in the breath. The echidna does not have highly concentrated urine, and around half of the estimated daily water loss of 120 g (4.2 oz) occurs in this manner, while most of the rest is through the skin and respiratory system. Most of this is replenished by its substantial eating of termites—one laboratory study reported ingestion of around 147 g (5.2 oz) a day, most of which was water. This can be supplemented by drinking water, if available, or licking morning dew from flora.
In the Australian autumn and winter, the echidna enters periods of torpor or deep hibernation. Because of its low body temperature, it becomes sluggish in very hot and very cold weather.
Like all monotremes, it has one orifice, the cloaca, for the passage of faeces, urine and reproductive products. The male has internal testes, no external scrotum and a highly unusual penis with four knobs on the tip, which is nearly a quarter of his body length when erect. The gestating female develops a pouch on her underside, where she raises her young.
The musculature of the short-beaked echidna has a number of unusual aspects. The panniculus carnosus, an enormous muscle just beneath the skin, covers the entire body. By contraction of various parts of the panniculus carnosus, the short-beaked echidna can change shape, the most characteristic shape change being achieved by rolling itself into a ball when threatened, so protecting its belly and presenting a defensive array of sharp spines. It has one of the shortest spinal cords of any mammal, extending only as far as the thorax. Whereas the human spinal cord ends at the first or second lumbar vertebra, for the echidna it occurs at the seventh thoracic vertebra. The shorter spinal cord is thought to allow flexibility to enable wrapping into a ball.
The musculature of the face, jaw and tongue is specialised for feeding. The tongue is the animal's sole means of catching prey, and can protrude up to 180 mm (7 in) outside the snout. The snout's shape, resembling a double wedge, gives it a significant mechanical advantage in generating a large moment, so makes it efficient for digging to reach prey or to build a shelter. The tongue is sticky because of the presence of glycoprotein-rich mucus, which both lubricates movement in and out of the snout and helps to catch ants and termites, which adhere to it. The tongue is protruded by contracting circular muscles that change the shape of the tongue and force it forwards and contracting two genioglossal muscles attached to the caudal end of the tongue and to the mandible. The protruded tongue is stiffened by a rapid flow of blood, which allows it to penetrate wood and soil. Retraction requires the contraction of two internal longitudinal muscles, known as the sternoglossi. When the tongue is retracted, the prey is caught on backward-facing keratinous "teeth", located along the roof of the buccal cavity, allowing the animal both to capture and grind food. The tongue moves with great speed, and has been measured to move in and out of the snout 100 times a minute. This is partly achieved through the elasticity of the tongue and the conversion of elastic potential energy into kinetic energy. The tongue is very flexible, particularly at the end, allowing it to bend in U-turns and catch insects attempting to flee in their labyrinthine nests or mounds. The tongue also has an ability to avoid picking up splinters while foraging in logs; the factors behind this ability are unknown. It can eat quickly; a specimen of around 3 kg (6.6 lb) can ingest 200 g (7.1 oz) of termites in 10 minutes.
The echidna's stomach is quite different from other mammals. It is devoid of secretory glands and has a cornified stratified epithelium, which resembles horny skin. Unlike other mammals, which typically have highly acidic stomachs, the echidna has low levels of acidity, almost neutral, with pH in the 6.2–7.4 range. The stomach is elastic, and gastric peristalsis grinds soil particulates and shredded insects together. Digestion occurs in the small intestine, which is around 3.4 m (11 ft) in length. Insect exoskeletons and soil are not digested, being ejected in the waste.
Numerous physiological adaptations aid the lifestyle of the short-beaked echidna. Because the animal burrows, it must tolerate very high levels of carbon dioxide in inspired air, and will voluntarily remain in situations where carbon dioxide concentrations are high. It can dig up to a metre into the ground to retrieve ants or evade predators, and can survive with low oxygen when the area is engulfed by bushfires. The echidna can also dive underwater, which can help it to survive sudden floods. During these situations, the heart rate drops to around 12 beats per minute, around one-fifth of the rate at rest. This process is believed to save oxygen for the heart and brain, which are the most sensitive organs to such a shortage; laboratory testing has revealed the echidna's cardiovascular system is similar to that of the seal. Following the devastation of a bushfire, echidnas can compensate for the lack of food by reducing their daytime body temperature and activity through use of torpor, for a period of up to three weeks.
The echidna's optical system is an uncommon hybrid of both mammalian and reptilian characteristics. The cartilaginous layer beneath the sclera of the eyeball is similar to that of reptiles and avians. The small corneal surface is keratinised and hardened, possibly to protect it from chemicals secreted by prey insects or self-impalement when it rolls itself up, which has been observed. The echidna has the flattest lens of any animal, giving it the longest focal length. This similarity to primates and humans allows it to see distant objects clearly. Unlike placental mammals, including humans, the echidna does not have a ciliary muscle to distort the geometry of the lens and thereby change the focal length and allow objects at different distances to be viewed clearly; the whole eye is believed to distort, so the distance between the lens and retina instead changes to allow focusing. The visual ability of an echidna is not great, and it is not known whether it can perceive colour; however, it can distinguish between black and white, and horizontal and vertical stripes. Eyesight is not a crucial factor in the animal's ability to survive, as blind echidnas are able to live healthily.
Its ears are sensitive to low-frequency sound, which may be ideal for detecting sounds emitted by termites and ants underground. The pinnae are obscured and covered by hair, predators therefore cannot grab them in an attack, and prey or foreign material cannot enter, although ticks are known to reside there. The macula of the ear is very large compared to other animals, and is used as a gravity sensor to orient the echidna. The large size may be important for burrowing downwards.
The leathery snout is keratinised and covered in mechano- and thermoreceptors, which provide information about the surrounding environment. These nerves protrude through microscopic holes at the end of the snout, which also has mucous glands on the end that act as electroreceptors. Echidnas can detect electric fields of 1.8 mV/cm—1000 times more sensitive than humans—and dig up buried batteries. A series of push rods protrude from the snout. These are columns of flattened, spinous cells, with roughly an average diameter of 50 micrometres (0.0020 in) and a length of 300 micrometres (0.012 in). The number of push rods per square millimetre of skin is estimated to be 30 to 40. Longitudinal waves are believed to be picked up and transmitted through the rods, acting as mechanical sensors, to allow prey detection.
A well-developed olfactory system may be used to detect mates and prey. A highly sensitive optic nerve has been shown to have visual discrimination and spatial memory comparable to those of a rat. The brain and central nervous system have been extensively studied for evolutionary comparison with placental mammals, particularly with its fellow monotreme, the platypus. The average brain volume is 25 ml (0.88 imp fl oz; 0.85 US fl oz), similar to a cat of approximately the same size; while the platypus has a largely smooth brain, the echidna has a heavily folded and fissured, gyrencephalic brain similar to humans, which is seen as a sign of a highly neurologically advanced animal. The cerebral cortex is thinner, and the brain cells are larger and more densely packed and organised in the echidna than the platypus, suggesting evolutionary divergence must have occurred long ago. Almost half of the sensory area in the brain is devoted to the snout and tongue, and the part devoted to smell is relatively large compared to other animals.
The short-beaked echidna has the largest prefrontal cortex relative to body size of any mammal, taking up 50% of the volume in comparison to 29% for humans. This part of the brain in humans is thought to be used for planning and analytical behaviour, leading to debate as to whether the echidna has reasoning and strategising ability. Experiments in a simple maze and with a test on opening a trap door to access food, and the echidna's ability to remember what it has learnt for over a month, has led scientists to conclude its learning ability is similar to that of a cat or a rat.
The echidna shows rapid eye movement during sleep, usually around its thermoneutral temperature of 25 °C (77 °F), and this effect is suppressed at other temperatures. Its brain has been shown to contain a claustrum similar to that of placental mammals, linking this structure to their common ancestor.
== Ecology and behaviour ==
No systematic study of the ecology of the short-beaked echidna has been published, but studies of several aspects of their ecological behaviour have been conducted. They live alone, and, apart from the burrow created for rearing young, they have no fixed shelter or nest site. They do not have a home territory they defend against other echidnas, but range over a wide area. The range area has been observed to be between 21–93 ha (52–230 acres), although one study in Kangaroo Island found the animals there covered an area between 9–192 ha (22–474 acres). Overall, the mean range areas across the various regions of Australia were 40–60 ha (99–148 acres). There was no correlation between sex and range area, but a weak one with size. Echidnas can share home ranges without incident, and sometimes share shelter sites if not enough are available for each animal to have one individually.
Short-beaked echidnas are typically active in the daytime, though they are ill-equipped to deal with heat because they have no sweat glands and do not pant. Therefore, in warm weather, they change their patterns of activity, becoming crepuscular or nocturnal. Body temperatures above 34 °C (93 °F) are believed to be fatal, and in addition to avoiding heat, the animal adjusts its circulation to maintain a sustainable temperature by moving blood to and from the skin to increase or lower heat loss. In areas where water is present, they can also swim to keep their body temperatures low. The "thermoneutral zone" for the environment is around 25 °C (77 °F), at which point the metabolism needed to maintain body temperature is minimised. The echidna is endothermic, and can maintain body temperatures of around 32 °C (90 °F). It can also reduce its metabolism and heart rate and body temperature.
In addition to brief and light bouts of torpor throughout the year, the echidna enters periods during the Australian winter when it hibernates, both in cold regions and in regions with more temperate climates. During hibernation, the body temperature drops to as low as 4 °C (39 °F). The heart rate falls to four to seven beats per minute—down from 50 to 68 at rest—and the echidna can breathe as infrequently as once every three minutes, 80 to 90% slower than when it is active. Metabolism can drop to one-eighth of the normal rate. Echidnas begin to prepare for hibernation between February and April, when they reduce their consumption and enter brief periods of torpor. Males begin hibernating first, while females that have reproduced start later. During periods of hibernation, the animals average 13 separate bouts of torpor, which are broken up by periods of arousal lasting 1.2 days on average. These interruptions tend to coincide with warmer periods. Males end their hibernation period in mid-June, while reproductive females return to full activity in July and August; nonreproductive females and immature echidnas may not end hibernation until two months later. During euthermia, the body temperature can vary by 4 °C per day. The metabolic rate is around 30% of that of placental mammals, making it the lowest energy-consuming mammal. This figure is similar to that of other animals that eat ants and termites; burrowing animals also tend to have low metabolism generally.
Echidnas hibernate even though it is seemingly unnecessary for survival; they begin their hibernation period while the weather is still warm, and food is generally always plentiful. One explanation is that echidnas maximize their foraging productivity by exercising caution with their energy reserves. Another hypothesis is that they are descended from ectothermic ancestors, but have taken to periodic endothermy for reproductive reasons, so that the young can develop more quickly. Supporters of this theory argue that males hibernate earlier than females because they finish their contribution to reproduction first, and they awake earlier to undergo spermatogenesis in preparation for mating, while females and young lag in their annual cycle. During the hibernation period, the animals stay in entirely covered shelter.
Short-beaked echidnas can live anywhere with a good supply of food, and regularly feast on ants and termites. They are believed to locate food by smell, using sensors in the tips of their snouts, by shuffling around seemingly arbitrarily, and using their snout in a probing manner. A study of echidnas in New England (New South Wales) has shown that they tend to dig up scarab beetle larvae in spring when the prey are active, but eschew this prey when it is inactive, leading to the conjecture that echidnas detect prey using hearing. Vision is not believed to be significant in hunting, as blind animals have been observed to survive in the wild.
Echidnas use their strong claws to pull apart nests and rotting logs to gain access to their prey. They avoid ants and termites that secrete repulsive liquids, and have a preference for the eggs, pupae and winged phases of the insects. Echidnas hunt most vigorously towards the end of the southern winter and early in spring, when their fat reserves have been depleted after hibernation and nursing. At this time, ants have high body fat, and the echidna targets their mounds. The animal also hunts beetles and earthworms, providing they are small enough to fit in a 5 mm (0.20 in) gap. The proportion of ants and termites in their diets depends on the availability of prey, and termites make up a larger part in drier areas where they are more plentiful. However, termites are preferred, if available, as their bodies contain a smaller proportion of indigestible exoskeleton. Termites from the Rhinotermitidae family are avoided due to their chemical defences. Scarab beetle larvae are also a large part of the diet when and where available. In the New England study, 37% of the food intake consisted of beetle larvae, although the echidna had to squash the prey in its snout as it ingested it, due to size.
Echidnas are powerful diggers, using their clawed front paws to dig out prey and create burrows for shelter. They may rapidly dig themselves into the ground if they cannot find cover when in danger. They bend their belly together to shield the soft, unprotected part, and can also urinate, giving off a pungent liquid, in an attempt to deter attackers. Males also have single small spurs on each rear leg, believed to be a defensive weapon that has since been lost through evolution. Echidnas typically try to avoid confrontation with predators. Instead, they use the colour of their spines, which is similar to the vegetation of the dry Australian environment, to avoid detection. They have good hearing and tend to become stationary if sound is detected.
It is likely that echidnas are keystone species in the ecosystem health in Australia, due to their contribution through bioturbation, the reworking of soils through their digging activity. This is based on the estimation that a single echidna will move up to 204 m3 (7,200 cu ft) of soil a year, that it is the most widespread of any terrestrial Australian species, is relatively common, and that other bioturbators have been heavily impacted by human settlement.
In Australia, they are most common in forested areas with abundant, termite-filled, fallen logs. In agricultural areas, they are most likely to be found in uncleared scrub; they may be found in grassland, arid areas, and in the outer suburbs of the capital cities. Little is known about their distribution in New Guinea. They have been found in southern New Guinea between Merauke in the west and the Kelp Welsh River, east of Port Moresby, in the east, where they may be found in open woodland.
Echidnas have the ability to swim, and have been seen cooling off near dams during high temperatures. They have also been seen crossing streams and swimming for brief periods in seas off Kangaroo Island. They swim with only the snout above water, using it as a snorkel.
=== Reproduction ===
The solitary short-beaked echidna looks for a mate between May and September; the precise timing of the mating season varies with geographic location. In the months before the mating season, the size of the male's testes increases by a factor of three or more before spermatogenesis occurs. Both males and females give off a strong, musky odour during the mating season, by turning their cloacas inside out and wiping them on the ground, secreting a glossy liquid believed to be an aphrodisiac. During courtship—observed for the first time in 1989—males locate and pursue females. Trains of up to 10 males, often with the youngest and smallest male at the end of the queue, may follow a single female in a courtship ritual that may last for up to four weeks; the duration of the courtship period varies with location. During this time, they forage for food together, and the train often changes composition, as some males leave and others join the pursuit. In cooler parts of their range, such as Tasmania, females may mate within a few hours of arousal from hibernation.
Before mating, the male smells the female, paying particular attention to the cloaca. This process can take a few hours, and the female can reject the suitor by rolling herself into a ball. After prodding and sniffing her back, the male is often observed to roll the female onto her side and then assume a similar position himself so the two animals are abdomen to abdomen, having dug a small crater in which to lie. They can lie with heads facing one another, or head to rear. If more than one male is in the vicinity, fighting over the female may occur. Each side of the bilaterally symmetrical, rosette-like, four-headed penis (similar to that of reptiles and 7 centimetres (2.8 in) in length) is used alternately, with the other half being shut down between ejaculations. Sperm bundles of around 100 each appear to confer increased sperm motility, which may provide the potential for sperm competition between males. This process takes between a half and three hours. Each mating results in the production of a single egg, and females are known to mate only once during the breeding season.
Fertilisation occurs in the oviduct. Gestation takes between 21 and 28 days after copulation, during which time the female constructs a nursery burrow. Following the gestation period, a single, rubbery-skinned egg between 13 and 17 mm (0.5 and 0.7 in) in diameter and 1.5 and 2.0 g (0.053 and 0.071 oz) in weight is laid from her cloaca directly into a small, backward-facing pouch that has developed on her abdomen. The egg is ovoid, leathery, soft, and cream-coloured. Between laying and hatching, some females continue to forage for food, while others dig burrows and rest there until hatching. Ten days after it is laid, the egg hatches within the pouch. The embryo develops an egg tooth during incubation, which it uses to tear open the egg; the tooth disappears soon after hatching.
Hatchlings are about 1.5 centimetres (0.6 in) long and weigh between 0.3 and 0.4 grams (0.011 and 0.014 oz). After hatching, young echidnas are known as "puggles". Although newborns are still semitranslucent and still surrounded by the remains of the egg yolk, and the eyes are still barely developed, they already have well-defined front limbs and digits that allow them to climb on their mothers' bodies. Hatchlings attach themselves to their mothers' milk areolae, specialised patches on the skin that secrete milk—monotremes lack nipples—through about 100–150 pores. The puggles were thought to have imbibed the milk by licking the mother's skin, but they are now thought to feed by sucking the areolae.
They have been observed ingesting large amounts during each feeding period, and mothers may leave them unattended in the burrow for between five and ten days to find food. Studies of captives have shown they can ingest milk once every two or three days and then increase their mass by 20% in one milk-drinking session lasting between one and two hours. Around 40% of the milk weight is converted into body mass, and as such, a high proportion of milk is converted into growth; a correlation with the growth of the puggle and its mother's size has been observed. By the time the puggle is around 200 g (7.1 oz), it is left in the burrow while the mother forages for food, and it reaches around 400 g (14 oz) after around two months. Juveniles are eventually ejected from the pouch at around two to three months of age, because of the continuing growth in the length of their spines. During this period, the young are left in covered burrows while the mothers forage, and the young are often preyed upon. Suckling gradually decreases until juveniles are weaned at about six months of age. The duration of lactation is about 200 days, and the young leave the burrow after 180 to 205 days, usually in January or February, at which time they weigh around 800 and 1,300 g (28 and 46 oz). There is no contact between the mother and young after this point.
The composition of the milk secreted by the mother changes over time. At the moment of birth, the solution is dilute and contains 1.25% fat, 7.85% protein, and 2.85% carbohydrates and minerals. Mature milk has much more concentrated nutrients, with 31.0, 12.4 and 2.8% of the aforementioned nutrients, respectively. Near weaning, the protein level continues to increase; this may be due to the need for keratin synthesis for hair and spines, to provide defences against the cold weather and predators.
The principal carbohydrate components of the milk are fucosyllactose and saialyllactose; it has a high iron content, which gives it a pink colour. The high iron content and low levels of free lactose differ from eutherian mammals. Lactose production is believed to proceed along the same lines as in the platypus.
The age of sexual maturity is uncertain, but may be four to five years. A 12-year field study found the short-beaked echidna reaches sexual maturity between five and 12 years of age, and the frequency of reproduction varies from once every two years to once every six years. In the wild, the short-beaked echidna has an average lifespan of 10 years, though they can live as long as 40. The longest-lived specimen reached 49 years of age in a zoo in Philadelphia. In contrast to other mammals, echidna rates of reproduction and metabolism are lower, and they live longer, as though in slow motion, something caused, at least in part, by their low body temperature, which rarely exceeds 33 °C (91 °F), even when they are not hibernating.
Like its fellow monotreme the platypus, the short-beaked echidna has a system of multiple sex chromosomes, in which males have four Y chromosomes and five X chromosomes. Males appear to be X1Y1X2Y2X3Y3X4Y4X5, while females are X1X1X2X2X3X3X4X4X5X5. Weak identity between chromosomes results in meiotic pairing that yields only two possible genotypes of sperm, X1X2X3X4X5 or Y1Y2Y3Y4, thus preserving this complex system.
== Conservation status ==
The short-beaked echidna is common throughout most of temperate Australia and lowland New Guinea, and is not listed as endangered. In Australia, it remains widespread across a wide range of habitats, including urban outskirts, coastal forests and dry inland areas, and is especially widespread in Tasmania and on Kangaroo Island.
The most common threats to the animal in Australia are motor vehicles and habitat destruction, which have led to localised extinctions. In Australia, the number of short-beaked echidnas has been less affected by land clearance than have some other species, since they do not require a specialised habitat beyond a good supply of ants and termites. As a result, they can survive in cleared land if the cut-down wood is left in the area, as the logs can be used as shelters and sources of insects. However, areas where the land has been completely cleared for single crops that can be mechanically harvested, such as wheat fields, have seen extinctions. Over a decade-long period, around one-third of echidna deaths reported to wildlife authorities in Victoria were due to motor vehicles, and the majority of wounded animals handed in were traffic accident victims. Studies have shown they often choose to traverse drainage culverts under roads, so this is seen as a viable means of reducing deaths on busy roads in rural areas or national parks where the animals are more common.
Despite their spines, they are preyed on by birds of prey, the Tasmanian devil, dingoes, snakes, lizards, goannas, cats, and red foxes, although almost all victims are young. Goannas are known for their digging abilities and strong sense of smell, and are believed to have been the main predators of the echidna before the introduction of eutherian mammals. Dingoes are known to kill echidnas by rolling them over onto their backs and attacking their underbellies. A tracking study of a small number of echidnas on Kangaroo Island concluded that goannas and cats were the main predators, although foxes—absent in Kangaroo Island—would be expected to be a major threat.
They were eaten by indigenous Australians and the early European settlers of Australia. Hunting and eating of the echidna in New Guinea has increased over time and caused a decline in the population and distribution areas; it is now believed to have disappeared from highland areas. The killing of echidnas was a taboo in traditional culture, but since the tribespeople have become increasingly Westernised, hunting has increased, and the animals have been more easily tracked down due to the use of dogs.
Infection with the introduced parasitic tapeworm Spirometra erinaceieuropaei is considered fatal for the echidna. This waterborne infection is contracted through sharing drinking areas with infected dogs, foxes, cats, and dingos, which do not die from the parasite. The infection is seen as being more dangerous in drier areas, where more animals are sharing fewer bodies of water, increasing the chance of transmission. The Wildlife Preservation Society of Queensland runs an Australia-wide survey, called Echidna Watch, to monitor the species. Echidnas are also known to be affected by other tapeworms, protozoans and herpes-like viral infections, but little is known of how the infections affect the health of the animals or the populations.
Although it is considered easy to keep echidnas healthy in captivity, breeding is difficult, partly due to the relatively infrequent cycle. In 2009, Perth Zoo managed to breed some captive short-beaked echidnas, and in 2015 the first zoo-born echidnas were successfully bred there. Until 2006, only five zoos have managed to breed short-beaked echidnas, but no captive-bred young have survived to maturity. Of these five institutions, only one in Australia—Sydney's Taronga Zoo—managed to breed echidnas, in 1977. The other four cases occurred in the Northern Hemisphere, two in the United States and the others in western Europe. In these cases, breeding occurred six months out of phase compared to Australia, after the animals had adapted to Northern Hemisphere seasons. The failure of captive breeding programs has conservation implications for the endangered species of echidna from the genus Zaglossus, and to a lesser extent for the short-beaked echidna.
== Cultural references ==
Short-beaked echidnas feature in the animistic culture of indigenous Australians, including their visual arts and stories. The species was a totem for some groups, including the Noongar people from Western Australia. Many groups have myths about the animal; one myth explains it was created when a group of hungry young men went hunting at night and stumbled across a wombat. They threw spears at the wombat, but lost sight of it in the darkness. The wombat adapted the spears for its own defence and turned into an echidna. The fictional character Knuckles the Echidna from Sonic the Hedgehog is a red short-beaked echidna who possesses superhuman strength.
The short-beaked echidna is an iconic animal in contemporary Australia, notably appearing on the five-cent coin (the smallest denomination), and on a $200 commemorative coin released in 1992. The anthropomorphic echidna Millie was a mascot for the 2000 Summer Olympics.
== See also ==
Echidna
Fauna of Australia
List of monotremes and marsupials
== References ==
== Works cited ==
== General references ==
== External links ==
Data related to Tachyglossus aculeatus at Wikispecies
Media related to Tachyglossus aculeatus at Wikimedia Commons
Tasmanian Department of Water, Primary Industries and Environment – Short-beaked echidna
Echidna Love Trains, article with sound clips and images of puggles | Wikipedia/Short-beaked_echidna |
The eastern long-beaked echidna (Zaglossus bartoni), also known as Barton's long-beaked echidna, is one of three species from the genus Zaglossus to occur in New Guinea. It is found mainly in the eastern half at elevations between 2,000 and 3,000 metres (6,600 and 9,800 ft).
== Description ==
The eastern long-beaked echidna can be distinguished from other members of the genus by the number of claws on the fore and hind feet: it has five claws on its fore feet and four on its hind feet. Its weight varies from 5 to 10 kilograms (11 to 22 lb); its body length ranges from 60 to 100 centimetres (24 to 39 in); it has no tail. It has dense black fur. It rolls into a spiny ball for defense. They have a lifespan of roughly 30 years.
Like the closely related platypus, echidnas have spurs on their hind legs. Unlike the platypus, echidna spurs are not venomous. All eastern long-beaked echidnas start with spurs on their hind feet and spur sheaths that cover them. Females typically lose their spurs later in life while males keep them. Females are also generally larger than males. Body mass tends to remain consistent most of their life, making it difficult to distinguish between adult and juvenile with body mass alone.
== Taxonomy ==
All long-beaked echidnas were classified as a single species, until 1998 when Tim Flannery published an article identifying several new species and subspecies. These species were then recognized based on various attributes such as body size, skull morphology, and the number of toes on the front and back feet.
There are four recognized subspecies of Zaglossus bartoni. The population of each subspecies is geographically isolated. The subspecies are:
Zaglossus bartoni bartoni (Thomas, 1907) – nominate subspecies, found in the Highlands Region.
Zaglossus bartoni clunius Thomas and W. Rothschild, 1922 – endemic to the Huon Peninsula of the Morobe Province. Z. b. clunius has five digits on each foot, rather than just the forefeet. It is isolated from conspecifics by the lowlands of the Markham Valley. The distinctiveness of this subspecies supports the high endemism of mammals in Huon.
Zaglossus bartoni smeenki Flannery and Groves, 1998 – the smallest subspecies. Z. b. smeenki has five digits on each foot, rather than just the forefeet. It is endemic to the Nanneau Mountain Range of the Oro Province.
Zaglossus bartoni diamondi Flannery and Groves, 1998 – the largest subspecies, and the largest extant monotreme. It is found throughout the mountains of central New Guinea, from the Paniai Lakes in Indonesia's Central Papua Province to the Kratke Range in Papua New Guinea's Eastern Highlands Province.
== Ecology ==
Eastern long-beaked echidnas are mainly insect eaters, or insectivores. The long snout proves essential for the echidna's survival because of its ability to get in between hard-to-reach places and scavenge for smaller insect organisms such as larvae and ticks. Along with this snout, they have a specific evolutionary adaptation in their tongues for snatching up various earthworms, which are its main type of food source.
Zaglossus bartoni habitats include tropical hill forests to sub-alpine forests, upland grasslands and scrub. The species has been found in locations up to an elevation of around 4,150 m (that is, the highest elevations available on New Guinea).
Zaglossus bartoni is currently listed as "vulnerable" on the Red List, improved from "critically endangered" until 2016. Deforestation is one of the factors leading to the decline of this species.
Humans are the main factor in diminishing populations of eastern long-beaked echidnas. Locals in areas surrounding regions that these organisms inhabit often prey upon them for food. Feral dogs are known to occasionally consume this species. These mammals dig burrows, providing some protection from predation. Factors of deforestation also impact this species negatively. There are four isolated subspecies that inhabit specific geographical regions.
== Reproduction ==
The eastern long-beaked echidna is a member of the order Monotremata. Although monotremes have some of the same mammal features such as hair and mammary glands, they do not give birth to live young, they lay eggs. Like birds and reptiles, monotremes have a single opening, the cloaca. The cloaca allows for the passage of urine and feces, the transmission of sperm, and the laying of eggs.
Little is actually known about the breeding behaviors of this animal, due to the difficulty of finding and tracking specimens. The way the spines on the echidna lie make it difficult to attach tracking devices, in addition to the difficulty in finding the animals themselves, as they are mainly nocturnal.
== References ==
== External links ==
EDGE of Existence (Zaglossus spp.) – Saving the World's most Evolutionarily Distinct and Globally Endangered (EDGE) species | Wikipedia/Eastern_long-beaked_echidna |
Knuckles the Echidna is a character from Sega's Sonic the Hedgehog series. He is a red anthropomorphic short-beaked echidna who is Sonic's secondary best friend and former rival. Determined and serious, but sometimes gullible, he fights his enemies using brute force and strength. His role is established as the guardian of the Master Emerald, a large gemstone which controls the series' integral Chaos Emeralds, and is the last living member of his tribe, the Knuckles Clan.
Knuckles debuted as one of the main antagonists in Sonic the Hedgehog 3 (1994); in Sonic & Knuckles, he first became a playable character. In the games' story, Doctor Eggman tricks him into opposing Sonic and Tails. After antagonizing the duo, he forms a temporary alliance with them after learning of Eggman's trickery. Since then, he has appeared in numerous playable and non-playable roles, as well as in several series of comic books, Western animated television, and Japanese anime, in addition to the feature films Sonic the Hedgehog 2 and Sonic the Hedgehog 3, he stars in the live action Knuckles television miniseries.
One of the series' most popular characters, Knuckles has appeared in most games in the franchise, including those for the main series and spin-offs. His likeness has been frequently utilized in Sonic the Hedgehog merchandise, with the character also being subject to various Internet memes.
== Concept and creation ==
During conception of Sonic the Hedgehog 3, the development team wanted to create a new rival for Sonic. The final design of Knuckles was the result of dozens of possible designs inspired by numerous different animals. In collaboration between the Sonic Team and Sega of America's product marketing manager, Pamela Kelly, the final character of "Knuckles" was chosen. The emphasis of the character was to break walls, with the original idea being a 'whirlwind' ability, rather than punching.
Knuckles was created by developer Takashi Yuda and Pamela Kelly who never intended him to be any more than a "supporting character". Knuckles was introduced in Sonic the Hedgehog 3 as an "intimidator" because of his powerful abilities and physical strength. He was given a headlining role in the next game, Sonic & Knuckles, where he made his first appearance as a playable character.
=== Voice portrayal ===
Knuckles has been voiced by several different actors over the years. In the Japanese dubs, he was voiced by Yasunori Matsumoto in Sonic the Hedgehog: The Movie
and by Nobutoshi Canna since 1998, beginning with Sonic Adventure.
In animation, he was voiced by Brian Drummond in Sonic Underground and by Bill Wise in the English dub of Sonic the Hedgehog: The Movie.
In the video games, Knuckles was originally voiced by Michael McGaharn in Sonic Adventure, and then by Ryan Drummond in Sonic Shuffle. Scott Dreier began voicing the character in 2001, starting with Sonic Adventure 2. He continued to voice the character for three more years until 2004, his final role as Knuckles was in Sonic Advance 3. Dan Green began voicing the character in the anime series Sonic X, he would later take over the role in the video games in 2005, starting with Shadow the Hedgehog. In 2010, he was replaced by Travis Willingham, beginning with Sonic Free Riders. Willingham continued voicing the character until 2018, and his final role as Knuckles was in Super Smash Bros. Ultimate. Since 2019, Knuckles has been voiced by Dave B. Mitchell, beginning with Team Sonic Racing. In the live-action subfranchise, Knuckles is voiced by Idris Elba. In the 2022 Sonic short film, Sonic Drone Home, Knuckles is voiced by Fred Tatasciore. In the Netflix series Sonic Prime, Knuckles is voiced by Adam Nurada, while his Shatterverse counterparts (respectively named Renegade Knucks, Gnarly Knuckles, and Knuckles the Dread) are voiced by Vincent Tong.
== Characteristics ==
Knuckles is a red anthropomorphic short-beaked echidna, the only living descendant of a well-established clan of echidnas. For many years, his clan guarded a giant gemstone called the Master Emerald, which controls the Chaos Emeralds, objects central to the Sonic the Hedgehog game series. As such, Knuckles has spent most of his life atop a floating island called Angel Island, guarding the Master Emerald from harm. He has grown up fairly introverted as a result.
Knuckles has a personality described as cool. However, he sometimes loses his composure and gets in fights with other characters, and he can be shy around girls. His favorite food is grapes, and his relationship with Sonic is ambivalent. However, in later games, their relationship became more unequivocal: Knuckles entered the series as an antagonist of Sonic but later becomes one of the protagonists and sees him as a partner, while envying Sonic's adventurous lifestyle. He is depicted as somewhat gullible and very rash, especially when angered. Knuckles has often been tricked by Doctor Robotnik due to his naivety, but is stated in one game manual to have become more skeptical of him, possibly due to the multiple times of getting fooled by Robotnik.
While slower than Sonic, Knuckles is depicted as one of the series's strongest characters and a skilled martial artist: his brawny physique allows him to lift objects many times his size and weight, while his powerful fists enable him to smash boulders and break through solid ground. He can also glide long distances and climb up walls using the spikes of his gloves. Unlike Sonic, Knuckles is able to swim. As is typical among Sonic characters, Knuckles can roll into a ball to attack enemies. He also has an empowered "super" form: using the Chaos Emeralds allows him to transform into Super Knuckles. Using the Super Emeralds allows him to transform into Hyper Knuckles.
== Appearances ==
=== In video games ===
Knuckles debuted in the 1994 Sega Genesis game Sonic the Hedgehog 3. Knuckles joins the series's primary antagonist Dr. Robotnik after being tricked into thinking that Sonic is attempting to steal the Master Emerald; Knuckles fights Sonic at several points throughout the game. Robotnik's betrayal is revealed late in Sonic & Knuckles when he steals the Master Emerald and attacks Knuckles, Sonic & Knuckles is also the first game where he became a player character, his story takes place after Sonic's Story. A similar plot follows in Sonic the Hedgehog: Triple Trouble. While Knuckles's canonical playable debut comes in Sonic & Knuckles, he is playable in Sonic 2 and 3 via the Genesis' lock-on technology. Knuckles starred in Knuckles' Chaotix for the Sega 32X, in which he serves as the guardian of an island amusement park and rescues his friends—collectively known as the Chaotix—from Robotnik in 1995. He teams up with them individually, creating an unusual gameplay style involving two characters being tethered together.
Eggman shatters the Master Emerald, thus freeing Chaos who appears before Knuckles, the pieces are scattered around, and Chaos flees in Sonic Adventure. To restore the Emerald, thereby protecting Angel Island, he searches through various expansive levels for pieces. At one point, he defeats Chaos, and Eggman tricks Knuckles into thinking that Sonic is trying to collect Emerald shards for his own purposes. Knuckles finds Sonic holding two Chaos Emeralds he thinks are Master Emerald shards, and attacks him. This knocks them out of Sonic's hands, so Eggman shows up to steal them and leaves. He initially stays on Earth to look for pieces while Sonic and Tails follow Eggman, but later joins them aboard Eggman's airship, the Egg Carrier, after seeing a vision of there being more pieces on it. He finds the final pieces and is confronted by Chaos' final form, then returns to the Emerald's island to restore it.
Early in Sonic Adventure 2, Knuckles and Rouge argue over the Emerald; she wants the pieces for her personal collection. Eggman tries to steal it, so Knuckles shatters it aboard Eggman's hovercraft, sending the pieces every which way, while also mentioning that if the shards are found they can be made whole. He spends the game recollecting the pieces like in Adventure. He later helps Sonic, Tails, and Amy find Eggman's base inside a giant pyramid and a key to an inner chamber housing a giant Space Shuttle. He follows them to a giant space station called the ARK with it, where he again scuffles with Rouge over the Emerald. He saves her from falling into a constructed pit of lava; she decides the shards are worthless and dismissively lets him keep them, so he reassembles the Emerald and runs off. The antagonist Gerald Robotnik, Eggman's grandfather, initiates a program to send the ARK on a collision course with Earth as revenge for an attack on the ARK decades earlier, so Knuckles teams up with the other playable characters to reroute it.
Knuckles serves as a power-based character in Sonic Heroes alongside Sonic and Tails, who respectively represent speed and flight. They team up to defeat Eggman after receiving a letter saying that he will destroy the world in three days. However, it turns out that Eggman is being impersonated by Metal Sonic, whom all of the other characters defeat together. Knuckles helps Sonic, Tails, Amy Rose, and Cream the Rabbit stop Eggman from building an empire in the Sonic Advance trilogy. With the same team, Knuckles recurs in Sonic Riders and its two sequels; in each game, they participate in board-racing competitions together. In another team-based installment, the role-playing game Sonic Chronicles: The Dark Brotherhood, Knuckles is a playable character with a major role in the story. The game begins with Tails informing Sonic that Knuckles has been kidnapped, so a team beginning as Sonic, Tails, Amy, and Rouge must rescue him. He is eventually saved, and it is revealed that the echidna race is still alive in the form of the helpful Shade the Echidna and her villainous tribe, the Nocturnus.
He is a minor character in Sonic Rush, where he accosts Blaze the Cat under the impression that she has stolen Chaos Emeralds. In the Nintendo DS version of Sonic Colors, Knuckles arrives at an amusement park Eggman has created after receiving a letter. Frustrated at having been tricked, he challenges Sonic to a race as a mission, but shortly learns that Rouge wrote the letter inviting him to the park. He has a short argument with Rouge. Modern Knuckles gives Classic and Modern Sonic missions and helpful advice in Sonic Generations. In Sonic Lost World, Knuckles and Amy look after forest animals while Sonic and Tails rescue the animals' friends. Later, the Deadly Six take control of one of Eggman's machines to drain life from the world, and Amy and Knuckles die, but they are brought back to life when Sonic and Tails replenish it. He is a playable character in Sonic Mania Plus, regaining his role from the first games alongside Sonic, Tails, Mighty and Ray. He appears in the game Sonic Forces, where he becomes the leader of a resistance created to fight back against Eggman's advancing forces. In Sonic Frontiers, Knuckles inadvertently arrives on the Starfall Islands while investigating some ruins on the Angel Island, once there he is captured by Sage. After Sonic releases his digital form who helps him search for the Chaos Emeralds, Knuckles notices that the ruins of Starfall Islands are similar to those on Angel Island, making him and Sonic wonder if the inhabitants of the islands resettled there after their arrival on the planet. After comparing the extinction of the Ancients and his own people reminds him that he is the last of his kind, Sonic encourages him to live his life to the fullest and not make the protection of the Master Emerald his sole purpose in life, with Knuckles deciding to heed his advice after he is free from Cyber space.
Knuckles has been a playable character in numerous spinoff games with little effect on the series's plot, such as the fighting game Sonic the Fighters, the racing title Sonic R, and the party title Sonic Shuffle, as well as crossover games like Mario & Sonic at the Olympic Games and Sonic & All-Stars Racing Transformed. He makes a cameo appearance in Sega Superstars Tennis, as a member of the audience in the Green Hill court and in Super Smash Bros. Brawl's Green Hill stage, where he, Tails, and Silver run through the vertical loop in the background. Knuckles appears as one of four playable characters in the action-adventure spin-off property Sonic Boom (Rise of Lyric and Shattered Crystal). In Lego Dimensions, Knuckles appears as a non-playable character in the Sonic the Hedgehog world, in which he requests the player to assist him in a sidequest to take down some of Eggman's robots, during which he makes a number of references to the rap songs about him in the Sonic Adventure games. Knuckles also makes a cameo as an easter egg in Deus Ex: Mankind Divided on the box of a video game entitled Knuckles the Echidna in Knuckles & Knuckles & Knuckles which stems off of a running joke regarding the "& Knuckles" part of the title card when Sonic 3 is locked on to the Sonic and Knuckles cartridge. In Super Smash Bros. Ultimate, Knuckles appears as an assist trophy that attacks enemy players when summoned; he also appears as a spirit.
Knuckles appears as an unlockable playable character in Super Monkey Ball Banana Rumble.
=== In comics ===
In Sonic the Comic, Knuckles plays a similar role to that of the games. When the Death Egg crashes on Angel Island, Knuckles is briefly tricked by Dr. Robotnik and thus allows Robotnik to place his robot armies on the island and construct a base to repair his Death Egg. Knuckles also assists him in fighting Sonic and stealing Sonic's own six Emeralds so they can be combined with Knuckles's into one set of Emeralds. However, Knuckles does not trust Robotnik enough to tell him that he possesses a seventh Emerald that can control the others, and when Robotnik tries to absorb the Emeralds' power into himself, Knuckles uses this Emerald to defeat him. From that point on, he works as an ally against Robotnik, starting by removing all traces of the doctor's influences from Angel Island.
In the comic series of Sonic the Hedgehog published by Archie Comics, Knuckles is the eighteenth guardian of the Floating Island, which is also called Angel Island. He is also a member of the Brotherhood of Guardians, a secret society that defends the island and is made up of Knuckles's predecessors/ancestors. In keeping with the incorporation of elements of the Sonic the Hedgehog cartoon into the series, Knuckles lives on the planet Mobius. Knuckles is supported in his efforts by the Chaotix, and often works together with Sonic the Hedgehog and the Freedom Fighters.
=== In animation ===
Knuckles's animation debut came with the 1996 Japanese Sonic the Hedgehog OVA. Sonic and Tails meet him during their trip into the Land of Darkness, and over the course of the film he helps them defeat Black Eggman/Metal Robotnik and Hyper Metal Sonic, two robots created by Eggman/Robotnik. As Metal is about to descend into a lava pit, Sonic attempts to save him after all, but Knuckles holds him back and Sonic is disappointed. Knuckles play-fights with Sonic a few times in the film as well.
Knuckles is a minor character in Sonic Underground. Sonic, Sonia, and Manic meet Knuckles atop his home, the Floating Island while searching for their mother. Knuckles is initially skeptical of them but soon accepts their help in protecting the Island and its guardian Chaos Emerald from villains Sleet and Dingo. Later on, the siblings recruit Knuckles to help them deactivate Doctor Robotnik's giant fortress, as it is powered by Emeralds and he can control them. They succeed, but Sleet and Dingo accidentally break the Emerald, unleashing gradually effective but massive energy upon the planet Mobius, and Knuckles enlists one of his relatives to help them control it, with mediocre results. Reluctantly, Knuckles cuts a deal with Robotnik to turn over the hedgehogs in exchange for setting Mobius right; Robotnik succeeds and starts turning the hedgehogs into robots, but Knuckles betrays Robotnik to rescue his friends.
Knuckles appears in all three seasons of Sonic X, where he is depicted as the guardian of the Master Emerald, and is said to have a "chip on his shoulder". The Sonic X version of Knuckles has been described as an "incredibly serious warrior with a deep, fleshed-out backstory" in comparison to the more comedic depictions of the character in recent years. After being stranded in the new world with Sonic, his only desire is to get back home quickly. He spends most of the first season traveling alone, but as the series continues he begins to travel with Sonic and the others more often, as well as befriending other characters. After returning home for the third season, he joins Sonic on the spaceship, "Blue Typhoon", which is captained by Tails after their planet was invaded by the Metarex.
Knuckles is among the main cast in the Sonic Boom animated series, and had been redesigned for it: now being taller and more muscular than before. As a somewhat exaggerated reference to his mainstream counterpart's easily deceived personality (as well as being based on the stereotypical team muscles), Knuckles is also portrayed as being somewhat slow-witted and goofy in this series.
Knuckles appears as a supporting character in Sonic Prime. After Sonic shatters the Paradox Prism, which results in the creation of multiple parallel dimensions at the expense of his own, multiple versions of Knuckles are made as well; such as Renegade Knucks who is a rebel against the Chaos Council of New Yoke City, the feral and paranoid Gnarly, and the pirate captain Knuckles the Dread. Knuckles is voiced by Adam Nurada and his variants are voiced by Vincent Tong.
=== In other media ===
While Knuckles does not appear in the Sonic series's first theatrical film, Sonic the Hedgehog, his existence is alluded to within the film's opening sequence in which a young Sonic and his caretaker Longclaw are attacked by a native clan of Echidnas. Co-writer Pat Casey has since stated that they are Echidnas within Sonic's world, thus confirming Knuckles's species does exist within that film's universe. Casey also hinted that a connection between the first film's Echidna tribe and Knuckles could be explored in the film's sequel.
Knuckles appears alongside Sonic and Tails in the second film, voiced by Idris Elba. In the film, it is revealed he is the last of the Echidna Tribe, as the rest of his kind went extinct due to a war between them and the owls, and has a grudge against Sonic for being Longclaw's apprentice. After being informed of Sonic's location by Dr. Robotnik, he teams up with the scientist and travels to Earth to defeat Sonic and seek out the Master Emerald to honor his ancestors. At the temple where the Emerald is located, Robotnik betrays Knuckles and leaves him to die, but he is rescued by Sonic. He teams up with Sonic and Tails to defeat Robotnik in Green Hills and reclaim the Master Emerald. The three agree to safeguard the Emerald as they live with Sonic's adoptive Earth family, the Wachowskis.
Knuckles is the primary protagonist of a spinoff miniseries of the same name released on Paramount+, with Elba reprising the role. In the miniseries, Knuckles (who is struggling to adjust to his new life and home on Earth) takes deputy sheriff Wade Whipple in as his "apprentice", training him in the ways of the Echidna warrior to help him prepare for a bowling tournament in Reno, Nevada where his estranged father will be competing. During their journey, Wade is reunited with his mother and sister, while Knuckles is pursued by "the Buyer", Dr. Robotnik's former operative who seeks to take Knuckles's power for himself.
Knuckles appears alongside Sonic and Tails in Sonic the Hedgehog 3, with Elba reprising the role, again. Knuckles continues to live with Sonic and Tails, with the Wachowskis, serving as the "muscle" of their team when they try to stop Shadow the Hedgehog. Knuckles continues to safeguard the Master Emerald with Wade's assistance until Sonic forces them to give him the Emerald, to use its powers to defeat Shadow. Knuckles continues to tend to go into confrontations eager to fight, or at least break something, but continues to remain loyal and even tries to give supportive advice to Sonic.
== Reception and impact ==
The character has received positive attention. According to IGN's Levi Buchanan, fans "seemed legitimately happy" with the addition of the character of Knuckles, who was popular enough to get marquee billing in Sonic & Knuckles, but Buchanan felt that characters who came after him were going "overboard". IGN's Colin Moriarty singled out the introduction of both Knuckles and Tails as when the series became "iffy" and listed them and all other characters in the series, sans Sonic and Robotnik, as being 2nd most in need to "die" on his top 10 list. In contrast, he was listed as the best Sonic character by Official Nintendo Magazine based on the impact he brought to the Sonic games in which he first appeared. Similarly, Complex writer Elijah Watson considers him a better character than Sonic. Watson praises his debut in Sonic the Hedgehog 3, and adds "Knuckles could have never been Sega's mascot; the echidna lacks the sociability of Sonic and his Nintendo counterpart, Mario. And yet this defining characteristic is what makes him so appealing. He is Sega's anti-hero: the dreadlocked brawler who is surprisingly selfless and has a soft spot for grapes and adorable animals."
According to official Sonic Team polls, Knuckles is the fourth most popular character in the series, following behind Tails, Shadow, and Sonic. Elton Jones from Complex listed Knuckles as his eleventh most wanted character in the next Super Smash Bros. game. Ravi Sinha of GamingBolt named Knuckles's appearance in Sonic Boom as one of their "Worst Video Game Character Design", stating that "For as annoying as Sonic’s rework was in Sonic Boom, Knuckles was way more baffling. Even worse is that his character is little more than a “dumb jock,” with oddly intellectual viewpoints in the animated series because it's randomly funny or something."
Mega Zone's review of Knuckles' Chaotix praised the introduction of a new protagonist, whom it deemed "rougher and tougher" in comparison to the "spineless" Sonic. Mean Machines Sega called Knuckles's powers "impressive" and the character overall more useful and promising than Tails. Sega Magazine stated that Knuckles "looks cooler" than Sonic, comparing him to Spider-Man, and suggested he be given his own game. Sega Magazine later called him "groovy" and "ace", concluding that they "love him." Knuckles's characterization in Sonic Boom earned praise from Polygon due to how "progressive" he is when mentioning feminism much to the shock of the characters.
Kenneth Shepard from Kotaku felt Knuckles did not have enough screentime in his Paramount+ show, and observed "Elba is providing voice work for roughly 76 minutes and 47 seconds of a 172-minute-long season. Those are just scenes Knuckles is in, not accounting for whether or not he’s actually contributing to the scene in a meaningful way." Rendy Jones at RogerEbert.com praised his characterization in the show, noting the character "diverting his muscle-head dim-witted traits into a confident and jovial guy with a heart of gold—an echidna himbo, if you will."
=== Ugandan Knuckles ===
In late December 2017, players began to flood the virtual reality video game VRChat with avatars depicting a deformed version of the character called "Ugandan Knuckles". The character stemmed from a 2017 review of Sonic Lost World by YouTube user Gregzilla as well as from fans of PlayerUnknown's Battlegrounds streamer Forsen who often make references to Uganda in the chat section of his streams. The character is often associated with quotes such as "Do you know da wae?" and "Save the queen!" among many other quotes, which originate from the 2010 Ugandan action comedy film Who Killed Captain Alex? as well as for "spitting" on other users whom they feel do not know "da wae".
The meme was criticized by some journalists as being racially insensitive; Polygon described it as "problematic". The creator of the avatar, DeviantArt user "tidiestflyer", has expressed regret over how it has been used, in particular saying that he hopes it is not used to annoy players of VRChat, and that he enjoys the game and he does not want to see anyone's rights get taken away because of the avatar. In response, in January 2018 the developers of VRChat published an open letter on Medium, stating that they were developing "new systems to allow the community to better self-moderate" and asking users to use the built-in muting features.
In April 2019, Canadian toy company Youtooz launched their line of vinyl collectible figurines with a depiction of Ugandan Knuckles.
=== ...& Knuckles ===
Another Knuckles-centric meme is derived from the video game Sonic 3 & Knuckles, a game which combined Sonic the Hedgehog 3 and Sonic & Knuckles, accessed by attaching the cartridge of the former to the latter. The awkward-sounding combination of names resulted in a meme where a fictitious and absurdly long video game name is created (usually one for a long-running franchise) with "& Knuckles" appended to the end of it. This meme was also used to poke fun at the Nintendo DS and Nintendo 3DS series of systems due to the large number of variants, with & Knuckles often appended to the end of an invented system, e.g. "New Nintendo 3DSi XL & Knuckles". This was later referenced in Sonic Mania, which featured an unlockable "& Knuckles" mode, allowing a computer-controlled Knuckles to follow the player's character, even if Knuckles is also chosen as the playable character.
== See also ==
List of Sonic the Hedgehog characters
== Notes ==
== References ==
== External links ==
Knuckles at Sonic-City (archived)
Knuckles at Sonic Channel (in Japanese) | Wikipedia/Knuckles_the_Echidna |
In Greek mythology, Echidna (; Ancient Greek: Ἔχιδνα, romanized: Ékhidna, lit. 'she-viper', pronounced [ékʰidna]) was a monster, half-woman and half-snake, who lived alone in a cave. She was the mate of the fearsome monster Typhon and was the mother of many of the most famous monsters of Greek myth.
== Genealogy ==
Echidna's family tree varies by author. The oldest genealogy relating to Echidna, Hesiod's Theogony (c. 8th – 7th century BC), is unclear on several points. According to Hesiod, Echidna was born to a "she" who was probably meant by Hesiod to be the sea goddess Ceto, making Echidna's likely father the sea god Phorcys; however the "she" might instead refer to the Oceanid Callirhoe, which would make Medusa's offspring Chrysaor the father of Echidna. The mythographer Pherecydes of Athens (5th century BC) has Echidna as the daughter of Phorcys, without naming a mother.
Other authors give Echidna other parents. According to the geographer Pausanias (2nd century AD), Epimenides (7th or 6th century BC) had Echidna as the daughter of the Oceanid Styx (goddess of the river Styx) and one Peiras (otherwise unknown to Pausanias), while according to the mythographer Apollodorus (1st or 2nd century AD), Echidna was the daughter of Tartarus and Gaia. In one account, from the Orphic tradition, Echidna was the daughter of Phanes (the Orphic father of all gods).
== Description ==
Hesiod's Echidna was half beautiful maiden and half fearsome snake. Hesiod described "the goddess fierce Echidna" as a flesh eating "monster, irresistible", who was like neither "mortal men" nor "the undying gods", but was "half a nymph with glancing eyes and fair cheeks, and half again a huge snake, great and awful, with speckled skin", who "dies not nor grows old all her days". Hesiod's apparent association of the eating of raw flesh with Echidna's snake half suggests that he may have supposed that Echidna's snake half ended in a snake-head. Aristophanes (late 5th century BC), who makes her a denizen of the underworld, gives Echidna a hundred heads (presumably snake heads), matching the hundred snake heads Hesiod says her mate Typhon had.
In the Orphic account (mentioned above), Echidna is described as having the head of a beautiful woman with long hair and a serpent's body from the neck down. Nonnus, in his Dionysiaca, describes Echidna as being "hideous" with "horrible poison".
== Offspring ==
According to Hesiod's Theogony, the "terrible" and "lawless" Typhon "was joined in love to [Echidna], the maid with glancing eyes" and she bore "fierce offspring". First there was Orthrus, the two-headed dog who guarded the Cattle of Geryon, second Cerberus, the multiheaded dog who guarded the gates of Hades, and third the Lernaean Hydra, the many-headed serpent who, when one of its heads was cut off, grew two back. The Theogony mentions a second ambiguous "she" as the mother of the Chimera (a fire-breathing beast that was part lion, part goat, and had a snake-headed tail) which may refer to Echidna, though possibly the Hydra or even Ceto was meant instead. Hesiod next names two more descendants of Echidna, the Sphinx, a monster with the head of a woman and the body of a winged lion, and the Nemean lion, killed by Heracles as his first labor. According to Hesiod, these two were the offspring of Echidna's son Orthrus and another ambiguous "she", read variously as the Chimera, Echidna herself, or again even Ceto. In any case, the lyric poet Lasus of Hermione (6th century BC) has Echidna and Typhon as the parents of the Sphinx, while the playwright Euripides (5th century BC), has Echidna as her mother, without mentioning a father. While mentioning Cerberus and "other monsters" as being the offspring of Echidna and Typhon, the mythographer Acusilaus (6th century BC) adds the Caucasian Eagle that ate the liver of Prometheus. Pherecydes also names Prometheus' eagle, and adds Ladon (though Pherecydes does not use this name), the dragon that guarded the golden apples in the Garden of the Hesperides (according to Hesiod, the offspring of Ceto and Phorcys).
Later authors mostly retain these offspring of Echidna and Typhon while adding others. Apollodorus, in addition to naming as their offspring Orthrus, the Chimera (citing Hesiod as his source), the Sphinx, the Caucasian Eagle, Ladon, and probably the Nemean lion (only Typhon is named), also adds the Crommyonian Sow, killed by the hero Theseus (unmentioned by Hesiod). Hyginus in his list of offspring of Echidna (all by Typhon), retains from the above Cerberus, the Chimera, the Sphinx, the Hydra and Ladon, and adds "Gorgon" (by which Hyginus means the mother of Medusa, whereas Hesiod's three Gorgons, of which Medusa was one, were the daughters of Ceto and Phorcys), the Colchian dragon that guarded the Golden Fleece and Scylla.
Nonnus makes Echidna the mother of an unnamed, venom-spitting, "huge" son, with "snaky" feet, an ally of Cronus in his war with Zeus, who was killed by Ares. The Harpies, in Hesiod the daughters of Thaumas and the Oceanid Electra, in one source, are said to be the daughters of Typhon, and so perhaps were also considered to be the daughters of Echidna. Likewise, the sea serpents which attacked the Trojan priest Laocoön during the Trojan War, which are called by Quintus Smyrnaeus "fearful monsters of the deadly brood of Typhon", may also have been considered Echidna's offspring. Echidna is sometimes identified with the Viper who was the mother by Heracles of Scythes, an eponymous king of the Scythians, along with his brothers Agathyrsus ("much raging") and Gelonus (see below).
=== List of principal offspring ===
The following table lists the principal offspring of Echidna as given by Hesiod, Apollodorus or Hyginus.
Legend:
✓✓ = Echidna and Typhon given as parents
✓? = Only Echidna given as parent
?✓ = Only Typhon given as parent
?? = Echidna and Typhon possibly meant as parents
? = Echidna possibly meant as parent
Notes:
== Cave ==
According to Hesiod, Echidna was born in a cave and apparently lived alone (in that same cave, or perhaps another), as Hesiod describes it, "beneath the secret parts of the holy earth ... deep down under a hollow rock far from the deathless gods and mortal men", a place appointed by the gods, where she "keeps guard in Arima". (Though Hesiod here may possibly be referring to Echidna's mother Ceto's home cave instead.) It was perhaps from this same cave that Echidna used to "carry off passersby".
Hesiod locates Echidna's cave in Arima (εἰν Ἀρίμοισιν). Presumably, this is the same place where, in Homer's Iliad, Zeus, with his thunderbolts, lashes the land about Echidna's mate Typhon, described as the land of the Arimoi (εἰν Ἀρίμοις), "where men say is the couch [bed] of Typhoeus", Typhoeus being another name for Typhon. But neither Homer nor Hesiod say anything more about where this Arima might be. The question of whether an historical place was meant, and its possible location, has been since ancient times the subject of speculation and debate.
The geographer Strabo (c. 20 AD) discusses the question in some detail. Several locales, Cilicia, Syria, Lydia, and the Island of Pithecussae (modern Ischia), each associated with Typhon in various ways, are given by Strabo as possible locations for Hesiod's "Arima" (or Homer's "Arimoi").
The region in the vicinity of the ancient Cilician coastal city of Corycus (modern Kızkalesi, Turkey) is often associated with Typhon's birth. The poet Pindar (c. 470 BC), who has Typhon born in Cilicia, and nurtured in "the famous Cilician cave" an apparent allusion to the Corycian cave, also has Zeus slaying Typhon "among the Arimoi". The fourth-century BC historian Callisthenes, located the Arimoi and the Arima mountains in Cilicia, near the Calycadnus river, the Corycian cave and the Sarpedon promontory. The b scholia to Iliad 2.783, preserving a possible Orphic tradition, has Typhon born "under Arimon in Cilicia", and Nonnus mentions Typhon's "bloodstained cave of Arima" in Cilicia.
Just across the Gulf of Issus from Corycus, in ancient Syria, was Mount Kasios (modern Jebel Aqra in Turkey) and the Orontes River, said to be the site of the battle of Typhon and Zeus. According to Strabo, the historian Posidonius identified the Arimoi with the Aramaeans of Syria.
According to some, Arima was instead located in a volcanic plain on the upper Gediz River called the Catacecaumene ("Burnt Land"), situated between the ancient kingdoms of Lydia, Mysia and Phrygia, near Mount Tmolus (modern Bozdağ) and Sardis, the ancient capital of Lydia. According to Strabo, some placed the Arimoi and the battle between Typhon and Zeus at Catacecaumene, while Xanthus of Lydia added that "a certain Arimus" ruled there. Strabo also tells us that, according to "some", Homer's "couch of Typhon" (and hence the Arimoi) was located "in a wooded place, in the fertile land of Hyde", with Hyde being another name for Sardis (or its acropolis), and that Demetrius of Scepsis thought that the Arimoi were most plausibly located "in the Catacecaumene country in Mysia". The third-century BC poet Lycophron placed Echidna's lair in this region.
Another place mentioned by Strabo as being associated with Arima is the volcanic island of Pithecussae, off the coast of ancient Cumae in Italy. According to Pherecydes of Athens, Typhon fled to Pithecussae during his battle with Zeus and, according to Pindar, Typhon lay buried beneath the island. Strabo reports the "myth" that when Typhon "turns his body the flames and the waters, and sometimes even small islands containing boiling water, spout forth". The connection to Arima comes from the island's Greek name Pithecussae, which derives from the Greek word for monkey, and, according to Strabo, residents of the island said that "arimoi" was also the Etruscan word for monkeys.
Quintus Smyrnaeus locates her cave "close on the borders of Eternal Night".
== Death ==
Although for Hesiod Echidna was immortal and ageless, according to Apollodorus Echidna continued to prey on the unfortunate "passers-by" until she was finally killed, while she slept, by Argus Panoptes, the hundred-eyed giant who served Hera.
== The Scythian echidna ==
From the fifth century BC historian Herodotus, we learn of a creature who, though Herodotus does not name as Echidna, is called an echidna ("she-viper") and resembles the Hesiodic Echidna in several respects. She was half woman half snake, lived in a cave, and was known as a mother figure, in this case, as the progenitor of the Scythians (rather than of monsters).
According to Herodotus, Greeks living in Pontus, a region on the southern coast of the Black Sea, told a story of an encounter between Heracles and this snaky creature. Heracles was driving the cattle of Geryones through what would later become Scythia, when one morning he awoke and discovered that his horses had disappeared. While searching for them, he "found in a cave a creature of double form that was half maiden and half serpent; above the buttocks she was a woman, below them a snake". She had the horses and promised to return them if Heracles would have sex with her. Heracles agreed and she had three sons by him: Agathyrsus, Gelonus and Scythes. She asked Heracles what she should do with his sons: "shall I keep them here (since I am queen of this country), or shall I send them away to you?". And Heracles gave her a bow and belt, and told her, that when the boys were grown, whichever would draw the bow and wear the belt, keep him and banish the others. The youngest son Scythes fulfilled the requirements and became the founder and eponym of the Scythians.
== The Viper in the Acts of Philip ==
A possibly related creature to the Hesiodic Echidna is the "Viper" (Echidna) cast into an abyss, by Philip the Apostle, in the apocryphal Acts of Philip. Called a "she dragon" (drakaina) and "the mother of the serpents", this Echidna ruled over many other monstrous dragons and snakes, and lived in a gated temple at Hierapolis, where she was worshipped by the people of that land. She, along with her temple and priests, was swallowed up by a hole in the ground that opened beneath her, as the result of Philip's curse.
== Delphyne ==
Echidna was perhaps associated with the monster killed by Apollo at Delphi. Though that monster is usually said to be the male serpent Python, in the oldest account of this story, the Homeric Hymn to Apollo, the god kills a nameless she-serpent (drakaina), subsequently called Delphyne, who had been Typhon's foster-mother. Echidna and Delphyne share several similarities. Both were half-maid and half-snake, and both were a "plague" (πῆμα) to men. And both were intimately connected to Typhon, and associated with the Corycian cave.
== Iconography ==
No certain ancient depictions of Echidna survive. According to Pausanias, Echidna was depicted, along with Typhon, on the sixth century BC Doric-Ionic temple complex at Amyclae known as the throne of Apollo, designed by Bathycles of Magnesia. Pausanias identifies two standing figures on the left as Echidna and Typhon, with Tritons standing on the right, with no other details concerning these figures given.
== See also ==
Echidna – a monotreme mammal of Australia and New Guinea named after the mythological monster
Nāgas – a race of water-dwelling beings of Hindu mythology who are also half-serpent
Nüwa – a goddess in ancient Chinese mythology best known for creating mankind and repairing the wall of heaven, often depicted as having the body of a snake, or the lower part of her body being that of a snake
== Notes ==
== References ==
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Athenagoras, Apology, Rev. B. P. Pratten translator, in Ante-Nicene Christian Library: Translations of the Writings of the Fathers Down to A.D. 325, Vol. II Justin Martyr and Athenagoras, Edinburgh, T. and T. Clark, 38 George Street, 1870.
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Herodotus; Histories, A. D. Godley (translator), Cambridge: Harvard University Press, 1920; ISBN 0674991338. Online version at the Perseus Digital Library.
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== External links ==
Media related to Echidna (mythology) at Wikimedia Commons | Wikipedia/Echidna_(mythology) |
Echidnas are Australian egg-laying mammals also known as spiny anteaters.
Echidna may also refer to:
Echidna (mythology), monster in Greek mythology and namesake of the mammal
(42355) Typhon I Echidna, the natural satellite of the asteroid 42355 Typhon
ECHIDNA, high-resolution neutron powder diffractometer at Australia's research reactor OPAL
Echidna (Re:Zero), a character in the light novel series Re:Zero − Starting Life in Another World
Echidna, character in the video game The Bouncer
Echidna, a demoness in the video game Devil May Cry 4
== Taxonomic genera ==
Echidna (fish) J. R. Forster, 1788, a genus of moray eels
Echidna Cuvier, 1797, a junior homonym referring to the mammals commonly known as echidnas
Echidna Merrem, 1820, junior homonym for a genus of African snakes now treated as Bitis
== See also ==
Knuckles the Echidna, character from the Sonic the Hedgehog video game series
Echidna Parass, fictional character from the Black Cat series | Wikipedia/Echidna_(disambiguation) |
The western long-beaked echidna (Zaglossus bruijnii) is one of the four extant echidnas and one of three species of Zaglossus that occurs in New Guinea. Originally described as Tachyglossus bruijnii, this is the type species of Zaglossus.
== Description ==
The western long-beaked echidna is an egg-laying mammal. Unlike the short-beaked echidna, which eats ants and termites, the long-beaked species eats earthworms. The long-beaked echidna is also larger than the short-beaked species, reaching up to 16.5 kilograms (36 lb); the snout is longer and turns downward; and the spines are almost indistinguishable from the long fur. It is distinguished from the other Zaglossus species by the number of claws on the fore and hind feet: three (rarely four). It is the largest extant monotreme.
== Distribution and habitat ==
The species is found in the Bird's Head and Bomberai Peninsulas in Western New Guinea of Indonesia, at elevations up to 2,500 metres (8,200 ft). Its preferred habitats are hill and montane forests.
=== Kimberley specimen ===
The Tring Collection of the British Museum of Natural History includes a western long-beaked echidna, with a collection label noting its collection by John T. Tunney in 1901. Curiously, the location of collection is noted as Mount Anderson, in the Kimberley region of north-west Australia. However, this species is otherwise thought to be extinct for millennia in Australia; the only other specimens of Zaglossus from Australia are fossils dated to the Pleistocene period.
It was presumed that the specimen was in fact collected from elsewhere and inadvertently attached to a Tunney collection label. Thus, the specimen received no further attention for many years.
A study by Helgen et al. (2012) examined the specimen and considered various aspects including the circumstantial improbability of a collection label misassignment, the uniqueness of ectoparasites found on the specimen, the similarity of some Kimberley forests to known habitat in New Guinea, an indigenous cave painting appearing to depict a long-beaked echidna, and the testimony of an Aboriginal elder. The study concludes that the specimen likely was collected in Australia as stated on the label. The researchers argue that the species ought to be recognised in the state's fauna as persisting into the modern era, and could potentially still be extant in poorly surveyed forests of north-western Australia; if locally extinct, reintroduction of this critically endangered species would be worth consideration.
Burbidge (2017) disputes this conclusion, arguing against each line of evidence, and concluding that the specimen is likely from New Guinea but assigned an incorrect label.
== Conservation ==
The species is listed as Critically Endangered by the IUCN; numbers have decreased due to human activities, including habitat loss and hunting. The western long-beaked echidna is considered a delicacy, and although commercial hunting of the species has been banned by the Indonesian government, traditional hunting is permitted.
== References ==
== Further reading ==
Augee, M and Gooden, B. 1993. Echidnas of Australia and New Guinea. Australian National History Press ISBN 978-0-86840-046-4 | Wikipedia/Western_long-beaked_echidna |
Zaglossus, from Ancient Greek ζα (za), from διά (diá), meaning "across", and γλῶσσα (glôssa), meaning "tongue", known as the long-beaked echidnas make up one of the two extant genera of echidnas: there are three extant species, all living in New Guinea. They are medium-sized, solitary mammals covered with coarse hair and spines made of keratin. They have short, strong limbs with large claws, and are powerful diggers. They forage in leaf litter on the forest floor, eating earthworms and insects.
The extant species are:
Western long-beaked echidna (Z. bruijni), of the highland forests;
Attenborough's long-beaked echidna (Z. attenboroughi), discovered by Western science in 1961 (described in 1998) and preferring a still higher habitat;
Eastern long-beaked echidna (Z. bartoni), of which four distinct subspecies have been identified.
The Eastern species is listed as vulnerable, while the Attenborough's and western long-beaked echidna species are listed as Critically Endangered by the IUCN.
A number of extinct species were known in the genus, but they are currently treated as members of their own genera, such as Murrayglossus and Megalibgwilia.
== General information ==
The long-beaked echidna is larger-bodied than the short-beaked and has fewer, shorter spines scattered among its coarse hairs. The snout is two-thirds of the head's length and curves slightly downward. There are five digits on both hind and forefeet, but on the former, only the three middle toes are equipped with claws. Like the other species of echidna, long-beaked echidnas have spurs on their hind legs. These spurs are vestigial; part of a repressed venom system akin to the one on the platypus. Male spurs are nonfunctional and females usually lose their spurs as they age.
=== Basal traits ===
The breeding female develops a temporary abdominal brood patch, in which her egg is incubated and in which the newborn young (or puggle) remains in safety as it feeds and develops. Since they reproduce by laying eggs which are incubated outside of the mother's body it is accompanied by the prototherian lactation process, which shows that they are basal mammals. The long-beaked echidna has a short weaning period. During this time milk is their only source of nutrition and protection for the hatchlings; they are altricial and immunologically naive.
The long-beaked echidna's limb posture is sprawled, similar to extant reptiles like lizards and crocodilians. Although the stances between the animal groups are similar, the way the limbs move are very different between the clades. The echidna swings its limbs at a 45 degree angle while a lizard's is more horizontal. They walk with two legs on one side of the body moving in unison.
The long-beaked echidna's walk presents multiple differences from a lizard's. An echidna's walking pattern is more upright than a lizard's, this represents a pattern closer to a parasagittal kind of therian. Echidnas and therians both have a dynamic equilibration rather than a static one.
=== Behavior ===
These echidnas are primarily nocturnal; foraging for its insect food on the forest floor. These animals are not usually found foraging in the daylight. The long-beaked echidna establish and are commonly found in dens or burrows.
A study published in 2015 shows that Zaglossus spp. in captivity exhibited "handedness" when performing certain behaviors related to foraging, locomotion, and male-female interactions. The results of this study suggest that handedness in mammals is a basal trait rather than one derived several times in extant mammals.
Little is known about the life of these rarely seen animals, but it is believed to have habits similar to those of the short-beaked echidna; unlike them, however, the long-beaked echidnas feed primarily on earthworms rather than ants, as they live in much more humid environments than the smaller Tachyglossus echidna. The population of echidnas in New Guinea is declining because of forest clearing and overhunting, and the animal is much in need of protection. In November 2023, a Zaglossus attenboroughi was first recorded alive on video in Indonesia's Cyclops Mountains, the first confirmed sightings of an individual in 62 years.
== Taxonomy ==
=== Zaglossus attenboroughi ===
Habitat: known only from the Cyclops Mountains of Jayapura Regency, Papua, Indonesia
Period: Holocene
Critically endangered
=== Zaglossus bartoni ===
Habitat: on the central cordillera between the Paniai Lakes and the Nanneau Range, as well as the Huon Peninsula
Period: Holocene
Vulnerable
=== Zaglossus bruijni ===
Habitat: highland forests of West Papua and Papua provinces, Indonesia, New Guinea
Period: Holocene
Critically endangered
== See also ==
Fossil monotremes
List of mammal genera
List of recently extinct mammals
List of prehistoric mammals
== References ==
Flannery, T. F.; Groves, C. P. (January 1998). "A revision of the genus Zaglossus (Monotremata, Tachyglossidae), with description of new species and subspecies" (PDF). Mammalia. 62 (3): 367–396. doi:10.1515/mamm.1998.62.3.367. S2CID 84750399. Archived from the original (PDF) on 2006-08-25.
== External links ==
EDGE of Existence (Zaglossus spp.) – Saving the World's most Evolutionarily Distinct and Globally Endangered (EDGE) species
ARKive – images and movies of the long-beaked echidna (Zaglossus spp.)
A summary, including references, on animalinfo.org
(Long Necked) Echidna find rewrites natural history books – 'Mount Anderson, West Kimberley' | Wikipedia/Long-beaked_echidna |
Carbon dioxide angiography is a diagnostic radiographic technique in which a carbon dioxide (CO2) based contrast medium is used - unlike traditional angiography where the contrast medium normally used is iodine based – to see and study the body vessels. Since CO2 is a non-radio-opaque contrast medium, angiographic procedures need to be performed in digital subtraction angiography (DSA).
== History ==
The use of carbon dioxide as a contrast agent goes back to 1920s when the gas was used to visualize retroperitoneal structures. In the 1950s and early 1960s, CO2 was injected intravenously to delineate the right atrium for the detection of pericardial effusion. This imaging technique developed from animal and clinical studies which demonstrated that CO2 was safe and well tolerated with venous injections. In the early 1970s, Dr. Hawkins and Dr. Cho started using and studying CO2 as a contrast agent also for peripheral vascular imaging and intervention. With the advent of digital subtraction angiography (DSA) technique in 1980s, CO2 has evolved into a safe and useful alternative contrast agent in both arteriography and venography. Because of its lack of renal toxicity and allergic potential, CO2 is a preferred contrast agent in patients with renal failure or iodinated contrast medium allergy, and particularly in patients who require large volumes of contrast medium for complex endovascular procedures.
== Technique ==
CO2 angiography is intended only for peripheral procedures. In case of procedures in the arterious system it is allowed to inject CO2 only below the diaphragm; while in the venous system it can also be investigated supradiaphragmatic, provided that the cerebral vessels are excluded. Taking this aspect into consideration, the practical approach follows that of the iodinated contrast procedures. The contrast injection can be carried out, similarly, both with manual devices and with automatic injectors (Automated Carbon Dioxide Angiography, ACDA).
== Properties ==
Being naturally present in the human body, CO2 is the only 100% biocompatible contrast agent, meaning no adverse reactions, such as allergy, nephrotoxicity, and hepatotoxicity.
Carbon dioxide is a negative contrast medium and it has a low radiopacity (while iodinated contrast media are defined as positive contrast media due to their high radiopacity). Contrast is caused by the different X-ray absorption coefficients between the tissue and the contrast agent. In the vascular imaging results produced using CO2, vessels look brighter rather than the surrounding tissues, because the contrast medium absorbs less X-ray radiations rather an iodine-based contrast medium, where the vessel are displayed in black.
The CO2 does not mix with blood. At atmospheric pressure CO2 is in gaseous form and, when it comes out from the catheter, it forms a train of bubbles which displaces blood, causing a transient ischemia, in relation to the bloodstream (systolic pressure). When added together by DSA “stacking” software, the result is a composite diagnostic image of the frames.
Carbon dioxide is highly soluble, allowing multiple injections without a maximum dosage (per procedure, while it is 100 mL per injection by the literature), but, in case of multiple injections, should be considered and adequate time interval between them, so to allow the gas to be expelled from the body. Compared with the oxygen, the most present gaseous substance in the body, CO2 is more than 20 times more soluble, meaning the possibility of injecting high quantities in the body.
High compressibility and explosive delivery. More pressure is exerted to the gas, more its density increases, resulting in a decrease in gas volume and an increase in gas pressure. The effusion of the gas from the catheter orifice into a state of lower pressure, such as a blood vessel, leads to a sudden increase in the volume of the gas - the “explosive delivery” or “jet effect” - which could lead to an excessive stress in vessels walls. To avoid this, immediately prior to the injection of CO2, a flush is performed, injecting small amounts of CO2 to reduce gas compression and guarantee gas delivery at a steady flow rate.
CO2 is 400 times less viscous than iodinated contrast medium, allowing its injection through devices with a very little inner lumen, as microcatheters, or, even, with other devices inserted in the catheter, as guidewires, balloons or as in atherectomy procedures. The low viscosity of CO2 makes it easy to pass through small vessels, visualizing tight stenosis, collaterals, small bleedings and endoleaks in AAA procedures.
Expulsion: Once dissolved in the plasma, CO2 is transported to the lungs and removed in a single pass by the alveoli, favoring the possibility of performing multiple injections without complications (in healthy patients, meaning no severe COPD or significant POF, especially in presence of pulmonary embolism).
Buoyancy is defined as the tendency of a body to float when submerged into a fluid. CO2 is lighter than blood and, therefore, floats above the bloodstream. The main advantage is represented by the simplicity of filling the more superficial (in transverse plane) vessels of the body, conversely the main disadvantage consists in a less ease of filling the deeper ones.
== Side effects ==
Pins and needles/burning sensation, nausea and temporary discomfort are possible sensations during CO2 angiography, mainly because the transient ischemia caused by the CO2 bubbles flowing in the bloodstream. CO2 is also neurotoxic, so brain injections should be avoided. The most feared complication for intravascular use is air embolism, which can result in stroke, myocardial infarction, paralysis, amputation, or death, although this risk across all patients is less than 1%. A large amount of CO2 trapped in the pulmonary artery or right side of the heart (only of concern during venography) obstructs venous return resulting in bradycardia and hypotension. The patient should be rotated into a left lateral decubitus position if this happens to attempt to separate the CO2 into a gas layer floating "on top of" and no longer interfering with the flow of the liquid and solid components of blood (vapor lock). Therefore, having a delivery system, which prevents air room diffusion, is a necessary safety measure for the patients.
== References == | Wikipedia/Carbon_Dioxide_Angiography |
Peripheral artery disease (PAD) is a vascular disorder that causes abnormal narrowing of arteries other than those that supply the heart or brain. PAD can happen in any blood vessel, but it is more common in the legs than the arms.
When narrowing occurs in the heart, it is called coronary artery disease (CAD), and in the brain, it is called cerebrovascular disease. Peripheral artery disease most commonly affects the legs, but other arteries may also be involved, such as those of the arms, neck, or kidneys.
Peripheral artery disease (PAD) is a form of peripheral vascular disease. Vascular refers to the arteries and veins within the body. PAD differs from peripheral veinous disease. PAD means the arteries are narrowed or blocked—the vessels that carry oxygen-rich blood as it moves from the heart to other parts of the body. Peripheral veinous disease, on the other hand, refers to problems with veins—the vessels that bring the blood back to the heart.
The classic symptom is leg pain when walking, which resolves with rest and is known as intermittent claudication. Other symptoms include skin ulcers, bluish skin, cold skin, or abnormal nail and hair growth in the affected leg. Complications may include an infection or tissue death, which may require amputation; coronary artery disease; or stroke. Up to 50% of people with PAD do not have symptoms.
The greatest risk factor for PAD is cigarette smoking. Other risk factors include diabetes, high blood pressure, kidney problems, and high blood cholesterol. PAD is primarily caused by the buildup of fatty plaque in the arteries, which is called atherosclerosis, especially in individuals over 40 years old. Other mechanisms include artery spasm, blood clots, trauma, fibromuscular dysplasia, and vasculitis. PAD is typically diagnosed by finding an ankle-brachial index (ABI) less than 0.90, which is the systolic blood pressure at the ankle divided by the systolic blood pressure of the arm. Duplex ultrasonography and angiography may also be used. Angiography is more accurate and allows for treatment at the same time; however, it is associated with greater risks.
It is unclear if screening for peripheral artery disease in people without symptoms is useful, as it has not been properly studied. For those with intermittent claudication from PAD, stopping smoking and supervised exercise therapy may improve outcomes. Medications, including statins, ACE inhibitors, and cilostazol, may also help. Aspirin, which helps with thinning the blood and thus improving blood flow, does not appear to help those with mild disease but is usually recommended for those with more significant disease due to the increased risk of heart attacks. Anticoagulants (blood thinners) such as warfarin show no definitive scientific evidence of benefit in PAD. Surgical procedures used to treat PAD include bypass grafting, angioplasty, and atherectomy.
In 2015, about 155 million people had PAD worldwide. It becomes more common with age. In the developed world, it affects about 5.3% of 45- to 50-year-olds and 18.6% of 85- to 90-year-olds. In the developing world, it affects 4.6% of people between the ages of 45 and 50 and 15% of people between the ages of 85 and 90. PAD in the developed world is equally common among men and women, though in the developing world, women are more commonly affected. In 2015, PAD resulted in about 52,500 deaths, which is an increase from the 16,000 deaths in 1990.
== Signs and symptoms ==
The signs and symptoms of peripheral artery disease are based on the affected body part. About 66% of patients affected by PAD either do not have symptoms or have atypical symptoms. The most common presenting symptom is intermittent claudication (IC), which typically refers to lower extremity skeletal muscle pain that occurs during exercise. IC presents when there is insufficient oxygen delivery to meet the metabolic requirements of the skeletal muscles. IC is a common manifestation of peripheral arterial disease (PAD). The pain is usually located in the calf muscles of the affected leg and is relieved by rest. This occurs because during exercise, the muscles require more oxygen. Normally, the arteries would be able to increase the amount of blood flow and therefore increase the amount of oxygen going to the exercised muscle. However, in PAD, the artery cannot respond appropriately to the increased muscular demand for oxygen. Therefore, the muscles are deprived of oxygen, leading to muscle pain that subsides with rest.
Other symptoms may include:
Pain, aches, and/or cramps in the buttocks, hip, or thigh
Muscle atrophy (muscle loss) of the affected limb
Hair loss of the affected limb
Skin that is smooth, shiny, or cool to the touch in the affected area
Decreased or absent pulse in the feet
Cold and/or numbness in the toes
Sores/ulcers on the affected limb that do not heal
In individuals with severe PAD, complications may arise, including critical limb ischemia and gangrene. Critical limb ischemia occurs when the obstruction of blood flow in the artery is compromised to the point where the blood cannot maintain oxygenation of the tissue at rest. This can lead to pain at rest, a feeling of coldness, or numbness in the affected foot and toes. Other complications of severe PAD include lower limb tissue loss (amputation), arterial insufficiency ulcers, erectile dysfunction, and gangrene. People with diabetes are affected by gangrene of the feet at a rate that is 30 times higher than the unaffected population. Many of these severe complications, such as those leading to amputation, are irreversible.
== Causes ==
=== Risk factors ===
Factors contributing to an increased risk of PAD are the same as those for atherosclerosis. These include age, sex, and ethnicity. PAD is twice as common in males as in females. In terms of ethnicity, PAD is more common in people of color compared to the white population in a 2:1 ratio. The factors with the greatest risk associations are hyperlipidemia, hypertension, diabetes mellitus, chronic kidney disease, and smoking. Presenting three of these factors or more increases the risk of developing PAD tenfold.
Smoking – Tobacco use in any form is the single greatest risk factor for peripheral artery disease internationally. Smokers have up to a 10-fold increase in the risk of PAD in a dose-response relationship. Exposure to second-hand smoke has also been shown to promote changes in the lining of blood vessels (endothelium), which can lead to atherosclerosis. Smokers are 2–3 times more likely to have lower extremity PAD than coronary artery disease. Greater than 80%–90% of patients with lower extremity peripheral arterial disease are current or former smokers. The risk of PAD increases with the number of cigarettes smoked per day and the number of years smoked.
High blood sugar – Diabetes mellitus is shown to increase the risk of PAD by 2–4 fold. It does this by causing endothelial and smooth-muscle cell dysfunction in peripheral arteries. The risk of developing lower extremity peripheral arterial disease is proportional to the severity and duration of diabetes.
High blood cholesterol – Dyslipidemia is an unhealthy pattern of cholesterol or fat in the blood. Dyslipidemia is characterized by a high level of a protein called low-density lipoprotein (LDL cholesterol), low levels of high-density lipoprotein (HDL cholesterol), elevation of total cholesterol, and/or high triglyceride levels. This abnormality in blood cholesterol levels has been correlated with accelerated peripheral artery disease. Management of dyslipidemia by diet, exercise, and/or medication is associated with a major reduction in rates of heart attack and stroke.
High blood pressure – Hypertension or elevated blood pressure can increase a person's risk of developing PAD. Similarly to PAD, there is a known association between high blood pressure and heart attacks, strokes, and abdominal aortic aneurysms. High blood pressure increases the risk of intermittent claudication, the most common symptom of PAD, by 2.5- to 4-fold in men and women, respectively.
Other risk factors that are being studied include levels of various inflammatory mediators such as C-reactive protein, fibrinogen, homocysteine, and lipoprotein A. Individuals with increased levels of homocysteine in their blood have a 2-fold risk of developing peripheral artery disease. While there are genetic factors leading to risk factors for peripheral artery disease, including diabetes and high blood pressure, there have been no specific genes or gene mutations directly associated with the development of peripheral artery disease.
=== High risk populations ===
Peripheral arterial disease is more common in these populations:
All people who have leg symptoms with exertion (suggestive of claudication) or ischemic rest pain
All people aged 65 years and over, regardless of risk factor status
All people between 50 and 69 who have a cardiovascular risk factor (particularly diabetes or smoking)
Age less than 50 years, with diabetes and one other atherosclerosis risk factor (smoking, dyslipidemia, hypertension, or hyperhomocysteinemia)
Individuals with an abnormal lower extremity pulse examination
Those with known atherosclerotic coronary, carotid, or renal artery disease
All people with a Framingham risk score of 10%–20%
All people who have previously experienced chest pain
== Etiology and pathophysiology ==
Peripheral arterial disease is considered to be a set of chronic or acute syndromes, generally derived from the presence of occlusive arterial disease, which causes inadequate blood flow to the limbs.
As previously mentioned, the most common etiology of peripheral artery disease, especially in patients over 40 years old, is atherosclerosis. Atherosclerosis is a narrowing of the arteries caused by lipid or fat buildup and calcium deposition in the wall of the affected arteries.
The pathophysiology of atherosclerosis involves complex interactions between cholesterol and vascular cells. In the early stages of PAD, the arteries compensate for plaque buildup by dilating to preserve flow through the vessel. Eventually, the artery cannot dilate further, and the atherosclerotic plaque narrows the arterial flow lumen.
When there is an imbalance between the needs of the peripheral tissues and the blood supply, the affected person is faced with ischemia.
From the pathophysiologic point of view, a restriction of blood supply (ischemia) to the lower limbs can be classified as either functional or critical. Functional ischemia occurs when the blood flow is normal at rest but insufficient during exercise, presenting clinically as intermittent claudication. Critical ischemia is produced when the reduction in blood flow results in a perfusion deficit at rest and is defined by the presence of pain at rest or trophic lesions in the legs. In this situation, precise diagnosis is fundamental, as there is a clear risk of limb loss if adequate blood flow is not re-established, either by surgery or endovascular therapy. Differentiating between the two concepts is important to establish the therapeutic indication and the prognosis in patients with PAD.
Other causes include vasculitis and in situ thrombosis related to hypercoagulable states. Additional mechanisms of peripheral artery disease include arterial spasm and fibromuscular dysplasia. The cause and pathophysiology of arterial spasm are not fully understood, but it is hypothesized that they can occur secondary to trauma. The symptoms of claudication ensue when the artery spasms, or clamps down on itself, creating an obstruction. Like atherosclerosis, this leads to decreased blood flow to the tissue downstream of the obstruction. Thrombosis, or the formation of a blood clot, usually occurs due to stasis or trauma.
== Diagnosis ==
Diagnosing or identifying peripheral artery disease requires a history of symptoms and a physical exam, followed by confirmatory testing. These tests could include CT scans (Computed Tomographic Angiography), MRA scans (Magnetic Resonance Angiography), or ultrasounds for imaging. A physician will examine an individual for specific exam findings if symptoms are consistent with peripheral artery disease. Abnormal physical exam findings can lead a healthcare provider to consider the diagnosis. However, to confirm a diagnosis, confirmatory testing is required.
These findings are associated with peripheral artery disease:
Decreased or absent pulses
Muscle atrophy or wasting
Noticeable blueness of the affected limb
Decreased temperature (coolness) in the affected limb when compared to the other
Thickened nails
Smooth or shiny skin and hair loss
Buerger's test can check for pallor when the affected limb is in an elevated position. The limb is then moved from an elevated to a sitting position and checked for redness, which is called reactive hyperemia. Buerger's test is an assessment of arterial sufficiency, which is the ability of the artery to supply oxygenated blood to the tissue that it goes to.
Nonhealing lower extremity wound
If peripheral artery disease is suspected, the initial study is the ankle–brachial index (ABI). The ABI is a simple, non-invasive test that measures the ratio of systolic blood pressure in the ankle to the systolic blood pressure in the upper arm. This is based on the idea that if blood pressure readings in the ankle are lower than those in the arm, a blockage in the arteries that provide blood from the heart to the ankle is suspected. An ABI range of 0.90 to 1.40 is considered normal. A person is considered to have PAD when the ABI is ≤ 0.90. However, PAD can be further graded as mild to moderate if the ABI is between 0.41 and 0.90, and severe if the ABI is less than 0.40. These categories can provide insight into the disease course. Furthermore, ABI values of 0.91 to 0.99 are considered borderline, and values >1.40 indicate noncompressible arteries. If an ABI >1.40 is calculated, this could indicate vessel wall stiffness caused by calcification, which can occur in people with uncontrolled diabetes. Abnormally high ABIs (>1.40) are usually considered false negatives, and thus, such results merit further investigation and higher-level studies. Individuals with noncompressible arteries have an increased risk of cardiovascular mortality within two years.
Individuals with suspected PAD with normal ABIs can undergo exercise testing for ABI. A baseline ABI is obtained before exercise. The patient is then asked to exercise (usually patients are made to walk on a treadmill at a constant speed) until claudication pain occurs (for a maximum of 5 minutes), after which the ankle pressure is again measured. A decrease in ABI of 15%–20% would be diagnostic of PAD.
If ABIs are abnormal, the next step is generally a lower limb Doppler ultrasound to look at the site of obstruction and the extent of atherosclerosis. Other imaging can be performed by angiography, where a catheter is inserted into the common femoral artery and selectively guided to the artery in question. While injecting a radio-dense contrast agent, an X-ray is taken. Any blood flow-limiting blockage found in the X-ray can be identified and treated by procedures including atherectomy, angioplasty, or stenting. Contrast angiography is the most readily available and widely used imaging technique. Modern computerized tomography (CT) scanners provide direct imaging of the arterial system. Studies have shown the sensitivity and specificity of CT in identifying lesions with >50% stenosis to be 95% and 96%, respectively. As such, CT may be considered as an alternative to invasive angiography. An important distinction between the two is that, unlike invasive angiography, assessment of the arterial system with CT does not allow for vascular intervention.
Magnetic resonance angiography (MRA) is a noninvasive diagnostic procedure that uses a combination of a large magnet, radio frequencies, and a computer to produce detailed images of blood vessels inside the body. The advantages of MRA include its safety and ability to provide high-resolution, three-dimensional imaging of the entire abdomen, pelvis, and lower extremities in one sitting.
=== Classification ===
The two most commonly used methods to classify peripheral artery disease are the Fontaine and Rutherford classification systems. The Fontaine stages were introduced by René Fontaine in 1954 to define the severity of chronic limb ischemia:
Stage I: asymptomatic
Stage IIa: intermittent claudication after walking a distance of more than 200 meters
Stage IIb: intermittent claudication after walking a distance of less than 200 meters
Stage III: rest pain
Stage IV: ulcers or gangrene of the limb
The Rutherford classification was created by the Society for Vascular Surgery and the International Society of Cardiovascular Surgery, introduced in 1986 and revised in 1997 (and known as the Rutherford classification after the lead author, Robert B. Rutherford). This classification system consists of four grades and seven categories (categories 0–6):
Grade 0, Category 0: asymptomatic
Grade I, Category 1: mild claudication
Grade I, Category 2: moderate claudication
Grade I, Category 3: severe claudication
Grade II, Category 4: rest pain
Grade III, Category 5: minor tissue loss; ischemic ulceration not exceeding ulcer of the digits of the foot
Grade IV, Category 6: major tissue loss; severe ischemic ulcers or frank gangrene
Moderate to severe PAD, classified by Fontaine's stages III to IV or Rutherford's categories 4 to 5, presents a limb threat (risk of limb loss) in the form of critical limb ischemia.
Recently, the Society for Vascular Surgery came out with a classification system based on "wound, ischemia and foot infection" (WIfI). This classification system, published in 2013, was created to account for the demographic changes that have occurred over the past forty years, including the increased incidence of high blood sugar and evolving techniques and abilities for revascularization. This system was created on the basis that ischemia and angiographic disease patterns are not the sole determinants of amputation risk. The WIfI classification system is broken up into two parts: wounds and ischemia. Wounds are graded 0 through 3 based on the presence of ulceration, gangrene, and ischemia.
Grade 0: no ulcer, no gangrene
Grade 1: small, shallow ulcer; no gangrene
Grade 2: deep ulcer with exposed tendon or bone, gangrene limited to toes
Grade 3: extensive, full-thickness ulcer; gangrene extending to the forefoot or midfoot
Ischemia is graded 0 through 3 based on ABI, ankle systolic pressure, and toe pressure.
Grade 0: ABI ≥0.80, ankle systolic pressure ≥100 mm Hg, toe pressure ≥60 mm Hg
Grade 1: arterial brachial index 0.6 to 0.79, ankle systolic pressure 70 to 100 mm Hg, toe pressure 40 to 59 mm Hg
Grade 2: ABI 0.4–0.59, ankle systolic pressure 50 to 70 mm Hg, toe pressure 30 to 39 mm Hg
Grade 3: ABI ≤0.39, ankle systolic pressure <50 mm Hg, toe pressure <30 mm Hg
The TASC (and TASC II) classification suggests PAD treatment is based on the severity of the disease seen on an angiogram.
=== Screening ===
It is unclear if screening for disease in the general population is useful, as it has not been extensively studied. This includes screening with the ankle-brachial index (ABI), although a systematic review of the literature did not support the use of routine ABI screening in asymptomatic patients.
Testing for coronary artery disease or carotid artery disease is of unclear benefit. While PAD is a risk factor for abdominal aortic aneurysms (AAA), there is no data on screening individuals with asymptomatic PAD for abdominal aortic aneurysms. For people with symptomatic PAD, screening by ultrasound for AAA is not unreasonable.
=== Wearable devices and remote patient monitoring ===
A 2022 review found that a variety of wearable medical devices measuring different parameters (such as body temperature) were being combined with remote patient monitoring of PAD patients, to improve health outcomes.
Some studies propose the development of devices measuring oxygen continuously during exercise. This is because resting perfusion and metabolic activity are extremely low and differences between non-patients and PAD patients are barely measurable. As such, testing of vascular function and energetics requires a physiological challenge. Pulse oximeters can be inconvenient to wear during exercise and only give oxygen values at discrete time points, nor is there sufficient evidence to support any use in identifying PAD. Some publications and studies therefore discuss the use of wearable sensors measuring oxygen levels continuously in PAD patients, such as through transcutaneous means. However, because transcutaneous measurements are affected by movement (such as during exercise) and body temperature, the use of oxygen sensors that are inserted subcutaneously as opposed to transcutaneously may most effectively help monitor a PAD patient's progress and direct therapy decisions. To date, one oxygen sensing system has been approved for use in Europe to measure tissue perfusion in all PAD patients.
== Treatment ==
Depending on the severity of the disease, these steps can be taken, according to these guidelines:
=== Lifestyle ===
Stopping smoking (cigarettes promote PAD and are a risk factor for cardiovascular disease)
Regular exercise for those with claudication helps open up alternative small vessels (collateral flow), and the limitation in walking often improves. Treadmill exercise (35 to 50 minutes, three or four times per week) has been reviewed as another treatment with several positive outcomes, including a reduction in cardiovascular events and improved quality of life. Supervised exercise programs increase pain-free walking time and the maximum walking distance in people with PAD.
=== Medication ===
Management of diabetes
Management of hypertension
Management of high cholesterol, and antiplatelet drugs such as aspirin and clopidogrel. Statins reduce clot formation and cholesterol levels, respectively, and can help with disease progression and address the other cardiovascular risks that the affected person is likely to have.
According to guidelines, taking aspirin or clopidogrel is recommended to reduce AMI ("heart attack"), stroke, and other causes of vascular death in people with symptomatic peripheral artery disease. It is recommended that aspirin and clopidogrel be taken alone and not in conjunction with one another (i.e., not as dual antiplatelet therapy). The recommended daily dosage of aspirin for treating PAD is between 75 and 325 mg, while the recommended daily dosage for clopidogrel is 75 mg. The effectiveness of both aspirin and clopidogrel to reduce the risk of cardiovascular ischemic events in people with symptomatic PAD is not well established. Research also suggests that low-dose rivaroxaban plus aspirin is effective as a new anti-thrombotic regimen for PAD.
Cilostazol can improve symptoms in some people. Pentoxifylline is of unclear benefit. Cilostazol may improve walking distance for people who experience claudication due to peripheral artery disease, but no strong evidence suggests that it improves the quality of life, decreases mortality, or decreases the risk of cardiovascular events.
Treatment with other drugs or vitamins is unsupported by clinical evidence, "but trials evaluating the effect of folate and vitamin B12 on hyperhomocysteinemia, a putative vascular risk factor, are near completion".
=== Revascularization ===
After a trial of the best medical treatment outlined above, if symptoms persist, patients may be referred to a vascular or endovascular surgeon. The benefit of revascularization is thought to correspond to the severity of ischemia and the presence of other risk factors for limb loss, such as wound and infection severity.
Angioplasty (or percutaneous transluminal angioplasty) can be done on solitary lesions in large arteries, such as the femoral artery, but may not have sustained benefits. Patency rates following angioplasty are highest for iliac arteries and decrease with arteries towards the toes. Other criteria that affect the outcome following revascularization are the length of the lesion and the number of lesions. There do not appear to be any long-term advantages or sustained benefits to placing a stent following angioplasty in order to hold the narrowing of the subsartorial artery open.
Atherectomy, in which the plaque is scraped off the inside of the vessel wall (albeit with no better results than angioplasty).
Vascular bypass grafting can be performed to circumvent a diseased area of the arterial vasculature. The great saphenous vein is used as a conduit if available, although artificial (Gore-Tex or PTFE) material is often used for long grafts when adequate venous conduit is unavailable.
When gangrene has set in, amputation may be required to prevent infected tissues from causing sepsis, a life-threatening illness.
Thrombolysis and thrombectomy are used in cases of arterial thrombosis or embolism.
shockwave intravascular lithotripsy, a minimally invasive method that uses ultrasound waves to break up plaque within the artery without the need for penetration. The method was first approved by the US Food and Drug Administration in February 2021, and has been used as a complement to more widely-used methods of atherectomy.
=== Guidelines ===
A guideline from the American College of Cardiology and American Heart Association for the diagnosis and treatment of lower extremity, renal, mesenteric, and abdominal aortic PAD was compiled in 2013, combining the 2005 and 2011 guidelines. For chronic limb-threatening ischemia, the ACCF/AHA guidelines recommend balloon angioplasty only for people with a life expectancy of 2 years or less or those who do not have an autogenous vein available. For those with a life expectancy greater than 2 years or who have an autogenous vein, bypass surgery is recommended.
== Prognosis ==
Individuals with PAD have an "exceptionally elevated risk for cardiovascular events and the majority will eventually die of a cardiac or cerebrovascular etiology". Prognosis is correlated with the severity of the PAD as measured by an ABI. Large-vessel PAD increases mortality from cardiovascular disease significantly. PAD carries a greater than "20% risk of a coronary event in 10 years".
The risk is low that an individual with claudication will develop severe ischemia and require amputation, but the risk of death from coronary events is three to four times higher than matched controls without claudication. Of patients with intermittent claudication, only "7% will undergo lower-extremity bypass surgery, 4% major amputations, and 16% worsening claudication", but stroke and heart attack events are elevated, and the "5-year mortality rate is estimated to be 30% (versus 10% in controls)".
== Epidemiology ==
The prevalence of PAD in the general population is 3–7%, affecting up to 20% of those over 70; 70%–80% of affected individuals are asymptomatic; only a minority ever require revascularization or amputation. Peripheral artery disease affects one in three diabetics over the age of 50. In the US, it affects 12–20 percent of Americans age 65 and older. Around 10 million Americans have PAD. Despite its prevalence and implications for cardiovascular risk, there are still low levels of awareness of risk factors and symptoms, with 26% of the population in the US reported to have knowledge of PAD.
In 2000, among people aged 40 years and older in the United States, rates of PAD were 4.3%. Rates were 14.5% for people aged 70 years or over. Within age groups, rates were generally higher for women than men. Non-Hispanic blacks had a rate of 7.9% compared to 4.4% in Non-Hispanic whites and 3.0% (1.4%–4.6%) in Mexican Americans.
The incidence of symptomatic PAD increases with age, from about 0.3% per year for men aged 40–55 years to about 1% per year for men aged over 75 years. The prevalence of PAD varies considerably depending on how PAD is defined and the age of the population being studied. People diagnosed with PAD have a greater risk of a MACE (Major Adverse Cardiac Event) and stroke. Their risk of developing a reinfarction, stroke, or transient ischemic attack within one year following a heart attack increases to 22.9%, compared to 11.4% for those without PAD.
The Diabetes Control and Complications Trial and the UK Prospective Diabetes Study trials in people with type 1 and type 2 diabetes, respectively, demonstrated that glycemic control is more strongly associated with microvascular disease than macrovascular disease. Pathologic changes occurring in small vessels may be more sensitive to chronically elevated glucose levels than atherosclerosis occurring in larger arteries.
== Research ==
Research is being done on therapies to prevent the progression of PAD. In those who have developed critically poor blood flow to the legs, the benefit of autotransplantation of autologous mononuclear cells is unclear.
Only one randomized controlled trial has been conducted comparing vascular bypass to angioplasty for the treatment of severe PAD. The trial found no difference in amputation-free survival between vascular bypass and angioplasty at the planned clinical endpoint, but the trial has been criticized as being underpowered, limiting endovascular options, and comparing inappropriate endpoints. As of 2017, two randomized clinical trials are being conducted to better understand the optimal revascularization technique for severe PAD and critical limb ischemia (CLI), the BEST-CLI (Best Endovascular Versus Best Surgical Therapy for Patients With Critical Limb Ischemia) Trial and the BASIL-2 (Bypass Versus Angioplasty in Severe Ischaemia of the Leg – 2 )Trial.
In 2011, pCMV-vegf165 was registered in Russia as the first-in-class gene therapy drug for the treatment of PAD, including the advanced stage of critical limb ischemia.
== References ==
== External links ==
"Peripheral Arterial Disease" at the National Heart, Lung and Blood Institute
Peripheral Arterial Disease (P.A.D.) at the American College of Foot and Ankle Surgeons
Gerhard-Herman MD, Gornik HL, Barrett C, Barshes NR, Corriere MA, Drachman DE, et al. (March 2017). "2016 AHA/ACC Guideline on the Management of Patients With Lower Extremity Peripheral Artery Disease: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines". Circulation. 135 (12): e686 – e725. doi:10.1161/CIR.0000000000000470. PMC 5479414. PMID 27840332. | Wikipedia/Peripheral_artery_occlusive_disease |
Digital subtraction angiography (DSA) is a fluoroscopy technique used in interventional radiology to clearly visualize blood vessels in a bony or dense soft tissue environment. Images are produced using contrast medium by subtracting a "pre-contrast image" or mask from subsequent images, once the contrast medium has been introduced into a structure. Hence the term "digital subtraction angiography. Subtraction angiography was first described in 1935 and in English sources in 1962 as a manual technique. Digital technology made DSA practical starting in the 1970s.
== Procedure ==
=== DSA and fluoroscopy ===
In traditional angiography, images are acquired by exposing an area of interest with time-controlled x-rays while injecting a contrast medium into the blood vessels. The image obtained includes the blood vessels, together with all overlying and underlying structures. The images are useful for determining anatomical position and variations, but unhelpful for visualizing blood vessels accurately.
In order to remove the distracting structures to see the vessels better, first a mask image is acquired. The mask image is simply an image of the same area before the contrast is administered. The radiological equipment used to capture this is usually an X-ray image intensifier, which then keeps producing images of the same area at a set rate (1 to 7.5 frames per second). Each subsequent image gets the original "mask" image subtracted out. (Mathematically, the incoming image is divided by the mask image) The radiologist controls how much contrast media is injected and for how long. Smaller structures require less contrast to fill the vessel than others. Images produced appear with a very pale grey background, which produces a high contrast to the blood vessels, which appear a very dark grey.
=== Intravenous digital subtraction angiography ===
Intravenous digital subtraction angiography (IV-DSA) is a form of angiography which was first developed in the late 1970s.
IV-DSA is a computer technique that compares an X-ray image of a region of the body before and after radiopaque iodine based dye has been injected intravenously into the body. Tissues and blood vessels on the first image are digitally subtracted from the second image, leaving a clear picture of the artery which can then be studied independently and in isolation from the rest of the body.
Some limited studies have indicated that IV-DSA is not suitable for patients with diabetes or kidney failure because the dye load is significantly higher than that used in arteriography. However, IV-DSA has been used successfully to study the vessels of the brain and heart and has helped detect carotid artery obstruction and to map patterns of cerebral blood flow. It also helps detect and diagnose lesions in the carotid arteries, a potential cause of strokes.
IV-DSA has also been useful in assessing patients prior to surgery and after coronary artery bypass surgery and some transplant operations.
== Applications ==
DSA is primarily used to image blood vessels. It is useful in the diagnosis and treatment of arterial and venous occlusions, including carotid artery stenosis, pulmonary embolisms, and acute limb ischaemia; arterial stenosis, which is particularly useful for potential kidney donors in detecting renal artery stenosis (DSA is the gold standard investigation for renal artery stenosis); cerebral aneurysms and arteriovenous malformations (AVM).
== The future ==
DSA is done less routinely in imaging departments. It is being replaced by computed tomography angiography (CTA), which can produce 3D images through a test which is less invasive and stressful for the patient, and magnetic resonance angiography (MRA), which avoids X-rays and nephrotoxic contrast agents.
== See also ==
Angiography
Computed tomography angiography (CTA)
Contrast medium
Peripheral artery disease
X-ray image intensifier
Digital variance angiography (DVA)
== References ==
== Further reading ==
Anagnostakos, Nicholas Peter; Tortora, Gerard J. (1990). Principles of Anatomy and Physiology. San Francisco: Harper & Row. ISBN 0-06-046694-4. | Wikipedia/Intravenous_digital_subtraction_angiography |
A specific branch of contrast-enhanced ultrasound, acoustic angiography is a minimally invasive and non-ionizing medical imaging technique used to visualize vasculature. Acoustic angiography was first developed by the Dayton Laboratory at North Carolina State University and provides a safe, portable, and inexpensive alternative to the most common methods of angiography such as Magnetic Resonance Angiography and Computed Tomography Angiography. Although ultrasound does not traditionally exhibit the high resolution of MRI or CT, high-frequency ultrasound (HFU) achieves relatively high resolution by sacrificing some penetration depth. HFU typically uses waves between 20 and 100 MHz and achieves resolution of 16-80μm at depths of 3-12mm. Although HFU has exhibited adequate resolution to monitor things like tumor growth in the skin layers, on its own it lacks the depth and contrast necessary for imaging blood vessels. Acoustic angiography overcomes the weaknesses of HFU by combining contrast-enhanced ultrasound with the use of a dual-element ultrasound transducer to achieve high resolution visualization of blood vessels at relatively deep penetration levels.
Acoustic angiography is performed by first injecting specially designed microbubbles with a low resonant frequency into the vessels. Next, a low-frequency transducer element with good depth penetration is used to send ultrasound waves into the sample at the resonant frequency of the microbubbles. This will generate a response from the microbubbles consisting of subharmonic, fundamental, and super-harmonic frequencies, as well as a response from the surrounding tissue consisting of only the fundamental and second-harmonic frequencies. Finally, a high-frequency transducer with high resolution is used to measure the super-harmonic frequencies, effectively removing any background signal from the microbubble signal, and allowing the vessels to be visualized
== Background ==
Angiography, or the examination of blood vessels, is essential in many areas of research and clinical practice. In particular, angiography is needed to monitor angiogenesis, which is the growth and development of new blood vessels. Angiogenesis is an essential process which is most often observed in organ growth in fetuses and children, the development of the placenta in adults, and wound healing. However, excessive angiogenesis has been observed in dozens of disorders, including diabetes, endometriosis, autoimmune disease, and asthma. Angiography has been used in the research, diagnosis, and treatment of many of these disorders. Perhaps the most important application of angiography for monitoring angiogenesis is in tumor growth. Tumors can exist for months or even years in a non-angiogeneic stage of development and only begin rapid growth once the angiogenic phenotype is expressed. Thus, angiogenesis has become a target for certain cancer therapies. Some therapies aim to promote organized development of blood vessels in tumor regions, which allows for more homogenous and effective distribution of chemotherapy. Other methods aim to block the start or progression of angiogenesis altogether. In both cases, angiography is essential for measuring the growth, recession, or shape of blood vessels in-vivo over time during these treatments and related research
Currently, the most common techniques used for angiography are X-ray CT and MRI. However, many other methods are used for performing angiography in special circumstances, such as the use of optical coherence tomography for performing angiography during retinal exams. MRI angiography provides the highest resolution of the current angiographic methods and can often be performed without the use of contrast agents by modifying the pulse sequence to visualize aspects of the vessels such as blood flow. On the other hand, x-ray CT angiography requires the use of a contrast agent, but still maintains relatively high resolution. Despite the high quality images produced by both of these techniques, there remain significant drawbacks. Both are relatively slow and require expensive equipment, while x-ray CT also exposes patients to potentially harmful ionizing radiation. Thus, there is still a need for an inexpensive, portable, and safe candidate for angiography. Acoustic angiography is able to fill this need. By using microbubbles as a contrast agent and a dual-element transducer for signal identification, acoustic angiography achieves depth, vessel contrast, and resolution not possible with other ultrasound techniques.
== Ultrasound contrast agents ==
Ultrasound contrast agents are particles used in ultrasound scans to improve image contrast. The first reported use of an ultrasound contrast agent was by Dr. Raymond Gramiak and Pravin Shah in 1968, when they injected saline into the aortic root of the heart and observed increased contrast. They hypothesized that the increase in contrast was a result of "mini bubbles produced by the rapid injection rate or possibly included in the contrast medium". Although most ultrasound contrast agents take the form of microbubbles, other types exist, such as perfluorocarbon nanoparticles or echogenic liposomes.
=== Components ===
Microbubble contrast agents generally have three main components:
Inner Gas: The gas inside the microbubble is generally air or a perfluorocarbon.
Lipid Shell: This shell serves to enclose the gas within it and is always made of lipids due to their hydrophobic property
Ligands: In the case of actively targeted microbubbles, ligands are attached to the outer surface of the lipid shell. These ligands are specific to membrane receptors in the body, and can be used to target certain physiological processes (such as inflammation) or organs. In the case of passively targeted microbubbles, no ligands are attached to the outer shell, and instead the microbubbles rely on factors such as surface charge in order to adhere to the endothelium.
=== Mechanism of contrast ===
Microbubbles work as contrast agents in ultrasound for two main reasons: The large difference in acoustic impedance between body tissues and the microbubbles and their quality of having a resonant frequency generally under 10 MHz. Due to the larger mismatch in acoustic impedances, the microbubbles are near-perfect reflectors of ultrasound waves in the body. This allows them to be point-sources of acoustic waves. Furthermore, at their resonant frequency, the microbubbles have a relatively large-magnitude broadband frequency response, which is picked up by the ultrasound transducer.
== Microbubble signal identification ==
In classical contrast-enhanced ultrasound, many methods exist for separating signal reflected by the microbubbles and signal reflected by surrounding body tissues. Most of these methods utilize the subharmonic and super harmonic response of the microbubbles, as well as the microbubbles nonlinear response to ultrasound waves, as opposed to body tissues linear response to ultrasound waves. Some of the more common filtering methods are listed below.
Subharmonic filtering: This works by filtering out all signals but the subharmonic signals. Since tissue generally does not have a subharmonic response, only the microbubble signal remains. However, since this filters for the low-frequency signals, the resolution is slightly degraded as spatial resolution in ultrasound is dependent on the acoustic frequency.
Super harmonic filtering: Similar to subharmonic filtering, this works by filtering all but the super harmonic frequencies, which are mostly emitted by the microbubbles and not surrounding tissue. Unlike subharmonic filtering, the resolution is actually improved since only the high-frequency response is received. However, most clinical transducers do not have the wide bandwidth necessary to be able to accomplish this.
Phase inversion: This filtering method utilizes the characteristically nonlinear response of the microbubbles to ultrasound waves. Here, nonlinear response means that the phase and magnitude of the acoustic wave reflected by the microbubble do not have a linear relationship with the phase and magnitude of the excitatory acoustic wave. In this method, two pulses with opposite phase are emitted by the transducer. The linear response of tissue will cause mostly destructive interference of the opposite-phased waves, while the nonlinear response of microbubbles will allow some signal to pass through.
With the creation of a dual-element transducer, these filtering methods are no longer critical. This is what distinguishes acoustic angiography from the more generic contrast-enhanced ultrasound. An element centered at a low frequency serves to excite the microbubbles at their resonant frequency, while an element centered at a high frequency receives the super harmonic response of the microbubbles. Since the tissue is excited by the low frequency input and does not produce a high frequency response, the only response received by the dual-element transducer is that originating from the microbubbles. Thus, little to no signal processing is necessary to remove tissue signal from the acquired data.
Because the inner element is receive only while the outer element is transmit only, special materials can be chosen to optimize the efficiency and sensitivity of this process. Lead Zirconate Titanate (PZT) works well as a material choice for the transmitting element because it has a high transmitting constant (d = 300 x 10^-12 m/V) while Polyvinylidene Fluoride (PVDF) works well as a material for the receiving element because it has a high receiving constant (g = 14 x 10^-2 Vm/N). Generally, PVDF is not a good choice for an ultrasound transducer because it has a relatively poor transmitting constant, however, since acoustic angiography separates the transmitting and receiving elements, this is no longer an issue.
== Image formation ==
=== Data acquisition ===
As acoustic angiography uses a dual-element ultrasonic transducer in the format of a focused ultrasound probe, it is not feasible to form an array of transducers as can be done in other forms of ultrasound imagining. Thus acoustic angiography images are formed by combining multiple a-mode images where each a-mode is a one-dimensional image identifying the acoustic boundaries along a vector originating at the transducer.
In order to form two or three dimensional images, the position and angle of the transducer and the resulting a-mode image must be mechanically manipulated. Two common configurations used to acquire these a-mode images include the wobbler configuration and mechanical sweep configuration.
In the wobbler configuration, the probe is rotated back and forth about a central axis in one plane so that the a-scans are radially oriented and the field of view, or region that is able to be imaged, is a cone. This allows for very quick acquisition of a-scans, but has nonhomogeneous resolution as the distance between each point on neighboring a-scans increases with depth.
In the linear sweep configuration, the ultrasound probe is mechanically moved, either by an external mechanism or hand, in a direction orthogonal to the direction of the a-scan. This configuration allows relatively consistent resolution as a function of depth as each point on neighboring a-scans is equidistant.
Once data has been collected as described above, it can be processed to form a variety of image types including projections and volumetric reconstruction.
=== Projection ===
Projection images in ultrasound are similar in concept to projection radiography. However, instead of projecting the degree of absorbance of X-ray photons along a given path, projection images in ultrasound generally project the mismatch of acoustic impedance and the location along a given boundary in tissue.
==== Maximum amplitude projection ====
The maximum amplitude projection or the maximum intensity projection is an image processing technique used to project three dimensional data onto a two dimensional image. This is a valuable tool as it allows the complex data to be formed into more readily understandable images that include the perception of depth.
In many forms of ultrasound imaging and photoacoustic imaging, the maximum amplitude of the signal along a given a-scan is used as the value for a pixel associated with that a-scan. As acoustic wave experience distance-dependent acoustic attenuation, the amplitude of a given signal along a given a-scan also encodes the distance to the object that generated that signal.
This simple image reconstruction technique allows for easily formed and interpretable projection images formed from acoustic signals.
==== Volumetric renderings ====
Volumetric renderings convert volumetric data into projection images. Most methods use data acquired in lower dimensions to generate voxels, volumetric pixels, that can form 3D images when combined.
=== Volumetric reconstruction ===
Volume reconstruction techniques are used to convert multiple 1D or 2D images into 3D volumes. Common volume reconstruction techniques include pixel-nearest-neighbors, voxel-nearest-neighbors, distance-weighted voxels, and function based methods used to statistically infer the value of a given voxel.
== Applications ==
As acoustic angiography is currently under development, this specific branch of contrast-enhanced ultrasound is not currently used in clinical settings. The majority of the previous work using acoustic angiography has studied angiogenesis in animal models for research purposes.
Though the FDA has only approved contrast-enhanced ultrasound use in one clinical application in the United States, echocardiography, the broader technique has been used throughout Europe and Asia to great success in a variety of clinical applications. To learn more, see the current applications of contrast enhanced ultrasound.
=== Currently investigated clinical uses ===
The only use of acoustic angiography that has been investigated in clinical settings to date studied angiogenesis in the peripheral vasculature of human breast tissue. This study investigated if acoustic angiography could be used to reduce the need for biopsy of breast tissue when diagnosing if lesions in breast tissue were cancerous or not.
Using acoustic angiography, the authors collected and reconstructed the 3D volumes associated with vasculature surrounding lesions in the breast. These reconstructed volumes were then analyzed for vascular density and tortuosity. This information is useful for diagnosis as it has been shown that when these two factors increase in the vasculature surrounding a lesion, there is an increased risk that the lesion is cancerous.
== References == | Wikipedia/Acoustic_angiography |
Bypass surgery refers to a class of surgery involving rerouting a tubular body part.
Types include:
Vascular bypass surgery such as coronary artery bypass surgery, a heart operation, in which the internal thoracic artery and great saphanous vein are used to bypass the coronary artery.
Cardiopulmonary bypass, a technique used in coronary artery bypass surgery
In on-pump bypass surgery, a heart-lung machine is used; in off-pump bypass surgery, the surgeon stabilizies the heart without use of the machine.
Weight loss or Bariatric surgery:
Vertical banded gastroplasty surgery or "stomach stapling", the upper part of the stomach is permanently stapled to create a smaller pouch
Adjustable gastric band or "lap band", a band creates a pocket in the stomach that can be adjusted with a port placed just under the skin
Roux-en-Y gastric bypass surgery, the small intestine is connected to the upper part of the stomach
Partial ileal bypass surgery, shortening the final portion of the small intestine
Popliteal bypass surgery, to treat diseased leg arteries above or below the knee
Jejunojejunostomy, surgery that connects two portions of small intestine and is no longer used
Ileojejunal bypass, surgery that connects the middle and final portions of the small intestine that was experimental and is no longer used.
== References == | Wikipedia/Bypass_surgery |
Periodontal surgery is a form of dental surgery that prevents or corrects anatomical, traumatic, developmental, or plaque-induced defects in the bone, gingiva, or alveolar mucosa. The objectives of this surgery include accessibility of instruments to the root surface, elimination of inflammation, creation of an oral environment for plaque control, periodontal disease control, oral hygiene maintenance, maintaining proper embrasure space, addressing gingiva–alveolar mucosa problems, and esthetic improvement.
Surgical procedures include crown lengthening, frenectomy, and mucogingival flap surgery.
== Indications ==
=== Contraindications ===
Some contraindications include:
Patient with poor standard of plaque control
Questionable long-term prognosis of patient dentition
Pregnancy
Smoking
Severe cardiovascular disease
Malignancy
Bleeding disorders
Uncontrolled diabetes
Kidney disease
Liver disease
=== Considerations ===
The procedural selection in a periodontal surgery should rely on simplicity, predictability, efficiency, Mucogingival considerations, osseous topography, anatomic and physical limitations, age and systemic factors.
The incisions should be clear, smooth, and well-defined to minimize the healing time. Such incisions prevent occurrence of uneven ragged flap edges.
To maintain the functional zone of the attached keratinized gingiva, flaps should be designed for maximum use and retention of keratinized gingival tissue, as it prevents the need of secondary procedures.
In the design of flaps, it needs to be ensured that there is adequate access and visibility. The design should also prevent bone exposure as it can lead to formation of dehiscence or fenestration.
For prevention of excessive bleeding, hematoma formation, displacement, bone exposure, or infection, adequate flap stabilization should be ensured.
The surgical procedure should be carried out such a manner that the postoperative healing takes place by primary intention and not by secondary intention.
== Surgical procedures ==
=== Crown lengthening ===
Crown lengthening is a technique for increasing crown height of teeth by flap surgery with or without bone surgery. There are two main types:
Aesthetic crown lengthening which is performed when a "gummy" smile is an issue for the patient
Functional crown lengthening is used to make an unrestorable tooth restorable. For example, a tooth with caries that extends below the gums may undergo crown lengthening so that the caries is no longer below the gums and a crown may be placed.
==== Contraindications ====
Untreated or unstable gum disease (periodontal disease) and gingival phenotype
==== Considerations ====
Strategic value of tooth
Crown/root ratio that will remain following surgery
Aesthetics will be affected such as longer clinical crowns and loss of interdental papillae leading to "black triangles"
It can result in exposure of furcations
Mobility of teeth
Post-op sensitivity due to root dentine exposure
Patient may need long-term treatment until gingival margin stabilised (3–6 months).
Patient must also be made aware prior to surgery that relapse is possible
==== Method ====
There are three main methods for surgical crown lengthening:
Gingivectomy
Apically repositioned flap (APF) surgery
Apically repositioned flap (APF) with osseous reduction (osteoplasty/ostectomy)
=== Frenectomy ===
Frenectomy is indicated by thick, prominent muscle attachments known as fraena or a frenum with close attachment to the gum margin. Thick frenum attachment or close attachment to gum margin can contribute to increased plaque accumulation, persistent inflammation, muscular pull on gum and affect gum contour.
Usual sites for frenectomy are buccal regions of upper and lower incisors, upper canines and premolars. Frenectomy is rarely required for lingual sites.
==== Procedure ====
Frenectomy consists of:
Cutting the attachment of the frenum to the gums
Administering local anaesthetic
Stretching the lip and gripping the frenum with forceps
Cutting through base of frenum on both sides of forceps
Incision on alveolar side near to bone leaving the periosteum intact.
Removal of the frenal tissue and suturing the edges of the wound closely with resorbable sutures
Placing swabs over the wound
The patient is instructed to rinse twice daily with chlorhexidine mouthwash.
=== Mucogingival flap surgery ===
Mucogingival surgery is a procedure where the gums are separated from teeth and temporarily folded back to allow the dentist to directly view and reach root surface of the tooth and bone. It is used for crown lengthening surgery. It also, if required, can be used for guided tissue regeneration or open flap debridement (OFD) to treat gum disease (periodontitis/periodontal disease). The presence of bacteria, in the form of dental plaque/tartar/calculus on the root of a tooth, can cause inflammation of the gums resulting in gum disease. This can lead to bone loss around the affected teeth and if left untreated, lead to tooth loss. When a tooth has very deep periodontal pockets it may not be possible to fully remove the dental plaque/tartar/calculus from the tooth's root surface with scaling alone. In open flap debridement (OFD) the gum is peeled back to make it possible for the dentist to see and ensure full removal of tartar/calculus from these difficult to access areas. Teeth with furcation defects as a result of gum recession may require open flap debridement (OFD) as these areas can be very difficult to clean.
==== Mucogingival flaps thickness ====
Full thickness flap involves incision down to bone. Using blunt dissection, the flap is raised from bone. Full thickness flap is a simple procedure which provides access to root surface and bone. The procedure leaves minimal post-operative discomfort. It provides limited mobility of flap and is unsuitable for grafting.
Split thickness flap involves sharp cutting of tissues and leaving the underlying periosteum intact. The procedure prevents exposure dehiscence and allows good blood supply for grafting. It does not provide access to underlying bone or root surface and results in greater post-operative discomfort.
== References == | Wikipedia/Periodontal_surgery |
Hypnosurgery is surgery where the patient is sedated using hypnotherapy rather than traditional anaesthetics. It is claimed that hypnosis for anaesthesia has been used since the 1840s where it was pioneered by the surgeon James Braid. There are occasional media reports of surgery being conducted under hypnosis, but since these are not carried out under controlled conditions, nothing can be concluded from them. In 2013 in the University of Padova, Italy, Hypnosis was used as sole anaesthesia for a skin tumour removal in a patient with multiple chemical sensitivity who couldn't use chemical drugs.
There is insufficient evidence to support the efficacy of hypnosis in managing pain in other contexts, such as childbirth or post-operative pain.
== History ==
Mesmerism, also called animal magnetism, is the term given by Franz Mesmer for what he believed to be an invisible natural force in animals. He also believed that it could have physical effects such as healing.
James Braid who is credited for pioneering hypnosurgery, first observed mesmerism while he was attending a public performance on magnetism by Charles Lafontaine. After attending two more shows he came to the conclusion that although there were observable physical effects, it was not caused by any magnetic interference. Braid then used self-experiment to prove his idea that mesmerism was achieved by vision and concentration of the subject. Braid therefore claimed that the phenomena demonstrated by Lafontaine had nothing to do with magnetism. James Braid then adopted the term “hypnotism” to prevent his work from being confounded with mesmerism.
It is claimed that hypnosis has been used in surgery for pain management, to control spasms in the alimentary canal, during rehabilitation, and as anaesthesia during an operation.
The first alleged case of hypnosis as an anesthetic in surgery was when Jules Germain Cloquet (1790–1883), a French surgeon, operated on a woman's breast while she was purportedly under the influence of hypnosis. The operation was for the removal of a tumor. Over the course of his career, he claimed to have performed several successful surgeries using hypnosis as the only form of anesthesia.
While stationed at the River Valley Road prisoner of war hospital in Singapore in 1945, with the supplies of chemical anesthetics severely restricted by the Japanese, Michael Woodruff and a medical/dental colleague from the Royal Netherlands Forces used hypnotism as the sole means of anesthesia for a wide range of dental and surgical procedures.
== Preparing the patient for hypnosurgery ==
At the present time, preparing a patient for hypnosurgery would include having several 50–60 minutes’ sessions of hypnotherapy done by a hypnotherapist. Each individual session focuses on controlling the pain and relaxing the mind. The number of hypnotherapy sessions varies according to the patient and their susceptibility to hypnosis. Generally, the patient would be ready for hypnosurgery after 6 weeks of training.
== Post-operative hypnosis ==
Hypnosis may also be helpful post-surgery in helping to facilitate faster healing in patients, with one study reporting faster tissue healing in patients who use hypnosis during surgical recovery. Several other studies have shown a psychological link with healing and recovery. In a study of patients up to seven weeks after undergoing a surgical procedure, researchers found greater healing and improvement in patients who had used hypnosis over those who only received supportive attention or standard "standard postoperative care".
A recent Cochrane review on the efficacy of various psychological therapies (including hypnosis) on post-surgical outcomes concluded that "the strength of evidence is insufficient to reach firm conclusions on the role of psychological preparation for surgery" and the quality of the evidence was reportedly "very low."
== See also ==
Surgery
Cardiac surgery
Trauma surgery
== References == | Wikipedia/Hypnosurgery |
Remote surgery (also known as cybersurgery or telesurgery) is the ability for a doctor to perform surgery on a patient even though they are not physically in the same location. It is a form of telepresence. A robot surgical system generally consists of one or more arms (controlled by the surgeon), a master controller (console), and a sensory system giving feedback to the user. Remote surgery combines elements of robotics, telecommunications such as high-speed data connections and elements of management information systems. While the field of robotic surgery is fairly well established, most of these robots are controlled by surgeons at the location of the surgery. Remote surgery is remote work for surgeons, where the physical distance between the surgeon and the patient is less relevant. It promises to allow the expertise of specialized surgeons to be available to patients worldwide, without the need for patients to travel beyond their local hospital.
== Surgical systems ==
Surgical robot systems have been developed from the first functional telesurgery system-ZEUS-to the da Vinci Surgical System, which is currently the only commercially available surgical robotic system. In Israel a company was established by Professor Moshe Schoham, from the faculty of Mechanical Engineering at the Technion. Used mainly for "on-site" surgery, these robots assist the surgeon visually, with better precision and less invasiveness to patients. The Da Vinci Surgical System has also been combined to form a Dual Da Vinci system which allows two surgeons to work together on a patient at the same time. The system gives the surgeons the ability to control different arms, switch command of arms at any point, and communicate through headsets during the operation.
== Costs ==
Marketed for $975,000, the ZEUS Robot Surgical System was less expensive than the da Vinci Surgical System, which cost $1 million. The cost of an operation through telesurgery is not precise but must pay for the surgical system, the surgeon, and contribute to paying for a year's worth of ATM technology which runs between $100,000-$200,000.
== The Lindbergh Operation ==
The first true and complete remote surgery was conducted on 7 September 2001 across the Atlantic Ocean, with a French surgeon (Dr. Jacques Marescaux) in New York City performing a cholecystectomy on a 68-year-old female patient 6,230 km away in Strasbourg, France. It was named Operation Lindbergh, after Charles Lindbergh's pioneering transatlantic flight from New York to Paris. France Telecom provided the redundant fiber optic ATM lines to minimize latency and optimize connectivity, and Computer Motion provided a modified Zeus robotic system. After clinical evaluation of the complete solution in July 2001, the human operation was successfully completed on 9/7/2001.
The success and exposure of the procedure led the robotic team to use the same technology within Canada, this time using Bell Canada's public internet between Hamilton, Ontario and North Bay, Ontario (a distance of about 400 kilometers). While operation Lindbergh used the most expensive ATM fiber optics communication to ensure reliability and success of the first telesurgery, the follow on procedures in Canada used standard public internet which was provisioned with QOS using MPLS QOS-MPLS. A series of complex laparoscopic procedures were performed where in this case, the expert clinician would support the surgeon who was less experienced, operating on his patient. This resulted in patient receiving the best care possible while remaining in their hometown, the less experienced surgeon gaining valuable experience, and the expert surgeon providing their expertise without travel. The robotic team's goal was to go from Lindbergh's proof of concept to a real-life solution. This was achieved with over 20 complex laparoscopic operations between Hamilton and North Bay.
== Applications ==
Since Operation Lindbergh, remote surgery has been conducted many times in numerous locations. To date Dr. Anvari, a laparoscopic surgeon in Hamilton, Canada, has conducted numerous remote surgeries on patients in North Bay, a city 400 kilometres from Hamilton. Even though he uses a VPN over a non-dedicated fiberoptic connection that shares bandwidth with regular telecommunications data, Dr. Anvari has not had any connection problems during his procedures.
Rapid development of technology has allowed remote surgery rooms to become highly specialized. At the Advanced Surgical Technology Center at Mt. Sinai Hospital in Toronto, Canada, the surgical room responds to the surgeon's voice commands in order to control a variety of equipment at the surgical site, including the lighting in the operating room, the position of the operating table and the surgical tools themselves. With continuing advances in communication technologies, the availability of greater bandwidth and more powerful computers, the ease and cost-effectiveness of deploying remote surgery units is likely to increase rapidly.
The possibility of being able to project the knowledge and the physical skill of a surgeon over long distances has many attractions. There is considerable research underway in the subject. The armed forces have an obvious interest since the combination of telepresence, teleoperation, and telerobotics can potentially save the lives of battle casualties by providing them with prompt attention in mobile operating theatres.
Another potential advantage of having robots perform surgeries is accuracy. A study conducted at Guy's Hospital in London, England compared the success of kidney surgeries in 304 dummy patients conducted traditionally as well as remotely and found that those conducted using robots were more successful in accurately targeting kidney stones.
In 2015, another test was conducted on the lag time involved in the robotic surgery. A Florida hospital successfully tested lag time created by the Internet for a simulated robotic surgery in Ft. Worth, Texas, more than 1,200 miles away from the surgeon who was at the virtual controls. The team found out that the lag time in robotic surgeries was insignificant. Roger Smith, CTO at the Florida Hospital Nicholson Center said that the team had concluded that telesurgery is something that is possible and generally safe for large areas within the United States.
In 2024, lung tumour surgery conducted over a 5G wireless connection from 5000km away.
== Unassisted robotic surgery ==
As the techniques of expert surgeons are studied and stored in special computer systems, robots might one day be able to perform surgeries with little or no human input. Carlo Pappone, an Italian surgeon, has developed a software program that uses data collected from several surgeons and thousands of operations to perform the surgery without human intervention. This could one day make expensive, complicated surgeries much more widely available, even to patients in regions which have traditionally lacked proper medical facilities.
== Force-feedback and time delay ==
The ability to carry out delicate manipulations relies greatly upon feedback. For example, it is easy to learn how much pressure is required to handle an egg. In robotic surgery, surgeons need to be able to perceive the amount of force being applied without directly touching the surgical tools. Systems known as force-feedback, or haptic technology, have been developed to simulate this. Haptics is the science of touch. Any type of Haptic feedback provides a responsive force in opposition to the touch of the hand. Haptic technology in telesurgery, making a virtual image of a patient or incision, would allow a surgeon to see what they are working on as well as feel it. This technology is designed to give a surgeon the ability to feel tendons and muscles as if it were actually the patient's body. However these systems are very sensitive to time-delays such as those present in the networks used in remote surgery.
== Depth perception ==
Being able to gauge the depth of an incision is crucial. Humans' binocular vision makes this easy in a three-dimensional environment. However, this can be much more difficult when the view is presented on a flat computer screen.
== Possible uses ==
One possible use of remote surgery is the Trauma-Pod project conceived by the US military under the Defense Advanced Research Agency. This system is intended to aid wounded soldiers in the battlefield by making use of the skills of remotely located medical personnel.
Another future possibility could be the use of remote surgery during long space exploration missions.
== Limitations ==
For now, remote surgery is not a widespread technology in part because it does not have sponsorship by the governments. Before its acceptance on a broader scale, many issues will need to be resolved. For example, establishing secure very fast connections between the two sites, establishing clinical protocols, training, and global compatibility of equipment. Another technological limitation is the risk of interference with the communications (hacking). Also, there is still the need for an anesthesiologist and a backup surgeon to be present in case there is a disruption of communications or a malfunction in the robot. Nevertheless, Operation Lindbergh proved that the technology exists today to enable delivery of expert care to remote areas of the globe.
== See also ==
Waldo (short story) by Robert A. Heinlein.
== References ==
== External links ==
BBC News SCI/TECH -- First transatlantic surgery | Wikipedia/Remote_surgery |
Orthopedic surgery or orthopedics (alternative spelling orthopaedics) is the branch of surgery concerned with conditions involving the musculoskeletal system. Orthopedic surgeons use both surgical and nonsurgical means to treat musculoskeletal trauma, spine diseases, sports injuries, degenerative diseases, infections, tumors and congenital disorders.
== Etymology ==
Nicholas Andry coined the word in French as orthopédie, derived from the Ancient Greek words ὀρθός orthos ("correct", "straight") and παιδίον paidion ("child"), and published Orthopedie (translated as Orthopædia: Or the Art of Correcting and Preventing Deformities in Children) in 1741. The word was assimilated into English as orthopædics; the ligature æ was common in that era for ae in Greek- and Latin-based words. As the name implies, the discipline was initially developed with attention to children, but the correction of spinal and bone deformities in all stages of life eventually became the cornerstone of orthopedic practice.
=== Differences in spelling ===
As with many words derived with the "æ" ligature, simplification to either "ae" or just "e" is common, especially in North America. In the US, the majority of college, university, and residency programmes, and even the American Academy of Orthopaedic Surgeons, still use the spelling with the digraph ae, though hospitals usually use the shortened form. Elsewhere, usage is not uniform; in Canada, both spellings are acceptable; "orthopaedics" is the normal spelling in the UK in line with other fields which retain "ae".
== History ==
=== Early orthopedics ===
Many developments in orthopedic surgery have resulted from experiences during wartime. On the battlefields of the Middle Ages, the injured were treated with bandages soaked in horses' blood, which dried to form a stiff, if unsanitary, splint.
Originally, the term orthopedics meant the correcting of musculoskeletal deformities in children. Nicolas Andry, a professor of medicine at the University of Paris, coined the term in the first textbook written on the subject in 1741. He advocated the use of exercise, manipulation, and splinting to treat deformities in children. His book was directed towards parents, and while some topics would be familiar to orthopedists today, it also included 'excessive sweating of the palms' and freckles.
Jean-André Venel established the first orthopedic institute in 1780, which was the first hospital dedicated to the treatment of children's skeletal deformities. He developed the club-foot shoe for children born with foot deformities and various methods to treat curvature of the spine.
Advances made in surgical technique during the 18th century, such as John Hunter's research on tendon healing and Percival Pott's work on spinal deformity steadily increased the range of new methods available for effective treatment. Robert Chessher, a pioneering British orthopedist, invented the double-inclined plane, used to treat lower-body bone fractures, in 1790. Antonius Mathijsen, a Dutch military surgeon, invented the plaster of Paris cast in 1851. Until the 1890s, though, orthopedics was still a study limited to the correction of deformity in children. One of the first surgical procedures developed was percutaneous tenotomy. This involved cutting a tendon, originally the Achilles tendon, to help treat deformities alongside bracing and exercises. In the late 1800s and first decades of the 1900s, significant controversy arose about whether orthopedics should include surgical procedures at all.
=== Modern orthopedics ===
Examples of people who aided the development of modern orthopedic surgery were Hugh Owen Thomas, a surgeon from Wales, and his nephew, Robert Jones. Thomas became interested in orthopedics and bone-setting at a young age, and after establishing his own practice, went on to expand the field into the general treatment of fracture and other musculoskeletal problems. He advocated enforced rest as the best remedy for fractures and tuberculosis, and created the so-called "Thomas splint" to stabilize a fractured femur and prevent infection. He is also responsible for numerous other medical innovations that all carry his name: Thomas's collar to treat tuberculosis of the cervical spine, Thomas's maneuvere, an orthopedic investigation for fracture of the hip joint, the Thomas test, a method of detecting hip deformity by having the patient lying flat in bed, and Thomas's wrench for reducing fractures, as well as a so-called "osteoclast" implement to break and reset bones.
Thomas's work was not fully appreciated in his own lifetime. Only during the First World War did his techniques come to be used for injured soldiers on the battlefield. His nephew, Sir Robert Jones, had already made great advances in orthopedics in his position as surgeon-superintendent for the construction of the Manchester Ship Canal in 1888. He was responsible for the injured among the 20,000 workers, and he organized the first comprehensive accident service in the world, dividing the 36-mile site into three sections, and establishing a hospital and a string of first-aid posts in each section. He had the medical personnel trained in fracture management. He personally managed 3,000 cases and performed 300 operations in his own hospital. This position enabled him to learn new techniques and improve the standard of fracture management. Physicians from around the world came to Jones' clinic to learn his techniques. Along with Alfred Tubby, Jones founded the British Orthopedic Society in 1894.
During the First World War, Jones served as a Territorial Army surgeon. He observed that treatment of fractures both, at the front and in hospitals at home, was inadequate, and his efforts led to the introduction of military orthopedic hospitals. He was appointed Inspector of Military Orthopedics, with responsibility for 30,000 beds. The hospital in Ducane Road, Hammersmith, became the model for both British and American military orthopedic hospitals. His advocacy of the use of Thomas splint for the initial treatment of femoral fractures reduced mortality of open fractures of the femur from 87% to less than 8% in the period from 1916 to 1918.
The use of intramedullary rods to treat fractures of the femur and tibia was pioneered by Gerhard Küntscher of Germany. This made a noticeable difference to the speed of recovery of injured German soldiers during World War II and led to more widespread adoption of intramedullary fixation of fractures in the rest of the world. Traction was the standard method of treating thigh bone fractures until the late 1970s, though, when the Harborview Medical Center group in Seattle popularized intramedullary fixation without opening up the fracture.
The modern total hip replacement was pioneered by Sir John Charnley, expert in tribology at Wrightington Hospital, in England in the 1960s. He found that joint surfaces could be replaced by implants cemented to the bone. His design consisted of a stainless steel, one-piece femoral stem and head, and a polyethylene acetabular component, both of which were fixed to the bone using PMMA (acrylic) bone cement. For over two decades, the Charnley low-friction arthroplasty and its derivative designs were the most-used systems in the world. This formed the basis for all modern hip implants.
The Exeter hip replacement system (with a slightly different stem geometry) was developed at the same time. Since Charnley, improvements have been continuous in the design and technique of joint replacement (arthroplasty) with many contributors, including W. H. Harris, the son of R. I. Harris, whose team at Harvard pioneered uncemented arthroplasty techniques with the bone bonding directly to the implant.
Knee replacements, using similar technology, were started by McIntosh in rheumatoid arthritis patients and later by Gunston and Marmor for osteoarthritis in the 1970s, developed by John Insall in New York using a fixed bearing system, and by Frederick Buechel and Michael Pappas using a mobile bearing system.
External fixation of fractures was refined by American surgeons during the Vietnam War, but a major contribution was made by Gavril Abramovich Ilizarov in the USSR. He was sent, without much orthopedic training, to look after injured Russian soldiers in Siberia in the 1950s. With no equipment, he was confronted with crippling conditions of unhealed, infected, and misaligned fractures. With the help of the local bicycle shop, he devised ring external fixators tensioned like the spokes of a bicycle. With this equipment, he achieved healing, realignment, and lengthening to a degree unheard of elsewhere. His Ilizarov apparatus is still used today as one of the distraction osteogenesis methods.
Modern orthopedic surgery and musculoskeletal research have sought to make surgery less invasive and to make implanted components better and more durable. On the other hand, since the emergence of the opioid epidemic, orthopedic surgeons have been identified as one of the highest prescribers of opioid medications. Decreasing prescription of opioids while still providing adequate pain control is a development in orthopedic surgery.
== Training ==
In the United States, orthopedic surgeons have typically completed four years of undergraduate education and four years of medical school and earned either a Doctor of Medicine (MD) or Doctor of Osteopathic Medicine (DO) degree. Subsequently, these medical school graduates undergo residency training in orthopedic surgery. The five-year residency is a categorical orthopedic surgery training.
Selection for residency training in orthopedic surgery is very competitive. Roughly 700 physicians complete orthopedic residency training per year in the United States. About 10% of current orthopedic surgery residents are women; about 20% are members of minority groups. Around 20,400 actively practicing orthopedic surgeons and residents are in the United States. According to the latest Occupational Outlook Handbook (2011–2012) published by the United States Department of Labor, 3–4% of all practicing physicians are orthopedic surgeons.
Many orthopedic surgeons elect to do further training, or fellowships, after completing their residency training. Fellowship training in an orthopedic sub-specialty is typically one year in duration (sometimes two) and sometimes has a research component involved with the clinical and operative training. Examples of orthopedic subspecialty training in the United States are:
Foot and ankle surgery
Hand and upper extremities
Hip and knee surgery
Orthopedic oncologist
Orthopedic trauma
Osseointegration
Pediatric orthopedics
Shoulder and elbow
Spine surgery
Surgical sports medicine
Total joint reconstruction (arthroplasty)
These specialized areas of medicine are not exclusive to orthopedic surgery. For example, hand surgery is practiced by some plastic surgeons, and spine surgery is practiced by most neurosurgeons. Additionally, foot and ankle surgery is also practiced by doctors of podiatric medicine (DPM) in the United States. Some family practice physicians practice sports medicine, but their scope of practice is nonoperative.
After completion of specialty residency or registrar training, an orthopedic surgeon is then eligible for board certification by the American Board of Medical Specialties or the American Osteopathic Association Bureau of Osteopathic Specialists. Certification by the American Board of Orthopedic Surgery or the American Osteopathic Board of Orthopedic Surgery means that the orthopedic surgeon has met the specified educational, evaluation, and examination requirements of the board. The process requires successful completion of a standardized written examination followed by an oral examination focused on the surgeon's clinical and surgical performance over a 6-month period. In Canada, the certifying organization is the Royal College of Physicians and Surgeons of Canada; in Australia and New Zealand, it is the Royal Australasian College of Surgeons.
In the United States, specialists in hand surgery and orthopedic sports medicine may obtain a certificate of added qualifications in addition to their board primary certification by successfully completing a separate standardized examination. No additional certification process exists for the other subspecialties.
== Practice ==
According to applications for board certification from 1999 to 2003, the top 25 most common procedures (in order) performed by orthopedic surgeons are:
Knee arthroscopy and meniscectomy
Shoulder arthroscopy and decompression
Carpal tunnel release
Knee arthroscopy and chondroplasty
Removal of support implant
Knee arthroscopy and anterior cruciate ligament reconstruction
Knee replacement
Repair of femoral neck fracture
Repair of trochanteric fracture
Debridement of skin/muscle/bone/ fracture
Knee arthroscopy repair of both menisci
Hip replacement
Shoulder arthroscopy/distal clavicle excision
Repair of rotator cuff tendon
Repair fracture of radius/ulna
Laminectomy
Repair of ankle fracture (bimalleolar type)
Shoulder arthroscopy and debridement
Lumbar spinal fusion
Repair fracture of the distal part of radius
Low back intervertebral disc surgery
Incise finger tendon sheath
Repair of ankle fracture (fibula)
Repair of femoral shaft fracture
Repair of trochanteric fracture
A typical schedule for a practicing orthopedic surgeon involves 50–55 hours of work per week divided among clinic, surgery, various administrative duties, and possibly teaching and/or research if in an academic setting. According to the American Association of Medical Colleges in 2021, the average work week of an orthopedic surgeon was 57 hours. This is a very low estimation however, as research derived from a 2013 survey of orthopedic surgeons who self identified as "highly successful" due to their prominent positions in the field indicated average work weeks of 70 hours or more.
== Arthroscopy ==
The use of arthroscopic techniques has been particularly important for injured patients. Arthroscopy was pioneered in the early 1950s by Masaki Watanabe of Japan to perform minimally invasive cartilage surgery and reconstructions of torn ligaments. Arthroscopy allows patients to recover from the surgery in a matter of days, rather than the weeks to months required by conventional, "open" surgery; it is a very popular technique. Knee arthroscopy is one of the most common operations performed by orthopedic surgeons today, and is often combined with meniscectomy or chondroplasty. The majority of upper-extremity outpatient orthopedic procedures are now performed arthroscopically.
== Arthroplasty ==
Arthroplasty is an orthopedic surgery where the articular surface of a musculoskeletal joint is replaced, remodeled, or realigned by osteotomy or some other procedure. It is an elective procedure that is done to relieve pain and restore function to the joint after damage by arthritis (rheumasurgery) or some other type of trauma. As well as the standard total knee replacement surgery, the unicompartmental knee replacement, in which only one weight-bearing surface of an arthritic knee is replaced, may be performed, but it bears a significant risk of revision surgery. Joint replacements are used for other joints, most commonly the hip or shoulder.
A post-surgical concern with joint replacements is wear of the bearing surfaces of components. This can lead to damage to the surrounding bone and contribute to eventual failure of the implant. The plastic chosen is usually ultra-high-molecular-weight polyethylene, which can also be altered in ways that may improve wear characteristics. The risk of revision surgery has also been shown to be associated with surgeon volume.
== Epidemiology ==
Between 2001 and 2016, the prevalence of musculoskeletal procedures drastically increased in the U.S., from 17.9% to 24.2% of all operating-room (OR) procedures performed during hospital stays.
In a study of hospitalizations in the United States in 2012, spine and joint procedures were common among all age groups except infants. Spinal fusion was one of the five most common OR procedures performed in every age group except infants younger than 1 year and adults 85 years and older. Laminectomy was common among adults aged 18–84 years. Knee arthroplasty and hip replacement were in the top five OR procedures for adults aged 45 years and older.
== See also ==
Bone grafting
Index of trauma and orthopaedics articles
List of orthopedic implants
Orthopaedic physician's assistant
Orthotics
Outline of trauma and orthopedics
== References ==
== External links ==
Media related to Orthopedics at Wikimedia Commons | Wikipedia/Orthopaedic_surgery |
Fluorescence guided surgery (FGS), also called fluorescence image-guided surgery, or in the specific case of tumor resection, fluorescence guided resection, is a medical imaging technique used to detect fluorescently labelled structures during surgery. Similarly to standard image-guided surgery, FGS has the purpose of guiding the surgical procedure and providing the surgeon of real time visualization of the operating field. When compared to other medical imaging modalities, FGS is cheaper and superior in terms of resolution and number of molecules detectable. As a drawback, penetration depth is usually very poor (100 μm) in the visible wavelengths, but it can reach up to 1–2 cm when excitation wavelengths in the near infrared are used.
== Imaging devices ==
FGS is performed using imaging devices with the purpose of providing real time simultaneous information from color reflectance images (bright field) and fluorescence emission. One or more light sources are used to excite and illuminate the sample. Light is collected using optical filters that match the emission spectrum of the fluorophore. Imaging lenses and digital cameras (CCD or CMOS) are used to produce the final image. Live video processing can also be performed to enhance contrast during fluorescence detection and improve signal-to-background ratio. In recent years a number of commercial companies have emerged to offer devices specializing in fluorescence in the NIR wavelengths, with the goal of capitalizing upon the growth in off label use of indocyanine green (ICG). However commercial systems with multiple fluorescence channels also exist commercially, for use with fluorescein and protoporphyrin IX (PpIX).
=== Excitation sources ===
Fluorescence excitation is accomplished using various kind of light sources. Halogen lamps have the advantage of delivering high power for a relatively low cost. Using different band-pass filters, the same source can be used to produce several excitation channels from the UV to the near infrared. Light-emitting diodes (LEDs) have become very popular for low cost broad band illumination and narrow band excitation in FGS. Because of their characteristic light emission spectrum, a narrow range of wavelengths that matches the absorption spectrum of a given fluorophore can be selected without using a filter, further reducing the complexity of the optical system. Both halogen lamps and LEDs are suitable for white light illumination of the sample. Excitation can also be performed using laser diodes, particularly when high power over a short wavelength range (typically 5-10 nm) is needed. In this case the system has to account for the limits of exposure to laser radiation.
=== Detection techniques ===
Live images from the fluorescent dye and the surgical field are obtained using a combination of filters, lenses and cameras. During open surgery, hand held devices are usually preferred for their ease of use and mobility. A stand or arm can be used to maintain the system on top of the operating field, particularly when the weight and complexity of the device is high (e.g. when multiple cameras are used). The main disadvantage of such devices is that operating theater lights can interfere with the fluorescence emission channel, with a consequent decrease of signal-to-background ratio. This issue is usually solved by dimming or switching off the theater lights during fluorescence detection.
FGS can also be performed using minimally invasive devices such as laparoscopes or endoscopes. In this case, a system of filters, lenses and cameras is attached to the end of the probe. Unlike open surgery, the background from external light sources is reduced. Nevertheless, the excitation power density at the sample is limited by the low light transmission of the fiber optics in endoscopes and laparoscopes, particularly in the near infrared. Moreover, the ability of collecting light is much reduced compared to standard imaging lenses used for open surgery devices.
FGS devices can also be implemented for robotic surgery (for example in the da Vinci Surgical System).
=== Clinical applications ===
The major limitation in FGS is the availability of clinically approved fluorescent dyes which have a novel biological indication. Indocyanine green (ICG) has been widely used as a non-specific agent to detect sentinel lymph nodes during surgery. ICG has the main advantage of absorbing and emitting light in the near infrared, allowing detection of nodes under several centimeters of tissue. Methylene blue can also be used for the same purpose, with an excitation peak in the red portion of the spectrum. First clinical applications using tumor-specific agents that detect deposits of ovarian cancer during surgery have been carried out.
=== History ===
The first uses of FGS dates back to the 1940s when fluorescein was first used in humans to enhance the imaging of brain tumors, cysts, edema and blood flow in vivo. In modern times the use has fallen off, until a multicenter trial in Germany concluded that FGS to help guide glioma resection based upon fluorescence from PpIX provided significant short-term benefit.
== See also ==
Endoscopy
Fluorescence
Image-guided surgery
Laparoscopy
Near infrared
Near-infrared window in biological tissue
Surgery
== References == | Wikipedia/Fluorescence_image-guided_surgery |
Exploratory surgery is surgery whose purpose is to look inside the body to help diagnose an ailment. Because surgery is an invasive and often risky intervention, it is typically only used when other methods such as external observation and testing body fluids have failed. Modern imaging techniques, starting with the invention of CT scans in 1972, have made it possible to look inside the body without surgery; these less-invasive techniques have significantly replaced exploratory surgery in humans. Exploratory surgery is still used for non-human animals, where tools for imaging are more expensive than exploratory surgery and often less available.
== Exploratory surgery in humans ==
As late as the early 1970s, when a patient presented to a hospital and reported severe pain for which there was no cause readily detectable from external observation or tests of body fluids, exploratory surgery was often the only way to make a definitive diagnosis while the patient was alive. This was highly risky. The patient could irreversibly decompensate from some undetected acute condition before the surgery could be initiated and completed, or the surgery might reveal no significant abnormalities. In a high percentage of cases, exploratory surgery was unable to provide a definitive answer, meaning the patient had endured great suffering for no net benefit.
Since the 1970s, exploratory surgery is used to make a diagnosis when typical imaging techniques fail to find an accurate diagnosis. The use of new technologies such as MRIs have made exploratory surgeries less frequent. For example, GE HealthCare reported in 2009 that in the United States, the number of laparatomies performed annually fell from 85,000 in 1993 to 35,000 in 2006, and the number of thoracotomies performed annually fell from 5,500 to 2,000 in 2006. Many kinds of exploratory surgeries can now be performed using endoscopy which uses a camera and minimal incisions instead of more invasive techniques.
The most common use of exploratory surgery in humans is in the abdomen, a laparotomy. If a camera is used, it's called a laparoscopy. A laparotomy can be used to diagnose cancer, endometriosis, gallstones, gastrointestinal perforation, appendicitis, diverticulitis, liver abscess, ectopic pregnancy, and other conditions involving abdominal organs. A biopsy can be performed during the procedure.
== Exploratory surgery in animals ==
Because animals cannot voice their symptoms as easily as humans, exploratory surgery is more common in animals. Exploratory surgery is done when looking for a foreign body that may be lodged in the animal's body, when looking for cancer, or when looking for various other gastrointestinal problems. It is a fairly routine procedure that is done only after tests and bloodwork reveal nothing abnormal.
== References == | Wikipedia/Exploratory_surgery |
Otorhinolaryngology ( oh-toh-RY-noh-LARR-in-GOL-ə-jee, abbreviated ORL and also known as otolaryngology, otolaryngology – head and neck surgery (ORL–H&N or OHNS), or ear, nose, and throat (ENT) ) is a surgical subspecialty within medicine that deals with the surgical and medical management of conditions of the head and neck. Doctors who specialize in this area are called otorhinolaryngologists, otolaryngologists, head and neck surgeons, or ENT surgeons or physicians.
Patients seek treatment from an otorhinolaryngologist for diseases of the ear, nose, throat, base of the skull, head, and neck. These commonly include functional diseases that affect the senses and activities of eating, drinking, speaking, breathing, swallowing, and hearing. In addition, ENT surgery encompasses the surgical management of cancers and benign tumors and reconstruction of the head and neck as well as plastic surgery of the face, scalp, and neck.
== Etymology ==
The term is a combination of Neo-Latin combining forms (oto- + rhino- + laryngo- + -logy) derived from four Ancient Greek words: (cf. Greek ωτορινολαρυγγολόγος 'otorhinolaryngologist').
== Training ==
Otorhinolaryngologists are physicians (MD, DO, MBBS, MBChB, etc.) who complete both medical school and an average of five–seven years of post-graduate surgical training in ORL-H&N. In the United States, trainees complete at least five years of surgical residency training. This comprises three to six months of general surgical training and four and a half years in ORL-H&N specialist surgery. In Canada and the United States, practitioners complete a five-year residency training after medical school.
Following residency training, some otolaryngologist-head & neck surgeons complete an advanced sub-specialty fellowship, where training can be one to two years in duration. Fellowships include head and neck surgical oncology, facial plastic surgery, rhinology and sinus surgery, neuro-otology, pediatric otolaryngology, and laryngology. In the United States and Canada, otorhinolaryngology is one of the most competitive specialties in medicine in which to obtain a residency position following medical school.
In the United Kingdom, entrance to higher surgical training is competitive and involves a rigorous national selection process. The training programme consists of 6 years of higher surgical training after which trainees frequently undertake fellowships in a sub-speciality prior to becoming a consultant.
The typical total length of education, training and post-secondary school is 12–14 years. Otolaryngology is among the more highly compensated surgical specialties in the United States. In 2022, the average annual income was $469,000.
== Sub-specialties ==
(*Currently recognized by American Board of Medical Subspecialties)
== Topics by subspecialty ==
=== Head and neck surgery ===
Head and neck surgical oncology (field of surgery treating cancer/malignancy of the head and neck)
Head and neck mucosal malignancy (cancer of the pink lining of the upper aerodigestive tract)
Oral cancer (cancer of lips, gums, tongue, hard palate, cheek, floor of mouth)
Oropharyngeal cancer (cancer of oropharynx, soft palate, tonsil, base of tongue)
Larynx cancer (voice box cancer)
Hypopharynx cancer (lower throat cancer)
Sinonasal cancer
Nasopharyngeal cancer
Skin cancer of the head & neck
Thyroid cancer
Salivary gland cancer
Head and neck sarcoma
Endocrine surgery of the head and neck
Thyroid surgery
Parathyroid surgery
Microvascular free flap reconstructive surgery
Skull base surgery
=== Otology and neurotology ===
Study of diseases of the outer ear, middle ear and mastoid, and inner ear, and surrounding structures (such as the facial nerve and lateral skull base)
Outer ear diseases
Otitis externa –
outer ear or ear canal inflammation
Exostoses or Surfer's ear are bony growths in the outer ear canal
Middle ear and mastoid diseases
Otitis media – middle ear inflammation
Perforated eardrum (hole in the eardrum due to infection, trauma, explosion or loud noise)
Mastoiditis
Inner ear diseases
BPPV – benign paroxysmal positional vertigo
Labyrinthitis/Vestibular neuronitis
Ménière's disease/Endolymphatic hydrops
Perilymphatic fistula
Acoustic neuroma, vestibular schwannoma
Facial nerve disease
Idiopathic facial palsy (Bell's Palsy)
Facial nerve tumors
Ramsay Hunt Syndrome
Symptoms
Hearing loss
Tinnitus (subjective noise in the ear)
Aural fullness (sense of fullness in the ear)
Otalgia (pain referring to the ear)
Otorrhea (fluid draining from the ear)
Vertigo
Imbalance
=== Rhinology ===
Rhinology includes nasal dysfunction and sinus diseases.
Nasal obstruction
Inferior turbinate hypertrophy
Nasal septum deviation
Chronic sinusitis with nasal polyps
Sinusitis – acute, chronic
Environmental allergies
Rhinitis
Pituitary tumor
Empty nose syndrome
Severe or recurrent epistaxis
=== Pediatric otorhinolaryngology ===
Adenoidectomy
Caustic ingestion
Cricotracheal resection
Decannulation
Laryngomalacia
Laryngotracheal reconstruction
Myringotomy and tubes
Obstructive sleep apnea – pediatric
Tonsillectomy
=== Laryngology ===
Dysphonia/hoarseness
Laryngitis
Reinke's edema
Vocal cord nodules and polyps
Spasmodic dysphonia
Tracheostomy
Cancer of the larynx
Vocology – science and practice of voice habilitation
=== Facial plastic and reconstructive surgery ===
Facial plastic and reconstructive surgery is a one-year fellowship open to otorhinolaryngologists who wish to begin learning the aesthetic and reconstructive surgical principles of the head, face, and neck pioneered by the specialty of Plastic and Reconstructive Surgery.
Rhinoplasty and septoplasty
Facelift (rhytidectomy)
Browlift
Blepharoplasty
Otoplasty
Genioplasty
Injectable cosmetic treatments
Trauma to the face
Nasal bone fracture
Mandible fracture
Orbital fracture
Frontal sinus fracture
Complex lacerations and soft tissue damage
Skin cancer (e.g. Basal Cell Carcinoma)
=== Sleep surgery ===
Sleep surgery encompasses any surgery that helps alleviate obstructive sleep apnea and can anatomically include any part of the upper airway.
Nasal cavity / nasopharynx
Septoplasty
Adenoidectomy (especially in pediatrics)
Oral cavity / oropharynx
Tonsillectomy (especially in pediatrics)
Uvulopalatopharyngoplasty
Transoral midline glossectomy
Genioglossus advancement
Other
Hyoid suspension
Maxillomandibular advancement
Hypoglossal nerve stimulation
=== Microvascular reconstruction repair ===
Microvascular reconstruction repair is a common operation that is done on patients who see an otorhinolaryngologist. It is a surgical procedure that involves moving a composite piece of tissue from the patient's body and to the head and/or neck. Microvascular head-and-neck reconstruction is used to treat head-and-neck cancers, including those of the larynx and pharynx, oral cavity, salivary glands, jaws, calvarium, sinuses, tongue and skin. The tissue that is most commonly moved during this procedure is from the arms, legs, and back, and can come from the skin, bone, fat, and/or muscle.
When performing this procedure, the decision on which is moved is determined on the reconstructive needs. Transfer of the tissue to the head and neck allows surgeons to rebuild the patient's jaw, optimize tongue function, and reconstruct the throat. When the pieces of tissue are moved, they require their own blood supply for a chance of survival in their new location. After the surgery is completed, the blood vessels that feed the tissue transplant are reconnected to new blood vessels in the neck. These blood vessels are typically no more than 1 to 3 millimeters in diameter, which means that these connections need to be made with a microscope, which is why the procedure is called "microvascular surgery".
== See also ==
== References == | Wikipedia/Head_and_neck_surgery |
Elective surgery or elective procedure is surgery that is scheduled in advance because it does not involve a medical emergency. Semi-elective surgery is a surgery that must be done to preserve the patient's life, but does not need to be performed immediately. Most surgeries are elective, scheduled at a time to suit the surgeon, hospital, and patient.
By contrast, an urgent surgery is one that can wait until the patient is medically stable, but should generally be done within 2 days, and an emergency surgery is one that must be performed without delay; the patient has no choice other than immediate surgery if permanent disability or death is to be avoided. Many surgeries can be performed as either elective or emergency surgeries, depending on the patient's needs.
== Description ==
An elective surgery or elective procedure (from the Latin: eligere, meaning to choose) is a surgery that does not involve a medical emergency and is scheduled in advance. Semi-elective surgery is a surgery that must be done to preserve the patient's life, but does not need to be performed immediately.
== Types ==
=== Elective ===
Most surgical medical treatments are elective, that is, scheduled at a time to suit the surgeon, hospital, and patient. These include inguinal hernia surgery, cataract surgery, mastectomy for breast cancer, and the donation of a kidney by a living donor.
Elective surgeries include all optional surgeries performed for non-medical reasons. This includes cosmetic surgery, such as facelifts, breast implants, liposuction, and breast reduction, which aim to subjectively improve a patient's physical appearance. Another optional surgery is LASIK—currently the top elective surgery in the United States—where a patient weighs the risks against increased quality of life expectations.
=== Semi-elective ===
When a condition is worsening but has not yet reached the point of a true emergency, surgeons speak of semi-elective surgery: the problem must be dealt with, but a brief delay is not expected to affect the outcome. Semi-elective procedures are typically scheduled within a time frame deemed appropriate for the patient's condition and disease. Removal of a malignancy, for example, is usually scheduled as semi-elective surgery, to be performed within a set number of days or weeks.
== Urgency ==
In a patient with multiple medical conditions, problems classified as needing semi-elective surgeries may be postponed until emergent conditions have been addressed and the patient is medically stable. For example, whenever possible, pregnant women typically postpone all elective and semi-elective procedures until after giving birth.
In some situations, an urgently needed surgery will be postponed briefly to permit even more urgent conditions to be addressed. In other situations, emergency surgery may be performed at the same time as life-saving resuscitation efforts.
Many surgeries can be performed as either elective or emergency surgeries, depending on the patient's needs. A sudden worsening of gallbladder disease may require immediate removal of the gallbladder by emergency surgery, but this surgery is more commonly scheduled in advance. An appendectomy is considered emergency surgery, but depending upon how early the diagnosis was made, the patient may have more time before the appendix risks rupturing or the infection spreads. Also, in certain emergency conditions, even ones like a heart attack or stroke, surgery may or may not need to be utilized.
== Best practices ==
Preoperative carbohydrates may decrease amount of time spent in hospital recovering.
== Non-elective surgery ==
Non-elective surgeries may be classified as urgent or emergency. An urgent surgery is one that can wait until the patient is medically stable, but should generally be done within 2 days. An emergency surgery is one that must be performed without delay; the patient has no choice other than immediate surgery if permanent disability or death is to be avoided. Urgent surgery is typically performed with 48 hours of diagnosis and emergency surgery is performed as soon as a surgeon is available. A trauma center is a hospital which supports emergency surgery on critically ill patients at the brink of death by ensuring that on a 24/7 basis, a surgeon is always on the premises (or "in-house") to evaluate patients and can take them immediately to the operating room.
== References ==
== Bibliography ==
C. Parchment-Smith (2006). Essential Revision Notes for Intercollegiate MRCS: Bk. 1. Knutsford, Cheshire, UK: PasTest, LLC. p. 439. ISBN 1-904627-36-6. | Wikipedia/Semi-elective_surgery |
Elective surgery or elective procedure is surgery that is scheduled in advance because it does not involve a medical emergency. Semi-elective surgery is a surgery that must be done to preserve the patient's life, but does not need to be performed immediately. Most surgeries are elective, scheduled at a time to suit the surgeon, hospital, and patient.
By contrast, an urgent surgery is one that can wait until the patient is medically stable, but should generally be done within 2 days, and an emergency surgery is one that must be performed without delay; the patient has no choice other than immediate surgery if permanent disability or death is to be avoided. Many surgeries can be performed as either elective or emergency surgeries, depending on the patient's needs.
== Description ==
An elective surgery or elective procedure (from the Latin: eligere, meaning to choose) is a surgery that does not involve a medical emergency and is scheduled in advance. Semi-elective surgery is a surgery that must be done to preserve the patient's life, but does not need to be performed immediately.
== Types ==
=== Elective ===
Most surgical medical treatments are elective, that is, scheduled at a time to suit the surgeon, hospital, and patient. These include inguinal hernia surgery, cataract surgery, mastectomy for breast cancer, and the donation of a kidney by a living donor.
Elective surgeries include all optional surgeries performed for non-medical reasons. This includes cosmetic surgery, such as facelifts, breast implants, liposuction, and breast reduction, which aim to subjectively improve a patient's physical appearance. Another optional surgery is LASIK—currently the top elective surgery in the United States—where a patient weighs the risks against increased quality of life expectations.
=== Semi-elective ===
When a condition is worsening but has not yet reached the point of a true emergency, surgeons speak of semi-elective surgery: the problem must be dealt with, but a brief delay is not expected to affect the outcome. Semi-elective procedures are typically scheduled within a time frame deemed appropriate for the patient's condition and disease. Removal of a malignancy, for example, is usually scheduled as semi-elective surgery, to be performed within a set number of days or weeks.
== Urgency ==
In a patient with multiple medical conditions, problems classified as needing semi-elective surgeries may be postponed until emergent conditions have been addressed and the patient is medically stable. For example, whenever possible, pregnant women typically postpone all elective and semi-elective procedures until after giving birth.
In some situations, an urgently needed surgery will be postponed briefly to permit even more urgent conditions to be addressed. In other situations, emergency surgery may be performed at the same time as life-saving resuscitation efforts.
Many surgeries can be performed as either elective or emergency surgeries, depending on the patient's needs. A sudden worsening of gallbladder disease may require immediate removal of the gallbladder by emergency surgery, but this surgery is more commonly scheduled in advance. An appendectomy is considered emergency surgery, but depending upon how early the diagnosis was made, the patient may have more time before the appendix risks rupturing or the infection spreads. Also, in certain emergency conditions, even ones like a heart attack or stroke, surgery may or may not need to be utilized.
== Best practices ==
Preoperative carbohydrates may decrease amount of time spent in hospital recovering.
== Non-elective surgery ==
Non-elective surgeries may be classified as urgent or emergency. An urgent surgery is one that can wait until the patient is medically stable, but should generally be done within 2 days. An emergency surgery is one that must be performed without delay; the patient has no choice other than immediate surgery if permanent disability or death is to be avoided. Urgent surgery is typically performed with 48 hours of diagnosis and emergency surgery is performed as soon as a surgeon is available. A trauma center is a hospital which supports emergency surgery on critically ill patients at the brink of death by ensuring that on a 24/7 basis, a surgeon is always on the premises (or "in-house") to evaluate patients and can take them immediately to the operating room.
== References ==
== Bibliography ==
C. Parchment-Smith (2006). Essential Revision Notes for Intercollegiate MRCS: Bk. 1. Knutsford, Cheshire, UK: PasTest, LLC. p. 439. ISBN 1-904627-36-6. | Wikipedia/Emergency_surgery |
Craniofacial surgery is a surgical subspecialty that deals with congenital and acquired deformities of the head, skull, face, neck, jaws and associated structures. Although craniofacial treatment often involves manipulation of bone, craniofacial surgery is not tissue-specific; craniofacial surgeons deal with bone, skin, nerve, muscle, teeth, and other related anatomy.
Defects typically treated by craniofacial surgeons include craniosynostosis (isolated and syndromic), rare craniofacial clefts, acute and chronic sequelae of facial fractures, cleft lip and palate, micrognathia, Treacher Collins Syndrome, Apert's Syndrome, Crouzon's Syndrome, Craniofacial microsomia, microtia and other congenital ear anomalies, and many others. Training in craniofacial surgery requires completion of a Craniofacial surgery fellowship. Such fellowships are available to individuals who have completed residency in oral and maxillofacial surgery, plastic and reconstructive surgery, or ear, nose, and throat surgery. Those who have completed residency in oral and maxillofacial surgery may be either single degree or dual-degree surgeons with no differences. There is no specific board for craniofacial surgery. In the US, cleft and craniofacial centers are found in many major academic centers.
== Craniosynostosis ==
The bones of the human skull are joined by cranial sutures (see figure 1). The anterior fontanelle is where the metopic, sagittal and coronal sutures meet. Normally the sutures gradually fuse within the first few years after birth. In infants where one or more of the sutures fuses too early the growth of the skull is restricted, resulting in compensation mechanisms which cause irregular growth patterns. Growth in the skull is perpendicular to the sutures. When a suture fuses too early, the growth perpendicular to that suture will be restricted, and the bone growth near the other sutures will be stimulated, causing an abnormal head shape. The expanding brain is the main stimulus for the rapid growth of the skull in the first years of life. Inhibited growth potential of the skull can restrict the volume, needed by the brain. In cases in which the compensation does not effectively provide enough space for the growing brain, craniosynostosis results in increased intracranial pressure.
Craniosynostosis is called simple when one suture is involved, and complex when two or more sutures are involved. It can occur as part of a syndrome or as an isolated defect (nonsyndromic).
=== Scaphocephaly ===
In scaphocephaly, the sagittal suture is prematurely fused. The sagittal suture runs from the front to the back of the head. The shape of this deformity is a long narrow head, formed like a boat (Greek skaphe, "light boat or skiff"). The compensatory head-growth forward at the coronal suture gives a prominent forehead, frontal bossing and a prominent back of the head, called coning. The incidence of scaphocephaly is 2.8 per 10,000 births in the Netherlands; therefore, it is the most common form of craniosynostosis.
=== Trigonocephaly ===
In trigonocephaly, the metopic suture is prematurely fused. The metopic suture is situated in the medial line of the forehead. Premature fusion of this suture causes the forehead to become pointed, giving the head a triangular shape when viewed from above (Greek trigono, "triangle"). The incidence of trigonocephaly is 1 - 1.9 per 10,000 births in the Netherlands.
=== Plagiocephaly ===
In plagiocephaly, one of the coronal sutures is prematurely fused. The coronal sutures run over the top of the head, just in front of the ears. The shape of this deformity is an asymmetrical distortion (flattening of one side of the head) as you can see in figure 2. The incidence is 1 in 10,000 births.
=== Brachycephaly ===
In brachycephaly, both of the coronal sutures are prematurely fused. The shape of this deformity is a wide and high head. The incidence at birth is 1/20,000.
== Team ==
Craniofacial surgery and follow-up care are usually conducted by a multidisclinary team of doctors, surgeons, nurses, and various therapists. As of 2016, there is a new multidisciplinary care team of Neuroplastic Surgeons working with Neurosurgeons to prevent and/or correct neurosurgical-related deformities and to maximize outcomes in adult patients.
== Surgical procedures ==
In cases where the forehead is involved (trigonocephaly and plagiocephaly), a technique called fronto-supraorbital advancement is used to correct the shape of the head. The procedure is performed at a young age in order to provide the brain with enough space to grow and prevent further abnormal growth of the skull. Fronto-orbital advancement literally means moving the front of the skull including the eye sockets forward. A section of the skull, ranging from the coronal sutures to the eye sockets is cut loose in order to correct the shape of the skull. The incision is cut in a zigzag shape from ear to ear so that the hair will cover the scar and make it less visible. The incision is made to the bone only, leaving the underlying meninges intact. The top half of the eye sockets is cut loose. Once the eye socket section has been cut loose, a vertical incision is made in the midline, and the whole section of the eye socket is bent outwards in order to correct the pointed shape of the forehead. Because the section is now too wide, a wedge needs to be cut on either side to allow the section to fit into the skull. Figure 4 shows the sections that are loosened and adjusted, and Figure 3 shows the location of the vertical incision (arrow A) and the two wedges (arrow B).
In scaphocephaly, the sagittal suture is prematurely fused, preventing the skull from growing perpendicular to the suture. Thus, the head becomes very narrow and long. If a scaphocephaly is diagnosed within 4 to 5 months after birth, it can be corrected with a relatively simple procedure whereby the sagittal suture is surgically reopened. Once the suture has been opened the bone segments will be able to grow again, and the head can regain its normal shape. This operation is only performed on patients younger than five months old with a scaphocephaly. This is due to the fact that the bone segments only have the ability to adapt so severely when the operation is performed at this young age. A scaphocephaly that is diagnosed and treated later in life requires a more extensive secondary operation than one that is treated before five months.
A major focus in craniosynostosis reconstruction is maintaining normalized aesthetics of temporal region, and avoiding temporal hollowing. Despite using overcorrection methods, autologous fat transfer, and bone grafts to prevent temporal hollowing, up to 50% of patients still experience post-operative depression in the temporal fossa.
Cranioplasty, or skull reconstruction, is the main concentration of a new field for adult neurosurgical patients known as Neuroplastic Surgery. There are now several centers around the world, including the United States and Israel. The first center of Neuroplastic Surgery was started at Johns Hopkins by Dr. Chad Gordon and the Department of Neurosurgery, which is where this new craniofacial subspecialty was born (c. 2016).
=== Complications in craniofacial surgery ===
Some of the surgical complications in craniofacial surgery may include Death, Shock, Haemorrhage, visual loss, Intracranial collection of air/fluid, Epileptic seizures, Unexpected respiratory complications, etc.
== See also ==
Plastic surgery
Oral and maxillofacial surgery
Orthognathic Surgery
Scalp reconstruction
Zygoma reduction plasty
Neuroplastic Surgery
Craniofacial Fellowship
== References ==
== Further reading ==
Parens, E., Ed. (2006). Surgically Shaping Children : Technology, Ethics, and the Pursuit of Normality. Baltimore, Johns Hopkins University Press. ISBN 0-8018-8305-9.
"Faltenkorrektur" (in German).
== External links ==
Journal of Craniofacial Surgery
American Society of Craniofacial Surgery | Wikipedia/Craniofacial_surgery |
Laparoscopy (from Ancient Greek λαπάρα (lapára) 'flank, side' and σκοπέω (skopéō) 'to see') is an operation performed in the abdomen or pelvis using small incisions (usually 0.5–1.5 cm) with the aid of a camera. The laparoscope aids diagnosis or therapeutic interventions with a few small cuts in the abdomen.
Laparoscopic surgery, also called minimally invasive procedure, bandaid surgery, or keyhole surgery, is a modern surgical technique. There are a number of advantages to the patient with laparoscopic surgery versus an exploratory laparotomy. These include reduced pain due to smaller incisions, reduced hemorrhaging, and shorter recovery time. The key element is the use of a laparoscope, a long fiber optic cable system that allows viewing of the affected area by snaking the cable from a more distant, but more easily accessible location.
Laparoscopic surgery includes operations within the abdominal or pelvic cavities, whereas keyhole surgery performed on the thoracic or chest cavity is called thoracoscopic surgery. Specific surgical instruments used in laparoscopic surgery include obstetrical forceps, scissors, probes, dissectors, hooks, and retractors. Laparoscopic and thoracoscopic surgery belong to the broader field of endoscopy. The first laparoscopic procedure was performed by German surgeon Georg Kelling in 1901.
== Types of laparoscopes ==
There are two types of laparoscope:
A telescopic rod lens system, usually connected to a video camera (single-chip CCD or three-chip CCD)
A digital laparoscope where a miniature digital video camera is placed at the end of the laparoscope, eliminating the rod lens system
The mechanism mentioned in the second type is mainly used to improve the image quality of flexible endoscopes, replacing conventional fiberscopes. Nevertheless, laparoscopes are rigid endoscopes. Rigidity is required in clinical practice. The rod-lens-based laparoscopes dominate overwhelmingly in practice, due to their fine optical resolution (50 μm typically, dependent on the aperture size used in the objective lens), and the image quality can be better than that of the digital camera if necessary. The second type of laparoscope is very rare in the laparoscope market and in hospitals.
Also attached is a fiber optic cable system connected to a "cold" light source (halogen or xenon) to illuminate the operative field, which is inserted through a 5 mm or 10 mm cannula or trocar. The abdomen is usually insufflated with carbon dioxide gas as the safety, harms, and benefits of other gasses (e.g., helium, argon, nitrogen, nitrous oxide, and room air) is uncertain. This elevates the abdominal wall above the internal organs to create a working and viewing space. CO2 is used because it is common to the human body and can be absorbed by tissue and removed by the respiratory system. It is also non-flammable, which is important because electrosurgical devices are commonly used in laparoscopic procedures.
== Procedures ==
=== Patient position ===
During the laparoscopic procedure, the position of the patient is either in Trendelenburg position or in reverse Trendelenburg. These positions have an effect on cardiopulmonary function. In Trendelenburg's position, there is an increased preload due to an increase in the venous return from lower extremities. This position results in cephalic shifting of the viscera, which accentuates the pressure on the diaphragm. In the case of reverse Trendelenburg position, pulmonary function tends to improve as there is a caudal shifting of viscera, which improves tidal volume by a decrease in the pressure on the diaphragm. This position also decreases the preload on the heart and causes a decrease in the venous return leading to hypotension. The pooling of blood in the lower extremities increases the stasis and predisposes the patient to develop deep vein thrombosis (DVT).
=== Gallbladder ===
Rather than a minimum 20 cm incision as in traditional (open) cholecystectomy, four incisions of 0.5–1.0 cm, or, beginning in the second decade of the 21st century, a single incision of 1.5–2.0 cm, will be sufficient to perform a laparoscopic removal of a gallbladder.
Since the gallbladder is similar to a small balloon that stores and releases bile, it can usually be removed from the abdomen by suctioning out the bile and then removing the deflated gallbladder through the 1 cm incision at the patient's navel.
The length of postoperative stay in the hospital is minimal,
and most patients can be safely discharged from the hospital the same day.
=== Colon and kidney ===
In certain advanced laparoscopic procedures, where the specimen removed is too large to pull through a trocar site (as is done with gallbladders), an incision larger than 10 mm must be made. The most common of these procedures are removal of all or part of the colon (colectomy), or removal of the kidney (nephrectomy). Some surgeons perform these procedures completely laparoscopically, making the larger incision toward the end of the procedure for specimen removal, or, in the case of a colectomy, to also prepare the remaining healthy bowel to be reconnected (create an anastomosis). Many other surgeons feel that since they will have to make a larger incision for specimen removal anyway, they might as well use this incision to have their hand in the operative field during the procedure to aid as a retractor, dissector, and to be able to feel differing tissue densities (palpate), as they would in open surgery. This technique is called hand-assist laparoscopy. Since they will still be working with scopes and other laparoscopic instruments, CO2 will have to be maintained in the patient's abdomen, so a device known as a hand access port (a sleeve with a seal that allows passage of the hand) must be used. Surgeons who choose this hand-assist technique feel it reduces operative time significantly versus the straight laparoscopic approach. It also gives them more options in dealing with unexpected adverse events (e.g., uncontrolled bleeding) that may otherwise require creating a much larger incision and converting to a fully open surgical procedure.
Conceptually, the laparoscopic approach is intended to minimise post-operative pain and speed up recovery times, while maintaining an enhanced visual field for surgeons. Due to improved patient outcomes in the early 21st century, laparoscopic surgery has been adopted by various surgical sub-specialties, including gastrointestinal surgery (including bariatric procedures for morbid obesity), gynecologic surgery, and urology. Based on numerous prospective randomized controlled trials, the approach has proven to be beneficial in reducing post-operative morbidities such as wound infections and incisional hernias (especially in morbidly obese patients), and is now deemed safe when applied to surgery for cancers such as cancer of colon.
The restricted vision, the difficulty in handling of the instruments (new hand-eye coordination skills are needed), the lack of tactile perception, and the limited working area are factors adding to the technical complexity of this surgical approach. For these reasons, minimally invasive surgery has emerged as a highly competitive new sub-specialty within various fields of surgery. Surgical residents who wish to focus on this area of surgery gain additional laparoscopic surgery training during one or two years of fellowship after completing their basic surgical residency. In OB-GYN residency programs, the average laparoscopy-to-laparotomy quotient (LPQ) is 0.55.
=== In veterinary medicine ===
Laparoscopic techniques have also been developed in the field of veterinary medicine. Due to the relatively high cost of the equipment required, it has not become commonplace in most traditional practices today but rather limited to specialty practices. Many of the same surgeries performed in humans can be applied to animal cases – everything from an egg-bound tortoise to a German Shepherd can benefit from MIS. A paper published in JAVMA (Journal of the American Veterinary Medical Association) in 2005 showed that dogs spayed laparoscopically experienced significantly less pain (65%) than those that were spayed with traditional "open" methods. Arthroscopy, thoracoscopy, and cystoscopy are all performed in veterinary medicine today.
=== Advantages ===
There are a number of advantages to the patient with laparoscopic surgery versus an open procedure. These include:
Reduced hemorrhaging, which reduces the chance of needing a blood transfusion.
Smaller incision, which reduces pain and shortens recovery time, as well as resulting in less post-operative scarring.
Less pain, leading to less pain medication needed.
Use of regional anesthesia (with the recommendation of using a combined spinal and epidural anaesthesia) for laparoscopic surgery, as opposed to general anesthesia required for many non-laparoscopic procedures, can produce fewer complications and quicker recovery.
Although procedure times are usually slightly longer, hospital stay is less, and often with a same day discharge which leads to a faster return to everyday living.
Reduced exposure of internal organs to possible external contaminants, thereby reduced risk of acquiring infections.
Although laparoscopy in adults is widely accepted, its advantages in children are questioned. Benefits of laparoscopy appear to recede with younger age. Efficacy of laparoscopy is inferior to open surgery in certain conditions such as pyloromyotomy for infantile hypertrophic pyloric stenosis. Although laparoscopic appendectomy has less wound problems than open surgery, the former is associated with more intra-abdominal abscesses.
=== Disadvantages ===
While laparoscopic surgery is clearly advantageous in terms of patient outcomes, the procedure is more difficult from the surgeon's perspective when compared to conventional, open surgery:
Laparoscopic surgery requires pneumoperitoneum for adequate visualization and operative manipulation.
The surgeon has a limited range of motion at the surgical site, resulting in a loss of dexterity.
Poor depth perception.
Surgeons must use tools to interact with tissue rather than manipulate it directly with their hands. This results in an inability to accurately judge how much force is applied to tissue and higher risk of damaging tissue by applying more force than necessary. This limitation also reduces tactile sensation, making it more difficult for the surgeon to feel tissue (sometimes an important diagnostic tool, such as when palpating for tumors) and making delicate operations such as tying sutures more difficult.
The tool endpoints move in the opposite direction to the surgeon's hands due to the pivot point, making laparoscopic surgery a non-intuitive motor skill that is difficult to learn. This is called the fulcrum effect.
Some surgeries (carpal tunnel for instance) generally turn out better for the patient when the area can be opened up, allowing the surgeon to see the surrounding physiology, to better address the issue at hand. In this regard, keyhole surgery can be a disadvantage.
== Risks ==
Some of the risks are briefly described below:
The major problems during laparoscopic surgery are related to the cardiopulmonary effect of pneumoperitoneum, systemic carbon dioxide absorption, venous gas embolism, unintentional injuries to intra-abdominal structures and patient positioning.
The most significant risks are from trocar injuries during insertion into the abdominal cavity, as the trocar is typically inserted blindly. Injuries include abdominal wall hematoma, umbilical hernias, umbilical wound infection, and penetration of blood vessels or small or large bowel. The risk of such injuries is increased in patients who have a low body mass index or have a history of prior abdominal surgery. While these injuries are rare, significant complications can occur, and they are primarily related to the umbilical insertion site. Vascular injuries can result in hemorrhage that may be life-threatening. Injuries to the bowel can cause a delayed peritonitis. It is very important that these injuries be recognized as early as possible.
In oncologic laparoscopic procedures there is a risk of port site metastases, especially in patients with peritoneal carcinomatosis. This incidence of iatrogenic dissemination of cancer might be reduced with special measures as trocar site protection and midline placement of trocars.
Some patients have sustained electrical burns unseen by surgeons who are working with electrodes that leak current into surrounding tissue. The resulting injuries can result in perforated organs and can also lead to peritonitis.
About 20% of patients undergo hypothermia during surgery and peritoneal trauma due to increased exposure to cold, dry gases during insufflation. The use of surgical humidification therapy, which is the use of heated and humidified CO2 for insufflation, has been shown to reduce this risk.
Not all of the CO2 introduced into the abdominal cavity is removed through the incisions during surgery. Gas tends to rise, and when a pocket of CO2 rises in the abdomen, it pushes against the diaphragm (the muscle that separates the abdominal from the thoracic cavities and facilitates breathing), and can exert pressure on the phrenic nerve. This produces a sensation of pain that may extend to the patient's shoulders in about 80% of women for example. In all cases, the pain is transient, as the body tissues will absorb the CO2 and eliminate it through respiration.
Coagulation disorders and dense adhesions (scar tissue) from previous abdominal surgery may pose added risk for laparoscopic surgery and are considered relative contra-indications for this approach.
Intra-abdominal adhesion formation is a risk associated with both laparoscopic and open surgery and remains a significant, unresolved problem. Adhesions are fibrous deposits that connect tissue to organ post surgery. Generally, they occur in 50-100% of all abdominal surgeries, with the risk of developing adhesions the same for both procedures. Complications of adhesions include chronic pelvic pain, bowel obstruction, and female infertility. In particular, small bowel obstruction poses the most significant problem. The use of surgical humidification therapy during laparoscopic surgery may minimise the incidence of adhesion formation. Other techniques to reduce adhesion formation include the use of physical barriers such as films or gels, or broad-coverage fluid agents to separate tissues during healing following surgery.
The gas used to make space and the smoke generated during surgical procedures can leak into the operating room through or around access devices as well as instruments. The gas plume can pollute the airspace shared by the operating team and patient with particles and potentially pathogens, including viral particles.
== Robotic laparoscopic surgery ==
In recent years, electronic tools have been developed to aid surgeons. Some of the features include:
Visual magnification — use of a large viewing screen improves visibility
Stabilization — Electromechanical damping of vibrations, due to machinery or shaky human hands
Simulators — use of specialized virtual reality training tools to improve physicians' proficiency in surgery
Reduced number of incisions
Robotic surgery has been touted as a solution to underdeveloped nations, whereby a single central hospital can operate several remote machines at distant locations. The potential for robotic surgery has had a strong military interest as well, with the intention of providing mobile medical care while keeping trained doctors safe from battle.
In January 2022, a robot performed the first ever successful laparoscopic surgery without the help of a human. The robot performed the surgery on the soft tissue of a pig. It succeeded at intestinal anastomosis, a procedure that involves connecting two ends of an intestine. The robot, named the Smart Tissue Autonomous Robot (STAR), was designed by a team of Johns Hopkins University researchers.
== Non-robotic hand-guided assistance systems ==
There are also user-friendly nonrobotic assistance systems that are single-hand guided devices with a high potential to save time and money. These assistance devices are not bound by the restrictions of common medical robotic systems. The systems enhance the manual possibilities of the surgeon and his/her team, regarding the need of replacing static holding force during the intervention.
With laparoscopy providing tissue diagnosis and helping to achieve the final diagnosis without any significant complication and less operative time, it can be safely concluded that diagnostic laparoscopy is a safe, quick, and effective adjunct to non‑surgical diagnostic modalities, for establishing a conclusive diagnosis, but whether it will replace imaging studies as a primary modality for diagnosis needs more evidence.
== History ==
It is difficult to credit one individual with the pioneering of the laparoscopic approach. In 1901, Georg Kelling of Dresden, Germany, performed the first laparoscopic procedure in dogs, and, in 1910, Hans Christian Jacobaeus of Sweden performed the first laparoscopic operation in humans.
In the ensuing several decades, numerous individuals refined and popularized the approach further for laparoscopy. The advent of computer chip-based television cameras was a seminal event in the field of laparoscopy. This technological innovation provided the means to project a magnified view of the operative field onto a monitor and, at the same time, freed both the operating surgeon's hands, thereby facilitating performance of complex laparoscopic procedures.
The first publication on modern diagnostic laparoscopy by Raoul Palmer appeared in 1947, followed by the publication of Hans Frangenheim and Kurt Semm, who both practised CO2 hysteroscopy from the mid-1970s.
Patrick Steptoe, one of the pioneers of IVF, was important in popularizing laparoscopy in the UK. He published a textbook, Laparoscopy in Gynaecology, in 1967.
In 1972, H. Courtenay Clarke invented, published, patented, presented, and recorded on film laparoscopic surgery, with instruments he invented and were marketed by the Ven Instrument Company of Buffalo, New York. He was the first to perform a surgical laparoscopic process with standard sutures and simple instruments. This was meant to facilitate the application of laparoscopic surgery to all economic sectors by avoiding expensive materials and devices.
In 1975, Tarasconi, from the Department of Ob-Gyn of the University of Passo Fundo Medical School (Passo Fundo, RS, Brazil), started his experience with organ resection by laparoscopy (Salpingectomy), first reported in the Third AAGL Meeting, Hyatt Regency Atlanta, November 1976 and later published in The Journal of Reproductive Medicine in 1981.
This laparoscopic surgical procedure was the first laparoscopic organ resection reported in medical literature.
In 1981, Semm, from the gynecological clinic of Kiel University, Germany, performed the first laparoscopic appendectomy. Following his lecture on laparoscopic appendectomy, the president of the German Surgical Society wrote to the Board of Directors of the German Gynecological Society suggesting suspension of Semm from medical practice. Subsequently, Semm submitted a paper on laparoscopic appendectomy to the American Journal of Obstetrics and Gynecology, at first rejected as unacceptable for publication on the grounds that the technique reported on was "unethical," but finally published in the journal Endoscopy. The abstract of his paper on endoscopic appendectomy can be found at the journal site.
Semm established several standard procedures that were regularly performed, such as ovarian cyst enucleation, myomectomy, treatment of ectopic pregnancy and finally laparoscopic-assisted vaginal hysterectomy (also termed cervical intra-fascial Semm hysterectomy). He also developed a medical instrument company Wisap in Munich, Germany, which still produces various endoscopic instruments. In 1985, he constructed the pelvi-trainer = laparo-trainer, a practical surgical model whereby colleagues could practice laparoscopic techniques. Semm published over 1000 papers in various journals. He also produced over 30 endoscopic films and more than 20,000 colored slides to teach and inform interested colleagues about his technique. His first atlas, More Details on Pelviscopy and Hysteroscopy was published in 1976, a slide atlas on pelviscopy, hysteroscopy, and fetoscopy in 1979, and his books on gynecological endoscopic surgery in German, English, and many other languages in 1984, 1987, and 2002.
In 1985, Erich Mühe, professor of surgery in Germany, performed the first laparoscopic cholecystectomy. Afterward, laparoscopy gained rapid acceptance for non-gynecologic applications. The first video-assisted laparoscopic surgery was performed in 1987, a laparoscopic cholecystectomy. Before this time, the operating field was visualised by surgeons directly via a laparoscope.
In 1987, Alfred Cuschieri performed the first minimally invasive surgery in the UK with his team at Ninewells Hospital after working with multiple researchers from across the world, including Patrick Steptoe. Cuschieri took advantage of smaller cameras to perform operations with smaller cuts and shorter recovery times. After some controversy and patient deaths, new laparoscopic training centres were set up as most surgeons lacked the necessary specialised training to perform laparoscopic surgery. The first opened in Dundee in 1991 and became the Cuschieri Skills Centre at Ninewells Hospital in 2004. As of 2008, 40 specialist centres around the world base their laparoscopic training on the Cuschieri Skills Centre.
Prior to Mühe, the only specialty performing laparoscopy on a widespread basis was gynecology, mostly for relatively short, simple procedures such as a diagnostic laparoscopy or tubal ligation. The introduction in 1990 of a laparoscopic clip applier with twenty automatically advancing clips (rather than a single load clip applier that would have to be taken out, reloaded and reintroduced for each clip application) made general surgeons more comfortable with making the leap to laparoscopic cholecystectomies ( gall bladder removal). On the other hand, some surgeons continue to use the single clip appliers as they save as much as $200 per case for the patient, detract nothing from the quality of the clip ligation, and add only seconds to case lengths. Both laparoscopy tubal ligations and cholecystectomies may be performed using suturing and tying, thus further reducing the expensive cost of single and multiclips (when compared to suture). Once again this may increase case lengths but costs are greatly reduced (ideal for developing countries) and widespread accidents of loose clips are eliminated.
The first transatlantic surgery performed was a laparoscopic gallbladder removal in 2001. The first robotic advanced pediatric surgery series were performed overseas in Egypt at Cairo University. Remote surgeries and robotic surgeries have since become more common and are typically laparoscopic procedures.
== Surgical associations ==
There are many International and American Surgical Associations involved in surgical education and training for laparoscopy, thoracoscopy and many minimally invasive procedures for both adults and pediatrics. These societies include:
=== For adults ===
Society of American Gastrointestinal and Endoscopic Surgeons (SAGES)
Society of Laparoscopic & Robotic Surgeons
World Association of Laparoscopic Surgeons
=== For pediatric surgery ===
International Pediatric Endosurgery Group (IPEG)
European Society of Paediatric Endoscopic Surgeons (ESPES)
British Association Of Paediatric Endoscopic Surgeons (BAPES)
== Gynecological diagnosis ==
In gynecology, diagnostic laparoscopy may be used to inspect the outside of the uterus, ovaries, and fallopian tubes, as, for example, in the diagnosis of female infertility. Usually, one incision is placed near the navel and a second near the pubic hairline. A special type of laparoscope called a fertiloscope, which is modified for transvaginal application, can be used. A dye test may be performed to detect any blockage in the reproductive tract, wherein a dark blue dye is passed up through the cervix and is followed with the laparoscope through its passage out into the fallopian tubes to the ovaries.
== See also ==
Arthroscopic surgery – Examination of a joint via small surgical incisionPages displaying short descriptions of redirect targets
Invasiveness of surgical procedures – Surgical technique that limits size of surgical incisions neededPages displaying short descriptions of redirect targets
Laparotomy – Surgical procedure to open the abdominal cavity
Minimally invasive procedure
Natural orifice translumenal endoscopic surgery – medical specialityPages displaying wikidata descriptions as a fallback
Percutaneous – A surgical procedure
Revision weight loss surgery
Single port laparoscopy – medical interventionPages displaying wikidata descriptions as a fallback
== References ==
== External links ==
Feder, Barnaby J. (17 March 2006). "Surgical Device Poses a Rare but Serious Peril". The New York Times. | Wikipedia/Laparoscopic_surgery |
Otorhinolaryngology ( oh-toh-RY-noh-LARR-in-GOL-ə-jee, abbreviated ORL and also known as otolaryngology, otolaryngology – head and neck surgery (ORL–H&N or OHNS), or ear, nose, and throat (ENT) ) is a surgical subspecialty within medicine that deals with the surgical and medical management of conditions of the head and neck. Doctors who specialize in this area are called otorhinolaryngologists, otolaryngologists, head and neck surgeons, or ENT surgeons or physicians.
Patients seek treatment from an otorhinolaryngologist for diseases of the ear, nose, throat, base of the skull, head, and neck. These commonly include functional diseases that affect the senses and activities of eating, drinking, speaking, breathing, swallowing, and hearing. In addition, ENT surgery encompasses the surgical management of cancers and benign tumors and reconstruction of the head and neck as well as plastic surgery of the face, scalp, and neck.
== Etymology ==
The term is a combination of Neo-Latin combining forms (oto- + rhino- + laryngo- + -logy) derived from four Ancient Greek words: (cf. Greek ωτορινολαρυγγολόγος 'otorhinolaryngologist').
== Training ==
Otorhinolaryngologists are physicians (MD, DO, MBBS, MBChB, etc.) who complete both medical school and an average of five–seven years of post-graduate surgical training in ORL-H&N. In the United States, trainees complete at least five years of surgical residency training. This comprises three to six months of general surgical training and four and a half years in ORL-H&N specialist surgery. In Canada and the United States, practitioners complete a five-year residency training after medical school.
Following residency training, some otolaryngologist-head & neck surgeons complete an advanced sub-specialty fellowship, where training can be one to two years in duration. Fellowships include head and neck surgical oncology, facial plastic surgery, rhinology and sinus surgery, neuro-otology, pediatric otolaryngology, and laryngology. In the United States and Canada, otorhinolaryngology is one of the most competitive specialties in medicine in which to obtain a residency position following medical school.
In the United Kingdom, entrance to higher surgical training is competitive and involves a rigorous national selection process. The training programme consists of 6 years of higher surgical training after which trainees frequently undertake fellowships in a sub-speciality prior to becoming a consultant.
The typical total length of education, training and post-secondary school is 12–14 years. Otolaryngology is among the more highly compensated surgical specialties in the United States. In 2022, the average annual income was $469,000.
== Sub-specialties ==
(*Currently recognized by American Board of Medical Subspecialties)
== Topics by subspecialty ==
=== Head and neck surgery ===
Head and neck surgical oncology (field of surgery treating cancer/malignancy of the head and neck)
Head and neck mucosal malignancy (cancer of the pink lining of the upper aerodigestive tract)
Oral cancer (cancer of lips, gums, tongue, hard palate, cheek, floor of mouth)
Oropharyngeal cancer (cancer of oropharynx, soft palate, tonsil, base of tongue)
Larynx cancer (voice box cancer)
Hypopharynx cancer (lower throat cancer)
Sinonasal cancer
Nasopharyngeal cancer
Skin cancer of the head & neck
Thyroid cancer
Salivary gland cancer
Head and neck sarcoma
Endocrine surgery of the head and neck
Thyroid surgery
Parathyroid surgery
Microvascular free flap reconstructive surgery
Skull base surgery
=== Otology and neurotology ===
Study of diseases of the outer ear, middle ear and mastoid, and inner ear, and surrounding structures (such as the facial nerve and lateral skull base)
Outer ear diseases
Otitis externa –
outer ear or ear canal inflammation
Exostoses or Surfer's ear are bony growths in the outer ear canal
Middle ear and mastoid diseases
Otitis media – middle ear inflammation
Perforated eardrum (hole in the eardrum due to infection, trauma, explosion or loud noise)
Mastoiditis
Inner ear diseases
BPPV – benign paroxysmal positional vertigo
Labyrinthitis/Vestibular neuronitis
Ménière's disease/Endolymphatic hydrops
Perilymphatic fistula
Acoustic neuroma, vestibular schwannoma
Facial nerve disease
Idiopathic facial palsy (Bell's Palsy)
Facial nerve tumors
Ramsay Hunt Syndrome
Symptoms
Hearing loss
Tinnitus (subjective noise in the ear)
Aural fullness (sense of fullness in the ear)
Otalgia (pain referring to the ear)
Otorrhea (fluid draining from the ear)
Vertigo
Imbalance
=== Rhinology ===
Rhinology includes nasal dysfunction and sinus diseases.
Nasal obstruction
Inferior turbinate hypertrophy
Nasal septum deviation
Chronic sinusitis with nasal polyps
Sinusitis – acute, chronic
Environmental allergies
Rhinitis
Pituitary tumor
Empty nose syndrome
Severe or recurrent epistaxis
=== Pediatric otorhinolaryngology ===
Adenoidectomy
Caustic ingestion
Cricotracheal resection
Decannulation
Laryngomalacia
Laryngotracheal reconstruction
Myringotomy and tubes
Obstructive sleep apnea – pediatric
Tonsillectomy
=== Laryngology ===
Dysphonia/hoarseness
Laryngitis
Reinke's edema
Vocal cord nodules and polyps
Spasmodic dysphonia
Tracheostomy
Cancer of the larynx
Vocology – science and practice of voice habilitation
=== Facial plastic and reconstructive surgery ===
Facial plastic and reconstructive surgery is a one-year fellowship open to otorhinolaryngologists who wish to begin learning the aesthetic and reconstructive surgical principles of the head, face, and neck pioneered by the specialty of Plastic and Reconstructive Surgery.
Rhinoplasty and septoplasty
Facelift (rhytidectomy)
Browlift
Blepharoplasty
Otoplasty
Genioplasty
Injectable cosmetic treatments
Trauma to the face
Nasal bone fracture
Mandible fracture
Orbital fracture
Frontal sinus fracture
Complex lacerations and soft tissue damage
Skin cancer (e.g. Basal Cell Carcinoma)
=== Sleep surgery ===
Sleep surgery encompasses any surgery that helps alleviate obstructive sleep apnea and can anatomically include any part of the upper airway.
Nasal cavity / nasopharynx
Septoplasty
Adenoidectomy (especially in pediatrics)
Oral cavity / oropharynx
Tonsillectomy (especially in pediatrics)
Uvulopalatopharyngoplasty
Transoral midline glossectomy
Genioglossus advancement
Other
Hyoid suspension
Maxillomandibular advancement
Hypoglossal nerve stimulation
=== Microvascular reconstruction repair ===
Microvascular reconstruction repair is a common operation that is done on patients who see an otorhinolaryngologist. It is a surgical procedure that involves moving a composite piece of tissue from the patient's body and to the head and/or neck. Microvascular head-and-neck reconstruction is used to treat head-and-neck cancers, including those of the larynx and pharynx, oral cavity, salivary glands, jaws, calvarium, sinuses, tongue and skin. The tissue that is most commonly moved during this procedure is from the arms, legs, and back, and can come from the skin, bone, fat, and/or muscle.
When performing this procedure, the decision on which is moved is determined on the reconstructive needs. Transfer of the tissue to the head and neck allows surgeons to rebuild the patient's jaw, optimize tongue function, and reconstruct the throat. When the pieces of tissue are moved, they require their own blood supply for a chance of survival in their new location. After the surgery is completed, the blood vessels that feed the tissue transplant are reconnected to new blood vessels in the neck. These blood vessels are typically no more than 1 to 3 millimeters in diameter, which means that these connections need to be made with a microscope, which is why the procedure is called "microvascular surgery".
== See also ==
== References == | Wikipedia/ENT_surgery |
Surgery is a medical specialty that uses operative treatment.
Surgery may also refer to:
== Medicine ==
Operating theater, where surgery is performed, or the offices of the practitioner, the surgeon
Doctor's surgery, British term for a doctor's office, a facility in which a general practitioner sees patients
Surgery (journal), a medical journal
== Mathematics ==
Surgery theory, a mathematical operation used in topology; two special cases are:
Dehn surgery
Hyperbolic Dehn surgery
== Arts, entertainment, and media ==
Surgery (band), an American noise rock band
The Surgery, a weekly radio show on BBC Radio 1
Surgery (album), a 2005 album by The Warlocks
"Surgery", a song by Robyn Hitchcock on his compilation album You & Oblivion
"Surgery", a song by Jack Off Jill on their album Clear Hearts Grey Flowers
"Surgery", a song by Two Door Cinema Club on their album Gameshow
"Surgery" (short story), a short story by Anton Chekhov
== Other uses ==
Surgery (politics), a series of one-to-one meetings that a political officeholder may have with his or her constituents | Wikipedia/Surgery_(disambiguation) |
Urology (from Greek οὖρον ouron "urine" and -λογία -logia "study of"), also known as genitourinary surgery, is the branch of medicine that focuses on surgical and medical diseases of the urinary system and the reproductive organs. Organs under the domain of urology include the kidneys, adrenal glands, ureters, urinary bladder, urethra, and the male reproductive organs (testes, epididymides, vasa deferentia, seminal vesicles, prostate, and penis).
The urinary and reproductive tracts are closely linked, and disorders of one often affect the other. Thus a major spectrum of the conditions managed in urology exists under the domain of genitourinary disorders. Urology combines the management of medical (i.e., non-surgical) conditions, such as urinary-tract infections and benign prostatic hyperplasia, with the management of surgical conditions such as bladder or prostate cancer, kidney stones, congenital abnormalities, traumatic injury, and stress incontinence.
Urological techniques include minimally invasive robotic and laparoscopic surgery, laser-assisted surgeries, and other scope-guided procedures. Urologists receive training in open and minimally invasive surgical techniques, employing real-time ultrasound guidance, fiber-optic endoscopic equipment, and various lasers in the treatment of multiple benign and malignant conditions. Urology is closely related to (and urologists often collaborate with the practitioners of) oncology, nephrology, gynaecology, andrology, pediatric surgery, colorectal surgery, gastroenterology, and endocrinology.
Urology is one of the most competitive and highly sought surgical specialties for physicians, with new urologists comprising less than 1.5% of United States medical-school graduates each year.
Urologists are physicians which have specialized in the field after completing their general degree in medicine. Upon successful completion of a residency program, many urologists choose to undergo further advanced training in a subspecialty area of expertise through a fellowship lasting an additional 12 to 36 months. Subspecialties may include: urologic surgery, urologic oncology and urologic oncological surgery, endourology and endourologic surgery, urogynecology and urogynecologic surgery, reconstructive urologic surgery (a form of reconstructive surgery), minimally-invasive urologic surgery, pediatric urology and pediatric urologic surgery (including adolescent urology, the treatment of premature or delayed puberty, and the treatment of congenital urological syndromes, malformations, and deformations), transplant urology (the field of transplant medicine and surgery concerned with transplantation of organs such as the kidneys, bladder tissue, ureters, and, recently, penises), voiding dysfunction, paruresis, neurourology, and androurology and sexual medicine. Additionally, some urologists supplement their fellowships with a master's degree (2–3 years) or with a Ph.D. (4–6 years) in related topics to prepare them for academic as well as focused clinical employment.
== Training ==
=== United States ===
As of 2022, there are 146 residency programs that offered 356 categorical positions. Urology is one of the early match programs, with results given to applicants by early February (6 weeks before NRMP match). Applications are accepted starting Sep 1, with some programs accepting applications until early Jan.
It is a relatively competitive specialty to match into, with only 65.6% of US seniors matching in the 2022 match cycle. The number of positions has grown from 278 in 2012 to 356 in 2022. Matching is significantly more difficult for IMGs and students who have a year or more off before residency - match rates were 27% and 55% respectively in 2012.
The medical school environment may also be a factor. A study in 2012 also showed after an analysis of match rates from schools between 2005 and 2009 that 20 schools sent more than 15 students into urology (1 standard deviation above the median), with Northwestern University sending 44 students over those five years.
After urology residency, there are seven subspecialties recognized by the AUA (American Urological Association):
Oncology
Calculi
Female Urology
Infertility
Pediatrics
Transplant (renal)
Neurourology.
=== Australia ===
Training is completed through the Royal Australasian College of Surgeons (RACS). The program requires six years of full-time training (for those who commenced prior to 2016), or five years for those who commenced after 2016. The program is accredited by the Australian Medical Council.
=== Nepal ===
In Nepal, the formal urologist degree awarded is MCh (Magister Chirurgiae). This is a three years course post masters and includes thesis and a mandatory publication. This degree is awarded after completing MBBS (four and half year plus a one-year rotatory internship) and MS (Mastery of surgery) in general surgery (three years course). Till now two universities Tribhuvan University and Kathmandu University as well as two Autonomous institutes BP Koirala Institute of health sciences and National Academy of Medical Sciences (Bir Hospital) run the MCh Urology programme. This degree is equivalent to Clinical PhD and called as "Chikitsa Bidhyabaridhi" by Tribhuvan University (Government University) and is considered to be the highest degree among the surgical discipline degrees.
=== Ethiopia ===
In Ethiopia, in 2001, there were only five qualified urologists. All trained abroad, in countries like India, Tanzania and Hungary. Before this chapter all urology cases were managed by general surgeons. The only urological unit in the country was at Tikur Anbessa Tertiary Hospital. The services provided included ESWL and endo-urology. The urology training program was started in 2009 with a curriculum for general surgeons which had a three-year training program. Up to 2019, six urologists have graduated by this program for general surgeons. The first residency program started accepting general practitioners in 2010 for a five-year program. The first two years were trainings in general surgery, the next three years were dedicated urology training program, which included the same three-year training as of the general surgeons three year curriculum. It started with two residents who graduated in 2015 with a certificate in specialty of urology. Up to 2019, seventeen urologists have graduated from this five-year residency program. From the start these programs in 2009 up to 2019, a total of 23 urologists have been trained in Tikur Anbessa Tertioary Hospital. As of 2020, there were 26 trainees in the programme. All of the urologists who graduated from Tikur Anbessa Tertioary Hospital were as of 2020 working in different parts of the country.
== Subdisciplines ==
As a medical discipline that involves the care of many organs and physiological systems, urology can be broken down into several subdisciplines. At many larger academic centers and university hospitals that excel in patient care and clinical research, urologists often specialize in a particular sub discipline.
=== Endourology ===
Endourology is the branch of urology that deals with the closed manipulation of the urinary tract. It has lately grown to include all minimally invasive urologic surgical procedures. As opposed to open surgery, endourology is performed using small cameras and instruments inserted into the urinary tract. Transurethral surgery has been the cornerstone of endourology. Most of the urinary tract can be reached via the urethra, enabling prostate surgery, surgery of tumors of the urothelium, stone surgery, and simple urethral and ureteral procedures. Recently, the addition of laparoscopy and robotics has further subdivided this branch of urology.
=== Laparoscopy ===
Laparoscopy is a rapidly evolving branch of urology and has replaced some open surgical procedures. Robot-assisted surgery of the prostate, kidney, and ureter has been expanding this field. Today, many prostatectomies in the United States are carried out by so-called robotic assistance. This has created controversy, however, as robotics greatly increase the cost of surgery and the benefit for the patient may or may not be proportional to the extra cost. Moreover, current (2011) market situation for robotic equipment is a de facto monopoly of one publicly held corporation which further fuels the cost-effectiveness controversy.
=== Urologic oncology ===
Urologic oncology concerns the surgical treatment of malignant genitourinary diseases such as cancer of the prostate, adrenal glands, bladder, kidneys, ureters, testicles, and penis, as well as the skin and subcutaneous tissue and muscle and fascia of those areas (that particular subspecialty overlaps with dermatological oncology and related areas of oncology). The treatment of genitourinary cancer is managed by either a urologist or an oncologist, depending on the treatment type (surgical or medical). Most urologic oncologists in Western countries use minimally invasive techniques (laparoscopy or endourology, robotic-assisted surgery) to manage urologic cancers amenable to surgical management.
=== Neurourology ===
Neurourology concerns nervous system control of the genitourinary system, and of conditions causing abnormal urination. Neurological diseases and disorders such as a stroke, multiple sclerosis, Parkinson's disease, and spinal cord injury can disrupt the lower urinary tract and result in conditions such as urinary incontinence, detrusor overactivity, urinary retention, and detrusor sphincter dyssynergia. Urodynamic studies play an important diagnostic role in neurourology. Therapy for nervous system disorders includes clean intermittent self-catheterization of the bladder, anticholinergic drugs, injection of Botulinum toxin into the bladder wall and advanced and less commonly used therapies such as sacral neuromodulation.
Less marked neurological abnormalities can cause urological disorders as well—for example, abnormalities of the sensory nervous system are thought by many researchers to play a role in disorders of painful or frequent urination (e.g. painful bladder syndrome also known as interstitial cystitis).
=== Pediatric urology ===
Pediatric urology concerns urologic disorders in children. Such disorders include cryptorchidism (undescended testes), congenital abnormalities of the genitourinary tract, enuresis, underdeveloped genitalia (due to delayed growth or delayed puberty, often an endocrinological problem), and vesicoureteral reflux.
=== Andrology ===
Andrology is the medical specialty that deals with male health, particularly relating to the problems of the male reproductive system and urological problems that are unique to men such as prostate cancer, male fertility problems, and surgery of the male reproductive system. It is the counterpart to gynaecology, which deals with medical issues that are specific to female health, especially reproductive and urologic health.
=== Reconstructive urology ===
Reconstructive urology is a highly specialized field of male urology that restores both structure and function to the genitourinary tract. Prostate procedures, full or partial hysterectomies, trauma (auto accidents, gunshot wounds, industrial accidents, straddle injuries, etc.), disease, obstructions, blockages (e.g., urethral strictures), and occasionally, childbirth, can necessitate reconstructive surgery. The urinary bladder, ureters (the tubes that lead from the kidneys to the urinary bladder) and genitalia are other examples of reconstructive urology.
=== Female urology ===
Female urology is a branch of urology dealing with overactive bladder, pelvic organ prolapse, and urinary incontinence. Many of these physicians also practice neurourology and reconstructive urology as mentioned above. Female urologists complete a 1–3-year fellowship after completion of a 5–6-year urology residency. Thorough knowledge of the female pelvic floor together with intimate understanding of the physiology and pathology of voiding are necessary to diagnose and treat these disorders. Depending on the cause of the individual problem, a medical or surgical treatment can be the solution. Their field of practice heavily overlaps with that of urogynecologists, physicians in a sub-discipline of gynecology, who have done a three-year fellowship after a four-year OBGYN residency.
== Journals and organizations ==
There are a number of peer-reviewed journals and publications about urology, including The Journal of Urology, European Urology, the African Journal of Urology, British Journal of Urology International, BMC Urology, Indian Journal of Urology, Nature Reviews Urology, and Urology.
There are national organizations such as the American Urological Association, the American Association of Clinical Urologists, European Association of Urology, the Large Urology Group Practice Association (LUGPA), and The Society for Basic Urologic Research. Urology is also included under the auspices of the International Continence Society.
Teaching organizations include the European Board of Urology, as well as the Vattikuti Urology Institute in Detroit, which also hosts an annual International Robotic Urology Symposium devoted to new technologies. The American non-profit IVUMed teaches urology in developing countries.
== List of urological topics ==
Benign prostatic hyperplasia
Bladder cancer
Bladder stones
Cystitis
Development of the urinary and reproductive organs
Epididymitis
Erectile dysfunction
Hard flaccid syndrome
Interstitial cystitis
Kidney cancer
Kidney stone
Kidney transplant
Peyronie's disease
Postorgasmic illness syndrome
Prostate cancer
Prostatitis
Replantation
Retrograde pyelogram
Retrograde ureteral
Testicular cancer
Vasectomy
Vasectomy reversal
== See also ==
Category:Urology journals
Category:Urology organizations
== References ==
== External links == | Wikipedia/Urological_surgery |
Postoperative cognitive dysfunction (POCD) is a decline in cognitive function (especially in memory and executive functions) that may last from 1–12 months after surgery, or longer. In some cases, this disorder may persist for several years after major surgery. POCD is distinct from emergence delirium. Its causes are under investigation and occurs commonly in older patients and those with pre-existing cognitive impairment.
The causes of POCD are not understood. It does not appear to be caused by lack of oxygen or impaired blood flow to the brain and is equally likely under regional and general anesthesia. The cause of postoperative cognitive dysfunction are not clear. It is thought that it may be caused by the body's inflammatory response to surgery, stress hormone release during surgery, ischemia, or hypoxaemia.
Post-operative cognitive dysfunction can complicate a person's recovery from surgery, delay discharge from hospital, delay returning to work following surgery, and reduce a person's quality of life.
== Causes ==
The body's inflammatory response to surgery likely plays an important role, at least in elderly patients. Various research initiatives during recent years have evaluated whether actions taken before, during and after surgery can lessen the possible deleterious effects of inflammation. For example, anti-inflammatory agents can be given before surgery. During surgery, inflammation can be modulated by temperature control, use of regional rather than general anesthesia or the use of beta blockers. After surgery, optimal pain management and infection control is important. Several studies have shown variable-significance positive effects when a multidisciplinary, multifactorial approach to elderly patient is followed during pre, peri and post-operative care.
The release of stress hormones during surgery, ischemia, or hypoxemia may also play a role in causing postoperative cognitive dysfunction.
The role of anesthetics in causing postoperative cognitive dysfunction is not clear. A comparison between inhalation anesthetics and intravenous anesthetics to determine which were more likely to cause postoperative cognitive dysfunction when used in the elderly for non-cardiac surgery found that fewer people experienced POCD with total intravenous anesthesia (TIVA) compared to inhalational anesthesia, however, these conclusions are of low quality and further research is necessary to determine differences between the two approaches to anesthesia.
== Prevention ==
Approaches to prevent postoperative cognitive dysfunction include monitoring of anesthetic during surgery and ensuring that the person is in the optimal range to ensure that they are not aware of their surroundings and do not feel pain. An electroencephalograph (EEG) may help guide the surgical team to determine the optimum depth of anesthesia and prevent high or low doses during the surgical procedure. This approach may reduce the risk of a neuroinflammatory response and/or neurological disturbances including cognitive dysfunction.
== Assessment ==
Cognitive tests are given prior to operations to establish a baseline. The same tests are again given post-operatively to determine the extent and duration of the decline for POCD. "A project examining adults 55 and older who have major non-cardiac surgeries is finding that 'upward of 30 percent of patients is testing significantly worse than their baseline 3 months later'".
== Epidemiology ==
POCD is common after cardiac surgery, and recent studies have now verified that POCD also exists after major non-cardiac surgery, although at a lower incidence. The risk of POCD increases with age, and the type of surgery is also important because there is a very low incidence associated with minor surgery. POCD is common in adult patients of all ages at hospital discharge after major noncardiac surgery, but only the elderly (aged 60 years or older) are at significant risk for long-term cognitive problems. Patients with POCD are at an increased risk of death in the first year after surgery. Research interest has increased since early 2000, especially as more elderly patients are able to undergo successful minor and major surgeries.
POCD has been studied through various institutions since the inception of the IPOCDS-I study centred in Eindhoven, Netherlands and Copenhagen, Denmark. This study found no causal relationship between cerebral hypoxia and low blood pressure and POCD. Age, duration of anaesthesia, introperative complications, and postoperative infections were found to be associated with POCD.
POCD is just as likely to occur after operations under regional anesthesia as under general anesthesia.
More likely after major operations than minor operations.
More likely after heart operations than other types of surgery.
More likely in aged than in younger patients.
More likely in older patients with high alcohol intake.
People with higher preoperative ASA physical status scores are more likely to develop POCD.
People with lower educational level are more likely to develop POCD than those with a higher educational level.
People with prior history of a stroke, even though there is complete functional recovery, are more likely to develop POCD.
More likely in the elderly with pre-existing declining mental functions, termed mild cognitive impairment (MCI). MCI is a transitional zone between normal mental function and evident Alzheimer's disease or other forms of dementia. It is insidious, and seldom recognized, except in retrospect after affected persons are evidently demented.
Delirium and severe worsening of mental function is very likely in those with clinically evident Alzheimer's disease or other forms of dementia, as well as those with a history of delirium after previous operations.
== Footnotes ==
== Further reading ==
Szokol, Joseph W. (2010). "Postoperative cognitive dysfunction" (PDF). Revista Mexicana de Anestesiología. 33 (1).
Muñoz-Corsini L, Gómez-Arnau J, Porras MC, Galindo S, Jiménez R (May 1997). "Postoperative cognitive dysfunction". Rev Esp Anestesiol Reanim. 44 (5): 191–200. PMID 9280997.
Crosby, Gregory; Culley, Deborah J. (2011). "Surgery and anesthesia: healing the body but harming the brain?". Anesthesia & Analgesia. 112 (5): 999–1001. doi:10.1213/ANE.0b013e3182160431. PMC 3092153. PMID 21515644.
Rasmussen, L. S. (November 1998). "Defining postoperative cognitive dysfunction". European Journal of Anaesthesiology. 15 (6): 761–764. doi:10.1097/00003643-199811000-00026. PMID 9884870.
Deiner, S.; Silverstein, J.H. (2009). "Postoperative delirium and cognitive dysfunction". British Journal of Anaesthesia. 103 (Suppl 1): i41 – i46. doi:10.1093/bja/aep291. PMC 2791855. PMID 20007989. | Wikipedia/Postoperative_cognitive_dysfunction |
Digestive system surgery, or gastrointestinal surgery, can be divided into upper GI surgery and lower GI surgery.
== Subtypes ==
=== Upper gastrointestinal ===
Upper gastrointestinal surgery, often referred to as upper GI surgery, refers to a practise of surgery that focuses on the upper parts of the gastrointestinal tract. There are many operations relevant to the upper gastrointestinal tract that are best done only by those who keep constant practise, owing to their complexity. Consequently, a general surgeon may specialise in 'upper GI' by attempting to maintain currency in those skills.
Upper GI surgeons would have an interest in, and may exclusively perform, the following operations:
Pancreaticoduodenectomy
Esophagectomy
Liver resection
=== Lower gastrointestinal ===
Lower gastrointestinal surgery includes colorectal surgery as well as surgery of the small intestine.
Academically, it refers to a sub-specialisation of medical practise whereby a general surgeon focuses on the lower gastrointestinal tract.
In the U.S., a student wanting to specialize and practice in adult lower GI surgery would generally have to go through four years of undergraduate college pre-medical education and get a bachelor's degree, then finish the four years of medical school, then finish a typically five-year-long residency in general surgery, and then perform a subsequent one-year-long (minimum) residency in surgery of the small intestine or large intestine (the colon- specifically, the cecum, the vermiform appendix, the ascending colon, the transverse colon, the hepatic flexure and the splenic flexure, the descending colon, and the sigmoid colon; and also the rectum and the anus).
A fellowship (in surgery of the small intestine or of the large bowel, or in pediatric/neonatal lower GI surgery, or in surgery of congenital abnormalities or rare disorders of the lower GI tract, or in emergency/trauma surgery or in cancer surgery of the area), would add on approximately one to three more years.
A lower GI surgeon might specialise in the following operations:
Colectomy
Low (anterior) (LAR) or ultra-low (anterior) resections (ULAR) for rectal cancer, etc.
Pelvic exenteration for advanced or recurrent cancer; usually performed in conjunction with other surgeons (e.g., urologists, obstetricians and gynecologists)
== References == | Wikipedia/Gastrointestinal_surgery |
Outpatient surgery, also known as ambulatory surgery, day surgery, day case surgery, or same-day surgery, is surgery that does not require an overnight hospital stay. The term “outpatient” arises from the fact that surgery patients may enter and leave the facility on the same day. The advantages of outpatient surgery over inpatient surgery include greater convenience and reduced costs.: 24–26
Outpatient surgery may occur in an inpatient facility, in a self-contained unit within a hospital (also known as a hospital outpatient department), in a freestanding self-contained unit (also known as an ambulatory surgery center), or in a physician's office-based unit.: 61 Between the late 20th century and early 21st century, outpatient surgery has grown in popularity in many countries.: 22 In the United States, 65% of surgeries at hospitals in 2012 were conducted on an outpatient basis, compared with 54% in 1992.
Studies have shown that outpatient surgery is as safe as or safer than inpatient surgery. For instance, complication rates and post-surgical hospitalization or readmission rates are comparable, and pain and infection rates are lower after outpatient surgery than inpatient surgery.: 24 Nevertheless, articles in the newsmedia (such as some discussing the 2014 death of Joan Rivers after an outpatient procedure) have questioned the safety of outpatient surgery performed at ambulatory surgery centers.
== Ambulatory surgery centers ==
Ambulatory surgery centers, also known as outpatient surgery centers, same day surgery centers, or surgicenters, are health care facilities where surgical procedures not requiring an overnight hospital stay are performed. Such surgery is commonly less complicated than that requiring hospitalization. Avoiding hospitalization can result in cost savings to the party responsible for paying for the patient's health care.
These centers specialize in providing surgery, including certain pain management and diagnostic (e.g., eye muscle surgery services) in an outpatient setting. Overall, the services provided can be generally called procedures. These can be considered procedures that are more intensive than those done in the average doctor's office but not so intensive as to require a hospital stay. An ambulatory surgery center and a specialty hospital often provide similar facilities and support similar types of procedures. The specialty hospital may provide the same procedures or slightly more complex ones and the specialty hospital will often allow an overnight stay. ASCs do not routinely provide emergency services to patients who have not been admitted to the ASC for another procedure.
=== Procedures ===
As of 2011, physicians performed more than 23 million procedures per year in over 5,300 ASCs in the United States.
In the 1980s and 1990s, many procedures that used to be performed exclusively in hospitals began taking place in ASCs as well. Many knee, shoulder, eye, spine and other surgeries are currently performed in ASCs. As of 2016, of procedures in ASCs funded by Medicare in the United States, the three most common were cataract surgery with intraocular lens insert (18.7% of all procedures), upper gastrointestinal endoscopy with biopsy (8.2%), and colonoscopy with biopsy (6.8%).
=== History ===
The first center in the USA was established in Phoenix, Arizona in 1970 by two physicians who wanted to provide timely, convenient and comfortable surgical services to patients in their community, avoiding more impersonal venues like regular hospitals. Five surgeons performed cases at the center on the first day it opened, and four of those procedures required general anesthesia.
ASCs rarely have a single owner. Physicians partners who perform surgeries in the center will often own at least some part of the facility. Ownership percentages vary considerably, but most ASCs involve physician owners. Occasionally, an ASC is entirely physician-owned. However, it is most common for development/management companies to own a percentage of the center.
Some large healthcare companies own many types of medical facilities, including ambulatory surgery centers. The largest ASC chains in terms of numbers of centers include Envision Healthcare, Tenet Healthcare/United Surgical Partners International, Surgical Care Affiliates, Hospital Corporation of America, Ambulatory Surgical Centers of America, and Surgery Partners and Physicians Endoscopy. Nearly 68 percent of ASC management companies reported having equity ownership in all freestanding entities they managed.
ASCs are in all 50 states and can be found throughout the world. In the US, most ASCs are licensed, certified by Medicare and accredited by one of the major health care accrediting organizations. California is the leading US state in the number of Medicare Certified ASCs, followed by Florida, and then Texas. California has 694 ASCs. It is followed by Florida with 387 ASCs and then Texas with 347 ASCs. With only 1 Medicare Certified ASC, Vermont is at the bottom of the list.
Although complications are very rare, ASCs are required by Medicare and the accreditation organizations to have a backup plan for transfer of patients to a hospital if the need arises.
The national nonprofit organizations that represents the interests of ASCs and their patients is Ambulatory Surgery Center Association (ASC Association), which was formed in 2008 when the Federated Ambulatory Surgery Association (FASA) and the American Association of Ambulatory Surgery Centers (AAASC) merged. William Prentice is the executive director of ASCA. He previously served as the director of the Washington office for the American Dental Association.
=== Accreditation ===
Accreditation organizations for ASCs provide standards of medical care, record keeping, and auditing. Some of the goals of these organizations include continuous improvement of medical care in surgery centers and providing an external organization where the public can get information on many aspects of ASCs. These accreditation organizations require members to receive periodic audits. These audits will come every one to three years, depending on the accreditation organization and the circumstances of the surgery center. In an audit, a team of auditors visits the facility and examines the ASC's medical records, written policies, and compliance with industry standards.
Effective in 1996, California was the first state in the United States to require accreditation for all outpatient surgery settings that administer anesthesia. The Centers for Medicare and Medicaid Services have approved five organizations to accredit ASCs: Accreditation Association for Ambulatory Health Care (AAAHC), American Association for Accreditation of Ambulatory Surgery Facilities (AAAASF), Healthcare Facilities Accreditation Program (HFAP), Institute for Medical Quality (IMQ), and The Joint Commission (TJC).
== See also ==
National Association for Ambulatory Urgent Care
== Notes ==
== References ==
== External links ==
Canadian Association for Accreditation of Ambulatory Surgical Facilities
International Association for Ambulatory Surgery
Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program
Outpatient Surgery Magazine | Wikipedia/Outpatient_surgery |
Pott's disease, or Pott disease, named for British surgeon Percivall Pott who first described the symptoms in 1799, is tuberculosis of the spine, usually due to haematogenous spread from other sites, often the lungs. The lower thoracic and upper lumbar vertebrae areas of the spine are most often affected.
It causes a kind of tuberculous arthritis of the intervertebral joints. The infection can spread from two adjacent vertebrae into the adjoining intervertebral disc space. If only one vertebra is affected, the disc is normal, but if two are involved, the disc, which is avascular, cannot receive nutrients, and collapses. In a process called caseous necrosis, the disc tissue dies, leading to vertebral narrowing and eventually to vertebral collapse and spinal damage. A dry soft-tissue mass often forms and superinfection is rare.
Spread of infection from the lumbar vertebrae to the psoas muscle, causing abscesses, is not uncommon.
== Diagnosis ==
The most common and earliest clinical symptom of Pott's Disease is back pain, often associated with local tenderness, worsening muscle spasms along the spine, and focal edema. These symptoms can lead to limited and painful movement in all directions of the spine.
The second most common clinical symptom is neurological deficits, which can vary depending on the level of the spine affected. An infection in the neck area can cause nerve problems affecting both the arms and legs, while an infection in the lower back typically affects only the legs and the area around the tailbone.
In the early stages of Pott’s Disease, imaging techniques such as CT scans, MRIs, or plain radiographs are ordered. For a radiolucent lesion to appear on a plain X-ray, there must be a 30% loss of bone mineral, making it difficult to diagnose the early stages of Pott's Disease with a plain radiograph. CT (computed tomography) is often used as a guide for biopsy. Overall, it is widely documented that MRI is superior to plain radiographs in diagnosing Pott’s Disease.
Initial suspicion of Pott’s Disease is usually based on clinical symptoms and imaging findings, but a definitive diagnosis requires isolating the organism by culture, identifying it, and determining its drug susceptibility. The typical lab procedure for clinical specimens involves an AFB (acid-fast bacilli) stain.
The ESR (erythrocyte sedimentation rate) and CRP (C-reactive protein) are also used as biomarkers for spinal tuberculosis.
Other labs include:
Blood tests
Complete blood count: leukocytosis
Elevated erythrocyte sedimentation rate: >100 mm/h
Tuberculin skin test
Tuberculin skin test (purified protein derivative [PPD]) results are positive in 84–95% of patients with Pott disease who are not infected with HIV.
Radiographs of the spine
Radiographic changes associated with Pott disease present relatively late. These radiographic changes are characteristic of spinal tuberculosis on plain radiography:
Lytic destruction of anterior portion of vertebral body
Increased anterior wedging
Collapse of vertebral body
Reactive sclerosis on a progressive lytic process
Enlarged psoas shadow with or without calcification
Additional radiographic findings may include:
Vertebral end plates are osteoporotic
Intervertebral disks may be shrunken or destroyed
Vertebral bodies show variable degrees of destruction
Fusiform paravertebral shadows suggest abscess formation
Bone lesions may occur at more than one level
Bone scan
Computed tomography of the spine
Bone biopsy
MRI
== Clinical presentation ==
The onset of symptoms is gradual and disease progresses slowly. The duration of symptoms before diagnosis ranges from 2 weeks to several years, The average period was at least 12 months, but it has recently decreased to 3 and 6 months. Presentation depends on disease stage, location, and complications such as neurological deficits and abscesses.
Non-spinal symptoms include weakness, loss of appetite, weight loss, evening fever, and night sweats. Clinical findings include back pain, paraparesis, kyphosis, sensory disturbances, and bowel and bladder dysfunction. Signs of associated extraskeletal tuberculosis include cough, expectoration, swollen lymp nodes, diarrhea, and abdominal swelling.
The earliest and most common symptom is back pain, which worsens with activity. Muscles relax when asleep which causes pain. As the infection progresses, the pain becomes more severe leading to para-spinal muscle spasms. The spasms cause all spinal movements to be restricted and painful.
The second most common symptom is neurological deficits which depends on the location of the infection. If the cervical spine is affected, upper and lower extremities will show signs of dysfunction. If the infection is in the lumbar, deficits are localized to the lower extremities and sacral area. These neurological symptoms are caused by direct pressure on nerves, invasion of neural tissue, tuberculous meningitis, dislocation or subluxation of vertebrae, or reduced blood flow to the spinal cord. Deficits progress from the front to the back, thus affecting the front of the spinal tract first. It heightens reflex and upper motor neuron deficit causing it to eventually advance to limb weakness and difficulty walking due to muscle spasms.
Pott's disease presents in children more frequently due to the increased vascularization of their spine. It also presents with back pain, neurological deficits, cold abscesses, and kyphosis deformities. In children, kyphosis is not limited to the disease being active, instead it increases or worsens in periods of growth, which further exacerbates other symptoms.
Certain presentations can cause abscesses to form, which puts the patient at a higher risk of spinal cord damage and possible paraplegia. The lesions responsible for abscesses occur more frequently in younger patients as their spine is highly vascularized compared to adults. Involvement of the front part of the spine or areas not involving the bone initially spares it and the disc of the spinal column. However, abscess formation allows disease to spread over multiple contiguous vertebrae using the front longitudinal ligament. These abscesses are granulomatous and, as they expand, lift the periosteum leading to bone devascularization, necrosis, and eventually deformity. Rear involvement follows a similar process but uses the longitudinal ligament in the back and often affects the neural arch. Paradiscal, central, and non-bone lesions account for 98% of all spinal TB cases, indicating that lesions originating in the back are much more rare.
Cold abscesses develop near lesions, and they are called 'cold' because they lack typical inflammatory signs like warmth and redness. They can grow significantly large which worsens the patient's symptoms. For example, if the primary lesion is located in the cervical spine, a cold abscess could form in the area behind the pharynx causing symptoms such as difficulty swallowing, breathing issues, or a hoarse voice.
== Pathogenesis ==
Infection of the lungs by the bacteria Mycobacterium tuberculosis (MTB) eventually spreads through the host's body. Without treatment and diagnosis, the infection becomes dormant in the lungs or spreads to other parts of the body through hematogenous dissemination.
When dissemination occurs, MTB enters the cancellous or spongy bone of the vertebra through the vascular system. It travels specifically from the front and back spinal arteries, and pressures within the torso spreads the infection throughout the vertebral body.
It impacts the front of the vertebral body along the subchondral plate. As it advances, progressive destruction occurs leading to vertebral collapse and kyphosis. The spinal canal may become narrowed due to abscesses, granulation tissue, or direct dural invasion resulting in compression of cord and neurological deficits. Kyphosis is a result of the front of the spine collapsing. Injury to the thoracic spine are more likely to result in kyphosis compared to lumbar spine injuries. A cold abscess can develop if infection spreads to ligaments and soft tissues. In the lower back, there is a chance the abscess can move down along the psoas muscle to the upper thigh and eventually break through the skin.
== Transmission ==
MTB is contracted and spread through aerosol droplets. Respiratory MTB or tuberculosis (TB) have been documented in patients that have negative results for specific cultures. The sum of two cases concluded that about 17% of transmission occurs from patients who have negative results. Another study concluded that TB infection outside the lungs increased the transmission rate, which has always been overlooked.
== Risk factors ==
Some known risk factors for Pott's Disease include immunodeficiencies (such as those caused by alcohol and drug abuse or HIV), exposure to infected patients, poverty, undernourishment, and lower socioeconomic status.
HIV has been identified as one of the primary risk factors for the development of Pott’s Disease and this is because HIV compromises the immune system by attacking and destroying crucial immune cells, thereby weakening the body's natural defenses. This impairment significantly reduces the body's ability to combat infections, including tuberculosis (TB), making it more difficult for the body to fight off TB germs effectively. In regions like Sub-Saharan Africa, where the disease is prevalent, HIV often coexists with spinal TB, significantly complicating management and diagnosis. Data collected in New York and Los Angeles shows that this disease primarily affects foreign-born individuals, African Americans, Asian Americans, and Hispanic Americans.
Vitamin D deficiency has also been correlated with an increased risk of Pott’s Disease, particularly spinal TB with caseous necrosis, increasing the risk of necrosis compared to individuals with normal vitamin D levels. A deficiency in vitamin D has been associated with the activation of tuberculosis (TB) for a long time. TB patients typically have lower serum vitamin D levels compared to healthy individuals. Extended TB treatment also leads to a reduction in serum vitamin D levels. Research has indicated that vitamin D plays a crucial role in modulating innate immune responses, acting as a cofactor in the induction of antimycobacterial activity.
In developed countries like the United States, Pott's Disease is primarily found in adults. However, in developing countries, data shows that Pott's Disease occurs mainly in young adults and older children. Crowded and poorly ventilated living and working conditions, which are often linked to poverty, significantly increase the risk of tuberculosis transmission. Undernutrition is another crucial factor that raises the likelihood of developing active TB. Additionally, poverty correlates with limited health knowledge and a lack of empowerment to utilize that knowledge, which results in greater exposure to various TB risk factors, including HIV, smoking, and alcohol abuse.
== Epidemiology ==
About 2% of all cases of tuberculosis are considered Pott's Disease and about half (50%) of the cases of musculoskeletal tuberculosis are Pott's Disease, of which 98% affect the anterior column. The disease can be attributed to 1.3 million deaths per year. There is a correlation between tuberculosis infections and cases of Pott's disease, as it's prevalent in areas where tuberculosis infections are common. Known risk factors like lower socioeconomic status, overcrowding, immunodeficiency, and interactions with people with tuberculosis can influence the rate of diagnosis.
Underdeveloped countries have a higher incidence rate of Pott's disease as it is associated with less ventilated rooms, crowded spaces, poorer hygiene, and less access to healthcare facilities. Increasing food security, reducing poverty, and improving living and working conditions will help to prevent infection and generally enhance the care of those sick.
Pott's disease is more common in the working-age population. Still any age group is at risk for developing the disease. Individuals who have use immunosuppressants or have compromised immune systems, chronic diseases like diabetes, or use tobacco have a significantly increased risk of becoming ill with tuberculosis infections. In older populations, the disease is often misdiagnosed, often being disregarded for other degenerative diseases. Children's spines contain more cartilage, increasing the effect of spinal deformations caused by the disease.
Multidrug resistant tuberculosis poses a threat to people with Pott's disease, making it difficult to determine infection in people because of the paucibacillary symptoms of the disease. Cases of tuberculosis have been on the decline; however, infections of multidrug resistant tuberculosis have remained constant since the 1990s.
== Prevention ==
As one type of tuberculosis infections, individuals can’t entirely prevent Pott’s Disease, but we are able to take steps to reduce the risk of TB (tuberculosis) infection by avoiding prolonged, close contact with someone who has an active TB (tuberculosis) infection and getting tested regularly for TB (tuberculosis) if you're at higher risk or live in a region where TB (tuberculosis) is common.
Controlling the spread of tuberculosis infection can prevent tuberculous spondylitis and arthritis. Patients who have a positive PPD test (but not active tuberculosis) may decrease their risk by properly taking medicines to prevent tuberculosis. To effectively treat tuberculosis, patients must take their medications exactly as prescribed.
== Management ==
When it comes to treatment of Pott's disease, the two main routes that are typically prescribed to patients are chemotherapy and surgical intervention. Guidelines from the WHO, CDC, and American Thoracic Society all present chemotherapy to be the first line when it comes to treatment of Pott's disease with surgical interventions being administered as needed for patients who are indicated for it. Antibiotics may also be recommended to help with the eradication of the disease. With early intervention, Pott's disease can be cured and completely eradicated from the patient. However, there are cases where the tuberculosis is drug-resistant, leading to poorer and possibly life-threatening outcomes in children, the elderly, and immunocompromised patients. Rehabilitation for patients who have just undergone surgery or are recovering from Pott's disease often consist of analgesics for pain management, immobilization of the affected spinal region, and physical therapy for pain-relieving modalities.
=== Chemotherapy ===
The treatment prescribed to patients diagnosed with Pott's disease is similar to treatment that is generally given to patients who have other forms of extrapulmonary tuberculosis. According to guidelines, typical treatment begins with a six to nine month course of chemotherapy. The regimen usually consists of an initial 2-month intensive phase of Isoniazid (INH), Rifampin (RIF), Pyrazinamide (PZA), and Ethambutol (EMB). Following the 2-month initial phase, PZA and EMB are discontinued while INH and RIF are continued for the remaining four to seven month continuation phase of the treatment period.
Some practices, however, have recommended treatment regimens of over 12 months given the mortality and disability risks associated with failure to completely eradicate the disease, and the difficulty in assessing the effectiveness of treatment.
=== Surgical intervention ===
Surgical intervention is required for patients with Pott's disease in the event that there is a need for tissue sampling to clarify diagnoses, resistance to chemotherapy (often found in patients with HIV), neurologic deficits (including but not limited to abnormal reflexes, problems with speech, decreased sensation, loss of balance, decreased mental function, vision/hearing problems, and paraplegia), paravertebral abscesses formed from bacterial induced immune response, and kyphotic deformities leading to instability of the spine. However, surgery is up to shared clinical decision making and not an intervention that is defaulted to, as guidelines tend to lead towards less invasive procedures such as chemotherapy and anti-tuberculosis medications.
Typical surgical techniques used are as follows:
Posterior decompression and fusion with bone autografts
Anterior debridement/decompression and fusion with bone autografts
Anterior debridement/decompression and fusion followed by simultaneous or sequential posterior fusion with instrumentation
Posterior fusion with instrumentation followed by simultaneous or sequential anterior debridement/decompression and fusion
==== Posterior decompression and fusion ====
In posterior decompression and fusion with bone autografts, the goal is to relieve pressure on the spinal cord and nerves in the lower back and prevent the progression of kyphosis in active disease. In this procedure, the lumbar (lower back) vertebrae (L1-L5) are exposed and the intervertebral discs and vertebral material impinging on the spinal cord and/or nerves are removed. The vertebrae (typically L4-L5 due to their load bearing nature and vulnerability to degradation) are then fused together with grafts or instrumentation to help provide more support to the back and spine of the patient.
==== Anterior debridement/Decompression and fusion ====
The goal of the anterior debridement/decompression and fusion with bone autografts procedure is to relieve pressure on the spinal cord and nerves along the anterior side of the spinal cord and help prevent the progression of kyphosis in active disease. The anterior approach is often recommended instead of the posterior approach in cases where only single segments of the vertebrae are affected, and in the event that there is no destruction or collapse of the posterior elements. In anterior debridement and decompression, tissue damaged by the onset of disease is removed along with vertebral elements and intervertebral discs that are impinging on the spinal cord and/or nerves in the spine. Vertebrae can then be fused together through the use of grafts or instrumentation to provide more structural support for the spine and back.
==== Kyphosis progression prevention ====
Surgical intervention is used in patients with kyphosis to primarily prevent the progression of kyphosis in active disease and correct it to a certain extent. However, surgical intervention is not meant to cure kyphosis in the patient and has variable rates of success in eradicating it in a patient. In the event that a patient shows signs of kyphosis, the earlier surgical intervention is given, the better the outcome for the patient.
==== Pediatric surgical interventions ====
In children with Pott's disease, earlier surgical intervention is often recommended to reduce their increased risk for kyphotic deformity. This increased risk for deformity is attributed to both the anatomy and biomechanics of children and their developmental stage of life. Due to the proportions of their bodies (larger head), limited muscular development, and increased flexibility, gravity can lead to greater deformation and presentation of kyphosis. After onset of the disease, growth plates in the spine may be destroyed and vertebral bodies suppressed due to kyphosis. These variable complications would then further deformation, leading to uncontrolled and/or suppressed growth.
== Prognosis ==
Paraplegia (so-called Pott's paraplegia), presents with refusal to stand or walk. It can generally be used to describe those who have lost feeling in their lower extremities/lower parts of the body or are unable to move them.
Vertebral collapse resulting in kyphosis, which is defined as an abnormally curved thoracic spine. This abnormal curve in the spine is not to be confused with the natural curve which serves to absorb shock. The main presentation of kyphosis is gradual onset of pain in patients that may be worse with activity.
Sinus formation is a complex form of recurrent tuberculosis.
Spinal cord compression occurs and can stop the nerves from functioning properly when pressure builds on the spinal cord. The consequence of this compression and pressure is symptoms such as back pain, trouble walking, and weakness in the arms and/or legs.
== History ==
Evidence of tubercular lesions of the vertebral column have been found from the fourth millennium BC in the form of Mesolithic remains in Liguria, Italy. Additionally, tuberculosis spondylitis has been discovered from 3400 BC in the mummified remains of Egyptians. Tuberculosis had affected humans long before it was identified by Sir Percivall Pott.
Important milestones in the development, understanding, and management of tuberculosis spondylitis include the Bacilli Calmette Guerin (BCG) vaccination in 1945, radiological exams, and accessibility of necessary anti tubular medications in the mid 1900's. MRI and CT scans implemented since 1987 for this disease have helped clinicians catch the disease early as well as identify rare complications of the disease. This helps to prevent further worsening of the disease and promote proper management.
Saint Gemma of Lucca had tuberculosis of the spine.
English poets Alexander Pope and William Ernest Henley both had Pott disease.
Anna Roosevelt Cowles, sister of President Theodore Roosevelt, had Pott disease.
Søren Kierkegaard may have died from Pott disease, according to professor Kaare Weismann and literature scientist Jens Staubrand
Chick Webb, a swing-era drummer and band leader, was affected by tuberculosis of the spine as a child, which left him hunchbacked, and eventually caused his death.
The Sicilian mafia boss Luciano Leggio had the disease and wore a brace.
Italian writer, poet, and philosopher Giacomo Leopardi had the disease.
American actor Pat Morita was hospitalized as a child with the disease, and when he recovered, was sent directly to an internment camp.
It features prominently in the book This Is a Soul, which chronicles the work of American physician Rick Hodes in Ethiopia.
Jane Addams, social activist and Nobel Peace Prize winner, had Pott disease.
Willem Ten Boom, brother of Corrie Ten Boom, died of tuberculosis of the spine in December 1946.
Writer Max Blecher had Pott disease and wrote about the affliction.
Marxist thinker and Communist leader Antonio Gramsci had Pott disease which, together with the bad conditions of his incarceration in fascist Italy during the 1930s, contributed to his death.
Gavrilo Princip, who assassinated Archduke Franz Ferdinand of Austria, leading to World War I, died in prison of bone tuberculosis.
English writer Denton Welch (1915–1948) died of spinal tuberculosis after being involved in a motor accident (1935) that irreparably damaged his spine.
Louis Joseph, Dauphin of France, son of King Louis XVI and Marie Antoinette
George Mercer Dawson, Canadian surveyor, geologist and president of the Geological Society of America, had Pott's disease.
Masaoka Shiki, Japanese poet, author and literary critic, had Pott's disease.
Lesya Ukrainka, Ukrainian poet, waged, in her own words, "Thirty Years' War with bone tuberculosis".
Alberto Moravia, Italian writer, was bedridden for five years due to the Pott's disease.
Lucie Coutaz, French clerical worker who belonged to the French Resistance during the Second World War and afterwards assisted Abbé Pierre in setting up the charity Emmaus, had Pott's disease at 16 years of age.
== In popular culture ==
Film director Hayao Miyazaki's mother, Yoshiko Miyazaki, was hospitalized for years, then continued treatment for Pott's disease at home. The director's mother is considered an influence on his work, including her health condition.
Max Blecher's semi-autobiographical novel Inimi cicatrizate (1937) is about a young man named Emanuel who is afflicted with Pott disease in a sanatorium, as is the Radu Jude film Scarred Hearts (2016), loosely based on it.
A. J. Cronin's story "Two Gentlemen of Verona," includes a character named Lucia with tuberculosis of spine.
In William Golding's novel The Spire (1964), Jocelin, the dean who wanted a spire on his cathedral, probably dies as a result of the disease.
Katharine Butler Hathaway's memoir The Little Locksmith (1943) is about the effects of spinal tuberculosis on her childhood and adult life.
In Victor Hugo's The Hunchback of Notre-Dame (1831) the title character has a gibbus deformity similar to the type caused by spinal tuberculosis.
In Henrik Ibsen's play A Doll's House (1879), Dr. Rank has "consumption of the spine."
In Sergio Leone's film Once Upon a Time in the West (1968), Morton, the railroad magnate, has the disease and needs crutches to walk.
In Ernest Poole's Pulitzer Prize-winning novel, His Family (1917), young Johnny Geer has a terminal case of Pott disease.
In Edmund Wilson's Memoirs of Hecate County (1946), the novella "The Princess with the Golden Hair," has a character with Pott disease.
== References ==
== Further reading ==
Jodra S, Alvarez C (21 February 2013). "Pott's Disease of the Thoracic Spine". New England Journal of Medicine. 368 (8): 756. doi:10.1056/NEJMicm1207442. PMID 23425168.
Bydon A, Dasenbrock HH, Pendleton C, McGirt MJ, Gokaslan ZL, Quinones-Hinojosa A (August 2011). "Harvey Cushing, the Spine Surgeon: The Surgical Treatment of Pott Disease". Spine. 36 (17): 1420–1425. doi:10.1097/BRS.0b013e3181f2a2c6. PMC 4612634. PMID 21224751.
Radcliffe C, Grant M (9 September 2021). "Pott Disease: A Tale of Two Cases". Pathogens. 10 (9): 1158. doi:10.3390/pathogens10091158. PMC 8465804. PMID 34578190.
Alajaji NM, Sallout B, Baradwan S (9 May 2022). "A 27-Year-Old Woman Diagnosed with Tuberculous Spondylitis, or Pott Disease, During Pregnancy: A Case Report". American Journal of Case Reports. 23: e936583. doi:10.12659/AJCR.936583. PMC 9195639. PMID 35684941.
== External links ==
Media related to Pott's disease at Wikimedia Commons | Wikipedia/Pott_disease |
Robot-assisted surgery or robotic surgery are any types of surgical procedures that are performed using robotic systems. Robotically assisted surgery was developed to try to overcome the limitations of pre-existing minimally-invasive surgical procedures and to enhance the capabilities of surgeons performing open surgery.
In the case of robotically assisted minimally-invasive surgery, instead of the surgeon directly moving the instruments, the surgeon uses one of two methods to perform dissection, hemostasis and resection, using a direct telemanipulator, or through computer control.
A telemanipulator (e.g. the da Vinci Surgical System) is a system of remotely controlled manipulators that allows the surgeon to operate real-time under stereoscopic vision from a control console separate from the operating table. The robot is docked next to the patient, and robotic arms carry out endoscopy-like maneuvers via end-effectors inserted through specially designed trocars. A surgical assistant and a scrub nurse are often still needed scrubbed at the tableside to help switch effector instruments or provide additional suction or temporary tissue retraction using endoscopic grasping instruments.
In computer-controlled systems, the surgeon uses a computer system to relay control data and direct the robotic arms and its end-effectors, though these systems can also still use telemanipulators for their input. One advantage of using the computerized method is that the surgeon does not have to be present on campus to perform the procedure, leading to the possibility for remote surgery and even AI-assisted or automated procedures.
Robotic surgery has been criticized for its expense, with the average costs in 2007 ranging from $5,607 to $45,914 per patient. This technique has not been approved for cancer surgery as of 2019 as the safety and usefulness is unclear.
== History ==
The concept of using standard hand grips to control manipulators and cameras of various sizes down to sub-miniature was described in the Robert Heinlein story 'Waldo' in August 1942, which also mentioned brain surgery.
The first robot to assist in surgery was the Arthrobot, which was developed and used for the first time in Vancouver in 1983. This robot assisted in being able to manipulate and position the patient's leg on voice command. Intimately involved were biomedical engineer James McEwen, Geof Auchinleck, a UBC engineering physics grad, and Dr. Brian Day as well as a team of engineering students. The robot was used in an orthopaedic surgical procedure on 12 March 1983, at the UBC Hospital in Vancouver. The next great step was in 1985. in brain biopsy under CT guidance with the assistance of a robotic arm—PUMA560. Over 60 arthroscopic surgical procedures were performed in the first 12 months, and a 1985. National Geographic video on industrial robots, The Robotics Revolution, featured the device. Other related robotic devices developed at the same time included a surgical scrub nurse robot, which handed operative instruments on voice command, and a medical laboratory robotic arm. A YouTube video entitled Arthrobot – the world's first surgical robot illustrates some of these in operation.
In 1985 a robot, the Unimation Puma 200, was used to orient a needle for a brain biopsy while under CT guidance during a neurological procedure. In the late 1980s, Imperial College in London developed PROBOT, which was then used to perform prostatic surgery. The advantages to this robot was its small size, accuracy and lack of fatigue for the surgeon. In the 1990s, computer-controlled surgical devices began to emerge, enabling greater precision and control in surgical procedures. One of the most significant advancements in this period was the da Vinci Surgical System, which was approved by the FDA for use in surgical procedures in 2000 (Intuitive Surgical, 2021). The da Vinci system uses robotic arms to manipulate surgical instruments, allowing surgeons to perform complex procedures with greater accuracy and control. In 1992, the ROBODOC was introduced and revolutionized orthopedic surgery by being able to assist with hip replacement surgeries. The latter was the first surgical robot that was approved by the FDA in 2008. The ROBODOC from Integrated Surgical Systems (working closely with IBM) could mill out precise fittings in the femur for hip replacement. The purpose of the ROBODOC was to replace the previous method of carving out a femur for an implant, the use of a mallet and broach/rasp.
Further development of robotic systems was carried out by SRI International and Intuitive Surgical with the introduction of the da Vinci Surgical System and Computer Motion with the AESOP and the ZEUS robotic surgical system. The first robotic surgery took place at The Ohio State University Medical Center in Columbus, Ohio under the direction of Robert E. Michler.
AESOP was a breakthrough in robotic surgery when introduced in 1994, as it was the first laparoscopic camera holder to be approved by the FDA. NASA initially funded the company that produces AESOP, Computer Motion, due to its goal to create a robotic arm that can be used in space, but this project ended up becoming a camera used in laparoscopic procedures. Voice control was then added in 1996 with the AESOP 2000 and seven degrees of freedom to mimic a human hand was added in 1998 with the AESOP 3000.
ZEUS was introduced commercially in 1998, and started the idea of telerobotics or telepresence surgery where the surgeon is at a distance from the robot on a console and operates on the patient. ZEUS was first used during a gynecological surgery in 1997 to reconnect Fallopian tubes in Cleveland Ohio, a beating heart coronary artery bypass graft in October 1999, and the Lindbergh Operation, which was a cholecystectomy performed remotely in September 2001. In 2003, ZEUS made its most prominent mark in cardiac surgery after successfully harvesting the left internal mammary arteries in 19 patients, all of which had very successful clinical outcomes.
The original telesurgery robotic system that the da Vinci was based on was developed at Stanford Research Institute International in Menlo Park with grant support from DARPA and NASA. A demonstration of an open bowel anastomosis was given to the Association of Military Surgeons of the US. Although the telesurgical robot was originally intended to facilitate remotely performed surgery in the battlefield to reduce casualties and to be used in other remote environments, it turned out to be more useful for minimally invasive on-site surgery. The patents for the early prototype were sold to Intuitive Surgical in Mountain View, California. The da Vinci senses the surgeon's hand movements and translates them electronically into scaled-down micro-movements to manipulate the tiny proprietary instruments. It also detects and filters out any tremors in the surgeon's hand movements, so that they are not duplicated robotically. The camera used in the system provides a true stereoscopic picture transmitted to a surgeon's console. Compared to the ZEUS, the da Vinci robot is attached to trocars to the surgical table, and can imitate the human wrist. In 2000, the da Vinci obtained FDA approval for general laparoscopic procedures and became the first operative surgical robot in the US. Examples of using the da Vinci system include the first robotically assisted heart bypass (performed in Germany) in May 1998, and the first performed in the United States in September 1999; and the first all-robotic-assisted kidney transplant, performed in January 2009. The da Vinci Si was released in April 2009 and initially sold for $1.75 million.
In 2005, a surgical technique was documented in canine and cadaveric models called the transoral robotic surgery (TORS) for the da Vinci robot surgical system as it was the only FDA-approved robot to perform head and neck surgery. In 2006, three patients underwent resection of the tongue using this technique. The results were more clear visualization of the cranial nerves, lingual nerves, and lingual artery, and the patients had a faster recovery to normally swallowing. In May 2006 the first artificial intelligence doctor-conducted unassisted robotic surgery was on a 34-year-old male to correct heart arrhythmia. The results were rated as better than an above-average human surgeon. The machine had a database of 10,000 similar operations, and so, in the words of its designers, was "more than qualified to operate on any patient". In August 2007, Dr. Sijo Parekattil of the Robotics Institute and Center for Urology (Winter Haven Hospital and University of Florida) performed the first robotic-assisted microsurgery procedure denervation of the spermatic cord for chronic testicular pain. In February 2008, Dr. Mohan S. Gundeti of the University of Chicago Comer Children's Hospital performed the first robotic pediatric neurogenic bladder reconstruction.
On 12 May 2008, the first image-guided MR-compatible robotic neurosurgical procedure was performed at University of Calgary by Dr. Garnette Sutherland using the NeuroArm. In June 2008, the German Aerospace Centre (DLR) presented a robotic system for minimally invasive surgery, the MiroSurge. In September 2010, the Eindhoven University of Technology announced the development of the Sofie surgical system, the first surgical robot to employ force feedback. In September 2010, the first robotic operation at the femoral vasculature was performed at the University Medical Centre Ljubljana by a team led by Borut Geršak.
In 2019 the Versius Surgical Robotic System was launched and is a rival of the Da Vinci surgical system and claims to be more flexible and versatile, having independent modular arms which are "quick and easy to set up". The small-scale design means that it is suitable for virtually any operating room and can be operated at either a standing or a sitting position.
== Uses ==
=== Ophthalmology ===
Ophthalmology is still part of the frontier for robotic-assisted surgeries. However, there are a couple of robotic systems that are capable of successfully performing surgeries.
PRECEYES Surgical System is being used for vitreoretinal surgeries. This is a single arm robot, that is tele manipulated by a surgeon. This system attaches to the head of the operating room table and provides surgeons with increased precision with the help of the intuitive motion controller. Preceyes is the only robotic instrument to be CE certified. Some other companies like Forsight Robotics, Acusurgical that raised 5.75 M€ (France), and Horizon (US) are working in this field.
The da Vinci Surgical System, though not specifically designed for ophthalmic procedures, uses telemanipulation to perform pterygium repairs and ex-vivo corneal surgeries.
=== Heart ===
Some examples of heart surgery being assisted by robotic surgery systems include:
Atrial septal defect repair – the repair of a hole between the two upper chambers of the heart,
Mitral valve repair – the repair of the valve that prevents blood from regurgitating back into the upper heart chambers during contractions of the heart,
Coronary artery bypass – rerouting of blood supply by bypassing blocked arteries that provide blood to the heart.
=== Thoracic ===
Robotic surgery has become more widespread in thoracic surgery for mediastinal pathologies, pulmonary pathologies and more recently complex esophageal surgery.
The da Vinci Xi system is used for lung and mediastinal mass resection. This minimally invasive approach as a comparable alternative to video-assisted thoracoscopic surgery (VATS) and the standard open thoracic surgery. Although VATS is the less expensive option, the robotic-assisted approach offers benefits such as 3D visualizations with seven degrees of freedom and improved dexterity while having equivalent perioperative outcomes.
=== ENT ===
The first successful robot-assisted cochlear implantation in a person took place in Bern, Switzerland in 2017. Surgical robots have been developed for use at various stages of cochlear implantation, including drilling through the mastoid bone, accessing the inner ear and inserting the electrode into the cochlea.
Advantages of robot-assisted cochlear implantation include improved accuracy, resulting in fewer mistakes during electrode insertion and better hearing outcomes for patients. The surgeon uses image-guided surgical planning to program the robot based on the patient's individual anatomy. This helps the implant team to predict where the contacts of the electrode array will be located within the cochlea, which can assist with audio processor fitting post-surgery. The surgical robots also allow surgeons to reach the inner ear in a minimally invasive way.
Challenges that still need to be addressed include safety, time, efficiency and cost.
Surgical robots have also been shown to be useful for electrode insertion with pediatric patients.
=== Gastrointestinal ===
Multiple types of procedures have been performed with either the 'Zeus' or da Vinci robot systems, including bariatric surgery and gastrectomy for cancer. Surgeons at various universities initially published case series demonstrating different techniques and the feasibility of GI surgery using the robotic devices. Specific procedures have been more fully evaluated, specifically esophageal fundoplication for the treatment of gastroesophageal reflux and Heller myotomy for the treatment of achalasia.
Robot-assisted pancreatectomies have been found to be associated with "longer operating time, lower estimated blood loss, a higher spleen-preservation rate, and shorter hospital stay[s]" than laparoscopic pancreatectomies; there was "no significant difference in transfusion, conversion to open surgery, overall complications, severe complications, pancreatic fistula, severe pancreatic fistula, ICU stay, total cost, and 30-day mortality between the two groups."
=== Gynecology ===
The first report of robotic surgery in gynecology was published in 1999 from the Cleveland Clinic. The adoption of robotic surgery has contributed to the increase in minimally invasive surgery for gynecologic disease. Gynecologic procedures may take longer with robot-assisted surgery and the rate of complications may be higher, but there are not enough high-quality studies to know at the present time. In the United States, robotic-assisted hysterectomy for benign conditions was shown to be more expensive than conventional laparoscopic hysterectomy in 2015, with no difference in overall rates of complications.
This includes the use of the da Vinci surgical system in benign gynecology and gynecologic oncology. Robotic surgery can be used to treat fibroids, abnormal periods, endometriosis, ovarian tumors, uterine prolapse, and female cancers. Using the robotic system, gynecologists can perform hysterectomies, myomectomies, and lymph node biopsies. The Hominis robotic system developed by Momentis Surgical™ is aimed to provide a robotic platform for natural orifice transluminal endoscopic surgery (NOTES) for myomectomy through the vagina.
A 2017 review of surgical removal of the uterus and cervix for early cervical cancer robotic and laparoscopic surgery resulted in similar outcomes with respect to the cancer.
=== Bone ===
Robots are used in orthopedic surgery.
ROBODOC is the first active robotic system that performs some of the surgical actions in a total hip arthroplasty (THA). It is programmed preoperatively using data from computer tomography (CT) scans. This allows for the surgeon to choose the optimal size and design for the replacement hip.
Acrobot and Rio are semi-active robotic systems that are used in THA. It consists of a drill bit that is controlled by the surgeon however the robotic system does not allow any movement outside the predetermined boundaries.
Mazor X is used in spinal surgeries to assist surgeons with placing pedicle screw instrumentation. Inaccuracy when placing a pedicle screw can result in neurovascular injury or construct failure. Mazor X functions by using templating imaging to locate itself to the target location of where the pedicle screw is needed.
=== Spine ===
Robotic devices started to be used in minimally invasive spine surgery starting in the mid-2000s. As of 2014, there were too few randomized clinical trials to judge whether robotic spine surgery is more or less safe than other approaches.
As of 2019, the application of robotics in spine surgery has mainly been limited to pedicle screw insertion for spinal fixation. In addition, the majority of studies on robot-assisted spine surgery have investigated lumbar or lumbosacral vertebrae only. Studies on use of robotics for placing screws in the cervical and thoracic vertebrae are limited.
=== Transplant surgery ===
The first fully robotic kidney transplantations were performed in the late 2000s. It may allow kidney transplantations in people who are obese who could not otherwise have the procedure. Weight loss however is the preferred initial effort.
In 2021, the team at Cedars-Sinai in Los Angeles, California completed the world's first robotic lung transplant, allowing a minimally invasive approach to the procedure.
=== General surgery ===
With regards to robotic surgery, this type of procedure is currently best suited for single-quadrant procedures, in which the operations can be performed on any one of the four quadrants of the abdomen. Cost disadvantages are applied with procedures such as a cholecystectomy and fundoplication, but are suitable opportunities for surgeons to advance their robotic surgery skills.
=== Hernia and abdominal wall surgery ===
Over the past several decades, there have been great advances in the field of abdominal wall and hernia surgery especially when it comes to robotic-assisted surgery. Unlike laparoscopic surgery, the robotic platform allows for the correction of large hernia defects with specialized techniques that would traditionally only be performed via an open approach. Compared to open surgery, robotic surgery for hernia repair can reduce pain, length of hospital stay, and improve outcomes. As the robotic instruments have 6 degrees of articulation, freedom of movement and ergonomics are greatly improved compared to laparoscopy.
The first robotic inguinal hernia repairs were done in conjunction with prostatectomies in 2007. The first ventral hernia repairs were performed robotically in 2009. Since then the field has rapidly expanded to include most types of reconstruction including anterior as well as posterior component separation.
With newer techniques such as direct access into the abdominal wall, major reconstruction of large hernias can be done without even entering the abdominal cavity. Due to its complexity, however, major reconstruction done robotically should be undertaken at advanced hernia centers such as the Columbia Hernia Center in New York City, NY, USA. The American Hernia Society and the European Hernia Society are moving towards specialty designation for hernia centers who are credentialed for complex hernia surgery, including robotic surgery.
=== Urology ===
Robotic surgery in the field of urology has become common, especially in the United States.
There is inconsistent evidence of benefits compared to standard surgery to justify the increased costs. Some have found tentative evidence of more complete removal of cancer and fewer side effects from surgery for prostatectomy.
In 2000, the first robot-assisted laparoscopic radical prostatectomy was performed.
Robotic surgery has also been utilized in radical cystectomies. A 2013 review found less complications and better short term outcomes when compared to open technique.
=== Pediatrics ===
Pediatric procedures are also benefiting from robotic surgical systems. The smaller abdominal size in pediatric patients limits the viewing field in most urology procedures. The robotic surgical systems help surgeons overcome these limitations. Robotic technology provides assistance in performing
Pyeloplasty - alternative to the conventional open dismembered pyeloplasty (Anderson-Hynes). Pyeloplasty is the most common robotic-assisted procedures in children.
Ureteral reimplantation - alternative to the open intravesical or extravesical surgery.
Ureteroureterostomy - alternative to the transperitoneal approach.
Nephrectomy and heminephrectomy - Traditionally done with laparoscopy, it is not likely that a robotic procedure offers significant advantage due to its high cost.
== Comparison to traditional methods ==
Major advances aided by surgical robots have been remote surgery, minimally invasive surgery and unmanned surgery. Due to robotic use, the surgery is done with precision, miniaturization, smaller incisions; decreased blood loss, less pain, and quicker healing time. Articulation beyond normal manipulation and three-dimensional magnification help to result in improved ergonomics. Due to these techniques, there is a reduced duration of hospital stays, blood loss, transfusions, and use of pain medication.
The existing open surgery technique has many flaws such as limited access to the surgical area, long recovery time, long hours of operation, blood loss, surgical scars, and marks.
The robot's costs range from $1 million to $2.5 million for each unit, and while its disposable supply cost is normally $1,500 per procedure, the cost of the procedure is higher. Additional surgical training is needed to operate the system. Numerous feasibility studies have been done to determine whether the purchase of such systems are worthwhile. As it stands, opinions differ dramatically. Surgeons report that, although the manufacturers of such systems provide training on this new technology, the learning phase is intensive and surgeons must perform 150 to 250 procedures to become adept in their use. During the training phase, minimally invasive operations can take up to twice as long as traditional surgery, leading to operating room tie-ups and surgical staffs keeping patients under anesthesia for longer periods. Patient surveys indicate they chose the procedure based on expectations of decreased morbidity, improved outcomes, reduced blood loss and less pain. Higher expectations may explain higher rates of dissatisfaction and regret.
Compared with other minimally invasive surgery approaches, robot-assisted surgery gives the surgeon better control over the surgical instruments and a better view of the surgical site. In addition, surgeons no longer have to stand throughout the surgery and do not get tired as quickly. Naturally occurring hand tremors are filtered out by the robot's computer software. Finally, the surgical robot can continuously be used by rotating surgery teams. Laparoscopic camera positioning is also significantly steadier with less inadvertent movements under robotic controls than compared to human assistance. The use of mixed reality to support robot-assisted surgery was developed at the Air Force Research Laboratory in 1992 through the creation of "virtual fixtures" that overlay virtual boundaries or guides that assist the human operator and has become a common method for increasing safety and precision.
There are some issues in regards to current robotic surgery usage in clinical applications. There is a lack of haptics in some robotic systems currently in clinical use, which means there is no force feedback, or touch feedback. No interaction between the instrument and the patient is felt. However, recently the Senhance robotic system by Asensus Surgical was developed with haptic feedback in order to improve the interaction between the surgeon and the tissue.
The robots can also be very large, have instrumentation limitations, and there may be issues with multi-quadrant surgery as current devices are solely used for single-quadrant application.
Critics of the system, including the American Congress of Obstetricians and Gynecologists, say there is a steep learning curve for surgeons who adopt the use of the system and that there's a lack of studies that indicate long-term results are superior to results following traditional laparoscopic surgery. Articles in the newly created Journal of Robotic Surgery tend to report on one surgeon's experience.
Complications related to robotic surgeries range from converting the surgery to open, re-operation, permanent injury, damage to viscera and nerve damage. From 2000 to 2011, out of 75 hysterectomies done with robotic surgery, 34 had permanent injury, and 49 had damage to the viscera. Prostatectomies were more prone to permanent injury, nerve damage and visceral damage as well. Very minimal surgeries in a variety of specialties had to actually be converted to open or be re-operated on, but most did sustain some kind of damage or injury. For example, out of seven coronary artery bypass grafting, one patient had to go under re-operation. It is important that complications are captured, reported and evaluated to ensure the medical community is better educated on the safety of this new technology. If something was to go wrong in a robot-assisted surgery, it is difficult to identify culpability, and the safety of the practice will influence how quickly and widespread these practices are used.
One drawback of the use of robotic surgery is the risk of mechanical failure of the system and instruments. A study from July 2005 to December 2008 was conducted to analyze the mechanical failures of the da Vinci Surgical System at a single institute. During this period, a total of 1797 robotic surgeries were performed used 4 da Vinci surgical systems. There were 43 cases (2.4%) of mechanical failure, including 24 (1.3%) cases of mechanical failure or malfunction and 19 (1.1%) cases of instrument malfunction. Additionally, one open and two laparoscopic conversions (0.17%) were performed. Therefore, the chance of mechanical failure or malfunction was found to be rare, with the rate of converting to an open or laparoscopic procedure very low.
There are also current methods of robotic surgery being marketed and advertised online. Removal of a cancerous prostate has been a popular treatment through internet marketing. Internet marketing of medical devices are more loosely regulated than pharmaceutical promotions. Many sites that claim the benefits of this type of procedure had failed to mention risks and also provided unsupported evidence. There is an issue with government and medical societies promotion a production of balanced educational material. In the US alone, many websites promotion robotic surgery fail to mention any risks associated with these types of procedures, and hospitals providing materials largely ignore risks, overestimate benefits and are strongly influenced by the manufacturer.
== Use in popular media ==
Since April 2018, medical insurance coverage was expanding in Japan, so doctors were considering promoting the procedure for cardiac surgery, as it has the advantage of reducing the burden on the patient. Japanese drama Black Pean takes on this challenge, showing both sides' point of view. Two University Hospitals are competing to be the best in the Cardiac Surgery Department. One, Tojo, has the best traditional surgeons, while the other, Teika, is all about researching and implementing the most recent technology. With this, Teika sends its technical specialist to Tojo to try to convince them to update their techniques, including the use of the Da Vinci robot (named in the drama as Darwin). Newhart Watanabe International Hospital, a pioneer in da Vinci surgery for the heart in Japan, was used as background for the drama, with Dr. Gou Watanabe providing technical support.
== See also ==
== References ==
== External links == | Wikipedia/Robotic_surgery |
Microsurgery is a general term for surgery requiring an operating microscope. The most obvious developments have been procedures developed to allow anastomosis of successively smaller blood vessels and nerves (typically 1 mm in diameter) which have allowed transfer of tissue from one part of the body to another and re-attachment of severed parts. Microsurgical techniques are utilized by several specialties today, such as general surgery, ophthalmology, orthopedic surgery, gynecological surgery, otolaryngology, neurosurgery, oral and maxillofacial surgery, endodontic microsurgery, plastic surgery, podiatric surgery and pediatric surgery.
== History ==
Otolaryngologists were the first physicians to use microsurgical techniques. A Swedish otolaryngologist, Carl-Olof Siggesson Nylén (1892–1978), was the father of microsurgery. In 1921, in the University of Stockholm, he built the first surgical microscope, a modified monocular Brinell-Leitz microscope. At first he used it for operations in animals. In November of the same year he used it to operate on a patient with chronic otitis who had a labyrinthine fistula. Nylen's microscope was soon replaced by a binocular microscope, developed in 1922 by his colleague Gunnar Holmgren (1875–1954).
Gradually the operating microscope began to be used for ear operations. In the 1950s many otologists began to use it in the fenestration operation, usually to perfect the opening of the fenestra in the lateral semicircular canal. The revival of the stapes mobilization operation by Rosen, in 1953, made the use of the microscope mandatory, although it was not used by the originators of the technique, Kessel (1878), Boucheron (1888) and Miot (1890). Mastoidectomies began to be performed with the surgical microscope and so were the tympanoplasty techniques that became known in the early 1950s. The stapes mobilization operation had varying results and was soon replaced by stapedectomy, first described by John Shea, Jr.; this was an operation that was always performed with the microscope.
Today neurosurgeons are very proud to use microscopes in their procedures. But it was not always so: many prestigious centers did not accept that idea and it had to be developed in relative isolation. In the late 1950s William House began to explore new techniques for temporal bone surgery. He developed the middle fossa approach and perfected the translabyrinthine approach and began to use these techniques to remove acoustic nerve tumors. The first neurosurgeon to make use of the surgical microscope was a Turkish emigrant, Gazi Yasargil. In 1953 he studied neurovascular surgery during work with Prof. Hugo Krayenbühl in Switzerland. His ideas interested Dr. Pete Donaghy, who invited Yasargil to his microvascular laboratory in Burlington, Vermont. After his return to Zürich in 1967 Yasargil concentrated on discovering clinical applications to their novel inventions. Publications on that topic: Micro-Vascular Surgery and Microsurgery Applied to Neurosurgery won him international recognition. His lifelong experiences with microsurgery were recapitulated in the four-volume textbook entitled simply Microneurosurgery.
Advances in the techniques and technology that popularized microsurgery began in the early 1960s to involve other medical areas. The first microvascular surgery, using a microscope to aid in the repair of blood vessels, was described by vascular surgeon, Julius H. Jacobson II of the University of Vermont in 1960. Using an operating microscope, he performed coupling of vessels as small as 1.4 mm and coined the term microsurgery. Hand surgeons at the University of Louisville, Drs. Harold Kleinert and Mort Kasdan, performed the first revascularization of a partial digital amputation in 1963.
Nakayama, a Japanese cardiothoracic surgeon, reported the first true series of microsurgical free-tissue transfers using vascularized intestinal segments to the neck for esophageal reconstruction after cancer resections using 3–4 mm vessels.
Contemporary reconstructive microsurgery was introduced by an American plastic surgeon, Dr. Harry J. Buncke. In 1964, Buncke reported a rabbit ear replantation, famously using a garage as a lab/operating theatre and home-made instruments
This was the first report of successfully using blood vessels 1 millimeter in size. In 1966, Buncke used microsurgery to transplant a primate's great toe to its hand.
During the late sixties and early 1970s, plastic surgeons ushered in many new microsurgical innovations that were previously unimaginable. The first human microsurgical transplantation of the second toe to thumb was performed in February 1966 by Dr. Dong-yue Yang and Yu-dong Gu, in Shanghai, China. Great toe (big toe) to thumb was performed in April 1968 by Dr. John Cobbett, in England. In Australia work by Dr. Ian Taylor saw new techniques developed to reconstruct head and neck cancer defects with living bone from the hip or the fibula.
A number of surgical specialties use microsurgical techniques. Otolaryngologists (ear, nose, throat and head and neck surgeons) perform microsurgery on structures of the inner ear and the vocal cords. Otolaryngologists and maxillofacial surgeons use microsurgical techniques when reconstructing defects from resection of head and neck cancers. Cataract surgery, corneal transplants, and treatment of conditions like glaucoma are performed by ophthalmologists. Urologists and gynecologists frequently now reverse vasectomies and tubal ligations to restore fertility.
== Free tissue transfer ==
Free tissue transfer is a surgical reconstructive procedure using microsurgery. A region of "donor" tissue is selected that can be isolated on a feeding artery and vein; this tissue is usually a composite of several tissue types (e.g., skin, muscle, fat, bone). Common donor regions include the rectus abdominis muscle, latissimus dorsi muscle, fibula, radial forearm bone and skin, and lateral arm skin. The composite tissue is transferred (moved as a free flap of tissue) to the region on the patient requiring reconstruction (e.g., mandible after oral cancer resection, breast after cancer resection, traumatic tissue loss, congenital tissue absence). The vessels that supply the free flap are anastomosed with microsurgery to matching vessels (artery and vein) in the reconstructive site. The procedure was first done in the early 1970s and has become a popular "one-stage" (single operation) procedure for many surgical reconstructive applications.
== Replantation ==
Replantation is the reattachment of a completely detached body part. Fingers and thumbs are the most common but the ear, scalp, nose, face, arm and penis have all been replanted. Generally replantation involves restoring blood flow through arteries and veins, restoring the bony skeleton and connecting tendons and nerves as required.
Robert Malt and Charles Mckhann reported the first replantation of two human upper extremities by microvascular means in 1964, with the first arm replanted in a child after a train injury in 1962 in Boston.
Initially, when the techniques were developed to make replantation possible, success was defined in terms of a survival of the amputated part alone. However, as more experience was gained in this field, surgeons specializing in replantation began to understand that survival of the amputated piece was not enough to ensure success of the replant. In this way, functional demands of the amputated specimen became paramount in guiding which amputated pieces should and should not be replanted. Additional concerns about the patient's ability to tolerate the long rehabilitation process that is necessary after replantation both on physical and psychological levels also became important. So, when fingers are amputated, for instance, a replantation surgeon must seriously consider the contribution of the finger to the overall function of the hand. In this way, every attempt will be made to salvage an amputated thumb, since a great deal of hand function is dependent on the thumb, while an index finger or small finger might not be replanted, depending on the individual needs of the patient and the ability of the patient to tolerate a long surgery and a long course of rehabilitation.
However, if an amputated specimen is not able to be replanted to its original location entirely, this does not mean that the specimen is unreplantable. In fact, replantation surgeons have learned that only a piece or a portion may be necessary to obtain a functional result, or especially in the case of multiple amputated fingers, a finger or fingers may be transposed to a more useful location to obtain a more functional result. This concept is called "spare parts" surgery.
== Transplantation ==
Microsurgical techniques have played a crucial role in the development of transplantation immunological research because it allowed the use of rodent models, which are more appropriate for transplantation research (there are more reagents, monoclonal antibodies, knockout animals, and other immunological tools for mice and rats than other species). Before it was introduced, transplant immunology was studied in rodents using the skin transplantation model, which is limited by the fact that it is not vascularized. Thus, microsurgery represents the link between surgery and transplant immunological research.
The first microsurgical experiments (porto-caval anastomosis in the rat) were performed by Dr. Sun Lee (pioneer of microsurgery) at the University of Pittsburgh in 1958. After a short time, many models of organ transplants in rat and mice have been established. Today, virtually every rat or mouse organ can be transplanted with relative high success rate.
Microsurgery was also important to develop new techniques for transplantation, that would be later performed in humans. In addition, it allows reconstruction of small arteries in clinical organ transplantation (e.g. accessory arteries in cadaver liver transplantation, polar arteries in renal transplantation and in living liver donor transplantation).
== Treatment of infertility ==
Microsurgery has been used to treat several pathologic conditions leading to infertility such as tubal obstructions, vas deferens obstructions, and varicocele, which is one of the most frequent cause of male infertility. Microsurgical drainages by placing microvascular bypasses between spermatic and inferior epigastric veins as proposed by Flati et al. have been successfully performed in treating male infertility due to varicocele. Microsurgical treatment has been shown to significantly improve fertility rate also in patients with recurrent varicocele who had previously undergone non-microsurgical treatments.
== References ==
== External links ==
E-Medicine Microsurgery Principles
Video recorded through Microscope of Ulnar Artery Repaired using Microsurgical Techniques | Wikipedia/Microsurgery |
The Disease Control Priorities Project (DCPP) is an ongoing project that aims to determine priorities for disease control across the world, particularly in low-income countries. The project is most well known for the second edition of the report Disease Control Priorities in Developing Countries (published in 2006, often abbreviated as DCP2 and sometimes referred to as "the DCP2 Report").
The Disease Control Priorities Project is a joint enterprise of a number of groups, including the University of Washington Department of Global Health, the World Bank, the Fogarty International Center (National Institutes of Health), World Health Organization, Population Reference Bureau, Gates Foundation, the Center for Disease Dynamics, Economics & Policy, and the International Decision Support Initiative. Notable editors involved in the project include Dean Jamison, Alan Lopez, Colin Mathers, Christopher J.L. Murray, George Alleyne, Ramanan Laxminarayan, Prabhat Jha, and Anne Mills.
== Publications ==
=== DCP1 ===
The first edition of Disease Control Priorities in Developing Countries, commonly referred to as DCP1, was published in 1993. DCP1 is cited in the 1993 World Development Report.
DCP1 is organized into five parts:
Introduction
The Unfinished Agenda, I · Infectious Disease
The Unfinished Agenda, II · Reproductive Health and Malnutrition
Emerging Problems
Conclusion
Each part has chapters within it; there are 29 chapters in all. The report spans more than 700 pages and has as contributors 79 authors in addition to the four editors.
=== DCP2 ===
The second edition of Disease Control Priorities in Developing Countries, commonly referred to as DCP2 and sometimes referred to as "the DCP2 Report", was published in 2006. DCP2 is organized into 73 chapters, and is a 1400-page report by more than 350 specialists around the world with the goal of providing policy recommendations to reduce global disease burdens. The report is in English, but translations for some of the chapters to Arabic, Chinese, French, and Spanish are available. The report has been released under the Creative Commons attribution license (CC-BY) and a copy of DCP2 can be downloaded from the World Bank's Open Knowledge Repository. The full text of the report can also be read online on the National Center for Biotechnology Information (National Institutes of Health) website.
In comparison to DCP1, DCP2 is more systematic in its coverage.: xviii
=== DCP3 ===
For third edition, the name of the report was shortened to Disease Control Priorities. The third edition is commonly referred to as DCP3, and was published in nine volumes over the time period 2015–2018.: 4
The nine volumes are as follows:
Essential Surgery
Reproductive, Maternal, Newborn, and Child Health
Cancer
Mental, Neurological, and Substance Use Disorders
Cardiovascular, Respiratory and Related Disorders
Major Infectious Diseases
Injury Prevention and Environmental Health
Child & Adolescent Development
Disease Control Priorities (summary volume)
DCP3 also has several companion publications:
Economic Dimensions of Noncommunicable Diseases in Latin America and the Caribbean
Optimizing Education Outcomes: High-Return Investments in School Health for Increased Participation and Learning
Re-Imagining School Feeding: A High Return Investment in Human Capital and Local Economies
=== Other publications ===
In addition to DCP1, DCP2, and DCP3, the DCPP has produced other background papers and major publications. These include the following:: xvii
Global Burden of Disease and Risk Factors (Lopez and others 2006) with the World Health Organization
Millions Saved: Proven Successes in Global Health (Levine and the What Works Working Group 2004) with the Center for Global Development
"The Intolerable Burden of Malaria: II. What's New, What's Needed" (Breman, Alilio, and Mills 2004) with the Multilateral Initiative on Malaria
Priorities in Health (Jamison and others 2006), a nontechnical companion to DCP2
== Reception ==
GiveWell found five errors in DCP2's cost-effectiveness estimate of soil-transmitted-helminth treatment, and found that correcting for these led to a cost-effectiveness estimate of $326.43 per DALY rather than the $3.41 per DALY figure given in DCP2. GiveWell also discovered that the schistosomiasis treatment cost-effectiveness figure had a critical typo, publishing $3.36–$6.92 per DALY, when it should be $336–$692 per DALY, although the number was correct on another page.
== See also ==
Copenhagen Consensus
Voices of the Poor
Moving Out of Poverty
== References ==
== External links ==
Official website | Wikipedia/Disease_Control_Priorities_Project |
Podiatry ( poh-DY-ə-tree), also known as chiropody (kai-RAW-puh-dee) or podiatric medicine and surgery ( POH-dee-AT-rik, poh-DY-ə-trik), is a branch of medicine devoted to the study, diagnosis, and treatment of disorders of the foot, ankle and lower limb. The healthcare professional is known as a podiatrist. The US podiatric medical school curriculum includes lower extremity anatomy, general human anatomy, physiology, general medicine, physical assessment, biochemistry, neurobiology, pathophysiology, genetics and embryology, microbiology, histology, pharmacology, women's health, physical rehabilitation, sports medicine, research, ethics and jurisprudence, biomechanics, general principles of orthopedic surgery, plastic surgery, and foot and ankle surgery.
Podiatry is practiced as a specialty in many countries. In Australia, graduates of recognised academic programs can register through the Podiatry Board of Australia as a "podiatrist", and those with additional recognised training may also receive endorsement to prescribe or administer restricted medications and/or seek specialist registration as a "podiatric surgeon".
Medical Group Management Association (MGMA) data shows that a general podiatrist with a single specialty earns a median salary of $230,357, while one with a multi-specialty practice type earns $270,263. However, a podiatry surgeon makes more with a single specialty, with the median at $304,474 compared to the multispecialty of $286,201. First-year salaries around $150,000 with performance and productivity incentives are common. Private practice revenues for solo podiatrists vary widely, with the majority of solo practices grossing between $200,000 and $600,000 before overhead.
== History ==
The professional care of feet existed in ancient Egypt, as depicted by bas-relief carvings at the entrance to Ankmahor's tomb from about 2400 BC.
Hippocrates described the treatment of corns and calluses by physically reducing the hard skin and removing the cause. The skin scrapers which he invented for this purpose were the original scalpels.
Until the turn of the 20th century, podiatrists were independently licensed physicians, separate from the rest of organized medicine. Lewis Durlacher, appointed as surgeon-podiatrist to the British royal household in 1823, called for podiatry to be a protected profession.
Prominent figures including Napoleon and French kings employed personal podiatrists. President Abraham Lincoln sent his personal podiatrist, Isachar Zachrie, on confidential missions to confer with leaders of the Confederacy during the U.S. Civil War.
The first podiatric society was established in New York in 1895, and still operates there today as NYSPMA. The first podiatric school opened in 1911. One year later, the British established a podiatric society at the London Foot Hospital; a school was added in 1919. The first American podiatric journal appeared in 1907, followed in 1912 by a UK journal. In Australia, professional podiatric associations were organized as early as 1924, followed by a podiatric training center and professional podiatric journal in 1939.
== Specific country practices ==
=== Australia ===
In Australia, podiatry is considered an allied health profession and is practised by individuals licensed by the Podiatry Board of Australia.
Australia recognizes two levels of professional accreditation (General Podiatrist and Podiatric Surgeon), with ongoing lobbying for the recognition of other subspecialties. Some Commonwealth countries recognize Australian qualifications, allowing Australian podiatrists to practise abroad.
==== Registration and regulation ====
Australian podiatrists must register with the Podiatry Board of Australia, which regulates podiatrists and podiatric surgeons. The board also assesses foreign-trained registrants in conjunction with the Australian & New Zealand Podiatry Accreditation Council (ANZPAC). It recognizes three pathways to attain specialist registration as a podiatric surgeon:
Fellowship of the Australasian College of Podiatric Surgeons
Doctor of Podiatric Surgery, University of Western Australia
Eligibility for Fellowship of the Australasian College of Podiatric Surgeons
Until 21 November 2019, ANZPAC approved the Doctor of Podiatric Surgery program of study offered by the University of Western Australia as providing a qualification for the purpose of specialist registration as a podiatric surgeon.
==== Education and training ====
To enter an undergraduate Podiatric Medicine program, applicants must have completed a Year 12 Certificate with an Australian Tertiary Admission Rank (ATAR). Cut-off scores from the Universities Admissions Centre (UAC) generally range from 70.00 to 95.00; prospective students who are 21 or older can instead apply directly to the university. The UWA DPM program has admission requirements of: completion of a UWA bachelor's degree or equivalent, a minimum GPA of 5.0 from the most recent three years (FTE) of valid study, suitable GAMSAT score, and English language competency. There is no interview requirement for the DPM at UWA (applications are handled via the university).
Australian podiatrists complete an undergraduate degree ranging from 3 to 4 years of education. The first 2 years of this program are generally focused on various biomedical science subjects, including functional anatomy, microbiology, biochemistry, physiology, pathophysiology, pharmacology, evidence-based medicine, sociology, and patient psychology, similar to the medical curriculum. The following year focuses on podiatry-specific areas such as podiatric anatomy & biomechanics, human gait, podiatric orthopaedics (the non-surgical management of foot abnormalities), podopaediatrics, sports medicine, rheumatology, diabetes, vascular medicine, mental health, wound care, neuroscience & neurology, pharmacology, general medicine, general pathology, local and general anaesthesia, minor and major podiatric surgical procedural techniques such as partial and total nail avulsions, matricectomy, cryotherapy, wound debridement, enucleation, suturing, other cutaneous and electro-surgical procedures and theoretical understanding of procedures performed by orthopaedic and podiatric surgeons.
Australian podiatric surgeons are specialist podiatrists with further advanced training in medicine and pharmacology, and training in foot surgery. Podiatrists wishing to pursue specialisation in podiatric surgery must meet the requirements for Fellowship with the Australasian College of Podiatric Surgeons. They must complete a 4-year degree, including 2 years of didactic study and 2 years of clinical experience, followed by a master's degree with a focus on biomechanics, medicine, surgery, general surgery, advanced pharmacology, advanced medical imaging, and clinical pathology. They then qualify for the status of Registrar with the Australasian College of Podiatric Surgeons. Following surgical training with a podiatric surgeon (3–5 years), rotations within other medical and surgeons' disciplines, overseas clinical rotations, and passing oral and written exams, Registrars may qualify for Fellowship status. Fellows are then given Commonwealth accreditation under the Health Insurance Act, recognising them as providers of professional attention for the purposes of health insurance rebates.
==== Australian podiatric medical schools ====
The following podiatric teaching centres are accredited by the Australian and New Zealand Podiatry Accreditation Council (ANZPAC):
University of Western Australia
Charles Sturt University
La Trobe University
University of Western Sydney
University of South Australia
University of Newcastle (Australia)
Queensland University of Technology
Central Queensland University
Southern Cross University
Auckland University of Technology (in New Zealand)
Some, including Charles Sturt University and University of Western Sydney, offer the degree Bachelor of Podiatric Medicine; others offer postgraduate degrees, such as the University of Western Australia's Doctor of Podiatric Medicine, and La Trobe University's Master of Podiatric Practice.
Two more podiatric schools are being developed, at the Australian Catholic University and the University of Ballarat.
==== Prescribing of scheduled medicines and referral rights ====
The prescribing rights of Australian podiatrists vary by state. All states allow registered podiatrists to use local anaesthesia for minor surgeries.
In Victoria, Western Australia, Queensland, South Australia, New South Wales: registered podiatrists and podiatric surgeons with an endorsement of scheduled medicines may prescribe relevant schedule 4 poisons.
In Western Australia and South Australia, podiatrists with Master's degrees in Podiatry and extensive training in pharmacology are authorised to prescribe Schedule 2, 3, 4, or 8 medicines (Australian Health Practitioner Regulation Agency).
In Queensland, Fellows of the Australasian College of Podiatric Surgeons are authorised to prescribe a range of Schedule 4 drugs and one Schedule 8 drug.
Prescriptions written by podiatrists do not qualify for the Pharmaceutical Benefits Scheme, despite lobbying to change this.
Some referrals from podiatrists (plain x-rays of the foot, leg, knee, and femur, and ultrasound examination of soft tissue conditions of the foot) are rebated by Medicare, while others (CTs, MRIs, bone scans, pathology testing, and other specialist medical practitioners) are not eligible for Medicare rebates.
=== Canada ===
In Canada, the definition and scope of the practice of podiatry varies by province. A number of provinces, including British Columbia, Alberta, and Quebec, accept the qualification of Doctor of Podiatric Medicine (DPM); in Quebec, other academic designations may also register.
In 2004, Université du Québec à Trois-Rivières started the first and only program of Podiatric Medicine in Canada based on the American definition of podiatry. This program enlists 25 students yearly across Canada and leads to a DPM upon obtaining 195 credits.
The province of Ontario has been registering chiropodists since 1944, with 701 chiropodists and 54 podiatrists registered by the College of Chiropodists of Ontario as of December 31, 2019. Ontario makes a distinction between podiatrists and chiropodists. Podiatrists are required to have a DPM, whereas chiropodists need only have a post-secondary diploma in chiropody. Podiatrists, unlike chiropodists, may bill OHIP, "communicate a diagnosis" to their patients, and perform surgical procedures on the bones of the forefoot. Registered podiatrists who relocate to Ontario are required to register with the province and practice as a chiropodist. Ontario legislation in 1991 imposed a cap on Ontario-trained chiropodists becoming podiatrists, while grandfathering in already-practising podiatrists.
=== Iran ===
There are no podiatric medical schools in Iran. The Ministry of Health and Medical Education (MoHME) reviews the dossier of podiatric applicants for medical registration according to the "Regulations on the Evaluation of the Educational Credentials of Foreign Graduates".
Applicants with podiatric degrees from the United States qualify for registration in Iran if they meet the following criteria:
possession of a bachelor's degree
passing score on the MCAT
completion of the podiatric curriculum of an accredited school, thereby obtaining the degree of Doctor of Podiatric Medicine (DPM)
completion of a one-year postgraduate training (if required by the home jurisdiction)
passing score on relevant board examinations
=== New Zealand ===
New Zealand established Chiropody (shortly thereafter renamed to Podiatry) as a registered profession in 1969, requiring all applicants to take a recognized three-year course of training. The New Zealand School of Podiatry was established at Petone in 1970, under the direction of John Gallocher. Later, the school moved to the Central Institute of Technology, Upper Hutt, Wellington. Today, Auckland University of Technology is the only provider of podiatry training in New Zealand.
In 1976, podiatrists in New Zealand gained the legal right to use a local anaesthetic, and began to include minor surgical procedures on ingrown toenails in their scope of practice. They received the right to refer patients to radiologists for X-rays in 1984, and (with suitable training) to acquire licensing to take their own X-rays in 1989. Diagnostic radiographic training is now incorporated into the podiatric degree syllabus, and on successful completion of the course, graduates register with the New Zealand National Radiation Laboratory.
=== United Kingdom ===
The scope of practice of podiatrists in the UK varies depending on their education and training, but may include simple skin care, the use of prescription-only medicines, injection therapy, and non-invasive surgery such as nail resection and removal. Podiatrists also interface between patients and multidisciplinary teams, recognising systemic disease as it manifests in the foot and referring on to the appropriate health care professionals.
To qualify as a podiatric surgeon, a podiatrist in the UK must undertake extensive postgraduate education and training, usually taking a minimum of 10 years to complete. Appropriately qualified podiatric surgeons may perform invasive bone and joint surgery.
Legislation in the UK protects the professional titles 'chiropodist' and 'podiatrist', but does not distinguish between the two. Those using protected titles must be registered with the Health and Care Professions Council (HCPC). Registration is normally only granted to those holding a bachelor's degree from one of 13 recognized schools of podiatry in the UK. Professional bodies recognised by the HCPC are:
The Society of Chiropodists and Podiatrists
The Alliance of Private Sector Practitioners
The Institute of Chiropodists and Podiatrists
The British Chiropody and Podiatry Association
In 1979, the Royal Commission on the National Health Service reported that about six and a half million NHS chiropody treatments were provided to just over one and a half million people in Great Britain in 1977, an increase of 19% over the number from three years before. Over 90% of patients receiving these treatments were aged 65 or over. At that time there were about 5,000 state registered chiropodists, but only about two-thirds worked for the NHS. The Commission agreed with the suggestion of the Association of Chief Chiropody Officers that more foot hygienists should be introduced, who could undertake, under the direction of a registered chiropodist, "nail cutting and such simple foot-care and hygiene as a fit person should normally carry out for himself."
=== United States ===
In the United States, medical and surgical care of the foot and ankle is mainly provided by two groups: podiatrists (with a Doctor of Podiatric Medicine degree) and orthopedic surgeons (with a Doctor of Medicine or Doctor of Osteopathic Medicine degree). In most states, their scope of practice is limited to the foot and ankle; however, some states include the leg, hand, or both.
In order to be considered for admission to podiatric medical school, an applicant must first complete a minimum of 90 semester hours at the university level, or (more commonly), complete a bachelor's degree with an appropriate emphasis. In addition, potential students are required to take the Medical College Admission Test (MCAT). In 2019, the average MCAT for matriculants was 500 and 3.5 average undergraduate cGPA.
The DPM degree itself takes a minimum of four years to complete. The first two years of podiatric medical school are similar to training that M.D. and D.O. students receive, but with greater emphasis on the foot and ankle.
The four-year podiatric medical school is followed by a surgical residency to provide hands-on training. As of July 2013, all residency programs in podiatry were required to transition to a minimum of three years of post-doctoral training. This upgrading of training was spearheaded in California by the state Board of Podiatric Medicine (BPM) and its California Liaison Committee (CLC). BPM’s Executive Officer James H. Rathlesberger included it in the Federation of Podiatric Medical Boards’ Model Law, which he wrote before becoming FPMB president in 2000.
Podiatric residents rotate through core areas of medicine and surgery. They work in such rotations as emergency medicine, internal medicine, infectious disease, behavioral medicine, physical medicine and rehabilitation, vascular surgery, general surgery, orthopedic surgery, plastic surgery, dermatology, and podiatric surgery and medicine. Fellowship training is available after residency in such fields such as geriatrics, foot and ankle traumatology, and infectious disease.
Upon completion of their residency, podiatrist candidates are eligible to sit for examinations for certification by one of two specialty boards accredited by the Council on Podiatric Medical Education (CPME), which itself is overseen and approved by the Department of Education. These are the American Board of Podiatric Medicine (ABPM) and the American Board of Foot and Ankle Surgery (ABFAS).
ABPM certification leads to fellowship in either the American Society of Podiatric Surgeons (ASPS) or the American College of Podiatric Medicine (ACPM). ABFAS certification leads to fellowship in the ASPS or the American College of Foot and Ankle Surgeons (ACFAS). ABPM is recognized by CPME as certification in primary podiatric medicine and orthopaedics and the ABFAS as certification in podiatric surgery. However, hospital credentialing committees often do not distinguish between the two.
There are two surgical certifications under ABFAS: foot surgery, and reconstructive rearfoot/ankle (RRA) surgery. In order to be board-certified in RRA, the sitting candidate has to have already achieved board certification in foot surgery. To receive ABFAS certification, the candidate must pass the written examination, submit surgical logs indicating experience and variety, pass an oral examination, and complete a computer-based clinical simulation.
==== Practice characteristics ====
Podiatric physicians practice in a variety of different settings. Some practice solo in a private practice setting; some belong to larger group practices. There are podiatrists in larger multi-specialty practices as well (such as orthopedic groups or groups for the treatment of diabetes) or clinic practices (such as the Indian Health Service (IHS), the Rural Health Centers (RHC), or the Community Health Center (FQHC)). Some work for government organizations, such as for Veterans Affairs hospitals and clinics.
Some podiatrists have primarily surgical practices. They may complete additional fellowship training in reconstruction of the foot and ankle from the effects of diabetes or physical trauma, or practice minimally invasive percutaneous surgery for cosmetic correction of hammer toes and bunions.
==== Colleges and education ====
There are 11 schools of podiatric medicine in the United States. These are governed by the American Association of Colleges of Podiatric Medicine (AACPM) and accredited by the Council on Podiatric Medical Education.
Arizona School of Podiatric Medicine at Midwestern University
Barry University School of Podiatric Medicine
Des Moines University College of Podiatric Medicine and Surgery
New York College of Podiatric Medicine
Kent State University College of Podiatric Medicine
Lake Erie College of Osteopathic Medicine School of Podiatric Medicine
Dr. William M. Scholl College of Podiatric Medicine at Rosalind Franklin University of Medicine and Science
Samuel Merritt University College of Podiatric Medicine
Temple University School of Podiatric Medicine
University of Texas Rio Grande Valley School of Podiatric Medicine
College of Podiatric Medicine at Western University of Health Sciences
== Podiatric subspecialties ==
Podiatrists treat a wide variety of foot and lower-extremity conditions through both nonsurgical and surgical approaches. While the terminology of subspecialties differ around the world, they generally fall into these categories:
Reconstructive foot and ankle surgery
Podiatric sports medicine (chronic overuse injuries and mechanical performance enhancement)
Podiatric dermatology
Lower extremity plastic and reconstructive surgery, limb salvage, and wound care
Podopediatrics (podiatry in children)
Forensic podiatry (the study of footprints, footwear, shoeprints and feet associated with crime scene investigations)
Podiatric assistants work as a part of a podiatric medical team in a variety of clinical and non-clinical settings. Worldwide, there are common professional accreditation pathways to be a podiatric assistant; for instance, in Australia, the qualification is a Certificate IV in Allied Health Assistance specialising in podiatry. Podiatric assistants may specialize in many different fields, such as:
Podiatric nurse
Podiatric surgical nurse
Foot carer
Podiatric support worker
Podiatric technician
Podiatric hygienist
Foot hygienist
Podiatric medical assistant
== Professional societies and organizations ==
Academy of Ambulatory Foot and Ankle Surgery (AAFAS)
Alberta Podiatry Association (APA)
Alpha Gamma Kappa fraternity
Alliance of Private Sector Practitioners
American Podiatric Medical Association (APMA)
American Society of Podiatric Surgeons (ASPS)
American Society of Forensic Podiatry
American College of Foot and Ankle Surgeons (ACFAS)
American Board of Foot and Ankle Surgery (ABFAS)
American College of Podiatric Medicine (ACPM)
American Board of Podiatric Medicine (ABPM
American Board of Multiple Specialties in Podiatric Medicine
American Board of Multiple Specialties in Podiatric Surgery
American Academy of Podiatric Sports Medicine (AAPSM)
American Society of Podiatric Dermatology (ASPD)
Australian Podiatry Association (APODA)
Association Belge des Podologues
Canadian Podiatric Medical Association (CPMA)
American Academy of Podiatric Practice Management (AAPPM)
International Federation of Podiatrists – Fédération Internationale des Podologues (FIP-IFP)
International Foot and Ankle Biomechanics Community (i-FAB)
Student National Podiatric Medical Association (SNPMA)
American Podiatric Medical Students' Association (APMSA)
Australian College of Podiatric Surgeons (ACPS)
Australian Podiatry Association (APodA)
Australian Podiatry Council (APodC)
Australasian Academy of Podiatric Sports Medicine (AAPSM)
Australasian Podiatric Rheumatology Specialist Interest Group (APRSIG)
Federation of Podiatric Medical Boards (FPMB)
Institute of Chiropodists and Podiatrists (IOCP)
Canadian Federation of Podiatric Medicine
Royal College of Podiatry (RCoP)
== References ==
== External links ==
The Kederminster Pharmacopolium
American Academy of Podiatric Sports Medicine
American College of Foot and Ankle Pediatrics | Wikipedia/Podiatric_surgery |
Cryosurgery (with cryo from the Ancient Greek κρύο 'icy cold') is the use of extreme cold in surgery to destroy abnormal or diseased tissue; thus, it is the surgical application of cryoablation.
Cryosurgery has been historically used to treat a number of diseases and disorders, especially a variety of benign and malignant skin conditions.
== History ==
In 1841, English physician James Arnott described therapeutic applications of extremely cold temperatures, namely a mixture of crushed ice and salt applied locally (to skin or mucous membrane). He theorized his technique was capable of "arresting the accompanying inflammation, and perhaps destroying the vitality of the cancer cell." His works were the first to hypothesize that extreme cold could be used to selectively damage or destroy harmful tissue.
== Uses ==
Warts, moles, skin tags, solar keratoses, molluscum, Morton's neuroma and small skin cancers are candidates for cryosurgical treatment. Several internal disorders are also treated with cryosurgery, including liver cancer, prostate cancer, lung cancer, oral cancers, cervical disorders and, more commonly in the past, hemorrhoids. Soft tissue conditions such as plantar fasciitis (jogger's heel) and fibroma (benign excrescence of connective tissue) can be treated with cryosurgery.
Cryosurgery works by taking advantage of the destructive force of freezing temperatures on cells. When their temperature sinks beyond a certain level ice crystals begin forming inside the cells and, because of their lower density, eventually tear apart those cells. Further harm to malignant growth will result once the blood vessels supplying the affected tissue begin to freeze.
Cryosurgery is used to treat a variety of benign skin lesions including:
Acne
Dermatofibroma
Hemangioma
Keloid (hypertrophic scar)
Molluscum contagiosum
Myxoid cyst
Pyogenic granuloma
Seborrheic keratoses
Skin tags
Warts (including anogenital warts)
Cryosurgery may also be used to treat low risk skin cancers such as basal cell carcinoma and squamous cell carcinoma but a biopsy should be obtained first to confirm the diagnosis, determine the depth of invasion and characterize other high risk histologic features.
== Method ==
=== Liquid nitrogen ===
A common method of freezing lesions is by using liquid nitrogen as the cryogen. The liquid nitrogen may be applied to lesions using a variety of methods, such as dipping a cotton or synthetic material tipped applicator in liquid nitrogen and then directly applying the cryogen onto the lesion. The liquid nitrogen can also be sprayed onto the lesion using a spray canister. The spray canister may utilize a variety of nozzles for different spray patterns. A cryoprobe, which is a metal applicator that has been cooled using liquid nitrogen, can also be directly applied onto lesions.
=== Carbon dioxide ===
Carbon dioxide is also available as a spray and is used to treat a variety of benign spots. Less frequently, doctors use carbon dioxide "snow" formed into a cylinder or mixed with acetone to form a slush that is applied directly to the treated tissue.
=== Argon ===
Recent advances in technology have allowed for the use of argon gas to drive ice formation using a principle known as the Joule-Thomson effect. This gives physicians excellent control of the ice and minimizes complications using ultra-thin 17 gauge cryoneedles.
=== Freeze sprays ===
A mixture of dimethyl ether and propane is used in some "freeze spray" preparations such as Dr. Scholl's Freeze Away. The mixture is stored in an aerosol spray type container at room temperature and drops to −41 °C (−42 °F) when dispensed. The mixture is often dispensed into a straw with a cotton-tipped swab. Similar products may use tetrafluoroethane or other substances.
== Products ==
Cryosurgical systems
A number of medical supply companies have developed cryogen delivery systems for cryosurgery. Most are based on the use of liquid nitrogen, although some employ the use of proprietary mixtures of gases that combine to form the cryogen.
== In cancer treatment ==
Cryosurgery is also used to treat internal and external tumors as well as tumors in the bone. To cure internal tumors, a hollow instrument called a cryoprobe is used, which is placed in contact with the tumor. Liquid nitrogen or argon gas is passed through the cryoprobe. Ultrasound or MRI is used to guide the cryoprobe and monitor the freezing of the cells. This helps in limiting damage to adjacent healthy tissues. A ball of ice crystals forms around the probe which results in freezing of nearby cells. When it is required to deliver gas to various parts of the tumor, more than one probe is used. After cryosurgery, the frozen tissue is either naturally absorbed by the body in the case of internal tumors, or it dissolves and forms a scab for external tumors.
== Results ==
Cryosurgery is a minimally invasive procedure, and is often preferred to other types of surgery because of its safety, ease of use, minimal pain and scarring as well as low cost; however, as with any medical treatment, there are risks involved, primarily that of damage to nearby healthy tissue. Damage to nerve tissue is of particular concern but is rare.
Cryosurgery cannot be used on lesions that would subsequently require biopsy as the technique destroys tissue and precludes the use of histopathology.
More common complications of cryosurgery include blistering and edema which are transient. Cryosurgery may cause complications due to damage of underlying structures. Destruction of the basement membrane may cause scarring and destruction of hair follicles can cause alopecia or hair loss. Occasionally, hypopigmentation may occur in the area of skin treated with cryosurgery, however, this complication is usually transient and often resolves as melanocytes migrate and repigment the area over several months. Bleeding can also occur, which can be delayed or immediate, due to damage of underlying arteries and arterioles. Tendon rupture and cartillage necrosis can occur, particularly if cryosurgery is done over bony prominences. These complications can be avoided or minimized if freeze times of less than 30 seconds are used during cryosurgery.
Patients undergoing cryosurgery usually experience redness and minor-to-moderate localized pain, which most of the time can be alleviated sufficiently by oral administration of mild analgesics such as ibuprofen, codeine or acetaminophen (paracetamol). Blisters may form as a result of cryosurgery, but these usually scab over and peel away within a few days.
== See also ==
Chemical cautery
Cryoneurolysis
Cryotherapy
Electrosurgery
== References == | Wikipedia/Cryosurgery |
Breast surgery is a form of surgery performed on the breast.
== Types ==
Types include:
Breast augmentation
Breast reduction
Breast-conserving surgery, a less radical cancer surgery than mastectomy
Lumpectomy
Mastectomy
Mastopexy, or breast lift surgery
Microdochectomy (removal of a lactiferous duct)
Surgery for breast abscess, including incision and drainage as well as excision of lactiferous ducts
Surgical breast biopsy
== Complications ==
After surgical intervention to the breast, complications may arise related to wound healing. As in other types of surgery, hematoma (post-operative bleeding), seroma (fluid accumulation), or incision-site breakdown (wound infection) may occur.
Breast hematoma due to an operation will normally resolve with time but should be followed up with more detailed evaluation if it does not. Breast abscess can occur as post-surgical complication, for example after cancer treatment or reduction mammaplasty. Furthermore, if a breast has already undergone irradiation (as in radiation therapy for treating breast cancer), there is a heightened risk of complications (e.g. reactive inflammation, occurrence of a chronic draining wound, etc.) for breast biopsies or other interventions to the breast, even those often considered "minor" surgeries. The combined effects of radiation and breast cancer surgery can in particular lead to complications such as breast fibrosis, secondary lymphoedema (which may occur in the arm, the breast or the chest, in particular after axillary lymph node dissection), breast asymmetry, and chronic/recurrent breast cellulitis, each of these having long-term effects.
Ultrasound can be used to distinguish between seroma, hematoma, and edema in the breast. Further possible complications are fat necrosis (premature cell death of fat cells) and scar retraction (shrinking of the area around the surgical scar). In rare cases after breast reconstruction or augmentation, late seroma may occur, defined as seroma occurring more than 12 months postoperatively.
There is preliminary evidence suggesting that negative-pressure wound therapy may be useful in healing complicated breast wounds resulting from surgery.
Postoperative pain is common following breast surgery. The incidence of poorly controlled acute postoperative pain following breast cancer surgery ranges between 14.0% to 54.1%. Regional anaesthesia is superior compared to general anaesthesia for the prevention of persistent postoperative pain three to 12 months after breast cancer surgery.
In post-surgical medical imaging, many findings can easily be mistaken for cancer. In MRI, scars that occurred many years before are normally "silent".
== References == | Wikipedia/Breast_surgery |
Minimally invasive procedures (also known as minimally invasive surgeries) encompass surgical techniques that limit the size of incisions needed, thereby reducing wound healing time, associated pain, and risk of infection. Surgery by definition is invasive, and many operations requiring incisions of some size are referred to as open surgery. Incisions made during open surgery can sometimes leave large wounds that may be painful and take a long time to heal. Advancements in medical technologies have enabled the development and regular use of minimally invasive procedures. For example, endovascular aneurysm repair, a minimally invasive surgery, has become the most common method of repairing abdominal aortic aneurysms in the US as of 2003. The procedure involves much smaller incisions than the corresponding open surgery procedure of open aortic surgery.
Interventional radiologists were the forerunners of minimally invasive procedures. Using imaging techniques, radiologists were able to direct interventional instruments through the body by way of catheters instead of the large incisions needed in traditional surgery. As a result, many conditions once requiring surgery can now be treated non-surgically.
Diagnostic techniques that do not involve incisions, puncturing the skin, or the introduction of foreign objects or materials into the body are known as non-invasive procedures. Several treatment procedures are classified as non-invasive. A major example of a non-invasive alternative treatment to surgery is radiation therapy, also called radiotherapy.
== Medical uses ==
Minimally invasive procedures were pioneered by interventional radiologists who had first introduced angioplasty and the catheter-delivered stent. Many other minimally invasive procedures have followed where images of all parts of the body can be obtained and used to direct interventional instruments by way of catheters (needles and fine tubes), so that many conditions once requiring open surgery can now be treated non-surgically. A minimally invasive procedure typically involves the use of arthroscopic (for joints and the spine) or laparoscopic devices and remote-control manipulation of instruments with indirect observation of the surgical field through an endoscope or large scale display panel, and is carried out through the skin or through a body cavity or anatomical opening. Interventional radiology now offers many techniques that avoid the need for surgery.
By use of a minimally invasive procedure, a patient may require only an adhesive bandage on the incision, rather than multiple stitches or staples to close a large incision. This usually results in less infection, a quicker recovery time and shorter hospital stays, or allow outpatient treatment. However, the safety and effectiveness of each procedure must be demonstrated with randomized controlled trials. The term was coined by John E. A. Wickham in 1984, who wrote of it in British Medical Journal in 1987.
== Specific procedures ==
Many medical procedures are called minimally invasive; those that involve small incisions through which an endoscope is inserted, end in the suffix -oscopy, such as endoscopy, laparoscopy, arthroscopy. Other examples of minimally invasive procedures include the use of hypodermic injection, and air-pressure injection, subdermal implants, refractive surgery, percutaneous surgery, cryosurgery, microsurgery, keyhole surgery, endovascular surgery using interventional radiology (such as angioplasty or embolization), coronary catheterization, permanent placement of spinal and brain electrodes, stereotactic surgery, the Nuss procedure, radioactivity-based medical imaging methods, such as gamma camera, positron emission tomography and SPECT (single photon emission tomography). Related procedures are image-guided surgery, and robot-assisted surgery.
== Equipment ==
Special medical equipment may be used, such as fiber optic cables, miniature video cameras and special surgical instruments handled via tubes inserted into the body through small openings in its surface. The images of the interior of the body are transmitted to an external video monitor and the surgeon has the possibility of making a diagnosis, visually identifying internal features and acting surgically on them.
== Benefits ==
Minimally invasive surgery should have less operative trauma, other complications and adverse effects than an equivalent open surgery. It may be more or less expensive (for dental implants, a minimally invasive method reduces the cost of installed implants and shortens the implant-prosthetic rehabilitation time with four–six months). Operative time is longer, but hospitalization time is shorter. It causes less pain and scarring, speeds recovery, and reduces the incidence of post-surgical complications, such as adhesions and wound rupture. Some studies have compared heart surgery.
== Risks ==
Risks and complications of minimally invasive procedures are the same as for any other surgical operation, among the risks are: death, bleeding, infection, organ injury, and thromboembolic disease.
There may be an increased risk of hypothermia and peritoneal trauma due to increased exposure to cold, dry gases during insufflation. The use of surgical humidification therapy, which is the use of heated and humidified CO2 for insufflation, may reduce this risk.
== Invasive procedures ==
Sometimes the use of non-invasive methods is not an option, so that the next level of minimally invasive techniques are looked to. These include the use of hypodermic injection (using the syringe), an endoscope, percutaneous surgery which involves needle puncture of the skin, laparoscopic surgery commonly called keyhole surgery, a coronary catheter, angioplasty and stereotactic surgery.
=== Open surgery ===
"Open surgery" is any surgical procedure where the incision made is enough to allow the surgery to take place. With tissues and structures exposed to the air, the procedure can be performed either with the unaided vision of the surgeon or with the use of loupes or microscopes. Some examples of open surgery used are for herniated disc commonly called a "slipped disc", and most types of cardiac surgery and neurosurgery.
== Associations ==
Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) for adults.
International Pediatric Endosurgery Group (IPEG) for pediatrics.
== See also ==
== References ==
== Further reading ==
== External links ==
Minimally invasive heart surgery. Medical Encyclopedia, MedlinePlus. | Wikipedia/Minimally_invasive_surgery |
An endoscopy is a procedure used in medicine to look inside the body. The endoscopy procedure uses an endoscope to examine the interior of a hollow organ or cavity of the body. Unlike many other medical imaging techniques, endoscopes are inserted directly into the organ.
There are many types of endoscopies. Depending on the site in the body and type of procedure, an endoscopy may be performed by a doctor or a surgeon. During the procedure, a patient may be fully conscious or anaesthetised. Most often, the term endoscopy is used to refer to an examination of the upper part of the gastrointestinal tract, known as an esophagogastroduodenoscopy.
Similar instruments are called borescopes for nonmedical use.
== History ==
Adolf Kussmaul was fascinated by sword swallowers who would insert a sword down their throat without gagging. This drew inspiration to insert a hollow tube for observation; the next problem to solve was how to shine light through the tube, as they were still relying on candles and oil lamps as light sources.
The term endoscope was first used on February 7, 1855, by engineer-optician Charles Chevalier, about the uréthroscope of Désormeaux, who himself began using the former term a month later. The self-illuminated endoscope was developed at Glasgow Royal Infirmary in Scotland (one of the first hospitals to have mains electricity) in 1894/5 by John Macintyre as part of his specialization in the investigation of the larynx.
== Medical uses ==
Endoscopy may be used to investigate symptoms in the digestive system including nausea, vomiting, abdominal pain, difficulty swallowing, and gastrointestinal bleeding. It is also used in diagnosis, most commonly by performing a biopsy to check for conditions such as anemia, bleeding, inflammation, and cancers of the digestive system. The procedure may also be used for treatment such as cauterization of a bleeding vessel, widening a narrow esophagus, clipping off a polyp, or removing a foreign object.
Specialty professional organizations that specialize in digestive problems advise that many patients with Barrett's esophagus receive endoscopies too frequently. Such societies recommend that patients with Barrett's esophagus and no cancer symptoms after two biopsies receive biopsies as indicated and no more often than the recommended rate.
=== Applications ===
Health care providers can use endoscopy to review any of the following body parts:
The gastrointestinal tract (GI tract):
oesophagus, stomach and duodenum (esophagogastroduodenoscopy)
small intestine (enteroscopy)
large intestine/colon (colonoscopy, sigmoidoscopy)
Magnification endoscopy
bile duct
endoscopic retrograde cholangiopancreatography (ERCP), duodenoscope-assisted cholangiopancreatoscopy, intraoperative cholangioscopy
rectum (rectoscopy) and anus (anoscopy), both also referred to as (proctoscopy)
The respiratory tract
The nose (rhinoscopy)
The upper respiratory tract (laryngoscopy)
The lower respiratory tract (bronchoscopy)
The ear (otoscope)
The Urinary bladder (cystoscopy)
The Ureter (ureteroscopy)
The female reproductive system (gynoscopy)
The cervix (colposcopy)
The uterus (hysteroscopy)
The fallopian tubes (falloposcopy)
Normally closed body cavities (through a small incision):
The abdominal or pelvic cavity (laparoscopy)
The interior of a joint (arthroscopy)
Organs of the chest (thoracoscopy and mediastinoscopy)
Endoscopy is used for many procedures:
During pregnancy
The amnion (amnioscopy)
The fetus (fetoscopy)
Plastic surgery
Panendoscopy (or triple endoscopy)
Combines laryngoscopy, esophagoscopy, and bronchoscopy
Orthopedic surgery
Hand surgery, such as endoscopic carpal tunnel release
Knee surgery, such as anterior cruciate ligament reconstruction
Epidural space (epiduroscopy)
Bursae (bursectomy)
Endodontic surgery
Maxillary sinus surgery
Apicoectomy
Endoscopic endonasal surgery
Endoscopic spinal surgery
Endoscopic nerve decompression for peripheral nerves
An endoscopy is a simple procedure that allows a doctor to look inside human bodies using an instrument called an endoscope. A cutting tool can be attached to the end of the endoscope, and the apparatus can then be used to perform minor procedures such as tissue biopsies, banding of oesophageal varices, or removal of polyps.
== Application in other fields ==
For non-medical use, such as internal inspection of complex technical systems, borescopes are used. These are similar to endoscopes.
The planning and architectural community use architectural endoscopy for pre-visualization of scale models of proposed buildings and cities
Endoscopes are also a tool helpful in the examination of improvised explosive devices by bomb disposal personnel.
Law enforcement uses endoscopes for conducting surveillance via tight spaces.
== Risks ==
The main risks are infection, over-sedation, perforation, or a tear of the stomach or esophagus lining and bleeding. Although perforation generally requires surgery, certain cases may be treated with antibiotics and intravenous fluids. Bleeding may occur at the site of a biopsy or polyp removal. Such typically minor bleeding may simply stop on its own or be controlled by cauterisation. Surgery became necessary. Perforation and bleeding are rare during gastroscopy. Other minor risks include drug reactions and complications related to other diseases the patient may have. Consequently, patients should inform their doctor of all allergic tendencies and medical problems. Occasionally, the site of the sedative injection may become inflamed and tender for a short time. This is usually not serious, and warm compresses for a few days are usually helpful. While any of these complications may occur, each of them occurs quite infrequently. A doctor can further discuss risks with the patient about the particular need for gastroscopy.
== After the endoscopy ==
After the procedure, the patient will be observed and monitored by a qualified individual in the endoscopy room or a recovery area until a significant portion of the medication has worn off. Occasionally, the patient is left with a mild sore throat, which may respond to saline gargles or chamomile tea. It may last for weeks or not happen at all. The patient may have a feeling of distention from the insufflated air that was used during the procedure. Both problems are mild and fleeting. When fully recovered, the patient will be instructed when to resume their usual diet (probably within a few hours) and will be allowed to be taken home. Where sedation has been used, most facilities mandate that the patient be taken home by another person and that they not drive or handle machinery for the remainder of the day. Patients who have had an endoscopy without sedation can leave unassisted.
== References ==
== External links ==
The Atlas of Gastrointestinal Endoscopy endoatlas.com
El Salvador Atlas of Gastrointestinal Endoscopy
Gastrolab: Site in English, Swedish and Finnish with gastrointestinal endoscopy photolibrary Archived 2020-07-10 at the Wayback Machine
Preventing cross-contamination from flexible endoscopes massdevice.com
Advances in Endoscopy Archived 2018-05-13 at the Wayback Machine advancedimagingpro.com | Wikipedia/Endoscopic_surgery |
A sexually transmitted infection (STI), also referred to as a sexually transmitted disease (STD) and the older term venereal disease (VD), is an infection that is spread by sexual activity, especially vaginal intercourse, anal sex, oral sex, or sometimes manual sex. STIs often do not initially cause symptoms, which results in a risk of transmitting them to others. The term sexually transmitted infection is generally preferred over sexually transmitted disease or venereal disease, as it includes cases with no symptomatic disease. Symptoms and signs of STIs may include vaginal discharge, penile discharge, ulcers on or around the genitals, and pelvic pain. Some STIs can cause infertility.
Bacterial STIs include chlamydia, gonorrhea, and syphilis. Viral STIs include genital warts, genital herpes, and HIV/AIDS. Parasitic STIs include trichomoniasis. Most STIs are treatable and curable; of the most common infections, syphilis, gonorrhea, chlamydia, and trichomoniasis are curable, while HIV/AIDS and genital herpes are not curable. Some vaccinations may decrease the risk of certain infections including hepatitis B and a few types of HPV. Safe sex practices such as the use of condoms, having smaller number of sexual partners, and being in a relationship in which each person only has sex with the other also decreases STIs risk. Comprehensive sex education may also be useful.
STI diagnostic tests are usually easily available in the developed world, but they are often unavailable in the developing world. There is often shame and stigma associated with STIs. In 2015, STIs other than HIV resulted in 108,000 deaths worldwide. Globally, in 2015, about 1.1 billion people had STIs other than HIV/AIDS. About 500 million have either syphilis, gonorrhea, chlamydia or trichomoniasis. At least an additional 530 million have genital herpes, and 290 million women have human papillomavirus. Historical documentation of STIs in antiquity dates back to at least the Ebers Papyrus (c. 1550 BCE) and the Hebrew Bible/Old Testament (8th/7th C. BCE).
== Signs and symptoms ==
Not all STIs are symptomatic, and symptoms may not appear immediately after infection. In some instances a disease can be carried with no symptoms, which leaves a greater risk of passing the disease on to others. Depending on the disease, some untreated STIs can lead to infertility, chronic pain or death.
The presence of an STI in prepubescent children may indicate sexual abuse.
== Cause ==
=== Transmission ===
A sexually transmitted infection present in a pregnant woman may be passed on to the infant before or after birth.
=== Bacterial ===
Chancroid (Haemophilus ducreyi)
Chlamydia (Chlamydia trachomatis)
Gonorrhea (Neisseria gonorrhoeae)
Granuloma inguinale or (Klebsiella granulomatis)
Mycoplasma genitalium
Mycoplasma hominis
Syphilis (Treponema pallidum)
Ureaplasma infection
=== Viral ===
Viral hepatitis (hepatitis B virus)—saliva, venereal fluids.(Note: hepatitis A and hepatitis E are transmitted via the fecal–oral route; hepatitis C is rarely sexually transmittable, and the route of transmission of hepatitis D (only if infected with B) is uncertain, but may include sexual transmission.)
Herpes simplex (Herpes simplex virus 1, 2) skin and mucosal, transmissible with or without visible blisters
HIV (Human Immunodeficiency Virus)—venereal fluids, semen, breast milk, blood
HPV (Human Papillomavirus)—skin and mucosal contact. 'High risk' types of HPV cause almost all cervical cancers, as well as some anal, penile, and vulvar cancer. Some other types of HPV cause genital warts.
Molluscum contagiosum (molluscum contagiosum virus MCV)—close contact
Zika virus
=== Parasites ===
Crab louse, colloquially known as "crabs" or "pubic lice" (Pthirus pubis). The infestation and accompanying inflammation is Pediculosis pubis
Scabies (Sarcoptes scabiei)
Trichomoniasis (Trichomonas vaginalis), colloquially known as "trich"
=== Main types ===
Sexually transmitted infections include:
Chlamydia is a sexually transmitted infection caused by the bacterium Chlamydia trachomatis. In women, symptoms may include abnormal vaginal discharge, burning during urination, and bleeding in between periods, although most women do not experience any symptoms. Symptoms in men include pain when urinating, and abnormal discharge from their penis. If left untreated in both men and women, chlamydia can infect the urinary tract and potentially lead to pelvic inflammatory disease (PID). PID can cause serious problems during pregnancy and even has the potential to cause infertility. It can cause a woman to have a potentially deadly ectopic pregnancy, in which the egg implants outside of the uterus. However, chlamydia can be cured with antibiotics.
The two most common forms of herpes are caused by infection with herpes simplex virus (HSV). HSV-1 is typically acquired orally and causes cold sores; HSV-2 is usually acquired during sexual contact and affects the genitals; however, either strain may affect either site. Some people are asymptomatic or have very mild symptoms. Those that do experience symptoms usually notice them 2 to 20 days after exposure which lasts 2 to 4 weeks. Symptoms can include small fluid-filled blisters, headaches, backaches, itching or tingling sensations in the genital or anal area, pain during urination, flu like symptoms, swollen glands, or fever. Herpes is spread through skin contact with a person infected with the virus. The virus affects the areas where it entered the body. This can occur through kissing, vaginal intercourse, oral sex or anal sex. The virus is most infectious during times when there are visible symptoms; however, those who are asymptomatic can still spread the virus through skin contact. The initial infection and symptoms are usually the most severe because the body does not have any antibodies built up. After the primary attack, one might have recurring attacks that are milder or might not even have future attacks. There is no cure for the disease but there are antiviral medications that treat its symptoms and lower the risk of transmission (Valtrex). Although HSV-1 is typically the "oral" version of the virus, and HSV-2 is typically the "genital" version of the virus, a person with HSV-1 orally can transmit that virus to their partner genitally. The virus, either type, will settle into a nerve bundle either at the top of the spine, producing the "oral" outbreak, or a second nerve bundle at the base of the spine, producing the genital outbreak.
The human papillomavirus (HPV) is the most common STI in the United States. There are more than 40 different strands of HPV and many do not cause any health problems. In 90% of cases, the body's immune system clears the infection naturally within two years. Some cases may not be cleared and can lead to genital warts (bumps around the genitals that can be small or large, raised or flat, or shaped like cauliflower) or cervical cancer and other HPV related cancers. Symptoms might not show up until advanced stages. It is important for women to get pap smears in order to check for and treat cancers. There are also two vaccines available for women (Cervarix and Gardasil) that protect against the types of HPV that cause cervical cancer. HPV can be passed through genital-to-genital contact as well as during oral sex. The infected partner might not have any symptoms.
Gonorrhea is caused by bacterium that lives on moist mucous membranes in the urethra, vagina, rectum, mouth, throat, and eyes. The infection can spread through contact with the penis, vagina, mouth, or anus. Symptoms of gonorrhea usually appear two to five days after contact with an infected partner; however, some men might not notice symptoms for up to a month. Symptoms in men include burning and pain while urinating, increased urinary frequency, discharge from the penis (white, green, or yellow in color), red or swollen urethra, swollen or tender testicles, or sore throat. Symptoms in women may include vaginal discharge, burning or itching while urinating, painful sexual intercourse, severe pain in lower abdomen (if infection spreads to fallopian tubes), or fever (if infection spreads to fallopian tubes); however, many women do not show any symptoms. Antibiotic resistant strains of Gonorrhea are a significant concern, but most cases can be cured with existing antibiotics.
Syphilis is an STI caused by a bacterium. Untreated, it can lead to complications and death. Clinical manifestations of syphilis include the ulceration of the uro-genital tract, mouth or rectum; if left untreated the symptoms worsen. In recent years, the prevalence of syphilis has declined in Western Europe, but it has increased in Eastern Europe (former Soviet states). A high incidence of syphilis can be found in places such as Cameroon, Cambodia, Papua New Guinea. Syphilis infections are increasing in the United States.
Trichomoniasis is a common STI that is caused by infection with a protozoan parasite called Trichomonas vaginalis. Trichomoniasis affects both women and men, but symptoms are more common in women. Most patients are treated with an antibiotic called metronidazole, which is very effective.
HIV (human immunodeficiency virus) damages the body's immune system, which interferes with its ability to fight off disease-causing agents. The virus kills CD4 cells, which are white blood cells that help fight off various infections. HIV is carried in body fluids and is spread by sexual activity. It can also be spread by contact with infected blood, breastfeeding, childbirth, and from mother to child during pregnancy. When HIV is at its most advanced stage, an individual is said to have AIDS (acquired immunodeficiency syndrome). There are different stages of the progression of and HIV infection. The stages include primary infection, asymptomatic infection, symptomatic infection, and AIDS. In the primary infection stage, an individual will have flu-like symptoms (headache, fatigue, fever, muscle aches) for about two weeks. In the asymptomatic stage, symptoms usually disappear, and the patient can remain asymptomatic for years. When HIV progresses to the symptomatic stage, the immune system is weakened and has a low cell count of CD4+ T cells. When the HIV infection becomes life-threatening, it is called AIDS. People with AIDS fall prey to opportunistic infections and die as a result. When the disease was first discovered in the 1980s, those who had AIDS were not likely to live longer than a few years. There are now antiretroviral drugs (ARVs) available to treat HIV infections. There is no known cure for HIV or AIDS but the drugs help suppress the virus. By suppressing the amount of virus in the body, people can lead longer and healthier lives. Even though their virus levels may be low they can still spread the virus to others.
=== Viruses in semen ===
Twenty-seven different viruses have been identified in semen. Information on whether or not transmission occurs or whether the viruses cause disease is uncertain. Some of these microbes are known to be sexually transmitted.
== Pathophysiology ==
Many STIs are (more easily) transmitted through the mucous membranes of the penis, vulva, rectum, urinary tract and (less often—depending on type of infection) the mouth, throat, respiratory tract and eyes. The visible membrane covering the head of the penis is a mucous membrane, though it produces no mucus (similar to the lips of the mouth). Mucous membranes differ from skin in that they allow certain pathogens into the body. The amount of contact with infective sources which causes infection varies with each pathogen but in all cases, a disease may result from even light contact from fluid carriers like venereal fluids onto a mucous membrane.
Some STIs such as HIV can be transmitted from mother to child either during pregnancy or breastfeeding.
Healthcare professionals suggest safer sex, such as the use of condoms, as a reliable way of decreasing the risk of contracting sexually transmitted infections during sexual activity, but safer sex cannot be considered to provide complete protection from an STI. The transfer of and exposure to bodily fluids, such as blood transfusions and other blood products, sharing injection needles, needle-stick injuries (when medical staff are inadvertently jabbed or pricked with needles during medical procedures), sharing tattoo needles, and childbirth are other avenues of transmission. These different means put certain groups, such as medical workers, and haemophiliacs and drug users, particularly at risk.
It is possible to be an asymptomatic carrier of sexually transmitted infections. In particular, sexually transmitted infections in women often cause the serious condition of pelvic inflammatory disease.
== Diagnosis ==
Testing may be for a single infection, or consist of a number of tests for a range of STIs, including tests for syphilis, trichomonas, gonorrhea, chlamydia, herpes, hepatitis, and HIV. No procedure tests for all infectious agents.
STI tests may be used for a number of reasons:
as a diagnostic test to determine the cause of symptoms or illness
as a screening test to detect asymptomatic or presymptomatic infections
as a check that prospective sexual partners are free of disease before they engage in sex without safer sex precautions (for example, when starting a long term mutually monogamous sexual relationship, in fluid bonding, or for procreation).
as a check prior to or during pregnancy, to prevent harm to the baby
as a check after birth, to check that the baby has not caught an STI from the mother
to prevent the use of infected donated blood or organs
as part of the process of contact tracing from a known infected individual
as part of mass epidemiological surveillance
Early identification and treatment results in less chance to spread disease, and for some conditions may improve the outcomes of treatment. There is often a window period after initial infection during which an STI test will be negative. During this period, the infection may be transmissible. The duration of this period varies depending on the infection and the test. Diagnosis may also be delayed by reluctance of the infected person to seek a medical professional. One report indicated that people turn to the Internet rather than to a medical professional for information on STIs to a higher degree than for other sexual problems.
=== Classification ===
Until the 1990s, STIs were commonly known as venereal diseases, an antiquated euphemism derived from the Latin venereus, being the adjectival form of Venus, the Roman goddess of love. However, in the post-classical education era the euphemistic effect was entirely lost, and the common abbreviation "VD" held only negative connotations. Other former euphemisms for STIs include "blood diseases" and "social diseases". The present euphemism is in the use of the initials "STI" rather than in the words they represent. The World Health Organization (WHO) has recommended the more inclusive term sexually transmitted infection since 1999. Public health officials originally introduced the term sexually transmitted infection, which clinicians are increasingly using alongside the term sexually transmitted disease in order to distinguish it from the former.
== Prevention ==
Strategies for reducing STI risk include: vaccination, mutual monogamy, reducing the number of sexual partners, and abstinence. Also potentially helpful is behavioral counseling for sexually active adolescents and for adults who are at increased risk. Such interactive counseling, which can be resource-intensive, is directed at a person's risk, the situations in which risk occurs, and the use of personalized goal-setting strategies.
The most effective way to prevent sexual transmission of STIs is to avoid contact of body parts or fluids which can lead to transfer with an infected partner. Not all sexual activities involve contact: cybersex, phone sex or masturbation from a distance are methods of avoiding contact. Proper use of condoms reduces contact and risk. Although a condom is effective in limiting exposure, some disease transmission may occur even with a condom.Both partners can get tested for STIs before initiating sexual contact, or before resuming contact if a partner engaged in contact with someone else. Many infections are not detectable immediately after exposure, so enough time must be allowed between possible exposures and testing for the tests to be accurate. Certain STIs, particularly certain persistent viruses like HPV, may be impossible to detect.
Some treatment facilities use in-home test kits and have the person return the test for follow-up. Other facilities strongly encourage that those previously infected return to ensure that the infection has been eliminated. Novel strategies to foster re-testing have been the use of text messaging and email as reminders. These types of reminders are now used in addition to phone calls and letters. After obtaining a sexual history, a healthcare provider can encourage risk reduction by providing prevention counseling. Prevention counseling is most effective if provided in a nonjudgmental and empathetic manner appropriate to the person's culture, language, gender, sexual orientation, age, and developmental level. Prevention counseling for STIs is usually offered to all sexually active adolescents and to all adults who have received a diagnosis, have had an STI in the past year, or have multiple sex partners.
=== Vaccines ===
Vaccines are available that protect against some viral STIs, such as hepatitis A, hepatitis B, and some types of HPV. Vaccination before initiation of sexual contact is advised to assure maximal protection. The development of vaccines to protect against gonorrhea is ongoing.
=== Condoms ===
Condoms and female condoms only provide protection when used properly as a barrier, and only to and from the area that they cover. Uncovered areas are still susceptible to many STIs.
In the case of HIV, sexual transmission routes almost always involve the penis, as HIV cannot spread through unbroken skin; therefore, properly shielding the penis with a properly worn condom from the vagina or anus effectively stops HIV transmission. An infected fluid to broken skin borne direct transmission of HIV would not be considered "sexually transmitted", but can still theoretically occur during sexual contact. This can be avoided simply by not engaging in sexual contact when presenting open, bleeding wounds.
Other STIs, even viral infections, can be prevented with the use of latex, polyurethane or polyisoprene condoms as a barrier. Some microorganisms and viruses are small enough to pass through the pores in natural skin condoms but are still too large to pass through latex or synthetic condoms.
Proper male condom usage entails:
Not putting the condom on too tight at the tip by leaving 1.5 centimetres (0.6 in) room for ejaculation. Putting the condom on too tightly can and often does lead to failure.
Wearing a condom too loose can defeat the barrier
Avoiding inverting or spilling a condom once worn, whether it has ejaculate in it or not
If a user attempts to unroll the condom, but realizes they have it on the wrong side, then this condom may not be effective
Being careful with the condom if handling it with long nails
Avoiding the use of oil-based lubricants (or anything with oil in it) with latex condoms, as oil can eat holes into them
Using flavored condoms for oral sex only, as the sugar in the flavoring can lead to yeast infections if used to penetrate
In order to best protect oneself and the partner from STIs, the old condom and its contents are to be treated as infectious and properly disposed of. A new condom is used for each act of intercourse, as multiple usages increase the chance of breakage, defeating the effectiveness as a barrier.
In the case of female condoms, the device consists of two rings, one in each terminal portion. The larger ring should fit snugly over the cervix and the smaller ring remains outside the vagina, covering the vulva. This system provides some protection of the external genitalia.
=== Other ===
The cap was developed after the cervical diaphragm. Both cover the cervix and the main difference between the diaphragm and the cap is that the latter must be used only once, using a new one in each sexual act. The diaphragm, however, can be used more than once. These two devices partially protect against STIs (they do not protect against HIV).
Researchers had hoped that nonoxynol-9, a vaginal microbicide would help decrease STI risk. Trials, however, have found it ineffective and it may put women at a higher risk of HIV infection. There is evidence that vaginal dapivirine probably reduces HIV in women who have sex with men, other types of vaginal microbicides have not demonstrated effectiveness for HIV or STIs.
There is little evidence that school-based interventions such as sexual and reproductive health education programmes on contraceptive choices and condoms are effective on improving the sexual and reproductive health of adolescents. Incentive-based programmes may reduce adolescent pregnancy but more data is needed to confirm this.
== Screening ==
Specific age groups, persons who participate in risky sexual behavior, or those have certain health conditions may require screening. The CDC recommends that sexually active women under the age of 25 and those over 25 at risk should be screened for chlamydia and gonorrhea yearly. Appropriate times for screening are during regular pelvic examinations and preconception evaluations. Nucleic acid amplification tests are the recommended method of diagnosis for gonorrhea and chlamydia. This can be done on either urine in both men and women, vaginal or cervical swabs in women, or urethral swabs in men. Screening can be performed:
to assess the presence of infection and prevent tubal infertility in women
during the initial evaluation before infertility treatment
to identify HIV infection
for men who have sex with men
for those who may have been exposed to hepatitis C
for HCV
== Management ==
In the case of rape, the person can be treated prophylacticly with antibiotics.
An option for treating partners of patients (index cases) diagnosed with chlamydia or gonorrhea is patient-delivered partner therapy, which is the clinical practice of treating the sex partners of index cases by providing prescriptions or medications to the patient to take to their partner without the health care provider first examining the partner. In term of preventing reinfection in sexually transmitted infection, treatment with both patient and the sexual partner of patient resulted in more successful than treatment of the patient without the sexual partner. There is no difference in reinfection prevention whether the sexual partner treated with medication without medical examination or after notification by patient.
== Epidemiology ==
In 2008, it was estimated that 500 million people were infected with either syphilis, gonorrhea, chlamydia or trichomoniasis. At least an additional 530 million people have genital herpes and 290 million women have human papillomavirus (HPV). STIs other than HIV resulted in 142,000 deaths in 2013. In the United States there were 19 million new cases of sexually transmitted infections in 2010.
In 2010, 19 million new cases of sexually transmitted infections occurred in women in the United States. A 2008 CDC study found that 25–40% of U.S. teenage girls has a sexually transmitted infection. Out of a population of almost 295,270,000 people there were 110 million new and existing cases of eight sexually transmitted infections.
Over 400,000 sexually transmitted infections were reported in England in 2017, about the same as in 2016, but there were more than 20% increases in confirmed cases of gonorrhoea and syphilis. Since 2008 syphilis cases have risen by 148%, from 2,874 to 7,137, mostly among men who have sex with men. The number of first cases of genital warts in 2017 among girls aged 15–17 years was just 441, 90% less than in 2009 – attributed to the national HPV immunisation programme.
AIDS is among the leading causes of death in present-day Sub-Saharan Africa. HIV/AIDS is transmitted primarily via unprotected sexual intercourse. More than 1.1 million persons are living with HIV/AIDS in the United States, and it disproportionately impacts African Americans. Hepatitis B is also considered a sexually transmitted infection because it can be spread through sexual contact. The highest rates are found in Asia and Africa and lower rates are in the Americas and Europe. Approximately two billion people worldwide have been infected with the hepatitis B virus.
== History ==
The first well-recorded European outbreak of what is now known as syphilis occurred in 1494 when it broke out among French troops besieging Naples in the Italian War of 1494–98. The disease may have originated from the Columbian Exchange. From Naples, the disease swept across Europe, killing more than five million people. As Jared Diamond describes it, "[W]hen syphilis was first definitely recorded in Europe in 1495, its pustules often covered the body from the head to the knees, caused flesh to fall from people's faces, and led to death within a few months," rendering it far more fatal than it is today. Diamond concludes, "[B]y 1546, the disease had evolved into the disease with the symptoms so well known to us today." Gonorrhea is recorded at least up to 700 years ago and associated with a district in Paris formerly known as "Le Clapiers". This is where the prostitutes were to be found at that time.
Prior to the invention of modern medicines, sexually transmitted infections were generally incurable, and treatment was limited to treating the symptoms of the infection. The first voluntary hospital for STIs was founded in 1746 at London Lock Hospital. Treatment was not always voluntary: in the second half of the 19th century, the Contagious Diseases Acts were used to arrest suspected prostitutes. In 1924, a number of states concluded the Brussels Agreement, whereby states agreed to provide free or low-cost medical treatment at ports for merchant seamen with STIs. A proponent of these approaches was Nora Wattie, OBE, Venereal Diseases Officer in Glasgow from 1929, encouraged contact tracing and volunteering for treatment, rather than the prevailing more judgemental view and published her own research on improving sex education and maternity care.
The first effective treatment for a sexually transmitted infection was salvarsan, a treatment for syphilis. With the discovery of antibiotics, a large number of sexually transmitted infections became easily curable, and this, combined with effective public health campaigns against STIs, led to a public perception during the 1960s and 1970s that they have ceased to be a serious medical threat.
During this period, the importance of contact tracing in treating STIs was recognized. By tracing the sexual partners of infected individuals, testing them for infection, treating the infected and tracing their contacts, in turn, STI clinics could effectively suppress infections in the general population.
In the 1980s, first genital herpes and then AIDS emerged into the public consciousness as sexually transmitted infections that could not be cured by modern medicine. AIDS, in particular, has a long asymptomatic period—during which time HIV (the human immunodeficiency virus, which causes AIDS) can replicate and the disease can be transmitted to others—followed by a symptomatic period, which leads rapidly to death unless treated. HIV/AIDS entered the United States from Haiti in about 1969. Recognition that AIDS threatened a global pandemic led to public information campaigns and the development of treatments that allow AIDS to be managed by suppressing the replication of HIV for as long as possible. Contact tracing continues to be an important measure, even when diseases are incurable, as it helps to contain infection.
== See also ==
List of sexually transmitted infections by prevalence
== References ==
== Further reading ==
Aral SO (2008). Behavioral Interventions for Prevention and Control of Sexually Transmitted Diseases. Springer Singapore Pte. Limited. ISBN 978-0-387-85768-8.
Faro S (2003). Sexually transmitted diseases in women. Lippincott Williams & Wilkins. ISBN 978-0-397-51303-1.
Ford CA, Bowers ES (2009). Living with Sexually Transmitted Diseases. Facts on File. ISBN 978-0-8160-7672-7. Sexually transmitted disease.
Edmund O (1911). "Venereal Diseases" . In Chisholm H (ed.). Encyclopædia Britannica. Vol. 27 (11th ed.). Cambridge University Press. pp. 983–85. This provides an overview of pre-modern medicine's approach to the diseases.
Sehgal VN (2003). Sexually Transmitted Diseases (4th ed.). Jaypee Bros. Medical Publishers. ISBN 978-81-8061-105-6.
Shoquist J, Stafford D (2003). The encyclopedia of sexually transmitted diseases. Facts on File. ISBN 978-0-8160-4881-6.
Workowski KA, Bachmann LH, Chan PA, Johnston CM, Muzny CA, Park I, et al. (July 2021). "Sexually Transmitted Infections Treatment Guidelines, 2021" (PDF). MMWR Recomm Rep. 70 (4): 1–187. doi:10.15585/mmwr.rr7004a1. PMC 8344968. PMID 34292926.
== External links ==
CDC Sexually Transmitted Diseases Treatment Guidelines, 2010
STD photo library Archived 21 July 2010 at the Wayback Machine at Dermnet
UNFPA: Breaking the Cycle of Sexually Transmitted Infections at UNFPA
STDs In Color: Sexually Transmitted Disease Facts and Photos
CDC: Sexually transmitted diseases in the U.S.
STI Watch: World Health Organization | Wikipedia/Venereal_disease |
Dentistry, also known as dental medicine and oral medicine, is the branch of medicine focused on the teeth, gums, and mouth. It consists of the study, diagnosis, prevention, management, and treatment of diseases, disorders, and conditions of the mouth, most commonly focused on dentition (the development and arrangement of teeth) as well as the oral mucosa. Dentistry may also encompass other aspects of the craniofacial complex including the temporomandibular joint. The practitioner is called a dentist.
The history of dentistry is almost as ancient as the history of humanity and civilization, with the earliest evidence dating from 7000 BC to 5500 BC. Dentistry is thought to have been the first specialization in medicine which has gone on to develop its own accredited degree with its own specializations. Dentistry is often also understood to subsume the now largely defunct medical specialty of stomatology (the study of the mouth and its disorders and diseases) for which reason the two terms are used interchangeably in certain regions. However, some specialties such as oral and maxillofacial surgery (facial reconstruction) may require both medical and dental degrees to accomplish. In European history, dentistry is considered to have stemmed from the trade of barber surgeons.
Dental treatments are carried out by a dental team, which often consists of a dentist and dental auxiliaries (such as dental assistants, dental hygienists, dental technicians, and dental therapists). Most dentists either work in private practices (primary care), dental hospitals, or (secondary care) institutions (prisons, armed forces bases, etc.).
The modern movement of evidence-based dentistry calls for the use of high-quality scientific research and evidence to guide decision-making such as in manual tooth conservation, use of fluoride water treatment and fluoride toothpaste, dealing with oral diseases such as tooth decay and periodontitis, as well as systematic diseases such as osteoporosis, diabetes, celiac disease, cancer, and HIV/AIDS which could also affect the oral cavity. Other practices relevant to evidence-based dentistry include radiology of the mouth to inspect teeth deformity or oral malaises, haematology (study of blood) to avoid bleeding complications during dental surgery, cardiology (due to various severe complications arising from dental surgery with patients with heart disease), etc.
== Terminology ==
The term dentistry comes from dentist, which comes from French dentiste, which comes from the French and Latin words for tooth. The term for the associated scientific study of teeth is odontology (from Ancient Greek: ὀδούς, romanized: odoús, lit. 'tooth') – the study of the structure, development, and abnormalities of the teeth.
== Dental treatment ==
Dentistry usually encompasses practices related to the oral cavity. According to the World Health Organization, oral diseases are major public health problems due to their high incidence and prevalence across the globe, with the disadvantaged affected more than other socio-economic groups.
The majority of dental treatments are carried out to prevent or treat the two most common oral diseases, which are dental caries (tooth decay) and periodontal disease (gum disease or pyorrhea). Common treatments involve the restoration of teeth, extraction or surgical removal of teeth, scaling and root planing, endodontic root canal treatment, and cosmetic dentistry.
By nature of their general training, dentists, without specialization, can carry out the majority of dental treatments such as restorative (fillings, crowns, bridges), prosthetic (dentures), endodontic (root canal) therapy, periodontal (gum) therapy, and extraction of teeth, as well as performing examinations, radiographs (x-rays), and diagnosis. Dentists can also prescribe medications used in the field such as antibiotics, sedatives, and any other drugs used in patient management. Depending on their licensing boards, general dentists may be required to complete additional training to perform sedation, dental implants, etc.
Dentists also encourage the prevention of oral diseases through proper hygiene and regular, twice or more yearly, checkups for professional cleaning and evaluation. Oral infections and inflammations may affect overall health, and conditions in the oral cavity may be indicative of systemic diseases, such as osteoporosis, diabetes, celiac disease or cancer. Many studies have also shown that gum disease is associated with an increased risk of diabetes, heart disease, and preterm birth. The concept that oral health can affect systemic health and disease is referred to as "oral-systemic health".
== Education and licensing ==
John M. Harris started the world's first dental school in Bainbridge, Ohio, and helped to establish dentistry as a health profession. It opened on 21 February 1828, and today is a dental museum. The first dental college, Baltimore College of Dental Surgery, opened in Baltimore, Maryland, US in 1840. The second in the United States was the Ohio College of Dental Surgery, established in Cincinnati, Ohio, in 1845. The Philadelphia College of Dental Surgery followed in 1852. In 1907, Temple University accepted a bid to incorporate the school.
Studies show that dentists who graduated from different countries, or even from different dental schools in one country, may make different clinical decisions for the same clinical condition. For example, dentists that graduated from Israeli dental schools may recommend the removal of asymptomatic impacted third molar (wisdom teeth) more often than dentists that graduated from Latin American or Eastern European dental schools.
In the United Kingdom, the first dental schools, the London School of Dental Surgery and the Metropolitan School of Dental Science, both in London, opened in 1859. The British Dentists Act of 1878 and the 1879 Dentists Register limited the title of "dentist" and "dental surgeon" to qualified and registered practitioners. However, others could legally describe themselves as "dental experts" or "dental consultants". The practice of dentistry in the United Kingdom became fully regulated with the 1921 Dentists Act, which required the registration of anyone practising dentistry. The British Dental Association, formed in 1880 with Sir John Tomes as president, played a major role in prosecuting dentists practising illegally. Dentists in the United Kingdom are now regulated by the General Dental Council.
Dentists in many countries complete between five and eight years of post-secondary education before practising. Though not mandatory, many dentists choose to complete an internship or residency focusing on specific aspects of dental care after they have received their dental degree. In a few countries, to become a qualified dentist one must usually complete at least four years of postgraduate study; Dental degrees awarded around the world include the Doctor of Dental Surgery (DDS) and Doctor of Dental Medicine (DMD) in North America (US and Canada), and the Bachelor of Dental Surgery/Baccalaureus Dentalis Chirurgiae (BDS, BDent, BChD, BDSc) in the UK and current and former British Commonwealth countries.
All dentists in the United States undergo at least three years of undergraduate studies, but nearly all complete a bachelor's degree. This schooling is followed by four years of dental school to qualify as a "Doctor of Dental Surgery" (DDS) or "Doctor of Dental Medicine" (DMD). Specialization in dentistry is available in the fields of Anesthesiology, Dental Public Health, Endodontics, Oral Radiology, Oral and Maxillofacial Surgery, Oral Medicine, Orofacial Pain, Pathology, Orthodontics, Pediatric Dentistry (Pedodontics), Periodontics, and Prosthodontics.
== Specialties ==
Some dentists undertake further training after their initial degree in order to specialize. Exactly which subjects are recognized by dental registration bodies varies according to location. Examples include:
Anesthesiology – the specialty of dentistry that deals with the advanced use of general anesthesia, sedation and pain management to facilitate dental procedures.
Cosmetic dentistry – focuses on improving the appearance of the mouth, teeth and smile.
Dental public health – the study of epidemiology and social health policies relevant to oral health.
Endodontics (also called endodontology) – root canal therapy and study of diseases of the dental pulp and periapical tissues.
Forensic odontology – the gathering and use of dental evidence in law. This may be performed by any dentist with experience or training in this field. The function of the forensic dentist is primarily documentation and verification of identity.
Geriatric dentistry or geriodontics – the delivery of dental care to older adults involving the diagnosis, prevention, and treatment of problems associated with normal aging and age-related diseases as part of an interdisciplinary team with other health care professionals.
Oral and maxillofacial pathology – the study, diagnosis, and sometimes the treatment of oral and maxillofacial related diseases.
Oral and maxillofacial radiology – the study and radiologic interpretation of oral and maxillofacial diseases.
Oral and maxillofacial surgery (also called oral surgery) – extractions, implants, and surgery of the jaws, mouth and face.
Oral biology – research in dental and craniofacial biology
Oral implantology – the replacement of extracted teeth with dental implants.
Oral medicine – the clinical evaluation and diagnosis of oral mucosal diseases
Orthodontics and dentofacial orthopedics – the straightening of teeth and modification of midface and mandibular growth.
Pediatric dentistry (also called pedodontics) – dentistry for children
Periodontology (also called periodontics) – the study and treatment of diseases of the periodontium (non-surgical and surgical) as well as placement and maintenance of dental implants
Prosthodontics (also called prosthetic dentistry) – dentures, bridges and the restoration of implants.
Some prosthodontists super-specialize in maxillofacial prosthetics, which is the discipline originally concerned with the rehabilitation of patients with congenital facial and oral defects such as cleft lip and palate or patients born with an underdeveloped ear (microtia). Today, most maxillofacial prosthodontists return function and esthetics to patients with acquired defects secondary to surgical removal of head and neck tumors, or secondary to trauma from war or motor vehicle accidents.
Special needs dentistry (also called special care dentistry) – dentistry for those with developmental and acquired disabilities.
Sports dentistry – the branch of sports medicine dealing with prevention and treatment of dental injuries and oral diseases associated with sports and exercise. The sports dentist works as an individual consultant or as a member of a sports medicine team.
Veterinary dentistry – the field of dentistry applied to the care of animals. It is a specialty of veterinary medicine.
== History ==
Tooth decay was low in pre-agricultural societies, but the advent of farming society about 10,000 years ago correlated with an increase in tooth decay (cavities). An infected tooth from Italy partially cleaned with flint tools, between 13,820 and 14,160 years old, represents the oldest known dentistry, although a 2017 study suggests that 130,000 years ago the Neanderthals already used rudimentary dentistry tools. In Italy evidence dated to the Paleolithic, around 13,000 years ago, points to bitumen used to fill a tooth and in Neolithic Slovenia, 6500 years ago, beeswax was used to close a fracture in a tooth. The Indus valley has yielded evidence of dentistry being practised as far back as 7000 BC, during the Stone Age. The Neolithic site of Mehrgarh (now in Pakistan's south western province of Balochistan) indicates that this form of dentistry involved curing tooth related disorders with bow drills operated, perhaps, by skilled bead-crafters. The reconstruction of this ancient form of dentistry showed that the methods used were reliable and effective. The earliest dental filling, made of beeswax, was discovered in Slovenia and dates from 6500 years ago. Dentistry was practised in prehistoric Malta, as evidenced by a skull which had a dental abscess lanced from the root of a tooth dating back to around 2500 BC. The practice of dentistry dates back thousands of years, with evidence of dental procedures such as tooth extraction and fillings found in ancient civilizations like the Egyptians and the Greeks. One notable historical figure is Pierre Fauchard, often referred to as the 'father of modern dentistry,' who wrote the first comprehensive book on the subject in 1728.
An ancient Sumerian text describes a "tooth worm" as the cause of dental caries. Evidence of this belief has also been found in ancient India, Egypt, Japan, and China. The legend of the worm is also found in the Homeric Hymns, and as late as the 14th century AD the surgeon Guy de Chauliac still promoted the belief that worms cause tooth decay.
Recipes for the treatment of toothache, infections and loose teeth are spread throughout the Ebers Papyrus, Kahun Papyri, Brugsch Papyrus, and Hearst papyrus of Ancient Egypt. The Edwin Smith Papyrus, written in the 17th century BC but which may reflect previous manuscripts from as early as 3000 BC, discusses the treatment of dislocated or fractured jaws. In the 18th century BC, the Code of Hammurabi referenced dental extraction twice as it related to punishment. Examination of the remains of some ancient Egyptians and Greco-Romans reveals early attempts at dental prosthetics. However, it is possible the prosthetics were prepared after death for aesthetic reasons.
Ancient Greek scholars Hippocrates and Aristotle wrote about dentistry, including the eruption pattern of teeth, treating decayed teeth and gum disease, extracting teeth with forceps, and using wires to stabilize loose teeth and fractured jaws. Use of dental appliances, bridges and dentures was applied by the Etruscans in northern Italy, from as early as 700 BC, of human or other animal teeth fastened together with gold bands. The Romans had likely borrowed this technique by the 5th century BC. The Phoenicians crafted dentures during the 6th–4th century BC, fashioning them from gold wire and incorporating two ivory teeth. In ancient Egypt, Hesy-Ra is the first named "dentist" (greatest of the teeth). The Egyptians bound replacement teeth together with gold wire. Roman medical writer Cornelius Celsus wrote extensively of oral diseases as well as dental treatments such as narcotic-containing emollients and astringents. The earliest dental amalgams were first documented in a Tang dynasty medical text written by the Chinese physician Su Kung in 659, and appeared in Germany in 1528.
During the Islamic Golden Age Dentistry was discussed in several famous books of medicine such as The Canon in medicine written by Avicenna and Al-Tasreef by Al-Zahrawi who is considered the greatest surgeon of the Middle Ages, Avicenna said that jaw fracture should be reduced according to the occlusal guidance of the teeth; this principle is still valid in modern times. Al-Zahrawi invented over 200 surgical tools that resemble the modern kind.
Historically, dental extractions have been used to treat a variety of illnesses. During the Middle Ages and throughout the 19th century, dentistry was not a profession in itself, and often dental procedures were performed by barbers or general physicians. Barbers usually limited their practice to extracting teeth which alleviated pain and associated chronic tooth infection. Instruments used for dental extractions date back several centuries. In the 14th century, Guy de Chauliac most probably invented the dental pelican (resembling a pelican's beak) which was used to perform dental extractions up until the late 18th century. The pelican was replaced by the dental key which, in turn, was replaced by modern forceps in the 19th century.
The first book focused solely on dentistry was the "Artzney Buchlein" in 1530, and the first dental textbook written in English was called "Operator for the Teeth" by Charles Allen in 1685.
In the United Kingdom, there was no formal qualification for the providers of dental treatment until 1859 and it was only in 1921 that the practice of dentistry was limited to those who were professionally qualified. The Royal Commission on the National Health Service in 1979 reported that there were then more than twice as many registered dentists per 10,000 population in the UK than there were in 1921.
=== Modern dentistry ===
It was between 1650 and 1800 that the science of modern dentistry developed. The English physician Thomas Browne in his A Letter to a Friend (c. 1656 pub. 1690) made an early dental observation with characteristic humour:
The Egyptian Mummies that I have seen, have had their Mouths open, and somewhat gaping, which affordeth a good opportunity to view and observe their Teeth, wherein 'tis not easie to find any wanting or decayed: and therefore in Egypt, where one Man practised but one Operation, or the Diseases but of single Parts, it must needs be a barren Profession to confine unto that of drawing of Teeth, and little better than to have been Tooth-drawer unto King Pyrrhus, who had but two in his Head.
The French surgeon Pierre Fauchard became known as the "father of modern dentistry". Despite the limitations of the primitive surgical instruments during the late 17th and early 18th century, Fauchard was a highly skilled surgeon who made remarkable improvisations of dental instruments, often adapting tools from watchmakers, jewelers and even barbers, that he thought could be used in dentistry. He introduced dental fillings as treatment for dental cavities. He asserted that sugar-derived acids like tartaric acid were responsible for dental decay, and also suggested that tumors surrounding the teeth and in the gums could appear in the later stages of tooth decay.
Fauchard was the pioneer of dental prosthesis, and he invented many methods to replace lost teeth. He suggested that substitutes could be made from carved blocks of ivory or bone. He also introduced dental braces, although they were initially made of gold, he discovered that the teeth position could be corrected as the teeth would follow the pattern of the wires. Waxed linen or silk threads were usually employed to fasten the braces. His contributions to the world of dental science consist primarily of his 1728 publication Le chirurgien dentiste or The Surgeon Dentist. The French text included "basic oral anatomy and function, dental construction, and various operative and restorative techniques, and effectively separated dentistry from the wider category of surgery".
After Fauchard, the study of dentistry rapidly expanded. Two important books, Natural History of Human Teeth (1771) and Practical Treatise on the Diseases of the Teeth (1778), were published by British surgeon John Hunter. In 1763, he entered into a period of collaboration with the London-based dentist James Spence. He began to theorise about the possibility of tooth transplants from one person to another. He realised that the chances of a successful tooth transplant (initially, at least) would be improved if the donor tooth was as fresh as possible and was matched for size with the recipient. These principles are still used in the transplantation of internal organs. Hunter conducted a series of pioneering operations, in which he attempted a tooth transplant. Although the donated teeth never properly bonded with the recipients' gums, one of Hunter's patients stated that he had three which lasted for six years, a remarkable achievement for the period.
Major advances in science were made in the 19th century, and dentistry evolved from a trade to a profession. The profession came under government regulation by the end of the 19th century. In the UK, the Dentist Act was passed in 1878 and the British Dental Association formed in 1879. In the same year, Francis Brodie Imlach was the first ever dentist to be elected President of the Royal College of Surgeons (Edinburgh), raising dentistry onto a par with clinical surgery for the first time.
=== Hazards in modern dentistry ===
Long term occupational noise exposure can contribute to permanent hearing loss, which is referred to as noise-induced hearing loss (NIHL) and tinnitus. Noise exposure can cause excessive stimulation of the hearing mechanism, which damages the delicate structures of the inner ear. NIHL can occur when an individual is exposed to sound levels above 90 dBA according to the Occupational Safety and Health Administration (OSHA). Regulations state that the permissible noise exposure levels for individuals is 90 dBA. For the National Institute for Occupational Safety and Health (NIOSH), exposure limits are set to 85 dBA. Exposures below 85 dBA are not considered to be hazardous. Time limits are placed on how long an individual can stay in an environment above 85 dBA before it causes hearing loss. OSHA places that limitation at 8 hours for 85 dBA. The exposure time becomes shorter as the dBA level increases.
Within the field of dentistry, a variety of cleaning tools are used including piezoelectric and sonic scalers, and ultrasonic scalers and cleaners. While a majority of the tools do not exceed 75 dBA, prolonged exposure over many years can lead to hearing loss or complaints of tinnitus. Few dentists have reported using personal hearing protective devices, which could offset any potential hearing loss or tinnitus.
=== Evidence-based dentistry ===
There is a movement in modern dentistry to place a greater emphasis on high-quality scientific evidence in decision-making. Evidence-based dentistry (EBD) uses current scientific evidence to guide decisions. It is an approach to oral health that requires the application and examination of relevant scientific data related to the patient's oral and medical health. Along with the dentist's professional skill and expertise, EBD allows dentists to stay up to date on the latest procedures and patients to receive improved treatment. A new paradigm for medical education designed to incorporate current research into education and practice was developed to help practitioners provide the best care for their patients. It was first introduced by Gordon Guyatt and the Evidence-Based Medicine Working Group at McMaster University in Ontario, Canada in the 1990s. It is part of the larger movement toward evidence-based medicine and other evidence-based practices, especially since a major part of dentistry involves dealing with oral and systemic diseases. Other issues relevant to the dental field in terms of evidence-based research and evidence-based practice include population oral health, dental clinical practice, tooth morphology etc.
== Digitalization of dentistry ==
Like other medical disciplines, dentistry is strongly influenced by the digital transformation of healthcare. Processes are changing fundamentally, affecting the effectiveness and accuracy of patient treatment.
Various technologies are being used in dentistry, including CAD/CAM systems in combination with 3D printing, artificial intelligence (AI), and electronic health records. The degree of implementation of such technologies varies significantly across dental practices.
Research shows that larger dental centers are adopting digital solutions more rapidly. Younger dentists, as well as those who regularly participate in digital training programs, show a higher willingness to implement new technologies. However, financial constraints and the lack of comprehensive training opportunities for the digitalization of dentistry currently represent major barriers to implementation.
== Ethical and medicolegal issues ==
Dentistry is unique in that it requires dental students to have competence-based clinical skills that can only be acquired through supervised specialized laboratory training and direct patient care. This necessitates the need for a scientific and professional basis of care with a foundation of extensive research-based education. According to some experts, the accreditation of dental schools can enhance the quality and professionalism of dental education.
== See also ==
== Notes ==
== References ==
== External links == | Wikipedia/Dental_surgery |
In chemistry, a solution is defined by IUPAC as "A liquid or solid phase containing more than one substance, when for convenience one (or more) substance, which is called the solvent, is treated differently from the other substances, which are called solutes. When, as is often but not necessarily the case, the sum of the mole fractions of solutes is small compared with unity, the solution is called a dilute solution. A superscript attached to the ∞ symbol for a property of a solution denotes the property in the limit of infinite dilution." One important parameter of a solution is the concentration, which is a measure of the amount of solute in a given amount of solution or solvent. The term "aqueous solution" is used when one of the solvents is water.
== Types ==
Homogeneous means that the components of the mixture form a single phase. Heterogeneous means that the components of the mixture are of different phase. The properties of the mixture (such as concentration, temperature, and density) can be uniformly distributed through the volume but only in absence of diffusion phenomena or after their completion. Usually, the substance present in the greatest amount is considered the solvent. Solvents can be gases, liquids, or solids. One or more components present in the solution other than the solvent are called solutes. The solution has the same physical state as the solvent.
=== Gaseous mixtures ===
If the solvent is a gas, only gases (non-condensable) or vapors (condensable) are dissolved under a given set of conditions. An example of a gaseous solution is air (oxygen and other gases dissolved in nitrogen). Since interactions between gaseous molecules play almost no role, non-condensable gases form rather trivial solutions. In the literature, they are not even classified as solutions, but simply addressed as homogeneous mixtures of gases. The Brownian motion and the permanent molecular agitation of gas molecules guarantee the homogeneity of the gaseous systems. Non-condensable gaseous mixtures (e.g., air/CO2, or air/xenon) do not spontaneously demix, nor sediment, as distinctly stratified and separate gas layers as a function of their relative density. Diffusion forces efficiently counteract gravitation forces under normal conditions prevailing on Earth. The case of condensable vapors is different: once the saturation vapor pressure at a given temperature is reached, vapor excess condenses into the liquid state.
=== Liquid solutions ===
Liquids dissolve gases, other liquids, and solids. An example of a dissolved gas is oxygen in water, which allows fish to breathe under water. An examples of a dissolved liquid is ethanol in water, as found in alcoholic beverages. An example of a dissolved solid is sugar water, which contains dissolved sucrose.
=== Solid solutions ===
If the solvent is a solid, then gases, liquids, and solids can be dissolved.
Gas in solids:
Hydrogen dissolves rather well in metals, especially in palladium; this is studied as a means of hydrogen storage.
Liquid in solid:
Mercury in gold, forming an amalgam
Water in solid salt or sugar, forming moist solids
Hexane in paraffin wax
Polymers containing plasticizers such as phthalate (liquid) in PVC (solid)
Solid in solid:
Steel, basically a solution of carbon atoms in a crystalline matrix of iron atoms
Alloys like bronze and many others
Radium sulfate dissolved in barium sulfate: a true solid solution of Ra in BaSO4
== Solubility ==
The ability of one compound to dissolve in another compound is called solubility. When a liquid can completely dissolve in another liquid the two liquids are miscible. Two substances that can never mix to form a solution are said to be immiscible.
All solutions have a positive entropy of mixing. The interactions between different molecules or ions may be energetically favored or not. If interactions are unfavorable, then the free energy decreases with increasing solute concentration. At some point, the energy loss outweighs the entropy gain, and no more solute particles can be dissolved; the solution is said to be saturated. However, the point at which a solution can become saturated can change significantly with different environmental factors, such as temperature, pressure, and contamination. For some solute-solvent combinations, a supersaturated solution can be prepared by raising the solubility (for example by increasing the temperature) to dissolve more solute and then lowering it (for example by cooling).
Usually, the greater the temperature of the solvent, the more of a given solid solute it can dissolve. However, most gases and some compounds exhibit solubilities that decrease with increased temperature. Such behavior is a result of an exothermic enthalpy of solution. Some surfactants exhibit this behaviour. The solubility of liquids in liquids is generally less temperature-sensitive than that of solids or gases.
== Properties ==
The physical properties of compounds such as melting point and boiling point change when other compounds are added. Together they are called colligative properties. There are several ways to quantify the amount of one compound dissolved in the other compounds collectively called concentration. Examples include molarity, volume fraction, and mole fraction.
The properties of ideal solutions can be calculated by the linear combination of the properties of its components. If both solute and solvent exist in equal quantities (such as in a 50% ethanol, 50% water solution), the concepts of "solute" and "solvent" become less relevant, but the substance that is more often used as a solvent is normally designated as the solvent (in this example, water).
== Liquid solution characteristics ==
In principle, all types of liquids can behave as solvents: liquid noble gases, molten metals, molten salts, molten covalent networks, and molecular liquids. In the practice of chemistry and biochemistry, most solvents are molecular liquids. They can be classified into polar and non-polar, according to whether their molecules possess a permanent electric dipole moment. Another distinction is whether their molecules can form hydrogen bonds (protic and aprotic solvents). Water, the most commonly used solvent, is both polar and sustains hydrogen bonds.
Salts dissolve in polar solvents, forming positive and negative ions that are attracted to the negative and positive ends of the solvent molecule, respectively. If the solvent is water, hydration occurs when the charged solute ions become surrounded by water molecules. A standard example is aqueous saltwater. Such solutions are called electrolytes. Whenever salt dissolves in water ion association has to be taken into account.
Polar solutes dissolve in polar solvents, forming polar bonds or hydrogen bonds. As an example, all alcoholic beverages are aqueous solutions of ethanol. On the other hand, non-polar solutes dissolve better in non-polar solvents. Examples are hydrocarbons such as oil and grease that easily mix, while being incompatible with water.
An example of the immiscibility of oil and water is a leak of petroleum from a damaged tanker, that does not dissolve in the ocean water but rather floats on the surface.
== See also ==
Molar solution – Measure of concentration of a chemicalPages displaying short descriptions of redirect targets
Percentage solution (disambiguation)
Solubility equilibrium – Thermodynamic equilibrium between a solid and a solution of the same compound
Total dissolved solids – Measurement in environmental chemistry is a common term in a range of disciplines, and can have different meanings depending on the analytical method used. In water quality, it refers to the amount of residue remaining after the evaporation of water from a sample.
Upper critical solution temperature – Critical temperature of miscibility in a mixture
Lower critical solution temperature – Critical temperature below which components of a mixture are miscible for all compositions
Coil–globule transition – Collapse of a macromolecule from an expanded coil state to a collapsed globule state
== References ==
IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) "solution". doi:10.1351/goldbook.S05746
== External links ==
Media related to Solutions at Wikimedia Commons | Wikipedia/Chemical_solutions |
Grafting refers to a surgical procedure to move tissue from one site to another on the body, or from another creature, without bringing its own blood supply with it. Instead, a new blood supply grows in after it is placed. A similar technique where tissue is transferred with the blood supply intact is called a flap. In some instances, a graft can be an artificially manufactured device. Examples of this are a tube to carry blood flow across a defect or from an artery to a vein for use in hemodialysis.
== Classification ==
Autografts and isografts are usually not considered as foreign and, therefore, do not elicit rejection. Allografts and xenografts may be recognized as foreign by the recipient and rejected.
Autograft: graft taken from one part of the body of an individual and transplanted onto another site in the same individual, e.g., skin graft.
Isograft: graft taken from one individual and placed on another individual of the same genetic constitution, e.g., grafts between identical twins.
Allograft: graft taken from one individual placed on a genetically non-identical member of the same species.
Xenograft: graft taken from one individual placed on an individual belonging to another species, e.g., animal to human.
== Types of grafting ==
The term grafting is most commonly applied to skin grafting, however many tissues can be grafted: skin, bone, nerves, tendons, neurons, blood vessels, fat, and cornea are tissues commonly grafted today.
Specific types include:
Skin grafting – often used to treat skin loss due to a wound, burn, infection, or surgery. In the case of damaged skin, it is removed, and new skin is grafted in its place. Skin grafting can reduce the course of treatment and hospitalization needed, and can also improve function and appearance. There are two types of skin grafts:
Split-thickness skin grafts (the epidermis and part of the dermis)
Full-thickness skin grafts (the epidermis and the entire thickness of the dermis)
Bone grafting – used in dental implants, as well as other instances. The bone may be autologous, typically harvested from the iliac crest of the pelvis, or banked bone/allograft.
Vascular grafting – the use of transplanted or prosthetic blood vessels in surgical procedures.
Ligament grafting repair – as with anterior cruciate ligament reconstruction or ulnar collateral ligament reconstruction.
Fat grafting – the process of harvesting adipose tissue through liposuction, processing/centrifugation and injection into soft tissue for improving coverage, volume and contour, typically in the breast, buttock and face.
== Indications ==
Large amount of skin loss due to infections
Burns
Skin cancer surgery
Chronic connective tissue disease
== Reasons for failure ==
Hematoma development when the graft is placed over an active bleed
Infection
Seroma development
Shear force disrupting growth of new blood supply
Inappropriate bed for new blood supply to grow from, such as cartilage, tendons, or bone
== References == | Wikipedia/Graft_(surgery) |
A surgical drain is a tube used to remove pus, blood or other fluids from a wound, body cavity, or organ. They are commonly placed by surgeons or interventional radiologists after procedures or some types of injuries, but they can also be used as an intervention for decompression. There are several types of drains, and selection of which to use often depends on the placement site and how long the drain is needed.
== Use and Management ==
Drains help to remove contents, usually fluids, from inside the body. This is beneficial since fluid accumulation may cause distension and pressure, which can lead to pain. For example, nasogastric (NG) tubes inserted through the nose and into the stomach can help remove stomach contents for patients who have a blockage further along in their gastrointestinal tract. After surgery, drains can be placed to remove blood, lymph, or other fluids that accumulate in the wound bed. This helps to promote wound healing and allows healthcare providers to monitor the wound for any signs of internal infection or damage to surgically repaired structures.
Drains may be classified as passive or active, open or closed, and external or internal. Passive drains rely on gravity or capillary action to remove fluid, whereas active drains rely on a suction/vacuum force, whether that be through connection to wall suction, a portable suction device, or a bulb that has been squeezed to create a vacuum. Open drains are commonly used for superficial wounds and drain into dressings or a stoma bag. Closed drains are tubes or other channel-like structures that are connected to a container, thereby creating a closed system. External drains go from inside the body to outside the body and can be seen, while internal drains are completely inside the body. An example of an internal drain is a ventriculo-peritoneal shunt, which is a tube that connects ventricles of the brain to the peritoneal cavity. This helps remove extra cerebrospinal fluid from the brain.
Accurate recording of the volume of drainage as well as the contents is vital to ensure proper healing and monitor for excessive bleeding. Depending on the amount of drainage, a patient may have the drain in place one day to weeks. Drains will have protective dressings that will need to be changed daily/as needed.
The routine use of drains for surgical procedures is diminishing as better radiological investigation and confidence in surgical technique have reduced their necessity. It is felt now that drains may hinder recovery by acting as an 'anchor' limiting mobility post surgery and the drain itself may allow infection into the wound. In certain situations their use is unavoidable.
== Complications ==
Drains risk becoming occluded or clogged, resulting in retained fluid that can contribute to infection or other complications. Thus efforts must be made to maintain and assess patency (condition of being open) when they are in use. Once a drain becomes clogged or occluded, it should be removed, as it is no longer providing any benefit.
== Types of drains ==
Surgical drains can be broadly classified into:
Jackson-Pratt drain – consists of a perforated round or flat tube connected to a negative pressure collection device. The collection device is typically a bulb with a drainage port which can be opened to remove fluid or air. After compressing the bulb to remove fluid or air, negative pressure is created as the bulb returns to its normal shape.
Blake drain – a round silicone tube with channels that carry fluid to a negative pressure collection device. Drainage is thought to be achieved by capillary action, allowing fluid to travel through the open grooves into a closed cross section, which contains the fluid and allows it to be suctioned through the tube.
Penrose drain – a soft rubber tube
Negative pressure wound therapy – Involves the use of enclosed foam and a suction device attached; this is one of the newer types of wound healing/drain devices which promotes faster tissue granulation, often used for large surgical/trauma/non-healing wounds.
Redivac drain – a high negative pressure drain. Suction is applied through the drain to generate a vacuum and draw fluids into a bottle.
Shirley drain
Pigtail drain – has an exterior screw to release the internal "pigtail" before it can be removed
Davol
Chest tube – is a flexible plastic tube that is inserted through the chest wall and into the pleural space or mediastinum
Wound manager
== See also ==
Wound healing
Incision and drainage
Instruments used in general surgery
== References ==
== External links ==
Media related to Surgical drains at Wikimedia Commons | Wikipedia/Drain_(surgery) |
Elective surgery or elective procedure is surgery that is scheduled in advance because it does not involve a medical emergency. Semi-elective surgery is a surgery that must be done to preserve the patient's life, but does not need to be performed immediately. Most surgeries are elective, scheduled at a time to suit the surgeon, hospital, and patient.
By contrast, an urgent surgery is one that can wait until the patient is medically stable, but should generally be done within 2 days, and an emergency surgery is one that must be performed without delay; the patient has no choice other than immediate surgery if permanent disability or death is to be avoided. Many surgeries can be performed as either elective or emergency surgeries, depending on the patient's needs.
== Description ==
An elective surgery or elective procedure (from the Latin: eligere, meaning to choose) is a surgery that does not involve a medical emergency and is scheduled in advance. Semi-elective surgery is a surgery that must be done to preserve the patient's life, but does not need to be performed immediately.
== Types ==
=== Elective ===
Most surgical medical treatments are elective, that is, scheduled at a time to suit the surgeon, hospital, and patient. These include inguinal hernia surgery, cataract surgery, mastectomy for breast cancer, and the donation of a kidney by a living donor.
Elective surgeries include all optional surgeries performed for non-medical reasons. This includes cosmetic surgery, such as facelifts, breast implants, liposuction, and breast reduction, which aim to subjectively improve a patient's physical appearance. Another optional surgery is LASIK—currently the top elective surgery in the United States—where a patient weighs the risks against increased quality of life expectations.
=== Semi-elective ===
When a condition is worsening but has not yet reached the point of a true emergency, surgeons speak of semi-elective surgery: the problem must be dealt with, but a brief delay is not expected to affect the outcome. Semi-elective procedures are typically scheduled within a time frame deemed appropriate for the patient's condition and disease. Removal of a malignancy, for example, is usually scheduled as semi-elective surgery, to be performed within a set number of days or weeks.
== Urgency ==
In a patient with multiple medical conditions, problems classified as needing semi-elective surgeries may be postponed until emergent conditions have been addressed and the patient is medically stable. For example, whenever possible, pregnant women typically postpone all elective and semi-elective procedures until after giving birth.
In some situations, an urgently needed surgery will be postponed briefly to permit even more urgent conditions to be addressed. In other situations, emergency surgery may be performed at the same time as life-saving resuscitation efforts.
Many surgeries can be performed as either elective or emergency surgeries, depending on the patient's needs. A sudden worsening of gallbladder disease may require immediate removal of the gallbladder by emergency surgery, but this surgery is more commonly scheduled in advance. An appendectomy is considered emergency surgery, but depending upon how early the diagnosis was made, the patient may have more time before the appendix risks rupturing or the infection spreads. Also, in certain emergency conditions, even ones like a heart attack or stroke, surgery may or may not need to be utilized.
== Best practices ==
Preoperative carbohydrates may decrease amount of time spent in hospital recovering.
== Non-elective surgery ==
Non-elective surgeries may be classified as urgent or emergency. An urgent surgery is one that can wait until the patient is medically stable, but should generally be done within 2 days. An emergency surgery is one that must be performed without delay; the patient has no choice other than immediate surgery if permanent disability or death is to be avoided. Urgent surgery is typically performed with 48 hours of diagnosis and emergency surgery is performed as soon as a surgeon is available. A trauma center is a hospital which supports emergency surgery on critically ill patients at the brink of death by ensuring that on a 24/7 basis, a surgeon is always on the premises (or "in-house") to evaluate patients and can take them immediately to the operating room.
== References ==
== Bibliography ==
C. Parchment-Smith (2006). Essential Revision Notes for Intercollegiate MRCS: Bk. 1. Knutsford, Cheshire, UK: PasTest, LLC. p. 439. ISBN 1-904627-36-6. | Wikipedia/Elective_surgery |
Cardiothoracic surgery is the field of medicine involved in surgical treatment of organs inside the thoracic cavity — generally treatment of conditions of the heart (heart disease), lungs (lung disease), and other pleural or mediastinal structures.
In most countries, cardiothoracic surgery is further subspecialized into cardiac surgery (involving the heart and the great vessels) and thoracic surgery (involving the lungs, esophagus, thymus, etc.); the exceptions are the United States, Australia, New Zealand, the United Kingdom, India and some European Union countries such as Portugal.
== Training ==
A cardiac surgery residency typically comprises anywhere from four to six years (or longer) of training to become a fully qualified surgeon. Cardiac surgery training may be combined with thoracic surgery and/or vascular surgery and called cardiovascular (CV) / cardiothoracic (CT) / cardiovascular thoracic (CVT) surgery. Cardiac surgeons may enter a cardiac surgery residency directly from medical school, or first complete a general surgery residency followed by a fellowship. Cardiac surgeons may further sub-specialize cardiac surgery by doing a fellowship in a variety of topics including pediatric cardiac surgery, cardiac transplantation, adult-acquired heart disease, weak heart issues, and many more problems in the heart.
=== Australia and New Zealand ===
The highly competitive Surgical Education and Training (SET) program in Cardiothoracic Surgery is six years in duration, usually commencing several years after completing medical school. Training is administered and supervised via a bi-national (Australia and New Zealand) training program. Multiple examinations take place throughout the course of training, culminating in a final fellowship exam in the final year of training. Upon completion of training, surgeons are awarded a Fellowship of the Royal Australasian College of Surgeons (FRACS), denoting that they are qualified specialists. Trainees having completed a training program in General Surgery and have obtained their FRACS will have the option to complete fellowship training in Cardiothoracic Surgery of four years in duration, subject to college approval. It takes around eight to ten years minimum of post-graduate (post-medical school) training to qualify as a cardiothoracic surgeon. Competition for training places and for public (teaching) hospital places is very high currently, leading to concerns regarding workforce planning in Australia.
=== Canada ===
Historically, cardiac surgeons in Canada completed general surgery followed by a fellowship in CV / CT / CVT. During the 1990s, the Canadian cardiac surgery training programs changed to six-year "direct-entry" programs following medical school. The direct-entry format provides residents with experience related to cardiac surgery they would not receive in a general surgery program (e.g. echocardiography, coronary care unit, cardiac catheterization etc.). Residents in this program will also spend time training in thoracic and vascular surgery. Typically, this is followed by a fellowship in either Adult Cardiac Surgery, Heart Failure/Transplant, Minimally Invasive Cardiac Surgery, Aortic Surgery, Thoracic Surgery, Pediatric Cardiac Surgery or Cardiac ICU. Contemporary Canadian candidates completing general surgery and wishing to pursue cardiac surgery often complete a cardiothoracic surgery fellowship in the United States. The Royal College of Physicians and Surgeons of Canada also provides a three-year cardiac surgery fellowship for qualified general surgeons that is offered at several training sites including the University of Alberta, the University of British Columbia and the University of Toronto.
Thoracic surgery is its own separate 2–3 year fellowship of general or cardiac surgery in Canada.
Cardiac surgery programs in Canada:
University of Alberta – 1 position
University of British Columbia – 1 position
University of Calgary – 1 position
Dalhousie University – 1 position every other year
Université Laval – 1 position every three years
University of Manitoba – 1 position
McGill University – 1 position every three years
McMaster University – 1 position every other year
Université de Montréal – 1 position every three years
University of Ottawa – 1 position
University of Toronto – 1 position
Western University – 1 position
=== United States ===
Cardiac surgery training in the United States is combined with general thoracic surgery and called cardiothoracic surgery or thoracic surgery. A cardiothoracic surgeon in the U.S. is a physician who first completes a general surgery residency (typically 5–7 years), followed by a cardiothoracic surgery fellowship (typically 2–3 years). The cardiothoracic surgery fellowship typically spans two or three years, but certification is based on the number of surgeries performed as the operating surgeon, not the time spent in the program, in addition to passing rigorous board certification tests. Two other pathways to shorten the duration of training have been developed: (1) a combined general-thoracic surgery residency consisting of four years of general surgery training and three years of cardiothoracic training at the same institution and (2) an integrated six-year cardiothoracic residency (in place of the general surgery residency plus cardiothoracic residency), which have each been established at many programs (over 20). Applicants match into the integrated six-year (I-6) programs directly out of medical school, and the application process has been extremely competitive for these positions as there were approximately 160 applicants for 10 spots in the U.S. in 2010. As of May 2013, there are 20 approved programs, which include the following:
Integrated six-year Cardiothoracic Surgery programs in the United States:
Medical College of Wisconsin
Stanford University – two positions
University of North Carolina at Chapel Hill
University of Virginia
Columbia University – two positions
University of Pennsylvania
University of Pittsburgh – two positions
University of Washington
Northwestern University
Mount Sinai Hospital, New York
University of Maryland
University of California, Los Angeles UCLA – two resident positions, one Transplant Fellowship; one Congenital resident position
University of Texas Health Science Center at San Antonio
Medical University of South Carolina
University of Southern California – two positions
University of Rochester
University of California, Davis
Indiana University
University of Kentucky
Emory University
University of Michigan
Yale University
The American Board of Thoracic Surgery offers a special pathway certificate in congenital cardiac surgery which typically requires an additional year of fellowship. This formal certificate is unique because congenital cardiac surgeons in other countries do not have formal evaluation and recognition of pediatric training by a licensing body.
== Cardiac surgery ==
The earliest operations on the pericardium (the sac that surrounds the heart) took place in the 19th century and were performed by Francisco Romero (1801) Dominique Jean Larrey, Henry Dalton, and Daniel Hale Williams. The first surgery on the heart itself was performed by Norwegian surgeon Axel Cappelen on 4 September 1895 at Rikshospitalet in Kristiania, now Oslo. He ligated a bleeding coronary artery in a 24-year-old man who had been stabbed in the left axilla and was in deep shock upon arrival. Access was through a left thoracotomy. The patient awoke and seemed fine for 24 hours, but became ill with increasing temperature and he ultimately died from what the post mortem proved to be mediastinitis on the third postoperative day. The first successful surgery of the heart, performed without any complications, was by Ludwig Rehn of Frankfurt, Germany, who repaired a stab wound to the right ventricle on September 7, 1896.
Surgery in great vessels (aortic coarctation repair, Blalock-Taussig shunt creation, closure of patent ductus arteriosus) became common after the turn of the century and falls in the domain of cardiac surgery, but technically cannot be considered heart surgery. One of the more commonly known cardiac surgery procedures is the coronary artery bypass graft (CABG), also known as "bypass surgery."
=== Early approaches to heart malformations ===
In 1925 operations on the heart valves were unknown. Henry Souttar operated successfully on a young woman with mitral stenosis. He made an opening in the appendage of the left atrium and inserted a finger into this chamber in order to palpate and explore the damaged mitral valve. The patient survived for several years but Souttar's physician colleagues at that time decided the procedure was not justified and he could not continue.
Cardiac surgery changed significantly after World War II. In 1948 four surgeons carried out successful operations for mitral stenosis resulting from rheumatic fever. Horace Smithy (1914–1948) revived an operation due to Dr Dwight Harken of the Peter Bent Brigham Hospital using a punch to remove a portion of the mitral valve. Charles Bailey (1910–1993) at the Hahnemann Hospital, Philadelphia, Dwight Harken in Boston and Russell Brock at Guy's Hospital all adopted Souttar's method. All these men started work independently of each other, within a few months. This time Souttar's technique was widely adopted although there were modifications.
In 1947 Thomas Holmes Sellors (1902–1987) of the Middlesex Hospital operated on a Fallot's Tetralogy patient with pulmonary stenosis and successfully divided the stenosed pulmonary valve. In 1948, Russell Brock, probably unaware of Sellor's work, used a specially designed dilator in three cases of pulmonary stenosis. Later in 1948 he designed a punch to resect the infundibular muscle stenosis which is often associated with Fallot's Tetralogy. Many thousands of these "blind" operations were performed until the introduction of heart bypass made direct surgery on valves possible.
=== Open heart surgery ===
Open heart surgery is a procedure in which the patient's heart is opened and surgery is performed on the internal structures of the heart. It was discovered by Wilfred G. Bigelow of the University of Toronto that the repair of intracardiac pathologies was better done with a bloodless and motionless environment, which means that the heart should be stopped and drained of blood. The first successful intracardiac correction of a congenital heart defect using hypothermia was performed by C. Walton Lillehei and F. John Lewis at the University of Minnesota on September 2, 1952. The following year, Soviet surgeon Aleksandr Aleksandrovich Vishnevskiy conducted the first cardiac surgery under local anesthesia.
Surgeons realized the limitations of hypothermia – complex intracardiac repairs take more time and the patient needs blood flow to the body, particularly to the brain. The patient needs the function of the heart and lungs provided by an artificial method, hence the term cardiopulmonary bypass. John Heysham Gibbon at Jefferson Medical School in Philadelphia reported in 1953 the first successful use of extracorporeal circulation by means of an oxygenator, but he abandoned the method, disappointed by subsequent failures. In 1954 Lillehei realized a successful series of operations with the controlled cross-circulation technique in which the patient's mother or father was used as a 'heart-lung machine'. John W. Kirklin at the Mayo Clinic in Rochester, Minnesota started using a Gibbon type pump-oxygenator in a series of successful operations, and was soon followed by surgeons in various parts of the world.
Nazih Zuhdi performed the first total intentional hemodilution open heart surgery on Terry Gene Nix, age 7, on February 25, 1960, at Mercy Hospital, Oklahoma City, OK. The operation was a success; however, Nix died three years later in 1963. In March, 1961, Zuhdi, Carey, and Greer, performed open heart surgery on a child, age 3+1⁄2, using the total intentional hemodilution machine. In 1985 Zuhdi performed Oklahoma's first successful heart transplant on Nancy Rogers at Baptist Hospital. The transplant was successful, but Rogers, who had cancer, died from an infection 54 days after surgery.
=== Modern beating-heart surgery ===
Since the 1990s, surgeons have begun to perform "off-pump bypass surgery" – coronary artery bypass surgery without the aforementioned cardiopulmonary bypass. In these operations, the heart is beating during surgery, but is stabilized to provide an almost still work area in which to connect the conduit vessel that bypasses the blockage; in the U.S., most conduit vessels are harvested endoscopically, using a technique known as endoscopic vessel harvesting (EVH).
Some researchers believe that the off-pump approach results in fewer post-operative complications, such as postperfusion syndrome, and better overall results. Study results are controversial as of 2007, the surgeon's preference and hospital results still play a major role.
=== Minimally invasive surgery ===
A new form of heart surgery that has grown in popularity is robot-assisted heart surgery. This is where a machine is used to perform surgery while being controlled by the heart surgeon. The main advantage to this is the size of the incision made in the patient. Instead of an incision being at least big enough for the surgeon to put his hands inside, it does not have to be bigger than "pencil-sized" holes for the robot's much smaller "hands" to enter a surgical patient's body.
In September 2024, the first successful fully robotic heart transplant took place at King Faisal Specialist Hospital and Research Centre in Riyadh, led by surgeon Feras Khaliel, head of the hospital's cardiac surgery and director of its Robotics and Minimally Invasive Surgery Program. In December 2024, the first robotic surgery for a combined robotic aortic valve replacement (AVR) and coronary artery bypass grafting (CABG) was successfully performed through one small incision at West Virginia University, led by surgeon Vinay Badhwar, who is the executive chair of the WVU Heart and Vascular Institute and a vice president of the Society of Thoracic Surgeons.
=== Pediatric cardiovascular surgery ===
Pediatric cardiovascular surgery is surgery of the heart of children. The first operations to repair cardio-vascular defects in children were performed by Clarence Crafoord in Sweden when he repaired coarctation of the aorta in a 12-year-old boy. The first attempts to palliate congenital heart disease were performed by Alfred Blalock with the assistance of William Longmire, Denton Cooley, and Blalock's experienced technician, Vivien Thomas in 1944 at Johns Hopkins Hospital. Techniques for repair of congenital heart defects without the use of a bypass machine were developed in the late 1940s and early 1950s. Among them was an open repair of an atrial septal defect using hypothermia, inflow occlusion and direct vision in a 5-year-old child performed in 1952 by Lewis and Lillihei. Lillihei used cross-circulation between a boy and his father to maintain perfusion while performing a direct repair of a ventricular septal defect in a 4-year-old child in 1954. He continued to use cross-circulation and performed the first corrections of tetralogy of Fallot and presented those results in 1955 at the American Surgical Association. In the long-run, pediatric cardiovascular surgery would rely on the cardiopulmonary bypass machine developed by Gibbon and Lillehei as noted above.
=== Risks of cardiac surgery ===
The development of cardiac surgery and cardiopulmonary bypass techniques has reduced the mortality rates of these surgeries to relatively low ranks. For instance, repairs of congenital heart defects are currently estimated to have 4–6% mortality rates. A major concern with cardiac surgery is the incidence of neurological damage. Stroke occurs in 5% of all people undergoing cardiac surgery, and is higher in patients at risk for stroke. A more subtle constellation of neurocognitive deficits attributed to cardiopulmonary bypass is known as postperfusion syndrome, sometimes called "pumphead". The symptoms of postperfusion syndrome were initially felt to be permanent, but were shown to be transient with no permanent neurological impairment.
To assess the performance of surgical units and individual surgeons, a popular risk model has been created called the EuroSCORE. This takes a number of health factors from a patient and using precalculated logistic regression coefficients attempts to give a percentage chance of survival to discharge. Within the UK this EuroSCORE was used to give a breakdown of all the centres for cardiothoracic surgery and to give some indication of whether the units and their individual surgeons performed within an acceptable range. The results are available on the CQC website. The precise methodology used has however not been published to date nor has the raw data on which the results are based.
Infection represents the primary non-cardiac complication from cardiothoracic surgery. Infections include mediastinitis, infectious myo- or pericarditis, endocarditis, cardiac device infection, pneumonia, empyema, and bloodstream infections. Clostridioides difficile colitis can develop when prophylactic or post-operative antibiotics are used.
Post-operative patients of cardiothoracic surgery are at risk of nausea, vomiting, dysphagia, and aspiration pneumonia.
== Thoracic surgery ==
A pleurectomy is a surgical procedure in which part of the pleura is removed. It is sometimes used in the treatment of pneumothorax and mesothelioma. In case of pneumothorax, only the apical and the diaphragmatic portions of the parietal pleura are removed.
=== Lung volume reduction surgery ===
Lung volume reduction surgery, or LVRS, can improve the quality of life for certain patients with COPD of emphysematous type, when other treatment options are not enough. Parts of the lung that are particularly damaged by emphysema are removed, allowing the remaining, relatively good lung to expand and work more efficiently. The beneficial effects are correlated with the achieved reduction in residual volume. Conventional LVRS involves resection of the most severely affected areas of emphysematous, non-bullous lung (aim is for 20–30%). This is a surgical option involving a mini-thoracotomy for patients in end stage COPD due to underlying emphysema, and can improve lung elastic recoil as well as diaphragmatic function.
The National Emphysema Treatment Trial (NETT) was a large multicentre study (N = 1218) comparing LVRS with non-surgical treatment. Results suggested that there was no overall survival advantage in the LVRS group, except for mainly upper-lobe emphysema + poor exercise capacity, and significant improvements were seen in exercise capacity in the LVRS group. Later studies have shown a wider scope of treatment with better outcomes.
Possible complications of LVRS include prolonged air leak (mean duration post surgery until all chest tubes removed is 10.9 ± 8.0 days.
In people who have a predominantly upper lobe emphysema, lung volume reduction surgery could result in better health status and lung function, though it also increases the risk of early mortality and adverse events.
LVRS is used widely in Europe, though its application in the United States is mostly experimental.
A less invasive treatment is available as a bronchoscopic lung volume reduction procedure.
=== Lung cancer surgery ===
Not all lung cancers are suitable for surgery. The stage, location and cell type are important limiting factors. In addition, people who are very ill with a poor performance status or who have inadequate pulmonary reserve would be unlikely to survive. Even with careful selection, the overall operative death rate is about 4.4%.
In non-small cell lung cancer staging, stages IA, IB, IIA, and IIB are suitable for surgical resection.
Pulmonary reserve is measured by spirometry. If there is no evidence of undue shortness of breath or diffuse parenchymal lung disease, and the FEV1 exceeds 2 litres or 80% of predicted, the person is fit for pneumonectomy. If the FEV1 exceeds 1.5 litres, the patient is fit for lobectomy.
There is weak evidence to indicate that participation in exercise programs before lung cancer surgery may reduce the risk of complications after surgery.
==== Complications ====
A prolonged air leak (PAL) can occur in 8–25% of people following lung cancer surgery. This complication delays chest tube removal and is associated with an increased length of hospital stay following a lung resection (lung cancer surgery). The use of surgical sealants may reduce the incidence of prolonged air leaks, however, this intervention alone has not been shown to results in a decreased length of hospital stay following lung cancer surgery.
There is no strong evidence to support using non-invasive positive pressure ventilation following lung cancer surgery to reduce pulmonary complications.
==== Types ====
Lobectomy (removal of a lobe of the lung)
Sublobar resection (removal of part of lobe of the lung)
Segmentectomy (removal of an anatomic division of a particular lobe of the lung)
Pneumonectomy (removal of an entire lung)
Wedge resection
Sleeve/bronchoplastic resection (removal of an associated tubular section of the associated main bronchial passage during lobectomy with subsequent reconstruction of the bronchial passage)
VATS lobectomy (minimally invasive approach to lobectomy that may allow for diminished pain, quicker return to full activity, and diminished hospital costs)
esophagectomy (removal of the esophagus)
== See also ==
Annals of Thoracic Surgery
European Journal of Cardio-Thoracic Surgery
Journal of Thoracic and Cardiovascular Surgery
== References ==
== External links ==
The Cardiothoracic Surgery Network
The Society of Thoracic Surgeons
American Association for Thoracic Surgery
International Society for Minimally Invasive Cardiothoracic Surgery | Wikipedia/Thoracic_surgery |
Flap surgery is a technique in plastic and reconstructive surgery where tissue with an intact blood supply is lifted from a donor site and moved to a recipient site. Flaps are distinct from grafts, which do not have an intact blood supply and relies on the growth of new blood vessels. Flaps are done to fill a defect such as a wound resulting from injury or surgery when the remaining tissue is unable to support a graft, wound contraction is to be avoided or to rebuild more complex anatomic structures like breasts or jaws. Flaps may also carry with them tissues such as muscle and bone that may be useful in the ultimate reconstruction.
== Uses ==
Flap surgery is a technique essential to plastic and reconstructive surgery. A flap is defined as tissue that can be moved to another site and has its own blood supply. This is in comparison to a skin graft which does not have its own blood supply and relies on vascularization from the recipient site. Flaps have many uses in wound healing and are used when wounds are large, complex, or need tissue of various types and bulk for successful closure and function.
== Anatomy ==
Flaps can contain many different combination of layers of tissue, from skin to bone (see § Classification). The main goal of a flap is to maintain blood flow to tissue to maintain survival, and understanding the anatomy in flap design is key to a successful flap surgery.
=== Skin anatomy ===
Flaps may include skin in their construction. Skin is important for many reasons, but namely its role in thermoregulation, immune function, and blood supply aid in flap survival. The skin can be divided into three main layers: the epidermis, dermis, and subcutaneous tissue. Blood is mainly supplied to the skin by two networks of blood vessels. The deep network lies between the dermis and the subcutaneous tissue, while the shallow network lies within the papillary layer of the dermis. The epidermis is supplied by diffusion from this shallow network and both networks are supplied by collaterals, and by perforating arteries that bring blood from deeper layers either between muscles (septocutaneous perforators) or through muscles (musculocutaneous perforators).
This robust and redundant blood supply is important in flap surgery, because flaps are cut off from other blood vessels when it is raised and removed from its surrounding native tissue. The remaining blood supply must then keep the tissue alive until additional blood supply can be formed through angiogenesis.
=== Angiosome ===
The angiosome is a concept first coined by Ian Taylor in 1987. It is a three-dimensional region of tissue that is supplied by a single artery and can include skin, soft tissue, and bone. Adjacent angiosomes are connected by narrower choke vessels, and multiple angiosomes can be supplied by a single artery. Knowledge of these supply arteries and their associated angiosomes is useful in planning the location, size, and shape of a flap.
== Classification ==
Flaps can be fundamentally classified by their mechanism of movement, the types of tissues present, or by their blood supply. The surgeon generally chooses the least complex type that will achieve the desired effect via a concept known as the reconstructive ladder.
=== Mechanism of movement ===
Local flaps are created by freeing a layer of tissue and then stretching the freed layer to fill a defect. This is the least complex type of flap and includes advancement flaps, rotation flaps, and transposition flaps, in order from least to most complex. With an advancement flap, incisions are extended out parallel from the wound, creating a rectangle with one edge remaining intact. This rectangle is freed from the deeper tissues and then stretched (or advanced) forward to cover the wound. The flap is disconnected from the body except for the uncut edge which contains the blood supply which feeds in horizontally. A rotation flap is similar except instead of being stretched in a straight line, the flap is stretched in an arc. The more complex transposition flap involves rotating an adjacent piece of tissue, resulting in the creation of a new defect that must then be closed.
Regional or interpolation flaps are not immediately adjacent to the defect. Instead, the freed tissue "island" is moved over or underneath normal tissue to reach the defect to be filled, with the blood supply still connected to the donor site via a pedicle. The pedicle can be removed after a new blood supply has formed. Examples: pectoralis major myocutaneous flap and deltopectoral flap for head and neck defects, and latissimus dorsi flap and traverse rectus abdominal muscle (TRAM) flap for breast reconstruction.
Distant flaps are used when the donor site is far from the defect. These are the most complex class of flap. Direct or tubed flaps involve having the flap connected to both the donor and recipient sites simultaneously, forming a bridge. This allows blood to be supplied by the donor site while a new blood supply from the recipient site is formed. Once this happens, the bridge can be disconnected from the donor site if necessary, completing the transfer. A free flap has the blood supply cut and then reattached microsurgically to a new blood supply at the recipient site.
=== Tissue type ===
Flaps can be classified by the content of the tissue within them.
Cutaneous flaps contain the full thickness of the skin, fat, and superficial fascia and are used to fill small defects. These are typically supplied by a random blood supply. Examples include Z-plasty, deep inferior epigastric perforator (DIEP) flaps, and V-Y advancement flaps.
Fasciocutaneous flaps contain subcutaneous tissue and deep fascia, resulting in a more robust blood supply and ability to fill a larger defect. The Cormack and Lamberty classification is used for the vascular supply of faciocutaneous flaps. Examples: temporoparietal and anterolateral thigh fascocutaneous flap, lateral fasciocutaneous flap, posterior fasciocutaneous flap.
Musculocutaneous and muscle flaps contain a layer of muscle to provide bulk that can fill a deeper defect. If skin cover is needed, a skin graft can be placed over top of it. Examples: gastrocnemius flap, latissimus dorsi flap, TRAM flap, and transverse upper gracillis flap.
Bone flaps contain bone and are used when structural support is needed such as in jaw reconstruction. Example: fibula flap.
Omental flaps can be used in chest wall defects, and intestinal flaps can be used to reconstruct tubular structures like the esophagus.
=== Vascular supply ===
Classification based on blood supply to the flap:
Axial flaps are supplied by a named artery and vein. This allows for a larger area to be freed from surrounding and underlying tissue, leaving only a small pedicle containing the vessels. Reverse-flow flaps are a type of axial flap in which the supply artery is cut on one end and blood is supplied by backwards flow from the other direction. Random flaps are simpler and have no named blood supply; they are supplied by the subdermal plexus.
Pedicled flaps remain attached to the donor site via a pedicle that contains the blood supply, in contrast to a free flap, where the vessels are cut and anastomosed to another blood supply.
== Contraindications ==
Anyone who is unstable for surgery should not undergo flap surgery. As with most surgeries, people who are sicker may have more difficulties with wound healing, which include individuals with comorbidities such as diabetes, smoking, immunosuppression, and vascular disease.
== Risks or complications ==
The risks of flap surgery include infection, wound breakdown, fluid accumulation, bleeding, damage to nearby structures, and scarring. The most notable risk in this procedure is flap death, where the flap loses blood supply. The loss of blood can be due to many reasons, but is commonly due to tension on the vascular supply and insufficient blood flow to the end segments of the flap. This can sometimes be fixed with another surgery or using additional methods of healing in the reconstructive ladder.
== Recovery ==
As with healing of any wound, healing of a flap maintains the same process of wound healing. There are four stages to wound healing: hemostasis, inflammation, proliferation, and remodeling, all of which can take up to a year to complete.
Following flap surgery, the biggest risk in recovery is flap death. Flap failure is an uncommon occurrence but does happen. The reported flap failure rate in free flaps is less than 5%. The most commonly cause is by venous insufficiency consisting of 54% of all causes. Venous insufficiency is commonly caused by a venous thrombus within the first 2 days following surgery. After the immediate postoperative risk, the flap will continue to heal adhering to the stages of normal wound healing and will take over 3 months for an incision to be at 80% tensile strength compared to normal tissue.
== History ==
Skin flaps are an essential part of a surgeon's toolbox in plastic surgery. It is part of the reconstructive ladder. The first known reports of surgical flaps originated in 600 BC in India by Sushruta where the tilemakers' caste would reconstruct noses using regional flaps due to the practice of nose amputations as a form of legal punishment. The next description of flap surgery comes from Celsus, an ancient Roman who described the advancement of skin flaps from 25 BC to 50 AD. In the 15th century, Gaspare Tagliacozzi, an Italian surgeon, helped develop the "Italian method" for nasal reconstruction, a delayed pedicle skin graft, where the skin from the arm would be attached to the nose for many months to create the reconstruction, first printed in the 1597 book De Curtorum Chirurgia per Insitionem. The Italian method was rediscovered in 1800 by German surgeon Carl Ferdinand von Graefe. Major advancements in modern plastic surgery are mostly attributed to Harold Gillies, who pioneered facial reconstruction during World War I using pedicled tube flaps on patients like Walter Yeo, and the development of the walking-stalk skin flap by Gilles' cousin Archibald McIndoe in 1930.
Advancements continued in flap surgery. With the introduction of the operating microscope, microvascular surgery advancements allowed for the anastomosis of blood vessels. This led to the ability of free tissue transfers, and in 1958 Bernard Seidenberg transferred a part of the jejunum to the esophagus to remove a cancer. Modern advancements in flap surgeries have continued since this time and are now commonly used in many procedures.
== See also ==
Breast reconstruction
DIEP flap
Hand surgery
List of plastic surgery flaps
Perforator flaps
Rhinoplasty
Rotation flap
Skin cancer
Z-plasty
== References ==
== External links ==
Flap surgery at eMedicine | Wikipedia/Flap_(surgery) |
Dermatology is the branch of medicine dealing with the skin. It is a speciality with both medical and surgical aspects. A dermatologist is a specialist medical doctor who manages diseases related to skin.
== Etymology ==
Attested in English in 1819, the word "dermatology" derives from the Greek δέρματος (dermatos), genitive of δέρμα (derma), "skin" (itself from δέρω dero, "to flay") and -λογία -logia. Neo-Latin dermatologia was coined in 1630, an anatomical term with various French and German uses attested from the 1730s.
== History ==
In 1708, the first great school of dermatology became a reality at the famous Hôpital Saint-Louis in Paris, and the first textbooks (Willan's, 1798–1808) and atlases (Alibert's, 1806–1816) appeared in print around the same time.
== Training ==
=== United States ===
After earning a medical degree (M.D. or D.O.), the length of training in the United States for a general dermatologist to be eligible for board certification by the American Academy of Dermatology, American Board of Dermatology, or American Osteopathic Board of Dermatology is four years. This training consists of an initial medical, transitional, surgical, or pediatric intern year followed by a three-year dermatology residency. Following this training, one- or two-year post-residency fellowships are available in immunodermatology, phototherapy, laser medicine, Mohs micrographic surgery, cosmetic surgery, dermatopathology, or pediatric dermatology. While these dermatology fellowships offer additional subspecialty training, many dermatologists proficiently provide these services without subspecialty fellowship training. For the past several years, dermatology residency positions in the United States have been one of the most competitive to obtain.
According to the American Academy of Dermatology, dermatologists are trained to diagnose and manage over 3,000 distinct skin, hair, and nail conditions across patients spanning various age groups.
The United States has been experiencing a national shortage of dermatologists for more than a decade. A study published by the Journal of the American Medical Association reported fewer than 3.4 dermatologists for every 100,000 people.
=== United Kingdom ===
In the UK, a dermatologist is a medically qualified practitioner who has gone on to specialise in medicine and then subspecialize in dermatology. This involves:
medical school for five years to obtain a medical degree (MB BS, MB ChB, MB BCh, MB BChir, BM BCh, BM BCh, MB, among other variations);
two years of foundation rotations in various specialties;
two to three years training in general medicine to obtain a higher degree in medicine and become a member of the Royal College of Physicians;
having obtained the MRCP examination, applying to become a Specialty Registrar (StR) in Dermatology and training for four years in dermatology; and
passing the Specialty Certificate Examination in dermatology before the end of training.
Upon successful completion of the four-year training period, the doctor becomes an accredited dermatologist and is able to apply for a consultant hospital post as a consultant dermatologist.
== Fields ==
=== Cosmetic dermatology ===
Dermatologists have been leaders in the field of cosmetic surgery. Some dermatologists complete fellowships in surgical dermatology. Many are trained in their residency on the use of botulinum toxin, fillers, and laser surgery. Some dermatologists perform cosmetic procedures including liposuction, blepharoplasty, and face lifts. Most dermatologists limit their cosmetic practice to minimally invasive procedures. Despite an absence of formal guidelines from the American Board of Dermatology, many cosmetic fellowships are offered in both surgery and laser medicine.
=== Dermatopathology ===
A dermatopathologist is a pathologist or dermatologist who specializes in the pathology of the skin. This field is shared by dermatologists and pathologists. Usually, a dermatologist or pathologist completes one year of dermatopathology fellowship and according to market projections, it is estimated to expand at a compound annual growth rate (CAGR) of 11.4% from 2022 to 2030. This usually includes six months of general pathology and six months of dermatopathology. Alumni of both specialties can qualify as dermatopathologists. At the completion of a standard residency in dermatology, many dermatologists are also competent at dermatopathology. Some dermatopathologists qualify to sit for their examinations by completing a residency in dermatology and one in pathology.
=== Trichology ===
Trichology specializes in diseases, which manifest with hair loss, hair abnormalities, hypertrichosis and scalp changes. Trichoscopy is a medical diagnostic method that is used by dermatologists with a special interest in trichology.
=== Immunodermatology ===
This field specializes in the treatment of immune-mediated skin diseases such as lupus, bullous pemphigoid, pemphigus vulgaris, and other immune-mediated skin disorders. Specialists in this field often run their own immunopathology labs. Immunodermatology testing is essential for the correct diagnosis and treatment of many diseases affecting epithelial organs including skin, mucous membranes, gastrointestinal and respiratory tracts. The various diseases often overlap in clinical and histological presentation and, although the diseases themselves are not common, may present with features of common skin disorders such as urticaria, eczema and chronic itch. Therefore, the diagnosis of an immunodermatological disease is often delayed. Tests are performed on blood and tissues that are sent to various laboratories from medical facilities and referring physicians across the United States.
=== Mohs surgery ===
The dermatologic subspecialty called Mohs surgery focuses on the excision of skin cancers using a technique that allows intraoperative assessment of most of the peripheral and deep tumor margins. Developed in the 1930s by Frederic E. Mohs, the procedure is defined as a type of CCPDMA processing. Physicians trained in this technique must be comfortable with both pathology and surgery, and dermatologists receive extensive training in both during their residency. Physicians who perform Mohs surgery can receive training in this specialized technique during their dermatology residency, but many seek additional training either through formal preceptorships to become fellows of the American Society for Mohs Surgery or through one-year Mohs surgery fellowship training programs administered by the American College of Mohs Surgery. In 2020, the American Board of Dermatology (ABD) received approval from the American Board of Medical Specialties (ABMS) to establish a board-certification exam in the subspecialty of Micrographic Dermatologic Surgery (Mohs Surgery). The exam was first offered in October 2021 to any US board-certified dermatologist who practices Mohs surgery, regardless of whether they received their training in dermatology residency or as part of a fellowship.
This technique requires the integration of the same doctor in two different capacities - surgeon and pathologist. In case either of the two responsibilities is assigned to another doctor or qualified health-care professional, it is not considered to be Mohs surgery.
=== Pediatric dermatology ===
Physicians can qualify for this specialization by completing both a pediatric residency and a dermatology residency. Or they might elect to complete a post-residency fellowship. This field encompasses the complex diseases of the neonates, hereditary skin diseases or genodermatoses, and the many difficulties of working with the pediatric population. Another area pediatric dermatologists may focus on is treating acne. Acne is formed when follicles under the skin become clogged. This can be caused by sebum, an oil that keeps the skin moist, or dead skin cells clogging the pores. This is very common in teens and young adults, and can be treated by prescription from a dermatologist.
=== Teledermatology ===
Teledermatology is a form of dermatological practice in which telecommunication technologies are used to exchange medical information and treatment through audio, visual, and data communication, including photos of dermatologic conditions, between dermatologists and nondermatologists who are evaluating patients, along with dermatologists directly with patients via distance. In India, during the severe coronavirus situations, some dermatologists have initiated online consultation with their patients using some of popular apps, such as Practo, Apollo Pharmacy, Skin Beauty Pal, Lybrate, etc. This subspecialty deals with options to view skin conditions over a large distance to provide knowledge exchange, to establish second-opinion services for experts, or to use this for follow-up of individuals with chronic skin conditions. Teledermatology can reduce wait times by allowing dermatologists to treat minor conditions online while serious conditions requiring immediate care are given priority for appointments.
=== Dermatoepidemiology ===
Dermatoepidemiology is the study of skin disease at the population level. One of its aspects is the determination of the global burden of skin diseases.
From 1990 to 2013, skin disease constituted about 2% of total global disease disability as measured in disability-adjusted life-years.
=== Comparative Dermatology ===
Comparative dermatology is a branch of dermatology that examines skin disorders across species, focusing on similarities and differences between humans and animals, such as dogs. This interdisciplinary approach is crucial for enhancing our understanding of dermatological conditions and developing more effective treatment and prevention strategies.
Skin disorders are common in dogs, significantly affecting their quality of life and often requiring veterinary intervention. While some breeds are genetically predisposed to specific skin issues, there remains a notable gap in research comparing these canine conditions to similar human skin disorders. Addressing this gap can yield insights into the shared mechanisms underlying these diseases. For instance, atopic dermatitis. It is a common, itchy, and often difficult-to-treat condition. The Merck Veterinary Manual highlights various congenital and inherited skin disorders in dogs that are influenced by these factors, emphasizing the need for comparative research to improve disease management across species. By comparing the disease in animals and humans, researchers can gain insights into its progression and variability in response to treatments.
Furthermore, research into the genetic underpinnings of skin disorders has demonstrated that certain genetic mutations in dogs are associated with inherited skin diseases, which may serve as models for understanding similar human conditions. Environmental factors, such as allergens and pollutants, also play a significant role in skin health. Studies published in journals focusing on inflammatory skin conditions in humans and veterinary research reveal how these environmental influences intersect with genetic predispositions, offering a comparative framework for further study.
Treatment strategies for skin disorders also differ between veterinary and human medicine. Veterinary treatments often prioritize symptomatic relief and prevention, while human dermatological care may involve a broader range of targeted pharmaceutical options. Comparative analysis of these treatment methodologies could lead to the development of new therapies beneficial to both fields, as discussed in microbiological research into skin health.
By emphasizing the comparative aspects of dermatology, researchers can contribute to a deeper understanding of skin health across species. This field underscores the importance of genetic research, environmental studies, and treatment innovations, as evidenced by ongoing research in dermatological and veterinary science.
== Therapies ==
Therapies provided by dermatologists include:
Excision and treatment of skin cancer
Cryosurgery for the treatment of warts, skin cancers, and other dermatoses
Cosmetic filler injections
Intralesional treatment with steroid drugs or chemotherapy
Laser therapy for the management of birth marks, skin disorders (like vitiligo), tattoo removal, and cosmetic resurfacing and rejuvenation
Chemical peels for the treatment of acne, melasma, and sun damage
Photodynamic therapy for the treatment of skin cancer and precancerous growths
Phototherapy including the use of narrowband UVB, broadband UVB, psoralen, and UVB
Tumescent liposuction: Invented by a gynecologist, a dermatologist (Jeffrey A. Klein) adapted the procedure to local infusion of dilute anesthetic called tumescent liposuction. This method is now widely practiced by dermatologists, plastic surgeons, and gynecologists.
Radiation therapy, although rarely practiced by dermatologists, some continue to provide it in their offices.
Vitiligo surgery includes procedures such as autologous melanocyte transplant, suction blister grafting, and punch grafting.
Allergy testing uses "patch" testing for contact dermatitis.
Systemic therapies include antibiotics, immunomodulators, and novel injectable products.
Topical therapies use many of the numerous products and compounds used topically.
Most dermatologic pharmacology can be categorized based on the Anatomical Therapeutic Chemical (ATC) classification system, specifically the ATC code D.
== See also ==
== References ==
== External links ==
Media related to Dermatology at Wikimedia Commons | Wikipedia/Skin_surgery |
Bariatric surgery (also known as metabolic surgery or weight loss surgery) is a surgical procedure used to manage obesity and obesity-related conditions. Long term weight loss with bariatric surgery may be achieved through alteration of gut hormones, physical reduction of stomach size (stomach reduction surgery), reduction of nutrient absorption, or a combination of these. Standard of care procedures include Roux en-Y bypass, sleeve gastrectomy, and biliopancreatic diversion with duodenal switch, from which weight loss is largely achieved by altering gut hormone levels responsible for hunger and satiety, leading to a new hormonal weight set point.
In morbidly obese people, bariatric surgery is the most effective treatment for weight loss and reducing complications. A 2021 meta-analysis found that bariatric surgery was associated with reduction in all-cause mortality among obese adults with or without type 2 diabetes. This meta-analysis also found that median life-expectancy was 9.3 years longer for obese adults with diabetes who received bariatric surgery as compared to routine (non-surgical) care, whereas the life expectancy gain was 5.1 years longer for obese adults without diabetes. The risk of death in the period following surgery is less than 1 in 1,000. Bariatric surgery may also lower disease risk, including improvement in cardiovascular disease risk factors, fatty liver disease, and diabetes management.
Stomach reduction surgery is frequently used for cases where traditional weight loss approaches, consisting of diet and physical activity, have proven insufficient, or when obesity already significantly affects well-being and general health. The weight-loss procedure involves reducing food intake. Some individuals might suppress bodily functions to reduce the absorption of carbohydrates, fats, calories, and proteins. The outcome is a significant reduction in BMI. The efficacy of stomach reduction surgery varies depending on the specific type of procedure. There are two primary divisions of surgery, specifically gastric sleeve surgery and gastric bypass surgery.
As of October 2022, the American Society of Metabolic and Bariatric Surgery and International Federation for the Surgery of Obesity recommended consideration of bariatric surgery for adults meeting two specific criteria: people with a body mass index (BMI) of more than 35 whether or not they have an obesity-associated condition, and people with a BMI of 30–35 who have metabolic syndrome. However, these designated BMI ranges do not hold the same meaning in particular populations, such as among Asian individuals, for whom bariatric surgery may be considered when a BMI is more than 27.5. Similarly, the American Academy of Pediatrics recommends bariatric surgery for adolescents 13 and older with a BMI greater than 120% of the 95th percentile for age and sex.
== Medical uses ==
Bariatric surgery has proven to be the most effective obesity treatment option for enduring weight loss. Along with this weight reduction, the procedure reduces risk of cardiovascular diseases, type 2 diabetes, fatty liver disease, depression syndromes, among others. While often effective, numerous barriers to shared decision making between the medical provider and person affected include lack of insurance coverage or understanding how it functions, a lack of knowledge about procedures, conflicts with organizational priorities and care coordination, and tools supporting people who need the surgery.
=== Eligibility and guidelines ===
Historically, eligibility for bariatric surgery was defined as a BMI greater than 40, or a BMI more than 35 with an obesity-associated comorbidity, as based on the 1991 NIH Consensus Statement. In the three decades that followed, obesity rates continued to rise, laparoscopic surgical techniques made the procedure safer, and high-quality research showed effectiveness at improving health among various conditions. In October 2022, ASMBS/IFSO revised the eligibility criteria, which include all adult patients with a BMI greater than 35, and those with a BMI more than 30 with metabolic syndrome. However, BMI is a limited measurement, for which factors such as ethnicity are not used in the BMI calculation. Eligibility criteria for bariatric surgery are modified for people who identify as a part of the Asian population with a BMI of more than 27.5.
Stomach reduction surgeries were highly recommended for patients who meet these criteria: BMI>40 (type 3 obesity), BMI>35 (type 2 obesity), with specific comorbid conditions such as type 2 diabetes, hypertension, dyslipidemia, etc.
As of 2019, the American Academy of Pediatrics recommended bariatric surgery without age-based eligibility limits under the following indications: BMI more than 35 with severe comorbidity, such as obstructive sleep apnea (Apnea-Hypopnea Index above 0.5), type 2 diabetes, idiopathic intracranial hypertension, nonalcoholic steatohepatitis, Blount disease, slipped capital femoral epiphysis, gastroesophageal reflux disease, and idiopathic hypertension or a BMI above 40 without comorbidities. Surgery is contraindicated with a medically correctable cause of obesity, substance abuse, concurrent or planned pregnancy, eating disorder, or inability to adhere to postoperative recommendations and mandatory lifestyle changes.
When counseling a patient on bariatric procedures, providers take an interdisciplinary approach. Psychiatric screening is also critical for determining postoperative success. People with a BMI of 40 or greater have a 5-fold risk of depression, and half of bariatric surgery candidates are depressed. Among bariatric surgery candidates and those who undergo bariatric surgery, mental health-related conditions including anxiety disorders, eating disorders, and substance use are also more commonly reported.
==== Age ====
Elderly patients will face higher postoperative complications due to frailty of elderly patients. The adolescents who performed stomach reduction surgery showed better results and there is no negative impact on linear/puberty growth.
=== Contraindications ===
Stomach reduction surgery is not suitable for people with the following conditions:
History of severe gastrointestinal disease:
Crohn's disease–RYGB surgery limited.
Active peptic ulcers disease.
Esophagitis in severe stage.
Severe cardiovascular disease
Heart failure
Coronary artery disease
Portal hypertension
Cancer: active cancer diagnosis
Pregnancy: pregnant (within 12-18 month)
Psychiatric: lower level of mental capacity or untreated mental disorders
Blood clotting: Coagulopathy issue
=== Weight loss ===
In adults, malabsorptive procedures lead to more weight loss than restrictive procedures, but they have a higher risk profile. Gastric banding is the least invasive, so it may offer fewer complications, while gastric bypass may offer the highest initial and most sustainable weight loss. A single protocol is not superior to the other. In one 2019 systematic review, estimated weight loss (EWL) for each surgical protocol is as follows: 56.7% for gastric bypass, 45.9% for gastric banding, 74.1% for biliopancreatic bypass +/- duodenal switch and 58.3% for sleeve gastrectomy. Most patients do remain obese (BMI 25-35) following surgery despite significant weight loss, and patients with BMI over 40 tended to lose more weight than those with BMI under 40.
Concerning metabolic syndrome, bariatric surgery patients were able to achieve remission 2.4 times as often as those who underwent nonsurgical treatment. No significant difference was noted for changes in cholesterol, or LDL, but HDL did increase in the surgical groups, and reduction in blood pressure was variable between studies.
=== Type 2 diabetes mellitus ===
Studies of bariatric surgery for type 2 diabetes (T2DM) within the obese population show that 58% prioritize the improvement of diabetes, while 33% pursued surgery for weight loss alone. While weight loss is essential in T2DM management, sustaining improvements long-term is challenging; 50% to 90% of people struggle to achieve adequate diabetes control, suggesting the need for alternative interventions. In this context, studies have reported an 85–90% resolution of T2DM after bariatric surgery, measured by reductions in fasting plasma glucose and HbA1C levels, and remission rates of up to 74% two years post-surgery. Bariatric surgery is considered for individuals with new-onset T2DM and obesity, although the level of improvement may be slightly less.
The relative risk reductions associated with bariatric surgery are 61%, 64%, and 77% for the development of T2DM, hypertension, and dyslipidemia, respectively, highlighting the efficacy of bariatric surgery in prevention as well as resolution of chronic obesity. Predictors for post-operative diabetes resolution include the current method of diabetes control, adequate blood sugar control, age, duration of diabetes, and waist circumference.
Bariatric surgery likewise plays a role in the reduction of medication use. During postoperative follow-up, 76% of people discontinued the use of insulin, while 62% no longer required T2DM medications at all.
=== Reduced mortality and morbidity ===
A 2021 meta-analysis found that bariatric surgery was associated with 59% and 30% reductions in all-cause mortality among obese adults with or without type 2 diabetes respectively. It also found that median life expectancy was 9 years longer for obese adults with diabetes who received bariatric surgery as compared to routine (non-surgical) care, whereas the life expectancy gain was 5 years longer for obese adults without diabetes. The overall cancer risk in bariatric surgery patients was decreased by 44%, especially in colorectal, endometrial, breast, and ovarian cancer. Improvements in cardiovascular health are the most well-described changes after bariatric surgery, with notable reductions in the incidence of stroke (except in patients with T2DM), heart attack, atrial fibrillation, all-cause cardiovascular mortality, and ischemic heart disease.
Bariatric surgery in older patients is a safety concern; the relative benefits and risks in this population are not known.
=== Fertility and pregnancy ===
In 2017, the American Society for Metabolic and Bariatric Surgery stated that it was not clear whether medical weight-loss treatments or bariatric surgery affected subsequent treatments for infertility in both men and women.
Bariatric surgery reduces the risk of gestational diabetes and hypertensive disorders of pregnancy in women who later become pregnant, but increases the risks of preterm birth and maternal anemia. A 2021 systematic review found that post-bariatric surgery normalized hormonal levels and menstrual cycles, and improved fertility, with no increased short-term risk of miscarriages or congenital malformations.
For women with polycystic ovary syndrome, post-operatively there tends to be a reduction in menstrual irregularity, hirsutism, infertility, and the overall prevalence of polycystic ovary syndrome is reduced by bariatric surgery at 12 and 23 months.
=== Mental health ===
Among people seeking bariatric surgery, pre-operative mental health disorders are commonly reported. Some studies indicate that psychological health can improve after bariatric surgery, due in part to improved body image, self-esteem, and change in self-concept; these findings were found in children (see Considerations in adolescent patients below). Bariatric surgery has consistently been associated with postoperative decreases in depression symptoms and reduced severity.
== Risks and complications ==
Weight loss surgery in adults is associated with an elevated risk of complications compared to nonsurgical treatments for obesity. Complications can be separated into 2 stages, early complication (within 30 days after surgeries) and late complications (after 30 days).
The overall risk of mortality is low in bariatric surgery at 0 to .01%. Severe complications, such as gastric perforation or necrosis, have been significantly reduced by improved surgical experience and training. Bariatric surgery morbidity is also low at 5%. In fact, several studies have reported a reduced overall long-term all-cause mortality compared to controls. However, obese populations maintain an elevated risk of disease and mortality compared to the general population even after surgery, therefore elevated mortality after surgery may be related to the ongoing complications of existing obesity-related disease.
The percentage of procedures requiring reoperations due to complications was 8% for adjustable gastric banding, 6% after Roux-en-Y gastric bypass, 1% for sleeve gastrectomy, and 5% after biliopancreatic diversion. Over a 10-year study while using a common data model to allow for comparisons, 9% of patients who received a sleeve gastrectomy required some form of reoperation within 5 years compared to 12% of patients who received a Roux-en-Y gastric bypass. Both of the effects were fewer than those reported with adjustable gastric banding.
=== Postoperative ===
Laparoscopic bariatric surgery requires an average hospital stay of 2–5 days, barring potential complications. Minimally invasive procedures (i.e. adjustable gastric band) tend to have less complications than open procedures (i.e. Roux-en-Y). Similar to other surgical procedures, there is a risk of atelectasis (collapse of small airways) and pleural effusion (fluid buildup in lungs), and pneumonia which tends to be less associated with minimally invasive procedures.
Complications specific to the laparoscopic gastric band procedure include esophageal perforation from the advancement of the calibration probe, gastric perforation from the creation of a retrograde gastric tunnel, esophageal dilation, and acute dilation of the gastric pouch due to malpositioning of the gastric band. Gastric band malpositioning can be devastating, leading to gastric prolapse, overdistention, and resultingly, gastric ischemia and necrosis. Erosion and migration of the band may also occur post-operatively, in which case, if over 50% of the circumference of the band migrates, then surgical repositioning is necessary.
Risks of Roux-en-Y gastric bypass include anastomotic stenosis (narrowing of the intestine where the two segments are rejoined), bleeding, leaks, fistula formation, ulcers (ulcers near the rejoined segment), internal hernia, small bowel obstruction, kidney stones, and gallstones. Bowel obstruction tends to be more difficult to diagnose in post-bariatric surgery patients due to their reduced ability to vomit; symptoms mainly involve abdominal pain and are intermittent due to twisting and untwisting of the intestinal mesentery.
Sleeve gastrectomy also carries a small risk of stenosis, staple line leak, stricture formation, leaks, fistula formation, bleeding, and gastro-esophageal reflux disease (also known as GERD or heartburn).
Deficiencies of micronutrients like iron (15%), vitamin D, vitamin B12, fat-soluble vitamins, thiamine, and folate are common after bariatric procedures. Such deficiencies are potentiated by alterations in absorption and lack of appetite and often require supplementation. Notably, chronic vitamin D deficiency may contribute to osteoporosis; insufficiency fractures, especially of the upper extremity, are of higher incidence in bariatric surgery patients. Sleeve gastrectomy leads to fewer long-term vitamin deficiencies compared to gastric banding.
==== Sleeve Gastrectomy (SG) ====
Early complication: Bleeding is present in approximately 5% of cases of sleeve gastrectomy. Symptoms can vary widely, ranging from gastrointestinal bleeding to internal bleeding. Venous thromboembolism (VTE) may occur, causing a decrease in flow through the splenic system, potentially leading to system collapse or death.
Late complications: They include gastric stenosis, nutrient deficiencies, and Gastroesophageal reflux disease. For gastric stenosis, the symptoms are food intolerance and vomiting. For the gastroesophageal reflux disease, which due to post-surgery changes of reduced lower esophageal sphincter tension and increased intragastric pressure. Patients may suffer from heartburn after eating or upper abdominal pain.
===== Roux-En-Y Gastric Bypass (RYGB) =====
An early complication of Roux-En-Y Gastric Bypass: Small bowel obstruction, which can be caused by the internal hernias due to the laparoscopic RYGB surgery techniques that were used. And it is life-threatening to patients since it is hard to diagnose through clinical or radiographic imaging. The symptoms included vomiting, abdominal pain and peritonitis. Common complications such as internal gastrointestinal hemorrhage (bleeding) and staple line leakage occur in both surgeries.
Late complication: For the anastomotic stricture, there is a 2.9%-23% chance for patients to experience gastrojejunal anastomosis. This complication more often occurs in the laparoscopic era than open RYGB surgery. Symptoms such as difficulty swallowing and vomiting.
=== Gastrointestinal ===
The most common complication, especially after sleeve gastrectomy, is GERD, which may occur in up to 25% of cases. Dumping syndrome (rapid emptying of undigested stomach contents) is another common complication of bariatric surgery, especially after Roux-en-Y, which is further classified into early and late dumping syndrome. Dumping syndrome in some cases may be associated with more efficient weight loss, however, it can be uncomfortable. Symptoms of dumping syndrome include nausea, diarrhea, painful abdominal cramps, bloating, and autonomic symptoms such as tachycardia, palpitations, flushing, and sweating. Early dumping syndrome (emptying within 1 hour of eating) is also associated with a rapid drop in blood pressure, which may cause fainting. Late dumping syndrome is characterized by low blood sugar 1–3 hours after a meal, presenting with palpitations, tremors, sweating, a feeling of faintness, and irritability. Dumping syndrome is best mitigated by consuming small meals and avoiding high carb or high-fat foods.
=== Gallstones ===
Rapid weight loss after obesity surgery can contribute to the development of gallstones, especially at 6 and 18 months. Estimates for prevalence of symptomatic gallstones after Roux-En-Y gastric bypass range from 3–13%. The risk of gallstones following bariatric surgery has shown to be higher among those of the female sex.
=== Kidney stones ===
Kidney stones are common after Roux-En-Y gastric bypass, with estimates of prevalence ranging from 7-11%. All surgical modalities are associated with a significant increase in the risk of kidney stones compared to nonsurgical weight loss treatment, with biliopancreatic diversion being the most associated at a ten-fold increase in one study.
=== Micronutrient malnutrition ===
Bariatric surgery as a treatment for obesity can lead to vitamin deficiencies. Long-term follow-up reported deficiencies for vitamins D, E, A, K and B12. There are guidelines for multivitamin supplementation, but adherence rates are reported to be less than 20%.
=== Pregnancy ===
Pregnancy in patients post-bariatric surgery must be carefully monitored. Infant mortality, preterm birth, small fetal size, congenital anomalies, and NICU admission are all elevated in bariatric surgery patients. This elevation in adverse outcomes is thought to be because of malnutrition. Most notably, a reduction in serum folate and iron are well-established correlates to neural tube defects and preterm birth, respectively. People considering pregnancy should consult with their physician before conceiving to optimize their health and nutritional status before pregnancy.
== Technique ==
=== Mechanisms of action ===
Bariatric procedures function by a variety of mechanisms, such as alteration of gut hormones, reduction of the gut size (reducing the amount of food that may pass through), and reduction or blockage of nutrient absorption. The distinction in these mechanisms, and which are at work for a particular bariatric procedure is not always clearly defined, as multiple mechanisms may be used by a single procedure. For instance, while sleeve gastrectomy (discussed below) was initially thought to work simply by reducing the size of the stomach, research has begun to elucidate changes in gut hormone signaling as well. The two most frequently performed procedures are sleeve gastrectomy and Roux-en-Y gastric bypass (also called gastric bypass), with sleeve gastrectomy accounting for more than half of all procedures since 2014.
==== Hormone regulation ====
Studies have shown that bariatric procedures may have additional effects on the hormones that affect hunger and satiety (such as ghrelin and leptin), despite initial development to target reduction of food intake and/or nutrient absorption. This is especially important when considering the durability of weight loss compared to lifestyle changes. While diet and exercise are essential for maintaining a healthy weight and physical fitness, metabolism typically slows as the individual loses weight, a process known as metabolic adaptation. Thus, efforts for obese individuals to lose weight often stall, or result in weight re-gain. Bariatric surgery is thought to affect the weight "set point," leading to a more durable weight loss. This is not completely understood but may involve the cell-signaling pathways and hunger/satiety hormones.
==== Restricting food intake ====
Procedures may reduce food intake by reducing the size of the stomach that is available to hold a meal (see below: gastric sleeve or stomach folding). Filling the stomach faster enables an individual to feel more full after a smaller meal.
==== Nutrient absorption ====
Procedures may reduce the amount of intestine that food passes through to decrease the absorption of nutrients from food. For example, a Roux-en-Y gastric bypass connects the stomach to a more distal part of the intestine, which reduces the ability of the intestines to absorb nutrients from the food.
==== Disruption of the gut-brain axis by partial vagotomy ====
Roux-en-Y gastric bypass disrupts the gastric branches of the vagal nerve completely and sleeve gastrectomy does so partially. Before current bariatriac was introduced, isolated vagotomy was used for the treatment of obesity. Vagotomy leads to a reduction of gastric acid and consequently to a reduction in nutrient absorption and a delay in gastric emptying. In addition, the effect of the hunger hormone Ghrelin is reduced, because it acts through the vagal nerve. This leads to a reduction of the hunger feeling and weight loss.
=== Most common techniques ===
==== Sleeve gastrectomy ====
Sleeve gastrectomy, also known as a gastric sleeve, is a surgical weight-loss procedure where the stomach size is reduced by the surgical removal of a large portion of the stomach, following along the major curve of the stomach. The open edges are then attached (typically with surgical staples, sutures, or both) to leave the stomach shaped more like a tube, or a sleeve, with a banana shape.
The procedure is performed laparoscopically and is not reversible. It has been found to produce a weight loss comparable to that of Roux-en-Y gastric bypass. The risk of ulcers or narrowing of the gut due to intestinal strictures is less so with sleeve gastrectomy versus Roux-en-Y gastric bypass, but it is not as effective at treating GERD or type 2 diabetes.
This was the most commonly performed bariatric surgery as of 2021 in the United States, and is one of the two most commonly performed bariatric surgeries in the world. Though initially thought to work strictly by reducing the size of the stomach, recent research has shown that there are also changes in gut signaling hormones with this procedure leading to weight loss.
The sleeve gastrectomy mechanism works by creating a narrow gastric lumen which restricts food intake and prevents receptive relaxation, alongside ongoing research into hormonal changes, and gastrointestinal motility.
The physical mechanism that will make the SG stand out to other bariatric surgery is its reduction of the storage of the stomach significantly, allowing patients to control their calorie intakes.
The mechanism related to hormone regulation, SG can help to improve Insulin sensitivity, aiming for better glucose regulation and contributing to the remission of type 2 diabetes in many patients. The levels of gut hormones such as GLP-1 and PYY increase after operation of SG. GLP-1 enhances insulin secretion and has a satiety-inducing effect, while PYY helps reduce appetite. These hormonal changes are pivotal in the metabolic improvements observed after SG, including better control of blood sugar levels and reduced hunger.
SG will affect the metabolism and absorption of nutrients, hence causing an effect on nutrient dynamics. Postoperative observation shows patients' nutrient levels of Vitamin B1 and B12 have significantly declined, necessitating careful postoperative nutritional management to prevent deficiencies.
Research suggests SG surgery can alter the composition of the gut microbiota, which plays a role in obesity and metabolic health. Changes in the gut microbial community post-SG may influence energy harvest from the diet, impact inflammatory pathways, and affect the host's metabolic profile.
The key mechanism is gastrointestinal motility adjustment of SG surgery, which impacts the speed and efficiency of food processing. Studies have observed a modification in the pressure of the lower esophageal sphincter and an increase in intragastric pressure post-surgery, which collectively impact the gastrointestinal motility.
Techniques:
Hiatal Hernia Repair. During SG, identifying and repairing a hiatal hernia (HH) is a significant step that can influence the surgery's outcome, especially concerning gastroesophageal reflux disease (GERD) management postoperatively. The procedure involves dissecting the pars flaccida to open a plane between the right crus of the liver and the esophagus, performing an intrathoracic esophageal dissection, and identifying the left crus. A hiatal hernia repair is conducted, if necessary, with a posterior cruroplasty using a durable suture material. This step is vital as it ensures the proper positioning of the gastroesophageal junction (GEJ) and reduces the risk of postoperative GERD by securing the stomach below the diaphragm, preventing potential acid reflux.
Bougie Sizing and Stapling Alongside. The insertion of a bougie during LSG is a crucial technique for guiding the creation of the gastric sleeve. The bougie, which ranges from 38 to 40 French in size, is inserted down to the pylorus under direct visualisation, serving as a mold around which the stomach is stapled and resected. This technique ensures that the sleeve is of uniform size and reduces the risk of narrowing a passage or obstruction post-surgery. Stapling begins 3-6 cm from the pylorus and proceeds upwards towards the angle of His, closely aligned with the bougie to create a narrow gastric tube. The careful placement and size of the bougie are instrumental in achieving optimal sleeve shape and function, minimising complications such as leaks or strictures.
After 1-3 postoperative days, patients begin oral intake, contingent on a successful gastrografin leak test, and receive continuous metabolic monitoring. To reduce early respiratory risk, prophylactic measures such as oxygen support and ultrasound evaluations are employed.
Late postoperative care involves careful observation for anastomotic leaks, patient change to a clear liquid diet, and managing potential nausea and vomiting. After discharge, the focus shifts to dietary management, starting with a full liquid diet and gradually incorporating soft, solid foods. Monitoring includes regular check-ups for weight and blood pressure, along with comprehensive lab tests to ensure optimal recovery.
==== Roux-en-Y gastric bypass surgery ====
Roux-en-Y gastric bypass surgery involves the creation of a new connection in the gastrointestinal tract, from a smaller portion of the stomach to the middle of the small intestine.
The surgery is a permanent procedure that aims to decrease the absorption of nutrients due to the new, limited connection created. The surgery also works by affecting gut hormones, resetting hunger and satiety levels. The physically smaller stomach and increase in baseline satiety hormones help people to feel full with less food after the surgery.
This is the most commonly performed operation for weight loss in the United States, with approximately 140,000 gastric bypass procedures performed in 2005. A 2021 evidence update comparing the benefits and harms of bariatric procedures found that Roux-en-Y gastric bypass surgery and sleeve gastrectomy both effectively reduced weight and led to Type 2 diabetes remission. After five years, Roux-en-Y resulted in greater weight loss (26% compared to 19% for sleeve gastrectomy) and a 25% lower rate of diabetes relapse. However, Roux-en-Y patients had a higher likelihood of hospitalization and additional abdominal surgeries compared to sleeve gastrectomy. Though, since 2013, sleeve gastrectomy has overtaken RYGB as the most common bariatric procedure. RYGB remains one of the two most commonly performed bariatric surgeries in the world.
Gastric bypass is the most frequently employed technique for weight reduction, the abnormal absorption in the intestines and the physical restriction of the stomach. The types of surgeries can be categorized by the effects and the changes made. Reconstruction of the small intestine to reduce the mucosal area which is used to absorb nutrients is called the Malabsorption operation. The jejunoileal bypass (JIB) is the most traditional technique for gastric bypass. This procedure has no limitations in the flow and processing of food; it only allows the transport of nutrients from the small intestine to the surrounding areas of the intestine. The impact of weight loss is apparent and remarkable. Individuals who undergo Roux-en-Y gastric bypass (RYGB) consume fewer snacks and meals compared to those who undergo JIB. The RYGB procedure has been proved to be the most effective medical treatment for type 2 diabetes and weight loss. After performing gastric bypass surgery, the two hormones related to obesity, leptin and insulin, fall in levels and while lose weight.
Roux-en-Y (RYGB) offers two surgical approaches for processing: an open technique or the laparoscopic technique. The majority of cases are still performed with laparoscopy. The laparoscopic approach is a safe procedure that is associated with fewer problems resulting from wound inflammation.
There are three main areas of techniques for performing laparoscopic RYGB: (1) Anastomotic technique including Linear Circular stapler. 2) Alimentary limb configuration, such as Antecolic or Retrocolic and Antegastric or Retrogastric. 3) Limb-length of the bilio-pancreatic (BP) limb.
Linear stapling: this technique has two variations. 1) Perform the jejuno-jejunal (JJ) anastomosis, then act on the gastro-jejunal (GJ) anastomosis. 2) reverse the first process.
Jejuno-jejunal first: This technique is prevalent within gastric bypass surgery.
JJ Anastomosis
In order to facilitate identification of duodenum-jejunum (DJ) flexion and Treitz ligaments, it will act on the Cephalic greater omentum using the laparoscopic staplers and Surgical energy device separate the mesentery. It also includes measuring the Roux limb between the distal end of the binding and the chosen length. For example, if the weight index is 40, the length should be 100cm.
Gastric pouch formation
On the lesser curve of the stomach, a window will be opened between the second and third vessel at the perigastric border. The pouch will be formed using the laparoscopic stapling device. The orogastric tube which will be removed before the first launch of the stapler horizontally. The pouch is produced over the tube with next firings in another direction. These may need the mobilisation to help further divide the stomach.
Gastro-jejunal anastomosis
Gastrostomy is created at the specific angle (the part of the pouch with the least blood supply). The separated alimentary limbs are translocated to the pouch antecolically. Enterotomy will processed within the jejunum. At the same time, between the gastric pouch and alimentary limb, the laparoscopic stapling devices create the single firing. According to the JJ anastomosis, the anastomotic defect closes with 2 continuously absorbed sutures. Finally, 50 ml of Dilute methylene blue dye is needed to assess leakage and ensure anastomotic integrity.
Other techniques include the Omega Loop Technique and Trans-abdominal technique employ different operating approaches along with different process orders. All of them will show positive weight loss results.
The duration of the recuperation phase typically ranges from 2 to 4 weeks. The length of the period is dependent upon the self-perception of the patients and their future state of mental and physical ability. For patients to resume their normal activities, a minimum of 3-5 weeks recovery period is required. Doctors should determine the length of the recovery period based on a range of body mass index.
==== Biliopancreatic diversion with duodenal switch ====
The biliopancreatic diversion with duodenal switch (BPD/DS) is a slightly less common bariatric procedure, but is increasing in use with proven efficacy for sustainable weight loss.
This procedure has multiple steps. First, a sleeve gastrectomy (see above section) is performed. This part of the procedure causes food intake restriction due to the physical reduction of the stomach size, and is permanent. Next, the stomach is then disconnected from the upper part of the small intestine and connected to a farther part of the small intestine (ileum), creating the alimentary limb. The leftover section of the far part of the small intestine is then used to make a connection that brings digestive fluids from the gallbladder and pancreas to the alimentary limb.
Weight loss following the surgery is largely due to the alteration of gut hormones that control hunger and satiety, as well as the physical restriction of the stomach and decrease in nutrient absorption. Compared to the sleeve gastrectomy and Roux-en-Y gastric bypass, BPD/DS produces better results with lasting weight loss and resolution of type 2 diabetes.
=== Other related bariatric procedures ===
==== Vertical banded gastroplasty ====
Vertical banded gastroplasty was more commonly used in the 1980s, and is not typically performed in the 21st century.
In the vertical banded gastroplasty, a part of the stomach is permanently stapled to create a smaller, new stomach. This new stomach is physically restricted, allowing people to feel full with smaller meals. Short-term weight loss is similar to other bariatric procedures, but long-term complications may be higher.
==== Gastric plication ====
This procedure is similar to the sleeve gastrectomy surgery, but a sleeve is created by suturing, rather than physically removing stomach tissue. This allows for the natural ability of the stomach to absorb nutrients to remain intact. This procedure is reversible, is a less invasive procedure, and does not use hardware or staples.
Gastric plication significantly reduces the volume of the patient's stomach, so smaller amounts of food provide a feeling of satiety. In a 2020 review and meta-analysis, long-term weight loss was not as durable as other, more common bariatric techniques. Gastric plication has not performed as well as the sleeve gastrectomy, with the sleeve gastrectomy associated with greater weight loss and fewer complications.
=== Implants and devices ===
==== Adjustable gastric band ====
The restriction of the stomach also can be created using a silicone band, which can be adjusted by the addition or removal of saline through a port placed just under the skin, a procedure called adjustable gastric band surgery. This operation can be performed laparoscopically, and is commonly referred to as a "lap band". Weight loss is predominantly due to the restriction of nutrient intake that is created by the small gastric pouch and the narrow outlet. It is considered somewhat of a safe surgical procedure, with a mortality rate of 0.05%.
==== Intragastric balloon ====
Intragastric balloon involves placing a deflated balloon into the stomach, and then filling it to decrease the amount of gastric space, resulting in the feeling of fullness after a smaller meal. The balloon can be left in the stomach for a maximum of 6 months and results in weight loss of 3 BMI or 3–8 kg within several study ranges. Weight loss with the gastric balloon tends to be more modest than other interventions. The intragastric balloon may be used before another bariatric surgery to assist the patient in reaching a weight that is suitable for surgery but can be used repeatedly and unrelated to other procedures.
==== Implantable gastric stimulation ====
This procedure where a device similar to a heart pacemaker that is implanted by a surgeon, with the electrical leads stimulating the external surface of the stomach, was under preliminary research in 2015. Electrical stimulation is thought to modify the activity of the enteric nervous system of the stomach, which is interpreted by the brain to give a sense of satiety, or fullness. Early evidence suggests that it is less effective than other forms of bariatric surgery.
== Recovery ==
People are followed closely both before and after bariatric procedures by a healthcare team. The care team may include people in a variety of disciplines, such as social workers, dietitians, and medical weight management specialists. Follow-up after surgery is typically focused on helping avoid complications and tracking the progress toward body weight goals. Having a structure of social support in the post-operative time may be beneficial as people work through the changes that present physically and emotionally following surgery.
=== Dietary recommendations ===
Dietary restrictions after recovery from surgery depend in part on the type of surgery. In general, immediately after bariatric surgery, the person is restricted to a clear liquid diet, which includes foods such as broth, diluted fruit juices, or sugar-free drinks. This diet is continued until the gastrointestinal tract begins to recover approximately 2–3 weeks after surgery. The next stage provides a puréed liquid or soft-solid diet that is slightly increased in viscosity. This may consist of high protein, liquid, or soft foods such as protein shakes, soft meats, and dairy products. People in recovery are encouraged to compose their diet mainly of plant-based foods and soft proteins (1.0–1.5g/kg/day). During recovery, people must adapt to eating more slowly and avoid eating past fullness; overeating may lead to nausea and vomiting. Alcohol is avoided completely in the first 6 months to 1 year after surgery. Some people may take a daily multivitamin to compensate for reduced absorption of essential nutrients.
=== Fertility and family planning ===
In general, women are advised to avoid pregnancy for 12–24 months after bariatric surgery to reduce the possibility of intrauterine growth restriction or nutrient deficiency, since a person having bariatric surgery will likely undergo significant weight loss and changes in metabolism. Over many years, the rates of potential adverse maternal and fetal outcomes have been reduced for mothers following bariatric surgery.
=== Post-operative bariatric plastic surgery ===
After a person successfully loses weight following bariatric surgery, excess skin may occur. Bariatric plastic surgery procedures, sometimes called body contouring, may be an option for people wishing to remove excess skin following the large change in weight. Targeted areas include the arms, buttocks and thighs, abdomen, and breasts, with changes occurring slowly over years.
== Society and culture ==
The rising prevalence of lawsuits related to gastric bypass surgery is a legal concern in different countries. The causes are complex, including the immature characteristics of this technology and an increasing number of patients. In the future, the number of emergent patients who have stomach reduction surgery, long-term complications, and the number of lawsuits due to non-eligible surgery will increase.
=== Economic implications ===
In the 21st century, obesity rates increased globally, and with this, a proportional rise in related diseases and complication. In the United States during 2017-20, an estimated 40% of adults were obese, up from 30% in 1999-2000. The costs of treating obesity and related conditions has a large economic impact globally. This economic impact results from direct treatment of obesity, treatment of obesity-related conditions, as well as other economic losses from decreased workforce productivity.
Bariatric surgery is cost-effective when compared to savings estimated from treatment or prevention of obesity-related conditions. Cost-effectiveness occurs at the individual level due to fewer healthcare expenses for medications, and nationally with a reduction in the overall lifetime healthcare costs.
== Special populations ==
=== Adolescents ===
During the early 21st century, obesity among children and adolescents increased globally, as did treatment options including lifestyle changes, drug treatments, and surgical procedures. The medical complications and health concerns associated with childhood obesity may have short or long-term effects, with a growing concern of a potential decline in overall life expectancy. Childhood obesity may affect mental health and impact eating practices.
Difficulties surrounding obesity treatment selection among children and adolescents include ethical considerations when obtaining consent from those who may be unable to do so without adult guidance or understanding the potential lasting effects of invasive procedures. Among high-quality randomized control trial data for surgical treatment of obesity, many studies are not specific to children and adolescents. Concerns for bullying about overweight or body image exist for those with childhood obesity; self-harm among children and adolescents bullied for their weight also occurs.
Bariatric surgical procedures available to adolescents include: Roux-en-Y gastric bypass, vertical sleeve gastrectomy, and adjustable gastric banding. Multiple organizations have created guidelines for bariatric surgery indications in children and adolescents. In 2022-23, such guidelines overlapped with recommendations for potential bariatric surgical management in children and adolescents with a BMI of 40 or higher, or a BMI of 35 or higher while also experiencing related experiences.
Reviews have shown similar weight loss in adolescents following bariatric surgery as in adults. Reduction of eating disorders for several years after bariatric surgery has also been shown in adolescents after bariatric surgery. Long-term reduction in or resolution of weight-related conditions, such as diabetes and high blood pressure, occurred in adolescents after bariatric surgery. Long-term effects of bariatric surgery in adolescents remains under research, as of 2023.
== History ==
Techniques for weight loss have been reported for decades, with a more formal transition to noting weight loss following surgical intervention in the 1950s when subsequent weight loss after surgical shortening of the small intestine in dogs and people was observed. Specifically, anastomosis between upper and lower portions of the small intestine to skip, or bypass, part of the small intestine led to what was called the jejuno-ileal bypass. A modified version of this procedure showed long-term improvement of lipid levels in people with known high levels of cholesterol following the procedure.
Further modification of the bypass procedure achieved weight loss in obesity, during which an anastomosis between the small intestine and upper lower intestine, known as a jejunocolic bypass, was performed. During the late 1960s, the initiation of bariatric surgery followed the development of a procedure to bypass portions of the stomach – the gastric bypass.
Sleeve gastrectomy (SG), is one of the most popular stomach reduction surgeries and was earliest performed in 1990 as a first-stage operation of duodenal switch (DS) surgery. Patients who go through SG typically experience substantial weight loss, preventing the need for the second phase of DS.
Laparoscopic techniques revolutionized bariatric surgery, making procedures less invasive and recovery quicker. The first laparoscopic gastric bypass performed by Alan Wittgrove in 1994 exemplifies this leap in surgical innovation.The SG laparoscopic version was first performed in 1999.
Historically, the RYGBP is the best bariatric surgery for obese patients, but now being rivalled by the SG. The complication of RYGBP leads people to find less intricate and safer surgeries, the complication including internal hernias and anastomotic complications. Nowadays, SG has a lower risk of complication, and the mortality rate has become the more favorable option for the patients.
== See also ==
Revision weight loss surgery
Endoscopic sleeve gastroplasty
== References ==
== External links ==
Media related to Bariatric surgery at Wikimedia Commons | Wikipedia/Bariatric_Surgery |
Oral rehydration therapy (ORT) also officially known as Oral Rehydration Solution is a type of fluid replacement used to prevent and treat dehydration, especially due to diarrhea. It involves drinking water with modest amounts of sugar and salts, specifically sodium and potassium. Oral rehydration therapy can also be given by a nasogastric tube. Therapy can include the use of zinc supplements to reduce the duration of diarrhea in infants and children under the age of 5. Use of oral rehydration therapy has been estimated to decrease the risk of death from diarrhea by up to 93%.
Side effects may include vomiting, high blood sodium, or high blood potassium. If vomiting occurs, it is recommended that use be paused for 10 minutes and then gradually restarted. The recommended formulation includes sodium chloride, sodium citrate, potassium chloride, and glucose. Glucose may be replaced by sucrose and sodium citrate may be replaced by sodium bicarbonate, if not available, although the resulting mixture is not shelf stable in high-humidity environments. It works as glucose increases the uptake of sodium and thus water by the intestines, and the potassium chloride and sodium citrate help prevent hypokalemia and acidosis, respectively, which are both common side effects of diarrhea. A number of other formulations are also available including versions that can be made at home. However, the use of homemade solutions has not been well studied.
Oral rehydration therapy was developed in the 1940s using electrolyte solutions with or without glucose on an empirical basis chiefly for mild or convalescent patients, but did not come into common use for rehydration and maintenance therapy until after the discovery that glucose promoted sodium and water absorption during cholera in the 1960s. It is on the World Health Organization's List of Essential Medicines. Globally, as of 2015, oral rehydration therapy is used by 41% of children with diarrhea. This use has played an important role in reducing the number of deaths in children under the age of five.
== Medical uses ==
ORT is less invasive than the other strategies for fluid replacement, specifically intravenous (IV) fluid replacement. Mild to moderate dehydration in children seen in an emergency department is best treated with ORT. Persons taking ORT should eat within six hours and return to their full diet within 24–48 hours.
Oral rehydration therapy may also be used as a treatment for the symptoms of dehydration and rehydration in burns in resource-limited settings.
=== Efficacy ===
ORT may lower the mortality rate of diarrhea by as much as 93%. Case studies in four developing countries also have demonstrated an association between increased use of ORS and reduction in mortality.
ORT using the original ORS formula has no effect on the duration of the diarrheic episode or the volume of fluid loss, although reduced osmolarity solutions have been shown to reduce stool volume.
=== Treatment algorithm ===
The degree of dehydration should be assessed before initiating ORT. ORT is suitable for people who are not dehydrated and those who show signs and symptoms of mild to moderate dehydration. People who have severe dehydration should seek professional medical help immediately and receive intravenous rehydration as soon as possible to rapidly replenish fluid volume in the body.
== Contraindications ==
ORT should be discontinued and fluids replaced intravenously when vomiting is protracted despite proper administration of ORT; or signs of dehydration worsen despite giving ORT; or the person is unable to drink due to a decreased level of consciousness; or there is evidence of intestinal blockage or ileus. ORT might also be contraindicated in people who are in hemodynamic shock due to impaired airway protective reflexes. Short-term vomiting is not a contraindication to receiving oral rehydration therapy. In persons who are vomiting, drinking oral rehydration solution at a slow and continuous pace will help resolve vomiting.
== Preparation ==
WHO and UNICEF have jointly developed official guidelines for the manufacture of oral rehydration solution and the oral rehydration salts used to make it (both often abbreviated ORS). They also describe other acceptable solutions, depending on material availability. Commercial preparations are available as prepared fluids and as packets of powder ready to mix with water.
A basic oral rehydration therapy solution can also be prepared when packets of oral rehydration salts are not available. The molar ratio of sugar to salt should be 1:1 and the solution should not be hyperosmolar. The Rehydration Project states, "Making the mixture a little diluted (with more than 1 litre of clean water) is not harmful."
The optimal fluid for preparing oral rehydration solution is clean water. However, if this is not available, the usually available water should be used. Oral rehydration solution should not be withheld simply because the available water is potentially unsafe; rehydration takes precedence.
When oral rehydration salts packets and suitable teaspoons for measuring sugar and salt are not available, the WHO has recommended that homemade gruels, soups, etc., may be considered to help maintain hydration. A Lancet review in 2013 emphasized the need for more research on appropriate home made fluids to prevent dehydration. Sports drinks are not optimal oral rehydration solutions, but they can be used if optimal choices are not available. They should not be withheld for lack of better options; again, rehydration takes precedence. But they are not replacements for oral rehydration solutions in nonemergency situations.
=== Reduced-osmolarity ===
In 2003, WHO and UNICEF recommended that the osmolarity of oral rehydration solution be reduced from 311 to 245 mOsm/L. These guidelines were also updated in 2006. This recommendation was based on multiple clinical trials showing that the reduced osmolarity solution reduces stool volume in children with diarrhea by about twenty-five percent and the need for IV therapy by about thirty percent when compared to standard oral rehydration solution. The incidence of vomiting is also reduced. The reduced osmolarity oral rehydration solution has lower concentrations of glucose and sodium chloride than the original solution, but the concentrations of potassium and citrate are unchanged.
The reduced osmolarity solution has been criticized by some for not providing enough sodium for adults with cholera. Clinical trials have, however, shown reduced osmolarity solution to be effective for adults and children with cholera. They seem to be safe but some caution is warranted according to the Cochrane review.
== Administration ==
ORT is based on evidence that water continues to be absorbed from the gastrointestinal tract even while fluid is lost through diarrhea or vomiting. The World Health Organization specify indications, preparations and procedures for ORT.
WHO/UNICEF guidelines suggest ORT should begin at the first sign of diarrhea in order to prevent dehydration. Babies may be given ORS with a dropper or a syringe. Infants under two may be given a teaspoon of ORS fluid every one to two minutes. Older children and adults should take frequent sips from a cup, with a recommended intake of 200–400 mL of solution after every loose movement. The WHO recommends giving children under two a quarter- to a half-cup of fluid following each loose bowel movement and older children a half- to a full cup. If the person vomits, the caregiver should wait 5–10 minutes and then resume giving ORS.: Section 4.2 ORS may be given by aid workers or health care workers in refugee camps, health clinics and hospital settings. Mothers should remain with their children and be taught how to give ORS. This will help to prepare them to give ORT at home in the future. Breastfeeding should be continued throughout ORT.
== Associated therapies ==
=== Zinc ===
As part of oral rehydration therapy, the WHO recommends supplemental zinc (10 to 20 mg daily) for ten to fourteen days, to reduce the severity and duration of the illness and make recurrent illness in the following two to three months less likely. Preparations are available as a zinc sulfate solution for adults, a modified solution for children and in tablet form.
=== Feeding ===
After severe dehydration is corrected and appetite returns, feeding the person speeds the recovery of normal intestinal function, minimizes weight loss and supports continued growth in children. Small frequent meals are best tolerated (offering the child food every three to four hours). Mothers should continue to breastfeed. A child with watery diarrhea typically regains their appetite as soon as dehydration is corrected, whereas a child with bloody diarrhea often eats poorly until the illness resolves. Such children should be encouraged to resume normal feeding as soon as possible. Once diarrhea is corrected, the WHO recommends giving the child an extra meal each day for two weeks, and longer if the child is malnourished.
=== Children with malnutrition ===
Dehydration may be overestimated in wasted children and underestimated in edematous children. Care of these children must also include careful management of their malnutrition and treatment of other infections. Useful signs of dehydration include an eagerness to drink, lethargy, cool and moist extremities, weak or absent radial pulse (wrist), and reduced or absent urine flow. In children with severe malnutrition, it is often impossible to reliably distinguish between moderate and severe dehydration. A severely malnourished child who has signs of severe dehydration but who does not have a history of watery diarrhea should be treated for septic shock.
The original ORS (90 mmol sodium/L) and the current standard reduced-osmolarity ORS (75 mmol sodium/L) both contain too much sodium and too little potassium for severely malnourished children with dehydration due to diarrhea. ReSoMal (Rehydration Solution for Malnutrition) is recommended for such children. It contains less sodium (45 mmol/L) and more potassium (40 mmol/L) than reduced osmolarity ORS. It can be obtained in packets produced by UNICEF or other manufacturers.
An exception is if the severely malnourished child also has severe diarrhea (in which case ReSoMal may not provide enough sodium), in which case standard reduced-osmolarity ORS (75 mmol sodium/L) is recommended. Malnourished children should be rehydrated slowly. The WHO recommends 10 milliliters of ReSoMal per kilogram body weight for each of the first two hours (for example, a 9-kilogram child should be given 90 mL of ReSoMal over the course of the first hour, and another 90 mL for the second hour) and then continuing at this same rate or slower based on the child's thirst and ongoing stool losses, keeping in mind that a severely dehydrated child may be lethargic. If the child drinks poorly, a nasogastric tube should be used. The IV route should not be used for rehydration except in cases of shock and then only with care, infusing slowly to avoid flooding the circulation and overloading the heart.
Feeding should usually resume within 2–3 hours after starting rehydration and should continue every 2–3 hours, day and night. For an initial cereal diet before a child regains his or her full appetite, the WHO recommends combining 25 grams skimmed milk powder, 20 grams vegetable oil, 60 grams sugar, and 60 grams rice powder or other cereal into 1,000 milliliters water and boiling gently for five minutes. Give 130 mL per kilogram of body weight during per 24 hours. A child who cannot or will not eat this minimum amount should be given the diet by nasogastric tube divided into six equal feedings. Later on, the child should be given cereal made with a greater amount of skimmed milk product and vegetable oil and slightly less sugar. As appetite fully returns, the child should be eating 200 mL per kilogram of body weight per day. Zinc, potassium, vitamin A, and other vitamins and minerals should be added to both recommended cereal products, or to the oral rehydration solution itself. Children who are breastfed should continue breastfeeding.
=== Antibiotics ===
The WHO recommends that all severely malnourished children admitted to hospital should receive broad-spectrum antibiotics (for example, gentamicin and ampicillin). In addition, hospitalized children should be checked daily for other specific infections.
If cholera is suspected give an antibiotic to which V. cholerae are susceptible. This reduces the volume loss due to diarrhea by 50% and shortens the duration of diarrhea to about 48 hours.
== Physiological basis ==
Fluid from the body enters the intestinal lumen during digestion. This fluid is isosmotic with the blood and contains a high quantity, about 142 mEq/L, of sodium. A healthy individual secretes 2000–3000 milligrams of sodium per day into the intestinal lumen. Nearly all of this is reabsorbed so that sodium levels in the body remain constant. In a diarrheal illness, sodium-rich intestinal secretions are lost before they can be reabsorbed. This can lead to life-threatening dehydration or electrolyte imbalances within hours when fluid loss is severe. The objective of therapy is the replenishment of sodium and water losses by ORT or intravenous infusion.
Sodium absorption occurs in two stages. The first is via intestinal epithelial cells (enterocytes). Sodium passes into these cells by co-transport with glucose, via the SGLT1 protein. From the intestinal epithelial cells, sodium is pumped by active transport via the sodium-potassium pump through the basolateral cell membrane into the extracellular space.
The sodium–potassium ATPase pump at the basolateral cell membrane moves three sodium ions into the extracellular space, while pulling into the enterocyte two potassium ions. This creates a "downhill" sodium gradient within the cell. SGLT proteins use energy from this downhill sodium gradient to transport glucose across the apical membrane of the cell against the glucose gradient. The co-transporters are examples of secondary active transport. The GLUT uniporters then transport glucose across the basolateral membrane. Both SGLT1 and SGLT2 are known as symporters, since both sodium and glucose are transported in the same direction across the membrane.
The co-transport of glucose into epithelial cells via the SGLT1 protein requires sodium. Two sodium ions and one molecule of glucose (or galactose) are transported together across the cell membrane via the SGLT1 protein. Without glucose, intestinal sodium is not absorbed. This is why oral rehydration salts include both sodium and glucose. For each cycle of the transport, hundreds of water molecules move into the epithelial cell to maintain osmotic equilibrium. The resultant absorption of sodium and water can achieve rehydration even while diarrhea continues.
== History ==
=== Definition ===
In the early 1980s, "oral rehydration therapy" meant only the preparation prescribed by the World Health Organization (WHO) and UNICEF. In 1988, the definition was changed to include recommended home-made solutions, because the official preparation was not always available. The definition was also amended in 1988, to include continued feeding as associated therapy. In 1991, the definition became "an increase in administered hydrational fluids"; in 1993, "an increase in administered fluids and continued feeding".
=== Development ===
In 1953, Hemendra Nath Chatterjee published in The Lancet the results of using ORS to treat people with mild cholera.According to his paper, He treated 186 patients with his oral glucose-sodium electrolyte solution and rehydrated all his patients with mild to moderately severe cholera. He gave the solution orally and rectally, along with Coleus extract, antihistamines, and antiemetics, without controls. The formula of the fluid replacement solution was 4 g of sodium chloride, 25 g of glucose, and 1000 mL of water. He did not publish any balance data, and his exclusion of patients with severe dehydration did not lead to any confirming study; his report remained anecdotal.
Robert Allan Phillips tried to make an effective ORT solution based on his discovery that, in the presence of glucose, sodium, and chloride could be absorbed in patients with cholera; but he failed because his solution was too hypertonic and he used it to try to stop the diarrhea rather than to rehydrate patients.
In the early 1960s, Robert K. Crane described the sodium-glucose co-transport mechanism and its role in intestinal glucose absorption. This, along with evidence that the intestinal mucosa appears undamaged in cholera, suggested that intestinal absorption of glucose and sodium might continue during the illness. This supported the notion that oral rehydration might be possible even during severe diarrhea due to cholera. In 1967–1968, Norbert Hirschhorn and Nathaniel F. Pierce showed that people with severe cholera can absorb glucose, salt, and water and that this can occur in sufficient amounts to maintain hydration. In 1968, David R. Nalin and Richard A. Cash, helped by Rafiqul Islam and Majid Molla, reported that giving adults with cholera an oral glucose-electrolyte solution in volumes equal to those of the diarrhea losses reduced the need for IV fluid therapy by eighty percent.[46]
In 1971, fighting during the Bangladesh Liberation War displaced millions and an epidemic of cholera ensued among the refugees. When IV fluid ran out in the refugee camps, Dilip Mahalanabis, a physician working with the Johns Hopkins International Center for Medical Research and Training in Calcutta, issued instructions to prepare an oral rehydration solution and to distribute it to family members and caregivers. Over 3,000 people with cholera received ORT in this way. The mortality rate was 3.6% among those given ORT, compared with 30% in those given IV fluid therapy. After Bangladesh won independence, there was a wide campaign to promote the use of saline in the treatment of diarrhea. In 1980, the World Health Organization recognized ORT and began a global program for its dissemination.
In the 1970s, Norbert Hirschhorn used oral rehydration therapy on the White River Apache Indian Reservation with a grant from the National Institute of Allergy and Infectious Diseases. He observed that children voluntarily drank as much of the solution as needed to restore hydration, and that rehydration and early re-feeding would protect their nutrition. This led to increased use of ORT for children with diarrhea, especially in developing countries.
In 1980, the Bangladeshi nonprofit BRAC created a door-to-door and person-to-person sales force to teach ORT for use by mothers at home. A task force of fourteen women, one cook, and one male supervisor traveled from village to village. After visiting with women in several villages, they hit upon the idea of encouraging the women in the village to make their own oral rehydration fluid. They used available household equipment, starting with a "half a seer" (half a quart) of water and adding a fistful of sugar and a three-finger pinch of salt. Later on, the approach was broadcast over television and radio, and a market for oral rehydration salts packets developed. Three decades later, national surveys have found that almost 90% of children with severe diarrhea in Bangladesh are given oral rehydration fluids at home or in a health facility. ORT is known in Bangladesh as Orosaline or Orsaline.
From 2006 to 2011, UNICEF estimated that worldwide about a third of children under 5 who had diarrhea received an oral rehydration solution, with estimates ranging from 30% to 41% depending on the region.
ORT is one of the principal elements of the UNICEF "GOBI FFF" program (growth monitoring; ORT; breast feeding; immunization; female education; family spacing and food supplementation). The program aims to increase child survival in developing nations through proven low-cost interventions.
== Awards ==
Centre for Health and Population Research, Dhaka, Bangladesh, 2001 Gates award for global health.
Norbert Hirschhorn, Dilip Mahalanabis, David Nalin, and Nathaniel Pierce, 2002 inaugural Pollin Prize for Pediatric Research.
Richard A. Cash, David Nalin, Dilip Mahalanabis and Stanley Schultz, 2006 Prince Mahidol Award.
== References ==
Sources
Guyton A, Hall J (19 July 2010). Guyton and Hall Textbook of Medical Physiology: Enhanced E-book. Philadelphia: Elsevier Health Sciences. p. 840. ISBN 978-0-7216-0240-0.
== Further reading ==
World Health Organization (2006). Oral rehydration salts : production of the new ORS (PDF). World Health Organization (WHO). hdl:10665/69227. WHO/FCH/CAH/06.1.
== External links ==
Rehydration Project | Wikipedia/Oral_rehydration_therapy |
Plastic surgery is a surgical specialty involving restoration, reconstruction, or alteration of the human body. It can be divided into two main categories: reconstructive surgery and cosmetic surgery. Reconstructive surgery covers a wide range of specialties, including craniofacial surgery, hand surgery, microsurgery, and the treatment of burns. This kind of surgery focuses on restoring a body part or improving its function. In contrast, cosmetic (or aesthetic) surgery focuses solely on improving the physical appearance of the body. A comprehensive definition of plastic surgery has never been established, because it has no distinct anatomical object and thus overlaps with practically all other surgical specialties. An essential feature of plastic surgery is that it involves the treatment of conditions that require or may require tissue relocation skills.
== Etymology ==
The word plastic in plastic surgery refers to the concept of "reshaping" and comes from the Greek πλαστική (τέχνη), plastikē (tekhnē), "the art of modelling" of malleable flesh. This meaning in English is seen as early as 1598. In the surgical context, the word "plastic" first appeared in 1816 and was established in 1838 by Eduard Zeis, preceding the modern technical usage of the word as "engineering material made from petroleum" by 70 years.
== History ==
Treatments for the plastic repair of a broken nose are first mentioned in the c. 1600 BC Egyptian medical text called the Edwin Smith papyrus. The early trauma surgery textbook was named after the American Egyptologist, Edwin Smith. Reconstructive surgery techniques were being carried out in India by 800 BC. Sushruta was a physician who made contributions to the field of plastic and cataract surgery in the 6th century BC.
The Romans also performed plastic cosmetic surgery, using simple techniques, such as repairing damaged ears, from around the 1st century BC. For religious reasons, they did not dissect either human beings or animals, thus, their knowledge was based in its entirety on the texts of their Greek predecessors. Notwithstanding, Aulus Cornelius Celsus left some accurate anatomical descriptions, some of which—for instance, his studies on the genitalia and the skeleton—are of special interest to plastic surgery.
Arabs practiced the plastic surgery, during the Abbasid Caliphate in 750 AD. The Arabic translations made their way into Europe via intermediaries. In Italy, the Branca family of Sicily and Gaspare Tagliacozzi (Bologna) became familiar with the techniques of Sushruta.
In all fields of surgery, the Arab physician, surgeon, and chemist Al-Zahrawi talks of the use of silk thread sutures to achieve good cosmesis. He describes what is thought to be the first attempt at reduction mammaplasty for the management of gynaecomastia. He gives detailed descriptions of other basic surgical techniques such as cautery and wound management.
British physicians travelled to India to see rhinoplasties being performed by Indian methods. Reports on Indian rhinoplasty performed by a Kumhar (potter) vaidya were published in the Gentleman's Magazine by 1794. Joseph Constantine Carpue spent 20 years in India studying local plastic surgery methods. Carpue was able to perform the first major surgery in the Western world in the year 1815. Instruments described in the Sushruta Samhita were further modified in the Western world.
In 1465, Sabuncu's book, description, and classification of hypospadias were more informative and up to date. Localization of the urethral meatus was described in detail. Sabuncuoglu also detailed the description and classification of ambiguous genitalia. In mid-15th-century Europe, Heinrich von Pfolspeundt described a process "to make a new nose for one who lacks it entirely, and the dogs have devoured it" by removing skin from the back of the arm and suturing it in place. However, because of the dangers associated with surgery in any form, especially that involving the head or face, it was not until the 19th and 20th centuries that such surgery became common.
In 1814, Joseph Carpue successfully performed an operative procedure on a British military officer who had lost his nose to the toxic effects of mercury treatments. In 1818, German surgeon Carl Ferdinand von Graefe published his major work entitled Rhinoplastik. Von Graefe modified the Italian method using a free skin graft from the arm instead of the original delayed pedicle flap.
The first American plastic surgeon was John Peter Mettauer, who, in 1827, performed the first cleft palate operation with instruments that he designed himself.
Johann Friedrich Dieffenbach specialized in skin transplantation and early plastic surgery. His work in rhinoplastic and maxillofacial surgery established many modern techniques of reconstructive surgery. In 1845, Dieffenbach wrote a comprehensive text on rhinoplasty, titled Operative Chirurgie, and introduced the concept of reoperation to improve the cosmetic appearance of the reconstructed nose. Dieffenbach has been called the "father of plastic surgery".
Another case of plastic surgery for nose reconstruction from 1884 at Bellevue Hospital was described in Scientific American.
In 1891, American otorhinolaryngologist John Roe presented an example of his work: a young woman on whom he reduced a dorsal nasal hump for cosmetic indications. In 1892, Robert Weir experimented unsuccessfully with xenografts (duck sternum) in the reconstruction of sunken noses. In 1896, James Israel, a urological surgeon from Germany, and in 1889 George Monks of the United States each described the successful use of heterogeneous free-bone grafting to reconstruct saddle nose defects. In 1898, Jacques Joseph, the German orthopaedic-trained surgeon, published his first account of reduction rhinoplasty. In 1910, Alexander Ostroumov, the Russian pharmacist, and perfume and cosmetics manufacturer, founded a unique plastic surgery department in his Moscow Institute of Medical Cosmetics. In 1928, Jacques Joseph published Nasenplastik und Sonstige Gesichtsplastik.
== Nascency of maxillofacial surgery ==
The development of weapons such as machine guns and explosive shells during World War I created trench warfare, which led to a rapid increase in the number of mutilations to the faces and the heads of soldiers because the trenches mainly offered protection to the body. The surgeons, who were not prepared for these injuries, were even less prepared for a large number of injuries and had to react quickly and intelligently to treat the greatest number. Facial injuries were hard to treat on the front line, and because of the sanitary conditions, many infections could occur. Sometimes, some stitches were made on a jagged wound without considering the amount of flesh that had been lost, so the resulting scars were hideous and disfigured soldiers. Some of the wounded had severe injuries, and the stitches were not sufficient, so some became blind or were left with gaping holes instead of their nose. Harold Gillies, scared by the number of new facial injuries and the lack of good surgical techniques, decided to dedicate an entire hospital to the reconstruction of facial injuries as fully as possible. He took into account the psychological dimension. Gillies introduced skin grafts to the treatments of soldiers, so they would be less horrified by looking at themselves in the mirror.
It is the multidisciplinary approach to the treatment of facial lesions, bringing together plastic surgeons, dental surgeons, technicians, and specialized nurses, which has made it possible to develop techniques leading to the reconstruction of injured faces. Before the dentist Auguste Charles Valadier and then Gillies identified the need to advance the specialty of maxillofacial surgery, which would be directly dedicated to the management of war wounds at this time. Gillies developed a new technique using rotational and transposition flaps but also bone grafts from the ribs and tibia to reconstruct facial defects caused by the weapons during the war. He experimented with this technique so he knew that he had to start by moving back healthy tissue to its normal position, and then he would be able to fill with tissue from another place on the body of the soldier. One of the most successful techniques in skin grafting had the aim of not completely severing the connection to the body. It was possible by releasing and lifting a flap of skin from the wound. The flap of skin, still connected to the donor site, would then be swung over the site of the wound, allowing the maintenance of physical connection and ensuring that blood is supplied to the skin, increasing the chances of the skin graft being accepted by the body. At this time, we also assisted in improving treating infections also meant that important injuries had become survivable, mostly thanks to the new technique of Gillies. Some soldiers arrived at the hospital of Gillies without noses, chins, cheekbones, or even eyes. But for them, the most important trauma was psychological.
== Development of modern techniques ==
The father of modern plastic surgery is generally considered to have been Sir Harold Gillies. A New Zealand otolaryngologist working in London, he developed many of the techniques of modern facial surgery in caring for soldiers with disfiguring facial injuries during the First World War.
During World War I, he worked as a medical minder with the Royal Army Medical Corps. After working with the French oral and maxillofacial surgeon Hippolyte Morestin on skin grafts, he persuaded the army's chief surgeon, Arbuthnot-Lane, to establish a facial injury ward at the Cambridge Military Hospital, Aldershot, later upgraded to a new hospital for facial repairs at Sidcup in 1917. There, Gillies and his colleagues developed many techniques of plastic surgery; more than 11,000 operations were performed on more than 5,000 men (mostly soldiers with facial injuries, usually from gunshot wounds). After the war, Gillies developed a private practice with Rainsford Mowlem, including many famous patients, and travelled extensively to promote his advanced techniques worldwide.
In 1930, Gillies' cousin, Archibald McIndoe, joined the practice and became committed to plastic surgery. When World War II broke out, plastic surgery provision was largely divided between the different services of the armed forces, and Gillies and his team were split up. Gillies himself was sent to Rooksdown House near Basingstoke, which became the principal army plastic surgery unit; Tommy Kilner (who had worked with Gillies during the First World War, and who now has a surgical instrument named after him, the kilner cheek retractor) went to Queen Mary's Hospital, Roehampton; and Mowlem went to St Albans. McIndoe, consultant to the RAF, moved to the recently rebuilt Queen Victoria Hospital in East Grinstead, Sussex, and founded a Centre for Plastic and Jaw Surgery. There, he treated very deep burns and serious facial disfigurement, such as loss of eyelids, typical of those caused to aircrew by burning fuel.
McIndoe is often recognized for not only developing new techniques for treating badly burned faces and hands but also for recognising the importance of the rehabilitation of the casualties and particularly of social reintegration back into normal life. He disposed of the "convalescent uniforms" and let the patients use their service uniforms instead. With the help of two friends, Neville and Elaine Blond, he also convinced the locals to support the patients and invite them to their homes. McIndoe kept referring to them as "his boys" and the staff called him "The Boss" or "The Maestro".
His other important work included the development of the walking-stalk skin graft, and the discovery that immersion in saline promoted healing as well as improving survival rates for patients with extensive burns—this was a serendipitous discovery drawn from observation of differential healing rates in pilots who had come down on land and in the sea. His radical, experimental treatments led to the formation of the Guinea Pig Club at Queen Victoria Hospital, Sussex. Among the better-known members of his "club" were Richard Hillary, Bill Foxley and Jimmy Edwards.
== Sub-specialties ==
Plastic surgery is a broad field and may be subdivided further. In the United States, plastic surgeons are board certified by American Board of Plastic Surgery. Subdisciplines of plastic surgery may include:
=== Aesthetic surgery ===
Aesthetic surgery is a central component of plastic surgery and includes facial and body aesthetic surgery. Plastic surgeons use cosmetic surgical principles in all reconstructive surgical procedures as well as isolated operations to improve overall appearance.
=== Burn surgery ===
Burn surgery generally takes place in two phases. Acute burn surgery is the treatment immediately after a burn. Reconstructive burn surgery takes place after the burn wounds have healed.
=== Craniofacial surgery ===
Craniofacial surgery is divided into pediatric and adult craniofacial surgery. Pediatric craniofacial surgery mostly revolves around the treatment of congenital anomalies of the craniofacial skeleton and soft tissues, such as cleft lip and palate, microtia, craniosynostosis, and pediatric fractures. Adult craniofacial surgery deals mostly with reconstructive surgeries after trauma or cancer and revision surgeries, along with orthognathic surgery and facial feminization surgery. Craniofacial surgery is an important part of all plastic surgery training programs. Further training and subspecialisation are obtained via a craniofacial fellowship. Craniofacial surgery is also practiced by maxillofacial surgeons.
=== Ethnic plastic surgery ===
Ethnic plastic surgery is plastic surgery performed to change ethnic attributes, often considered used as a way of "passing".
=== Hand surgery ===
Hand surgery is concerned with acute injuries and chronic diseases of the hand and wrist, correction of congenital malformations of the upper extremities, and peripheral nerve problems (such as brachial plexus injuries or carpal tunnel syndrome). Hand surgery is an important part of training in plastic surgery, as well as microsurgery, which is necessary to replant an amputated extremity. The hand surgery field is also practiced by orthopedic surgeons and general surgeons. Scar tissue formation after surgery can be problematic on the delicate hand, causing loss of dexterity and digit function if severe enough. There have been cases of surgery on women's hands in order to correct perceived flaws to create the perfect engagement ring photo.
=== Microsurgery ===
Microsurgery is generally concerned with the reconstruction of missing tissues by transferring a piece of tissue to the reconstruction site and reconnecting blood vessels. Popular subspecialty areas are breast reconstruction, head and neck reconstruction, hand surgery/replantation, and brachial plexus surgery.
=== Pediatric plastic surgery ===
Children often face medical issues very different from the experiences of an adult patient. Many birth defects or syndromes present at birth are best treated in childhood, and pediatric plastic surgeons specialize in treating these conditions in children. Conditions commonly treated by pediatric plastic surgeons include craniofacial anomalies, Syndactyly (webbing of the fingers and toes), Polydactyly (excess fingers and toes at birth), cleft lip and palate, and congenital hand deformities.
=== Prison plastic surgery ===
Plastic surgery was performed on an incarcerated population in order to affect their recidivism rate, a practice instituted in the early 20th century that lasted until the mid-1990s. Separate from surgery performed for medical need.
== Techniques and procedures ==
In plastic surgery, the transfer of skin tissue (skin grafting) is a very common procedure. Skin grafts can be derived from the recipient or donors:
Autografts are taken from the recipient. If absent or deficient of natural tissue, alternatives can be cultured sheets of epithelial cells in vitro or synthetic compounds, such as integra, which consists of silicone and bovine tendon collagen with glycosaminoglycans.
Allografts are taken from a donor of the same species. Kidney transplants are an example of allograft transfer. Joseph Murray is credited for completing the first successful kidney transplantation in 1954.
Xenografts are taken from a donor of a different species.
Usually, good results would be expected from plastic surgery that emphasize careful planning of incisions so that they fall within the line of natural skin folds or lines, appropriate choice of wound closure, use of best available suture materials, and early removal of exposed sutures so that the wound is held closed by buried sutures.
== Cosmetic surgery procedures ==
Cosmetic surgery is a voluntary or elective surgery that is performed on normal parts of the body with the only purpose of improving a person's appearance or removing signs of aging. Some cosmetic surgeries such as breast reduction are also functional and can help to relieve symptoms of discomfort such as back ache or neck ache. Cosmetic surgeries are also undertaken following breast cancer and mastectomy to recreate the natural breast shape which has been lost during the process of removing the cancer. In 2014, nearly 16 million cosmetic procedures were performed in the United States alone. The number of cosmetic procedures performed in the United States has almost doubled since the start of the century. 92% of cosmetic procedures were performed on women in 2014, up from 88% in 2001. 15.6 million cosmetic procedures were performed in 2020, with the five most common surgeries being rhinoplasties, blepharoplasties, rhytidectomies, liposuctions, and breast augmentation. Breast augmentation continues to be one of the top 5 cosmetic surgical procedures and has been since 2006. Silicone implants were used in 84% and saline implants in 16% of all breast augmentations in 2020. The American Society for Aesthetic Plastic Surgery looked at the statistics for 34 different cosmetic procedures. Nineteen of the procedures were surgical, such as rhinoplasties or rhytidectomies. The nonsurgical procedures included botox and laser hair removal. In 2010, their survey revealed that there were 9,336,814 total procedures in the United States. Of those, 1,622,290 procedures were surgical (p. 5). They also found that a large majority, 81%, of the procedures were done on Caucasian people (p. 12).
In 1949, 15,000 Americans underwent cosmetic surgery procedures and by 1969 this number rose to almost half a million people. The American Society of Plastic Surgeons estimates that more than 333,000 cosmetic procedures were performed on patients 18 years of age or younger in the US in 2005 compared to approx. 14,000 in 1996. In 2018, more than 226,994 patients between the ages of 13 and 19 underwent plastic surgery compared to just over 218,900 patients in the same age group in 2010. Concerns about young people undergoing plastic surgery include the financial burden of additional surgical procedures needed to correct problems after the initial cosmetic surgery, long-term health complications from plastic surgery, and unaddressed mental health issues that may have led to surgery. The increased use of cosmetic procedures crosses racial and ethnic lines in the U.S., with increases seen among African-Americans, Asian Americans and Hispanic Americans as well as Caucasian Americans. In Asia, cosmetic surgery has become more popular, and countries such as China and India have become Asia's biggest cosmetic surgery markets. South Korea is also rising in popularity in Asian and Western countries due to their expertise in facial bone surgeries (see cosmetic surgery in South Korea).
Plastic surgery is increasing slowly, rising 115% from 2000 to 2015. "According to the annual plastic surgery procedural statistics, there were 15.9 million surgical and minimally-invasive cosmetic procedures performed in the United States in 2015, a 2 percent increase over 2014." A study from 2021 found that requests for cosmetic procedures had increased significantly since the beginning of the COVID-19 pandemic, possibly due to the increase in videoconferencing; cited estimates include a 10% increase in the United States and a 20% increase in France.
The most popular aesthetic/cosmetic procedures include:
Abdominoplasty ("tummy tuck"): reshaping and firming of the abdomen
Blepharoplasty ("eyelid surgery"): reshaping of upper/lower eyelids including Asian blepharoplasty
While blepharoplasty remains the most common procedure for modifying eyelid shape, non-surgical alternatives are increasingly sought after, especially in East Asia.
Methods such as double eyelid tape, eyelid glue, and structured eyelid training systems allow individuals to temporarily or semi-permanently create a double eyelid crease without surgery. Some of these products, such as D-UP Eyelid Tape, AB Mezical, and Optifold, use mechanical reinforcement to encourage crease retention over time.
Unlike traditional adhesive-based tapes, structured eyelid training tapes aim to replicate mechanotransduction—a biological process where skin tension encourages crease formation. Studies on long-term non-surgical crease retention remain limited, but anecdotal evidence suggests some users achieve lasting results after sustained use.
Phalloplasty ("penile surgery"): construction (or reconstruction) of a penis or, sometimes, artificial modification of the penis by surgery, often for cosmetic purposes
Mammoplasty:
Breast augmentations ("breast implant" or "boob job"): augmentation of the breasts by means of fat grafting, saline, or silicone gel prosthetics, which was initially performed for women with micromastia
Reduction mammoplasty ("breast reduction"): removal of skin and glandular tissue, which is done to reduce back and shoulder pain in women with gigantomastia and for men with gynecomastia
Mastopexy ("breast lift"): Lifting or reshaping of breasts to make them less saggy, often after weight loss (after a pregnancy, for example). It involves the removal of breast skin as opposed to glandular tissue
Augmentation mastopexy ("breast lift with breast implants"): Lifting breasts to make them less saggy, repositioning the nipple to a higher location, and increasing breast size with saline or silicone gel implants. Recent studies of a newer technique for simultaneous augmentation mastopexy (SAM) indicate that it is a safe surgical procedure with minimal medical complications. The SAM technique involves invaginating and tacking the tissues first, in order to previsualize the result, before making any surgical incisions to the breast.
Buttock augmentation ("butt implant"): enhancement of the buttocks using silicone implants or fat grafting ("Brazilian butt lift") where fat is transferred from other areas of the body
Cryolipolysis: refers to a medical device used to destroy fat cells. Its principle relies on controlled cooling for the non-invasive local reduction of fat deposits to reshape body contours.
Cryoneuromodulation: Treatment of superficial and subcutaneous tissue structures using gaseous nitrous oxide, including temporary wrinkle reduction, temporary pain reduction, treatment of dermatologic conditions, and focal cryo-treatment of tissue
Calf augmentation: done by silicone implants or fat transfer to add bulk to calf muscles
Labiaplasty: surgical reduction and reshaping of the labia
Lip augmentation: alters the appearance of the lips by increasing their fullness through surgical enlargement with lip implants or nonsurgical enhancement with injectable fillers
Cheiloplasty: surgical reconstruction of the lip
Rhinoplasty ("nose job"): reshaping of the nose sometimes used to correct breathing impaired by structural defects.
Otoplasty ("ear surgery"/"ear pinning"): reshaping of the ear, most often done by pinning the protruding ear closer to the head.
Rhytidectomy ("face lift"): removal of wrinkles and signs of aging from the face
Neck lift: tightening of lax tissues in the neck. This procedure is often combined with a facelift for lower face rejuvenation.
Browplasty ("brow lift" or "forehead lift"): elevates eyebrows, smoothens forehead skin
Midface lift ("cheek lift"): tightening of the cheeks
Genioplasty: augmentation of the chin with an individual's bones or with the use of an implant, usually silicone, by suture of the soft tissue
Mentoplasty: surgery to the chin. This can involve either enhancing or reducing the size of the chin. Enhancements are achieved with the use of facial implants. Reduction of the chin involves reducing the size of the chin bone.
Cheek augmentation ("cheek implant"): implants to the cheek
Orthognathic surgery: altering the upper and lower jaw bones (through osteotomy) to correct jaw alignment issues and correct the teeth alignment
Fillers injections: collagen, fat, and other tissue filler injections, such as hyaluronic acid
Brachioplasty ("Arm lift"): reducing excess skin and fat between the underarm and the elbow
Laser skin rejuvenation or laser resurfacing: the lessening of the depth of facial pores and exfoliation of dead or damaged skin cells
Liposuction ("suction lipectomy"): removal of fat deposits by traditional suction technique or ultrasonic energy to aid fat removal
Zygoma reduction plasty: reducing the facial width by performing osteotomy and resecting part of the zygomatic bone and arch
Jaw reduction: reduction of the mandible angle to smooth out an angular jaw and creating a slim jaw
Buccal fat extraction: extraction of the buccal pads
Body contouring: the removal of this excess skin and fat from numerous areas of the body, restoring the appearance of skin elasticity of the remaining skin. The surgery is prominent in those who have undergone significant weight loss, resulting in excess sagging skin being present around areas of the body. The skin loses elasticity (a condition called elastosis) once it has been stretched past capacity and is unable to recoil back to its standard position against the body and also with age.
Sclerotherapy: removing visible 'spider veins' (Telangiectasia), which appear on the surface of the skin.
Dermal fillers: Dermal fillers are injected below the skin to give a more fuller, more youthful appearance of a feature or section of the face. One type of dermal filler is hyaluronic acid. Hyaluronic acid is naturally found throughout the human body. It plays a vital role in moving nutrients to the cells of the skin from the blood. It is also commonly used in patients with arthritis as it acts like a cushion to the bones which have depleted the articular cartilage casing. Development within this field has occurred over time with synthetic forms of hyaluronic acid is being created, playing roles in other forms of cosmetic surgery such as facial augmentation.
Micropigmentation: is the creation of permanent makeup using natural pigments to places such as the eyes to create the effect of eye shadow, lips creating lipstick and cheek bones to create a blush like look. The pigment is inserted beneath the skin using a machine which injects a small needle at a very fast rate carrying pigment into the skin, creating a lasting colouration of the desired area.
In 2015, the most popular surgeries were botox, liposuction, blepharoplasties, breast implants, rhynoplasties, and rhytidectomies. According to the 2020 Plastic Surgery Statistics Report, which is published by the American Society of Plastic Surgeons, the most surgical procedure performed in the U.S. was rhinoplasty (nose reshaping) accounting for 15.2% of all cosmetic surgical procedures that year, followed by blepharoplasty (eyelid surgery), which accounted for 14% of all procedures. The third most populous procedure was rhytidectomy (facelift) (10% of all procedures), then liposuction (9.1% of all procedures).
== Complications, risks, and reversals ==
All surgery has risks. Common complications of cosmetic surgery includes hematoma, nerve injury, infection, scarring, implant failure and end organ damage. Breast implants can have many complications, including rupture. In a study of his 4761 augmentation mammaplasty patients, Eisenberg reported that overfilling saline breast implants 10–13% significantly reduced the rupture-deflation rate to 1.83% at 8-years post-implantation. In 2011 FDA stated that one in five patients who received implants for breast augmentation will need them removed within 10 years of implantation.
== Psychological disorders ==
Although media and advertising do play a large role in influencing many people's lives, such as by making people believe plastic surgery to be an acceptable course to change one's identity to their liking, researchers believe that plastic surgery obsession is linked to psychological disorders such as body dysmorphic disorder. There exists a correlation between those with BDD and the predilection toward cosmetic plastic surgery in order to correct a perceived defect in their appearance.
BDD is a disorder resulting in the individual becoming "preoccupied with what they regard as defects in their bodies or faces". Alternatively, where there is a slight physical anomaly, then the person's concern is markedly excessive. While 2% of people have body dysmorphic disorder in the United States, 15% of patients seeing a dermatologist and cosmetic surgeons have the disorder. Half of the patients with the disorder who have cosmetic surgery performed are not pleased with the aesthetic outcome. BDD can lead to suicide in some people with the condition. While many with BDD seek cosmetic surgery, the procedures do not treat BDD, and can ultimately worsen the problem. The psychological root of the problem is usually unidentified; therefore causing the treatment to be even more difficult. Some say that the fixation or obsession with correction of the area could be a sub-disorder such as anorexia or muscle dysmorphia. The increased use of body and facial reshaping applications such as Snapchat and Facetune have been identified as potential triggers of BDD. Recently, a phenomenon referred to as 'Snapchat dysmorphia' has appeared to describe people who request surgery to resemble the edited version of themselves as they appear through Snapchat filters. In response to the detrimental trend, Instagram banned all augmented reality (AR) filters that depict or promote cosmetic surgery.
In some cases, people whose physicians refuse to perform any further surgeries, have turned to "do it yourself" plastic surgery, injecting themselves and facing extreme safety risks.
== See also ==
Biomaterial
Body modification
Cosmetic surgery in Australia
Dental trauma
Dermatologic surgical procedure
Ethnic plastic surgery
List of plastic surgery flaps
Plastic and Reconstructive Surgery
Scalp reconstruction
Serdev suture
Rejuvenation
== References ==
== Further reading ==
Atkinson M (2008). "Exploring Male Femininity in the 'Crisis': Men and Cosmetic Surgery". Body & Society. 14: 67–87. doi:10.1177/1357034X07087531. S2CID 143604536.
Fraser S (2003). Cosmetic surgery, gender and culture. Palgrave. ISBN 978-1-4039-1299-2.
Gilman S (2005). Creating Beauty to Cure the Soul: Race and Psychology in the Shaping of Aesthetic Surgery. Duke University Press. ISBN 978-0-8223-2144-6.
Haiken E (1997). Venus Envy: A History of Cosmetic Surgery. Johns Hopkins University Press. ISBN 978-0-8018-5763-8.
Kolle FS (1911). Plastic and Cosmetic Surgery. D. Appleton and Company.
Kalaskar D, Butler P, Ghali S, eds. (2016). Textbook of Plastic and Reconstructive Surgery. UCL Press. ISBN 9781910634394.
== External links ==
Countries with the largest total number of cosmetic procedures, Statista, 2019
Cosmetic Surgery Statistics, American Cosmetic Association, 2023 | Wikipedia/Reconstructive_plastic_surgery |
Rheumatology (from Greek ῥεῦμα (rheûma) 'flowing current') is a branch of medicine devoted to the diagnosis and management of disorders whose common feature is inflammation in the bones, muscles, joints, and internal organs. Rheumatology covers more than 100 different complex diseases, collectively known as rheumatic diseases, which includes many forms of arthritis as well as lupus and Sjögren's syndrome. Doctors who have undergone formal training in rheumatology are called rheumatologists.
Many of these diseases are now known to be disorders of the immune system, and rheumatology has significant overlap with immunology, the branch of medicine that studies the immune system.
== Rheumatologist ==
A rheumatologist is a physician who specializes in the field of medical sub-specialty called rheumatology. A rheumatologist holds a board certification after specialized training. In the United States, training in this field requires four years of undergraduate school, four years of medical school, and then three years of residency, followed by two or three years of additional Fellowship training. The requirements may vary in other countries. Rheumatologists are internists who are qualified by additional postgraduate training and experience in the diagnosis and treatment of arthritis and other diseases of the joints, muscles, and bones. Many rheumatologists also conduct research to determine the cause and better treatments for these disabling and sometimes fatal diseases. Treatment modalities are based on scientific research, currently, the practice of rheumatology is largely evidence-based.
Rheumatologists treat arthritis, autoimmune diseases, pain disorders affecting joints, and osteoporosis. There are more than 200 types of these diseases, including rheumatoid arthritis, osteoarthritis, gout, lupus, back pain, osteoporosis, and tendinitis. Some of these are very serious diseases that can be difficult to diagnose and treat. They treat soft tissue problems related to the musculoskeletal system and sports-related soft tissue disorders.
Pediatric rheumatologist:
A pediatric rheumatologist is a pediatrician who specializes in the treatment of children with rheumatic disease. Both specialties are important to address a child's milestone development and disease treatment throughout childhood. However, recognition of this sub-specialty has been slow, which has resulted in a global shortage of pediatric rheumatologists, and as a consequence, the demand for healthcare support far exceeds current service capacities. Raising awareness of this is important to attract more upcoming pediatricians into this rewarding area of healthcare.
== Diseases ==
Diseases diagnosed or managed by rheumatologists include:
=== Degenerative arthropathies ===
Osteoarthritis
=== Inflammatory arthropathies ===
Rheumatoid arthritis
Spondyloarthropathies
Ankylosing spondylitis
Reactive arthritis (reactive arthropathy)
Psoriatic arthropathy
Enteropathic arthropathy
Juvenile Idiopathic Arthritis (JIA)
Crystal arthropathies: gout, pseudogout
Septic arthritis
Raynaud's Disease
=== Systemic conditions and connective tissue diseases ===
Lupus
Ehlers-Danlos syndrome
Sjögren's syndrome
Scleroderma (systemic sclerosis)
Polymyositis
Dermatomyositis
Polymyalgia rheumatica
Mixed connective tissue disease
Relapsing polychondritis
Adult-onset Still's disease
Sarcoidosis
Fibromyalgia
Myofascial pain syndrome
Vasculitis
Microscopic polyangiitis
Eosinophilic granulomatosis with polyangiitis
Granulomatosis with polyangiitis
Polyarteritis nodosa
Henoch–Schönlein purpura
Serum sickness
Giant cell arteritis, Temporal arteritis
Takayasu's arteritis
Behçet's disease
Kawasaki disease (mucocutaneous lymph node syndrome)
Thromboangiitis obliterans
Hereditary periodic fever syndromes
=== Soft tissue rheumatism ===
Local diseases and lesions affecting the joints and structures around the joints including tendons, ligaments capsules, bursae, stress fractures, muscles, nerve entrapment, vascular lesions, and ganglia. For example:
Low back pain
Tennis elbow
Golfer's elbow
Olecranon bursitis
== Diagnosis ==
=== Physical examination ===
Following are examples of methods of diagnosis able to be performed in a normal physical examination.
Schober's test tests the flexion of the lower back.
Multiple joint inspection
Musculoskeletal Examination
Screening Musculoskeletal Exam (SMSE) - a rapid assessment of structure and function
General Musculoskeletal Exam (GMSE) - a comprehensive assessment of joint inflammation
Regional Musculoskeletal Exam (RMSE) - focused assessments of structure, function and inflammation combined with special testing
=== Specialized ===
Laboratory tests (e.g. Erythrocyte Sedimentation Rate, Rheumatoid Factor, Anti-CCP (Anti-citrullinated protein antibody), ANA (Anti-Nuclear Antibody) )
X-rays, Ultrasounds, and other imaging methods of affected joints
Cytopathology and chemical pathology of fluid aspirated from affected joints (e.g. to differentiate between septic arthritis and gout)
== Treatment ==
Most rheumatic diseases are treated with analgesics, NSAIDs (nonsteroidal anti-inflammatory drug), steroids (in serious cases), DMARDs (disease-modifying antirheumatic drugs), monoclonal antibodies, such as infliximab and adalimumab, the TNF inhibitor etanercept, and methotrexate for moderate to severe rheumatoid arthritis. The biologic agent rituximab (anti-B cell therapy) is now licensed for use in refractory rheumatoid arthritis.
Physiotherapy is vital in the treatment of many rheumatological disorders. Occupational therapy can help patients find alternative ways for common movements that would otherwise be restricted by their disease. Patients with rheumatoid arthritis often need a long term, coordinated and a multidisciplinary team approach towards management of individual patients. Treatment is often tailored according to the individual needs of each patient which is also dependent on the response and the tolerability of medications.
Beginning in the 2000s, the incorporation of biopharmaceuticals (which include inhibitors of TNF-alpha, certain interleukins, and the JAK-STAT signaling pathway) into standards of care is one of the paramount developments in modern rheumatology.
=== Rheumasurgery ===
Rheumasurgery (or rheumatoid surgery) is a subfield of orthopedics occupied with the surgical treatment of patients with rheumatic diseases. The purpose of the interventions is to limit disease activity, soothe pain and improve function.
Rheumasurgical interventions can be divided in two groups. The one is early synovectomies, that is the removal of the inflamed synovia in order to prevent spreading and stop destruction. The other group is the so-called corrective intervention, i.e. an intervention done after destruction has taken place. Among the corrective interventions are joint replacements, removal of loose bone or cartilage fragments, and a variety of interventions aimed at repositioning and/or stabilizing joints, such as arthrodesis.
== Research directions ==
Recently, a large body of scientific research deals with the background of autoimmune disease, the cause of many rheumatic disorders. Also, the field of osteoimmunology has emerged to further examine the interactions between the immune system, joints, and bones. Epidemiological studies and medication trials are also being conducted. The Rheumatology Research Foundation is the largest private funding source of rheumatology research and training in the United States.
== History ==
Rheumasurgery emerged in the cooperation of rheumatologists and orthopedic surgeons in Heinola, Finland, during the 1950s.
In 1970 a Norwegian investigation estimated that at least 50% of patients with rheumatic symptoms needed rheumasurgery as an integrated part of their treatment.
The European Rheumatoid Arthritis Surgical Society (ERASS) was founded in 1979.
Around the turn of the 21st century, focus for treatment of patients with rheumatic disease shifted, and pharmacological treatment became dominant, while surgical interventions became rarer.
== References ==
== External links ==
Association des medecins rhumatologues du Quebec
American College of Rheumatology
European League Against Rheumatism
Consortium of Rheumatology Researchers of North America, Inc.
British Society for Rheumatology
Canadian Rheumatology Association
Association of Rheumatology Health Professionals (archived 3 March 2009)
German Society for Rheumatology | Wikipedia/Rheumasurgery |
The miasma theory (also called the miasmic theory) is an abandoned medical theory that held that diseases—such as cholera, chlamydia, or plague—were caused by a miasma (μίασμα, Ancient Greek for 'pollution'), a noxious form of "bad air", also known as night air. The theory held that epidemics were caused by miasma, emanating from rotting organic matter. Though miasma theory is typically associated with the spread of contagious diseases, some academics in the early nineteenth century suggested that the theory extended to other conditions as well, e.g. one could become obese by inhaling the odor of food.
The miasma theory was advanced by Hippocrates in the fourth century BC and accepted from ancient times in Europe and China. The theory was eventually abandoned by scientists and physicians after 1880, replaced by the germ theory of disease: specific germs, not miasma, caused specific diseases. However, cultural beliefs about getting rid of odor made the clean-up of waste a high priority for cities. It also encouraged the construction of well-ventilated hospital facilities, schools and other buildings.
== Etymology ==
The word miasma comes from ancient Greek and though conceptually, there is no word in English that has the same exact meaning, it can be loosely translated as 'stain' or 'pollution'.
The idea later gave rise to the name malaria (literally 'bad air' in Medieval Italian).
== Views worldwide ==
Miasma was considered to be a poisonous vapor or mist filled with particles from decomposed matter (miasmata) that caused illnesses. The miasmatic position was that diseases were the product of environmental factors such as contaminated water, foul air, and poor hygienic conditions. Such infection was not passed between individuals but would affect individuals within the locale that gave rise to such vapors. It was identifiable by its foul smell. It was also initially believed that miasmas were propagated through worms from ulcers within those affected by a plague.
=== Europe ===
In the fifth or fourth century BC, Hippocrates wrote about the effects of the environs over the human diseases:
Whoever wishes to investigate medicine properly, should proceed thus: in the first place to consider the seasons of the year, and what effects each of them produces for they are not at all alike, but differ much from themselves in regard to their changes. Then the winds, the hot and the cold, especially such as are common to all countries, and then such as are peculiar to each locality. We must also consider the qualities of the waters, for as they differ from one another in taste and weight, so also do they differ much in their qualities. In the same manner, when one comes into a city to which he is a stranger, he ought to consider its situation, how it lies as to the winds and the rising of the sun; for its influence is not the same whether it lies to the north or the south, to the rising or to the setting sun. These things one ought to consider most attentively, and concerning the waters which the inhabitants use, whether they be marshy and soft, or hard, and running from elevated and rocky situations, and then if saltish and unfit for cooking; and the ground, whether it be naked and deficient in water, or wooded and well watered, and whether it lies in a hollow, confined situation, or is elevated and cold; and the mode in which the inhabitants live, and what are their pursuits, whether they are fond of drinking and eating to excess, and given to indolence, or are fond of exercise and labor, and not given to excess in eating and drinking.
In the 1st century BC, the Roman architectural writer Vitruvius described the potential effects of miasma (Latin nebula) from fetid swamplands when visiting a city:
For when the morning breezes blow toward the town at sunrise, if they bring with them mist from marshes and, mingled with the mist, the poisonous breath of creatures of the marshes to be wafted into the bodies of the inhabitants, they will make the site unhealthy.
The miasmatic theory of disease remained popular in the Middle Ages and a sense of effluvia contributed to Robert Boyle's Suspicions about the Hidden Realities of the Air.
In the 1850s, miasma was used to explain the spread of cholera in London and in Paris, partly justifying Haussmann's later renovation of the French capital. The disease was said to be preventable by cleansing and scouring of the body and items. Dr. William Farr, the assistant commissioner for the 1851 London census, was an important supporter of the miasma theory. He believed that cholera was transmitted by air, and that there was a deadly concentration of miasmata near the River Thames' banks. Such a belief was in part accepted because of the general lack of air quality in urbanized areas. The wide acceptance of miasma theory during the cholera outbreaks overshadowed the partially correct theory brought forth by John Snow that cholera was spread through water. This slowed the response to the major outbreaks in the Soho district of London and other areas. The Crimean War nurse Florence Nightingale (1820–1910) was a proponent of the theory and worked to make hospitals sanitary and fresh-smelling. It was stated in 'Notes on Nursing for the Labouring Classes' (1860) that Nightingale would "keep the air [the patient] breathes as pure as the external air."
Fear of miasma registered in many early nineteenth-century warnings concerning what was termed "unhealthy fog". The presence of fog was thought to strongly indicate the presence of miasma. The miasmas were thought to behave like smoke or mist, blown with air currents, wafted by winds. It was thought that miasma did not simply travel on air but changed the air through which it propagated; the atmosphere was infected by miasma, as diseased people were.
=== China ===
In China, miasma (Chinese: 瘴氣; pinyin: Zhàngqì; alternative names 瘴毒, 瘴癘) is an old concept of illness, used extensively by ancient Chinese local chronicles and works of literature. Miasma has different names in Chinese culture. Most of the explanations of miasma refer to it as a kind of sickness, or poison gas.
The ancient Chinese thought that miasma was related to the environment of parts of Southern China. The miasma was thought to be caused by the heat, moisture and the dead air in the Southern Chinese mountains. They thought that insects' waste polluted the air, the fog, and the water, and the untouched forest harbored a great environment for miasma to occur.
In descriptions by ancient travelers, soldiers, or local officials (most of them are men of letters) of the phenomenon of miasma, fog, haze, dust, gas, or poison geological gassing were always mentioned. The miasma was thought to have caused a lot of diseases such as the cold, influenza, heat strokes, malaria, or dysentery. In the medical history of China, malaria had been referred to by different names in different dynasty periods. Poisoning and psittacosis were also called miasma in ancient China because they did not accurately understand the cause of disease.
In the Sui dynasty (581–618 CE), doctor Chao Yuanfang mentioned miasma in his book On Pathogen and Syndromes (諸病源候論). He thought that miasma in Southern China was similar to typhoid fever in Northern China. However, in his opinion, miasma was different from malaria and dysentery. In his book, he discussed dysentery in another chapter, and malaria in a single chapter. He also claimed that miasma caused various diseases, so he suggested that one should find apt and specific ways to resolve problems.
The concept of miasma developed in several stages. First, before the Western Jin dynasty, the concept of miasma was gradually forming; at least, in the Eastern Han dynasty, there was no description of miasma. During the Eastern Jin, large numbers of northern people moved south, and miasma was then recognized by men of letters and nobility. After the Sui and the Tang dynasty, scholars-bureaucrats sent to be the local officials recorded and investigated miasma. As a result, the government became concerned about the severe cases and the causes of miasma by sending doctors to the areas of epidemic to research the disease and heal the patients. In the Ming dynasty and Qing dynasty, versions of local chronicles record different miasma in different places.
However, Southern China was highly developed in the Ming and Qing dynasties. The environment changed rapidly, and after the 19th century, western science and medical knowledge were introduced into China, and people knew how to distinguish and deal with the disease. The concept of miasma therefore faded out due to the progress of medicine in China.
==== Influence in Southern China ====
The terrifying miasma diseases in the southern regions of China made it the primary location for relegating officials and sending criminals to exile since the Qin-Han dynasty. Poet Han Yu (韓愈) of the Tang dynasty, for example, wrote to his nephew who came to see him off after his banishment to the Chao Prefecture in his poem, En Route (左遷至藍關示姪孫湘):
At dawn I sent a single warning to the throne of the Nine Steps;
At evening I was banished to Chao Yang, eight thousand leagues.
Striving on behalf of a noble dynasty to expel an ignoble government,
How should I, withered and worn, deplore my future lot?
The clouds gather on Ch'in Mountains, I cannot see my home;
The snow bars the passes of Lan, my horse cannot go forward.
But I know that you will come from afar, to fulfil your set purpose,
And lovingly gather my bones, on the banks of that plague-stricken river.
The prevalent belief and predominant fear of the southern region with its "poisonous air and gases" is evident in historical documents.
Similar topics and feelings toward the miasma-infected south are often reflected in early Chinese poetry and records. Most scholars of the time agreed that the geological environments in the south had a direct impact on the population composition and growth. Many historical records reflect that females were less prone to miasma infection, and mortality rates were much higher in the south, especially for the men. This directly influenced agriculture cultivation and the southern economy, as men were the engine of agriculture production. Zhou Qufei (周去非), a local magistrate from the Southern Song dynasty, described in his treatise Representative Answers from the South: "... The men are short and tan, while the women were plump and seldom came down with illness," and exclaimed at the populous female population in the Guangxi region.
This inherent environmental threat also prevented immigration from other regions. Hence, development in the damp and sultry south was much slower than in the north, where the dynasties' political power resided for much of early Chinese history.
=== India ===
In India, there was also a miasma theory. Gambir was considered the first antimiasmatic application. This gambir tree is found in Southern India and Sri Lanka.
== Developments from 19th century onwards ==
=== Zymotic theory ===
Based on zymotic theory, people believed vapors called miasmata (singular: miasma) rose from the soil and spread diseases. Miasmata were believed to come from rotting vegetation and foul water—especially in swamps and urban ghettos.
Many people, especially the weak or infirm, avoided breathing night air by going indoors and keeping windows and doors shut. In addition to ideas associated with zymotic theory, there was also a general fear that cold or cool air spread disease. The fear of night air gradually disappeared as understanding about disease increased as well as with improvements in home heating and ventilation. Particularly important was the understanding that the agent spreading malaria was the mosquito (active at night) rather than miasmata.
=== Contagionism versus miasmatism ===
Prior to the late 19th century, night air was considered dangerous in most Western cultures. Throughout the 19th century, the medical community was divided on the explanation for disease proliferation. On one side were the contagionists, believing disease was passed through physical contact, while others believed disease was present in the air in the form of miasma, and thus could proliferate without physical contact. Two members of the latter group were Dr. Thomas S. Smith and Florence Nightingale.
Thomas Southwood Smith spent many years comparing the miasmatic theory to contagionism.
To assume the method of propagation by touch, whether by the person or of infected articles, and to overlook that by the corruption of the air, is at once to increase the real danger, from exposure to noxious effluvia, and to divert attention from the true means of remedy and prevention.
Florence Nightingale:
The idea of "contagion", as explaining the spread of disease, appears to have been adopted at a time when, from the neglect of sanitary arrangements, epidemics attacked whole masses of people, and when men had ceased to consider that nature had any laws for her guidance. Beginning with the poets and historians, the word finally made its way into scientific nomenclature, where it has remained ever since [...] a satisfactory explanation for pestilence and an adequate excuse for non-exertion to prevent its recurrence.
The current germ theory accounts for disease proliferation by both direct and indirect physical contact.
=== Influence on sanitary engineering reforms ===
In the early 19th century, the living conditions in industrialized cities in Britain were increasingly unsanitary. The population was growing at a much faster rate than the infrastructure could support. For example, the population of Manchester doubled within a single decade, leading to overcrowding and a significant increase in waste accumulation. The miasma theory of disease made sense to the sanitary reformers of the mid-19th century. Miasmas explained why cholera and other diseases were epidemic in places where the water was stagnant and foul-smelling. A leading sanitary reformer, London's Edwin Chadwick, asserted that "all smell is disease", and maintained that a fundamental change in the structure of sanitation systems was needed to combat increasing urban mortality rates.
Chadwick saw the problem of cholera and typhoid epidemics as being directly related to urbanization, and he proposed that new, independent sewerage systems should be connected to homes. Chadwick supported his proposal with reports from the London Statistical Society which showed dramatic increases in both morbidity and mortality rates since the beginning of urbanization in the early 19th century. Though Chadwick proposed reform on the basis of the miasma theory, his proposals did contribute to improvements in sanitation, such as preventing the reflux of noxious air from sewers back into houses by using separate drainage systems in the design of sanitation. That led, incidentally, to decreased outbreaks of cholera and thus helped to support the theory.
The miasma theory was consistent with the observation that disease was associated with poor sanitation, and hence foul odours, and that sanitary improvements reduced disease. However, it was inconsistent with the findings arising from microbiology and bacteriology in the later 19th century, which eventually led to the adoption of the germ theory of disease, although consensus was not reached immediately. Concerns over sewer gas, which was a major component of the miasma theory developed by Galen, and brought to prominence by the "Great Stink" in London in the summer of 1858, led proponents of the theory to observe that sewers enclosed the refuse of the human bowel, which medical science had discovered could teem with typhoid, cholera, and other microbes.
The Nuisances Removal and Diseases Prevention Act 1846 was passed to identify whether the transmission of cholera was by air or by water. The act was used to encourage owners to clean their dwellings and connect them to sewers.
Even though eventually disproved by the understanding of bacteria and the discovery of viruses, the miasma theory helped establish the connection between poor sanitation and disease. That encouraged cleanliness and spurred public health reforms which, in Britain, led to the Public Health Act 1848 the Public Health Act 1858, and the Local Government Act 1858. The latter of those enabled the instituting of investigations into the health and sanitary regulations of any town or place, upon the petition of residents or as a result of death rates exceeding the norm. Early medical and sanitary engineering reformers included Henry Austin, Joseph Bazalgette, Edwin Chadwick, Frank Forster, Thomas Hawksley, William Haywood, Henry Letheby, Robert Rawlinson, John Simon, John Snow and Thomas Wicksteed. Their efforts, and associated British regulatory improvements, were reported in the United States as early as 1865.
Particularly notable in 19th century sanitation reform is the work of Joseph Bazalgette, chief engineer to London's Metropolitan Board of Works. Encouraged by the Great Stink, Parliament sanctioned Bazalgette to design and construct a comprehensive system of sewers, which intercepted London's sewage and diverted it away from its water supply. The system helped purify London's water and saved the city from epidemics. In 1866, the last of the three great British cholera
epidemics took hold in a small area of Whitechapel. However, the area was not yet connected to Bazalgette's system, and the confined area of the epidemic acted as testament to the efficiency of the system's design.
Years later, the influence of those sanitary reforms on Britain was described by Richard Rogers:
London was the first city to create a complex civic administration which could coordinate modern urban services, from public transport to housing, clean water to education. London's County Council was acknowledged as the most progressive metropolitan government in the world. Fifty years earlier, London had been the worst slum city of the industrialized world: over-crowded, congested, polluted and ridden with disease...
The miasma theory did contribute to containing disease in urban settlements, but did not allow the adoption of a suitable approach to the reuse of excreta in agriculture. It was a major factor in the practice of collecting human excreta from urban settlements and reusing them in the surrounding farmland. That type of resource recovery scheme was common in major cities in the 19th century before the introduction of sewer-based sanitation systems. Nowadays, the reuse of excreta, when done in a hygienic manner, is known as ecological sanitation, and is promoted as a way of "closing the loop".
Throughout the 19th century, concern about public health and sanitation, along with the influence of the miasma theory, were reasons for the advocacy of the then-controversial practice of cremation. If infectious diseases were spread by noxious gases emitted from decaying organic matter, that included decaying corpses. The public health argument for cremation faded with the eclipsing of the miasma theory of disease.
== Replacement by germ theory ==
Although the connection between germ and disease was proposed quite early, it was not until the late 1800s that the germ theory was generally accepted. The miasmatic theory was challenged by John Snow, suggesting that there was some means by which the disease was spread via a poison or morbid material (orig: materies morbi) in the water. He suggested this before and in response to a cholera epidemic on Broad Street in central London in 1854. Because of the miasmatic theory's predominance among Italian scientists, the discovery in the same year by Filippo Pacini of the bacillus that caused the disease was completely ignored. It was not until 1876 that Robert Koch proved that the bacterium Bacillus anthracis caused anthrax, which brought a definitive end to miasma theory.
=== 1854 Broad Street cholera outbreak ===
The work of John Snow is notable for helping to make the connection between cholera and typhoid epidemics and contaminated water sources, which contributed to the eventual demise of miasma theory. During the cholera epidemic of 1854, Snow traced high mortality rates among the citizens of Soho to a water pump in Broad Street. Snow convinced the local government to remove the pump handle, which resulted in a marked decrease in cases of cholera in the area. In 1857, Snow submitted a paper to the British Medical Journal which attributed high numbers of cholera cases to water sources that were contaminated with human waste. Snow used statistical data to show that citizens who received their water from upstream sources were considerably less likely to develop cholera than those who received their water from downstream sources. Though his research supported his hypothesis that contaminated water, not foul air, was the source of cholera
epidemics, a review committee concluded that Snow's findings were not significant enough to warrant change, and they were summarily dismissed. Additionally, other interests intervened in the process of reform. Many water companies and civic authorities pumped water directly from contaminated sources such as the Thames to public wells, and the idea of changing sources or implementing filtration techniques was an unattractive economic prospect. In the face of such economic interests, reform was slow to be adopted.
In 1855, John Snow made a testimony against the Amendment to the "Nuisances Removal and Diseases Prevention Act" that regularized air pollution of some industries. He claimed that:
That is possible; but I believe that the poison of the cholera is either swallowed in water, or got directly from some other person in the family, or in the room; I believe it is quite an exception for it to be conveyed in the air; though if the matter gets dry it may be wafted a short distance.
The same year, William Farr, who was then the major supporter of the miasma theory, issued a report to criticize the germ theory. Farr and the Committee wrote that:
After careful inquiry, we see no reason to adopt this belief. We do not feel it established that the water was contaminated in the manner alleged; nor is there before us any sufficient evidence to show whether inhabitants of that district, drinking from that well, suffered in proportion more than other inhabitants of the district who drank from other sources.
=== Experiments by Louis Pasteur ===
The more formal experiments on the relationship between germ and disease were conducted by Louis Pasteur between 1860 and 1864. He discovered the pathology of the puerperal fever and the pyogenic vibrio in the blood, and suggested using boric acid to kill these microorganisms before and after confinement.
By 1866, eight years after the death of John Snow, William Farr publicly acknowledged that the miasma theory on the transmission of cholera was wrong, by his statistical justification on the death rate.
=== Anthrax ===
Robert Koch is widely known for his work with anthrax, discovering the causative agent of the fatal disease to be Bacillus anthracis. He published the discovery in a booklet as Die Ätiologie der Milzbrand-Krankheit, Begründet auf die Entwicklungsgeschichte des Bacillus Anthracis (The Etiology of Anthrax Disease, Based on the Developmental History of Bacillus Anthracis) in 1876 while working in Wöllstein. His publication in 1877 on the structure of anthrax bacterium marked the first photography of a bacterium. He discovered the formation of spores in anthrax bacteria, which could remain dormant under specific conditions. However, under optimal conditions, the spores were activated and caused disease. To determine this causative agent, he dry-fixed bacterial cultures onto glass slides, used dyes to stain the cultures, and observed them through a microscope. His work with anthrax is notable in that he was the first to link a specific microorganism with a specific disease, rejecting the idea of spontaneous generation and supporting the germ theory of disease.
== See also ==
Germ theory of disease
Airborne disease
Indoor air quality
== References ==
== Further reading ==
Beasley, Brett (September 30, 2015). "Bad Air: Pollution, Sin, and Science Fiction in William Delisle Hay's The Doom of the Great City (1880)". The Public Domain Review. 5 (18).
Sterner, Carl S. (2007). "A Brief History of Miasmic Theory" (PDF). Bulletin of the History of Medicine. 22 (1948): 747.
Thorsheim, Peter (2006). Inventing Pollution: Coal, Smoke, and Culture in Britain since 1800. Ohio University Press. ISBN 978-0-8214-1681-5.
== External links ==
Prevailing theories before the germ theory
Cholera theories
Term definition | Wikipedia/Miasma_theory_of_disease |
Minimally invasive procedures (also known as minimally invasive surgeries) encompass surgical techniques that limit the size of incisions needed, thereby reducing wound healing time, associated pain, and risk of infection. Surgery by definition is invasive, and many operations requiring incisions of some size are referred to as open surgery. Incisions made during open surgery can sometimes leave large wounds that may be painful and take a long time to heal. Advancements in medical technologies have enabled the development and regular use of minimally invasive procedures. For example, endovascular aneurysm repair, a minimally invasive surgery, has become the most common method of repairing abdominal aortic aneurysms in the US as of 2003. The procedure involves much smaller incisions than the corresponding open surgery procedure of open aortic surgery.
Interventional radiologists were the forerunners of minimally invasive procedures. Using imaging techniques, radiologists were able to direct interventional instruments through the body by way of catheters instead of the large incisions needed in traditional surgery. As a result, many conditions once requiring surgery can now be treated non-surgically.
Diagnostic techniques that do not involve incisions, puncturing the skin, or the introduction of foreign objects or materials into the body are known as non-invasive procedures. Several treatment procedures are classified as non-invasive. A major example of a non-invasive alternative treatment to surgery is radiation therapy, also called radiotherapy.
== Medical uses ==
Minimally invasive procedures were pioneered by interventional radiologists who had first introduced angioplasty and the catheter-delivered stent. Many other minimally invasive procedures have followed where images of all parts of the body can be obtained and used to direct interventional instruments by way of catheters (needles and fine tubes), so that many conditions once requiring open surgery can now be treated non-surgically. A minimally invasive procedure typically involves the use of arthroscopic (for joints and the spine) or laparoscopic devices and remote-control manipulation of instruments with indirect observation of the surgical field through an endoscope or large scale display panel, and is carried out through the skin or through a body cavity or anatomical opening. Interventional radiology now offers many techniques that avoid the need for surgery.
By use of a minimally invasive procedure, a patient may require only an adhesive bandage on the incision, rather than multiple stitches or staples to close a large incision. This usually results in less infection, a quicker recovery time and shorter hospital stays, or allow outpatient treatment. However, the safety and effectiveness of each procedure must be demonstrated with randomized controlled trials. The term was coined by John E. A. Wickham in 1984, who wrote of it in British Medical Journal in 1987.
== Specific procedures ==
Many medical procedures are called minimally invasive; those that involve small incisions through which an endoscope is inserted, end in the suffix -oscopy, such as endoscopy, laparoscopy, arthroscopy. Other examples of minimally invasive procedures include the use of hypodermic injection, and air-pressure injection, subdermal implants, refractive surgery, percutaneous surgery, cryosurgery, microsurgery, keyhole surgery, endovascular surgery using interventional radiology (such as angioplasty or embolization), coronary catheterization, permanent placement of spinal and brain electrodes, stereotactic surgery, the Nuss procedure, radioactivity-based medical imaging methods, such as gamma camera, positron emission tomography and SPECT (single photon emission tomography). Related procedures are image-guided surgery, and robot-assisted surgery.
== Equipment ==
Special medical equipment may be used, such as fiber optic cables, miniature video cameras and special surgical instruments handled via tubes inserted into the body through small openings in its surface. The images of the interior of the body are transmitted to an external video monitor and the surgeon has the possibility of making a diagnosis, visually identifying internal features and acting surgically on them.
== Benefits ==
Minimally invasive surgery should have less operative trauma, other complications and adverse effects than an equivalent open surgery. It may be more or less expensive (for dental implants, a minimally invasive method reduces the cost of installed implants and shortens the implant-prosthetic rehabilitation time with four–six months). Operative time is longer, but hospitalization time is shorter. It causes less pain and scarring, speeds recovery, and reduces the incidence of post-surgical complications, such as adhesions and wound rupture. Some studies have compared heart surgery.
== Risks ==
Risks and complications of minimally invasive procedures are the same as for any other surgical operation, among the risks are: death, bleeding, infection, organ injury, and thromboembolic disease.
There may be an increased risk of hypothermia and peritoneal trauma due to increased exposure to cold, dry gases during insufflation. The use of surgical humidification therapy, which is the use of heated and humidified CO2 for insufflation, may reduce this risk.
== Invasive procedures ==
Sometimes the use of non-invasive methods is not an option, so that the next level of minimally invasive techniques are looked to. These include the use of hypodermic injection (using the syringe), an endoscope, percutaneous surgery which involves needle puncture of the skin, laparoscopic surgery commonly called keyhole surgery, a coronary catheter, angioplasty and stereotactic surgery.
=== Open surgery ===
"Open surgery" is any surgical procedure where the incision made is enough to allow the surgery to take place. With tissues and structures exposed to the air, the procedure can be performed either with the unaided vision of the surgeon or with the use of loupes or microscopes. Some examples of open surgery used are for herniated disc commonly called a "slipped disc", and most types of cardiac surgery and neurosurgery.
== Associations ==
Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) for adults.
International Pediatric Endosurgery Group (IPEG) for pediatrics.
== See also ==
== References ==
== Further reading ==
== External links ==
Minimally invasive heart surgery. Medical Encyclopedia, MedlinePlus. | Wikipedia/Open_surgery |
Plastic surgery is a surgical specialty involving restoration, reconstruction, or alteration of the human body. It can be divided into two main categories: reconstructive surgery and cosmetic surgery. Reconstructive surgery covers a wide range of specialties, including craniofacial surgery, hand surgery, microsurgery, and the treatment of burns. This kind of surgery focuses on restoring a body part or improving its function. In contrast, cosmetic (or aesthetic) surgery focuses solely on improving the physical appearance of the body. A comprehensive definition of plastic surgery has never been established, because it has no distinct anatomical object and thus overlaps with practically all other surgical specialties. An essential feature of plastic surgery is that it involves the treatment of conditions that require or may require tissue relocation skills.
== Etymology ==
The word plastic in plastic surgery refers to the concept of "reshaping" and comes from the Greek πλαστική (τέχνη), plastikē (tekhnē), "the art of modelling" of malleable flesh. This meaning in English is seen as early as 1598. In the surgical context, the word "plastic" first appeared in 1816 and was established in 1838 by Eduard Zeis, preceding the modern technical usage of the word as "engineering material made from petroleum" by 70 years.
== History ==
Treatments for the plastic repair of a broken nose are first mentioned in the c. 1600 BC Egyptian medical text called the Edwin Smith papyrus. The early trauma surgery textbook was named after the American Egyptologist, Edwin Smith. Reconstructive surgery techniques were being carried out in India by 800 BC. Sushruta was a physician who made contributions to the field of plastic and cataract surgery in the 6th century BC.
The Romans also performed plastic cosmetic surgery, using simple techniques, such as repairing damaged ears, from around the 1st century BC. For religious reasons, they did not dissect either human beings or animals, thus, their knowledge was based in its entirety on the texts of their Greek predecessors. Notwithstanding, Aulus Cornelius Celsus left some accurate anatomical descriptions, some of which—for instance, his studies on the genitalia and the skeleton—are of special interest to plastic surgery.
Arabs practiced the plastic surgery, during the Abbasid Caliphate in 750 AD. The Arabic translations made their way into Europe via intermediaries. In Italy, the Branca family of Sicily and Gaspare Tagliacozzi (Bologna) became familiar with the techniques of Sushruta.
In all fields of surgery, the Arab physician, surgeon, and chemist Al-Zahrawi talks of the use of silk thread sutures to achieve good cosmesis. He describes what is thought to be the first attempt at reduction mammaplasty for the management of gynaecomastia. He gives detailed descriptions of other basic surgical techniques such as cautery and wound management.
British physicians travelled to India to see rhinoplasties being performed by Indian methods. Reports on Indian rhinoplasty performed by a Kumhar (potter) vaidya were published in the Gentleman's Magazine by 1794. Joseph Constantine Carpue spent 20 years in India studying local plastic surgery methods. Carpue was able to perform the first major surgery in the Western world in the year 1815. Instruments described in the Sushruta Samhita were further modified in the Western world.
In 1465, Sabuncu's book, description, and classification of hypospadias were more informative and up to date. Localization of the urethral meatus was described in detail. Sabuncuoglu also detailed the description and classification of ambiguous genitalia. In mid-15th-century Europe, Heinrich von Pfolspeundt described a process "to make a new nose for one who lacks it entirely, and the dogs have devoured it" by removing skin from the back of the arm and suturing it in place. However, because of the dangers associated with surgery in any form, especially that involving the head or face, it was not until the 19th and 20th centuries that such surgery became common.
In 1814, Joseph Carpue successfully performed an operative procedure on a British military officer who had lost his nose to the toxic effects of mercury treatments. In 1818, German surgeon Carl Ferdinand von Graefe published his major work entitled Rhinoplastik. Von Graefe modified the Italian method using a free skin graft from the arm instead of the original delayed pedicle flap.
The first American plastic surgeon was John Peter Mettauer, who, in 1827, performed the first cleft palate operation with instruments that he designed himself.
Johann Friedrich Dieffenbach specialized in skin transplantation and early plastic surgery. His work in rhinoplastic and maxillofacial surgery established many modern techniques of reconstructive surgery. In 1845, Dieffenbach wrote a comprehensive text on rhinoplasty, titled Operative Chirurgie, and introduced the concept of reoperation to improve the cosmetic appearance of the reconstructed nose. Dieffenbach has been called the "father of plastic surgery".
Another case of plastic surgery for nose reconstruction from 1884 at Bellevue Hospital was described in Scientific American.
In 1891, American otorhinolaryngologist John Roe presented an example of his work: a young woman on whom he reduced a dorsal nasal hump for cosmetic indications. In 1892, Robert Weir experimented unsuccessfully with xenografts (duck sternum) in the reconstruction of sunken noses. In 1896, James Israel, a urological surgeon from Germany, and in 1889 George Monks of the United States each described the successful use of heterogeneous free-bone grafting to reconstruct saddle nose defects. In 1898, Jacques Joseph, the German orthopaedic-trained surgeon, published his first account of reduction rhinoplasty. In 1910, Alexander Ostroumov, the Russian pharmacist, and perfume and cosmetics manufacturer, founded a unique plastic surgery department in his Moscow Institute of Medical Cosmetics. In 1928, Jacques Joseph published Nasenplastik und Sonstige Gesichtsplastik.
== Nascency of maxillofacial surgery ==
The development of weapons such as machine guns and explosive shells during World War I created trench warfare, which led to a rapid increase in the number of mutilations to the faces and the heads of soldiers because the trenches mainly offered protection to the body. The surgeons, who were not prepared for these injuries, were even less prepared for a large number of injuries and had to react quickly and intelligently to treat the greatest number. Facial injuries were hard to treat on the front line, and because of the sanitary conditions, many infections could occur. Sometimes, some stitches were made on a jagged wound without considering the amount of flesh that had been lost, so the resulting scars were hideous and disfigured soldiers. Some of the wounded had severe injuries, and the stitches were not sufficient, so some became blind or were left with gaping holes instead of their nose. Harold Gillies, scared by the number of new facial injuries and the lack of good surgical techniques, decided to dedicate an entire hospital to the reconstruction of facial injuries as fully as possible. He took into account the psychological dimension. Gillies introduced skin grafts to the treatments of soldiers, so they would be less horrified by looking at themselves in the mirror.
It is the multidisciplinary approach to the treatment of facial lesions, bringing together plastic surgeons, dental surgeons, technicians, and specialized nurses, which has made it possible to develop techniques leading to the reconstruction of injured faces. Before the dentist Auguste Charles Valadier and then Gillies identified the need to advance the specialty of maxillofacial surgery, which would be directly dedicated to the management of war wounds at this time. Gillies developed a new technique using rotational and transposition flaps but also bone grafts from the ribs and tibia to reconstruct facial defects caused by the weapons during the war. He experimented with this technique so he knew that he had to start by moving back healthy tissue to its normal position, and then he would be able to fill with tissue from another place on the body of the soldier. One of the most successful techniques in skin grafting had the aim of not completely severing the connection to the body. It was possible by releasing and lifting a flap of skin from the wound. The flap of skin, still connected to the donor site, would then be swung over the site of the wound, allowing the maintenance of physical connection and ensuring that blood is supplied to the skin, increasing the chances of the skin graft being accepted by the body. At this time, we also assisted in improving treating infections also meant that important injuries had become survivable, mostly thanks to the new technique of Gillies. Some soldiers arrived at the hospital of Gillies without noses, chins, cheekbones, or even eyes. But for them, the most important trauma was psychological.
== Development of modern techniques ==
The father of modern plastic surgery is generally considered to have been Sir Harold Gillies. A New Zealand otolaryngologist working in London, he developed many of the techniques of modern facial surgery in caring for soldiers with disfiguring facial injuries during the First World War.
During World War I, he worked as a medical minder with the Royal Army Medical Corps. After working with the French oral and maxillofacial surgeon Hippolyte Morestin on skin grafts, he persuaded the army's chief surgeon, Arbuthnot-Lane, to establish a facial injury ward at the Cambridge Military Hospital, Aldershot, later upgraded to a new hospital for facial repairs at Sidcup in 1917. There, Gillies and his colleagues developed many techniques of plastic surgery; more than 11,000 operations were performed on more than 5,000 men (mostly soldiers with facial injuries, usually from gunshot wounds). After the war, Gillies developed a private practice with Rainsford Mowlem, including many famous patients, and travelled extensively to promote his advanced techniques worldwide.
In 1930, Gillies' cousin, Archibald McIndoe, joined the practice and became committed to plastic surgery. When World War II broke out, plastic surgery provision was largely divided between the different services of the armed forces, and Gillies and his team were split up. Gillies himself was sent to Rooksdown House near Basingstoke, which became the principal army plastic surgery unit; Tommy Kilner (who had worked with Gillies during the First World War, and who now has a surgical instrument named after him, the kilner cheek retractor) went to Queen Mary's Hospital, Roehampton; and Mowlem went to St Albans. McIndoe, consultant to the RAF, moved to the recently rebuilt Queen Victoria Hospital in East Grinstead, Sussex, and founded a Centre for Plastic and Jaw Surgery. There, he treated very deep burns and serious facial disfigurement, such as loss of eyelids, typical of those caused to aircrew by burning fuel.
McIndoe is often recognized for not only developing new techniques for treating badly burned faces and hands but also for recognising the importance of the rehabilitation of the casualties and particularly of social reintegration back into normal life. He disposed of the "convalescent uniforms" and let the patients use their service uniforms instead. With the help of two friends, Neville and Elaine Blond, he also convinced the locals to support the patients and invite them to their homes. McIndoe kept referring to them as "his boys" and the staff called him "The Boss" or "The Maestro".
His other important work included the development of the walking-stalk skin graft, and the discovery that immersion in saline promoted healing as well as improving survival rates for patients with extensive burns—this was a serendipitous discovery drawn from observation of differential healing rates in pilots who had come down on land and in the sea. His radical, experimental treatments led to the formation of the Guinea Pig Club at Queen Victoria Hospital, Sussex. Among the better-known members of his "club" were Richard Hillary, Bill Foxley and Jimmy Edwards.
== Sub-specialties ==
Plastic surgery is a broad field and may be subdivided further. In the United States, plastic surgeons are board certified by American Board of Plastic Surgery. Subdisciplines of plastic surgery may include:
=== Aesthetic surgery ===
Aesthetic surgery is a central component of plastic surgery and includes facial and body aesthetic surgery. Plastic surgeons use cosmetic surgical principles in all reconstructive surgical procedures as well as isolated operations to improve overall appearance.
=== Burn surgery ===
Burn surgery generally takes place in two phases. Acute burn surgery is the treatment immediately after a burn. Reconstructive burn surgery takes place after the burn wounds have healed.
=== Craniofacial surgery ===
Craniofacial surgery is divided into pediatric and adult craniofacial surgery. Pediatric craniofacial surgery mostly revolves around the treatment of congenital anomalies of the craniofacial skeleton and soft tissues, such as cleft lip and palate, microtia, craniosynostosis, and pediatric fractures. Adult craniofacial surgery deals mostly with reconstructive surgeries after trauma or cancer and revision surgeries, along with orthognathic surgery and facial feminization surgery. Craniofacial surgery is an important part of all plastic surgery training programs. Further training and subspecialisation are obtained via a craniofacial fellowship. Craniofacial surgery is also practiced by maxillofacial surgeons.
=== Ethnic plastic surgery ===
Ethnic plastic surgery is plastic surgery performed to change ethnic attributes, often considered used as a way of "passing".
=== Hand surgery ===
Hand surgery is concerned with acute injuries and chronic diseases of the hand and wrist, correction of congenital malformations of the upper extremities, and peripheral nerve problems (such as brachial plexus injuries or carpal tunnel syndrome). Hand surgery is an important part of training in plastic surgery, as well as microsurgery, which is necessary to replant an amputated extremity. The hand surgery field is also practiced by orthopedic surgeons and general surgeons. Scar tissue formation after surgery can be problematic on the delicate hand, causing loss of dexterity and digit function if severe enough. There have been cases of surgery on women's hands in order to correct perceived flaws to create the perfect engagement ring photo.
=== Microsurgery ===
Microsurgery is generally concerned with the reconstruction of missing tissues by transferring a piece of tissue to the reconstruction site and reconnecting blood vessels. Popular subspecialty areas are breast reconstruction, head and neck reconstruction, hand surgery/replantation, and brachial plexus surgery.
=== Pediatric plastic surgery ===
Children often face medical issues very different from the experiences of an adult patient. Many birth defects or syndromes present at birth are best treated in childhood, and pediatric plastic surgeons specialize in treating these conditions in children. Conditions commonly treated by pediatric plastic surgeons include craniofacial anomalies, Syndactyly (webbing of the fingers and toes), Polydactyly (excess fingers and toes at birth), cleft lip and palate, and congenital hand deformities.
=== Prison plastic surgery ===
Plastic surgery was performed on an incarcerated population in order to affect their recidivism rate, a practice instituted in the early 20th century that lasted until the mid-1990s. Separate from surgery performed for medical need.
== Techniques and procedures ==
In plastic surgery, the transfer of skin tissue (skin grafting) is a very common procedure. Skin grafts can be derived from the recipient or donors:
Autografts are taken from the recipient. If absent or deficient of natural tissue, alternatives can be cultured sheets of epithelial cells in vitro or synthetic compounds, such as integra, which consists of silicone and bovine tendon collagen with glycosaminoglycans.
Allografts are taken from a donor of the same species. Kidney transplants are an example of allograft transfer. Joseph Murray is credited for completing the first successful kidney transplantation in 1954.
Xenografts are taken from a donor of a different species.
Usually, good results would be expected from plastic surgery that emphasize careful planning of incisions so that they fall within the line of natural skin folds or lines, appropriate choice of wound closure, use of best available suture materials, and early removal of exposed sutures so that the wound is held closed by buried sutures.
== Cosmetic surgery procedures ==
Cosmetic surgery is a voluntary or elective surgery that is performed on normal parts of the body with the only purpose of improving a person's appearance or removing signs of aging. Some cosmetic surgeries such as breast reduction are also functional and can help to relieve symptoms of discomfort such as back ache or neck ache. Cosmetic surgeries are also undertaken following breast cancer and mastectomy to recreate the natural breast shape which has been lost during the process of removing the cancer. In 2014, nearly 16 million cosmetic procedures were performed in the United States alone. The number of cosmetic procedures performed in the United States has almost doubled since the start of the century. 92% of cosmetic procedures were performed on women in 2014, up from 88% in 2001. 15.6 million cosmetic procedures were performed in 2020, with the five most common surgeries being rhinoplasties, blepharoplasties, rhytidectomies, liposuctions, and breast augmentation. Breast augmentation continues to be one of the top 5 cosmetic surgical procedures and has been since 2006. Silicone implants were used in 84% and saline implants in 16% of all breast augmentations in 2020. The American Society for Aesthetic Plastic Surgery looked at the statistics for 34 different cosmetic procedures. Nineteen of the procedures were surgical, such as rhinoplasties or rhytidectomies. The nonsurgical procedures included botox and laser hair removal. In 2010, their survey revealed that there were 9,336,814 total procedures in the United States. Of those, 1,622,290 procedures were surgical (p. 5). They also found that a large majority, 81%, of the procedures were done on Caucasian people (p. 12).
In 1949, 15,000 Americans underwent cosmetic surgery procedures and by 1969 this number rose to almost half a million people. The American Society of Plastic Surgeons estimates that more than 333,000 cosmetic procedures were performed on patients 18 years of age or younger in the US in 2005 compared to approx. 14,000 in 1996. In 2018, more than 226,994 patients between the ages of 13 and 19 underwent plastic surgery compared to just over 218,900 patients in the same age group in 2010. Concerns about young people undergoing plastic surgery include the financial burden of additional surgical procedures needed to correct problems after the initial cosmetic surgery, long-term health complications from plastic surgery, and unaddressed mental health issues that may have led to surgery. The increased use of cosmetic procedures crosses racial and ethnic lines in the U.S., with increases seen among African-Americans, Asian Americans and Hispanic Americans as well as Caucasian Americans. In Asia, cosmetic surgery has become more popular, and countries such as China and India have become Asia's biggest cosmetic surgery markets. South Korea is also rising in popularity in Asian and Western countries due to their expertise in facial bone surgeries (see cosmetic surgery in South Korea).
Plastic surgery is increasing slowly, rising 115% from 2000 to 2015. "According to the annual plastic surgery procedural statistics, there were 15.9 million surgical and minimally-invasive cosmetic procedures performed in the United States in 2015, a 2 percent increase over 2014." A study from 2021 found that requests for cosmetic procedures had increased significantly since the beginning of the COVID-19 pandemic, possibly due to the increase in videoconferencing; cited estimates include a 10% increase in the United States and a 20% increase in France.
The most popular aesthetic/cosmetic procedures include:
Abdominoplasty ("tummy tuck"): reshaping and firming of the abdomen
Blepharoplasty ("eyelid surgery"): reshaping of upper/lower eyelids including Asian blepharoplasty
While blepharoplasty remains the most common procedure for modifying eyelid shape, non-surgical alternatives are increasingly sought after, especially in East Asia.
Methods such as double eyelid tape, eyelid glue, and structured eyelid training systems allow individuals to temporarily or semi-permanently create a double eyelid crease without surgery. Some of these products, such as D-UP Eyelid Tape, AB Mezical, and Optifold, use mechanical reinforcement to encourage crease retention over time.
Unlike traditional adhesive-based tapes, structured eyelid training tapes aim to replicate mechanotransduction—a biological process where skin tension encourages crease formation. Studies on long-term non-surgical crease retention remain limited, but anecdotal evidence suggests some users achieve lasting results after sustained use.
Phalloplasty ("penile surgery"): construction (or reconstruction) of a penis or, sometimes, artificial modification of the penis by surgery, often for cosmetic purposes
Mammoplasty:
Breast augmentations ("breast implant" or "boob job"): augmentation of the breasts by means of fat grafting, saline, or silicone gel prosthetics, which was initially performed for women with micromastia
Reduction mammoplasty ("breast reduction"): removal of skin and glandular tissue, which is done to reduce back and shoulder pain in women with gigantomastia and for men with gynecomastia
Mastopexy ("breast lift"): Lifting or reshaping of breasts to make them less saggy, often after weight loss (after a pregnancy, for example). It involves the removal of breast skin as opposed to glandular tissue
Augmentation mastopexy ("breast lift with breast implants"): Lifting breasts to make them less saggy, repositioning the nipple to a higher location, and increasing breast size with saline or silicone gel implants. Recent studies of a newer technique for simultaneous augmentation mastopexy (SAM) indicate that it is a safe surgical procedure with minimal medical complications. The SAM technique involves invaginating and tacking the tissues first, in order to previsualize the result, before making any surgical incisions to the breast.
Buttock augmentation ("butt implant"): enhancement of the buttocks using silicone implants or fat grafting ("Brazilian butt lift") where fat is transferred from other areas of the body
Cryolipolysis: refers to a medical device used to destroy fat cells. Its principle relies on controlled cooling for the non-invasive local reduction of fat deposits to reshape body contours.
Cryoneuromodulation: Treatment of superficial and subcutaneous tissue structures using gaseous nitrous oxide, including temporary wrinkle reduction, temporary pain reduction, treatment of dermatologic conditions, and focal cryo-treatment of tissue
Calf augmentation: done by silicone implants or fat transfer to add bulk to calf muscles
Labiaplasty: surgical reduction and reshaping of the labia
Lip augmentation: alters the appearance of the lips by increasing their fullness through surgical enlargement with lip implants or nonsurgical enhancement with injectable fillers
Cheiloplasty: surgical reconstruction of the lip
Rhinoplasty ("nose job"): reshaping of the nose sometimes used to correct breathing impaired by structural defects.
Otoplasty ("ear surgery"/"ear pinning"): reshaping of the ear, most often done by pinning the protruding ear closer to the head.
Rhytidectomy ("face lift"): removal of wrinkles and signs of aging from the face
Neck lift: tightening of lax tissues in the neck. This procedure is often combined with a facelift for lower face rejuvenation.
Browplasty ("brow lift" or "forehead lift"): elevates eyebrows, smoothens forehead skin
Midface lift ("cheek lift"): tightening of the cheeks
Genioplasty: augmentation of the chin with an individual's bones or with the use of an implant, usually silicone, by suture of the soft tissue
Mentoplasty: surgery to the chin. This can involve either enhancing or reducing the size of the chin. Enhancements are achieved with the use of facial implants. Reduction of the chin involves reducing the size of the chin bone.
Cheek augmentation ("cheek implant"): implants to the cheek
Orthognathic surgery: altering the upper and lower jaw bones (through osteotomy) to correct jaw alignment issues and correct the teeth alignment
Fillers injections: collagen, fat, and other tissue filler injections, such as hyaluronic acid
Brachioplasty ("Arm lift"): reducing excess skin and fat between the underarm and the elbow
Laser skin rejuvenation or laser resurfacing: the lessening of the depth of facial pores and exfoliation of dead or damaged skin cells
Liposuction ("suction lipectomy"): removal of fat deposits by traditional suction technique or ultrasonic energy to aid fat removal
Zygoma reduction plasty: reducing the facial width by performing osteotomy and resecting part of the zygomatic bone and arch
Jaw reduction: reduction of the mandible angle to smooth out an angular jaw and creating a slim jaw
Buccal fat extraction: extraction of the buccal pads
Body contouring: the removal of this excess skin and fat from numerous areas of the body, restoring the appearance of skin elasticity of the remaining skin. The surgery is prominent in those who have undergone significant weight loss, resulting in excess sagging skin being present around areas of the body. The skin loses elasticity (a condition called elastosis) once it has been stretched past capacity and is unable to recoil back to its standard position against the body and also with age.
Sclerotherapy: removing visible 'spider veins' (Telangiectasia), which appear on the surface of the skin.
Dermal fillers: Dermal fillers are injected below the skin to give a more fuller, more youthful appearance of a feature or section of the face. One type of dermal filler is hyaluronic acid. Hyaluronic acid is naturally found throughout the human body. It plays a vital role in moving nutrients to the cells of the skin from the blood. It is also commonly used in patients with arthritis as it acts like a cushion to the bones which have depleted the articular cartilage casing. Development within this field has occurred over time with synthetic forms of hyaluronic acid is being created, playing roles in other forms of cosmetic surgery such as facial augmentation.
Micropigmentation: is the creation of permanent makeup using natural pigments to places such as the eyes to create the effect of eye shadow, lips creating lipstick and cheek bones to create a blush like look. The pigment is inserted beneath the skin using a machine which injects a small needle at a very fast rate carrying pigment into the skin, creating a lasting colouration of the desired area.
In 2015, the most popular surgeries were botox, liposuction, blepharoplasties, breast implants, rhynoplasties, and rhytidectomies. According to the 2020 Plastic Surgery Statistics Report, which is published by the American Society of Plastic Surgeons, the most surgical procedure performed in the U.S. was rhinoplasty (nose reshaping) accounting for 15.2% of all cosmetic surgical procedures that year, followed by blepharoplasty (eyelid surgery), which accounted for 14% of all procedures. The third most populous procedure was rhytidectomy (facelift) (10% of all procedures), then liposuction (9.1% of all procedures).
== Complications, risks, and reversals ==
All surgery has risks. Common complications of cosmetic surgery includes hematoma, nerve injury, infection, scarring, implant failure and end organ damage. Breast implants can have many complications, including rupture. In a study of his 4761 augmentation mammaplasty patients, Eisenberg reported that overfilling saline breast implants 10–13% significantly reduced the rupture-deflation rate to 1.83% at 8-years post-implantation. In 2011 FDA stated that one in five patients who received implants for breast augmentation will need them removed within 10 years of implantation.
== Psychological disorders ==
Although media and advertising do play a large role in influencing many people's lives, such as by making people believe plastic surgery to be an acceptable course to change one's identity to their liking, researchers believe that plastic surgery obsession is linked to psychological disorders such as body dysmorphic disorder. There exists a correlation between those with BDD and the predilection toward cosmetic plastic surgery in order to correct a perceived defect in their appearance.
BDD is a disorder resulting in the individual becoming "preoccupied with what they regard as defects in their bodies or faces". Alternatively, where there is a slight physical anomaly, then the person's concern is markedly excessive. While 2% of people have body dysmorphic disorder in the United States, 15% of patients seeing a dermatologist and cosmetic surgeons have the disorder. Half of the patients with the disorder who have cosmetic surgery performed are not pleased with the aesthetic outcome. BDD can lead to suicide in some people with the condition. While many with BDD seek cosmetic surgery, the procedures do not treat BDD, and can ultimately worsen the problem. The psychological root of the problem is usually unidentified; therefore causing the treatment to be even more difficult. Some say that the fixation or obsession with correction of the area could be a sub-disorder such as anorexia or muscle dysmorphia. The increased use of body and facial reshaping applications such as Snapchat and Facetune have been identified as potential triggers of BDD. Recently, a phenomenon referred to as 'Snapchat dysmorphia' has appeared to describe people who request surgery to resemble the edited version of themselves as they appear through Snapchat filters. In response to the detrimental trend, Instagram banned all augmented reality (AR) filters that depict or promote cosmetic surgery.
In some cases, people whose physicians refuse to perform any further surgeries, have turned to "do it yourself" plastic surgery, injecting themselves and facing extreme safety risks.
== See also ==
Biomaterial
Body modification
Cosmetic surgery in Australia
Dental trauma
Dermatologic surgical procedure
Ethnic plastic surgery
List of plastic surgery flaps
Plastic and Reconstructive Surgery
Scalp reconstruction
Serdev suture
Rejuvenation
== References ==
== Further reading ==
Atkinson M (2008). "Exploring Male Femininity in the 'Crisis': Men and Cosmetic Surgery". Body & Society. 14: 67–87. doi:10.1177/1357034X07087531. S2CID 143604536.
Fraser S (2003). Cosmetic surgery, gender and culture. Palgrave. ISBN 978-1-4039-1299-2.
Gilman S (2005). Creating Beauty to Cure the Soul: Race and Psychology in the Shaping of Aesthetic Surgery. Duke University Press. ISBN 978-0-8223-2144-6.
Haiken E (1997). Venus Envy: A History of Cosmetic Surgery. Johns Hopkins University Press. ISBN 978-0-8018-5763-8.
Kolle FS (1911). Plastic and Cosmetic Surgery. D. Appleton and Company.
Kalaskar D, Butler P, Ghali S, eds. (2016). Textbook of Plastic and Reconstructive Surgery. UCL Press. ISBN 9781910634394.
== External links ==
Countries with the largest total number of cosmetic procedures, Statista, 2019
Cosmetic Surgery Statistics, American Cosmetic Association, 2023 | Wikipedia/Cosmetic_surgery |
Pediatric plastic surgery is plastic surgery performed on children. Its procedures are predominantly conducted for reconstructive purposes, although some cosmetic procedures are performed on children as well. In children, the line between cosmetic and reconstructive surgery is often blurred, as many congenital deformities impair physical function as well as aesthetics.
Children make up roughly 3% of all plastic surgery procedures, and the majority of these procedures correct a congenital deformity. Cleft lip, syndactyly, and polydactyly are among the most common conditions treated with pediatric reconstructive surgery. Common pediatric cosmetic procedures include breast augmentation or reduction, auricular reconstruction, and rhinoplasty.
== Reconstructive plastic surgery ==
Reconstructive plastic surgery is performed on abnormal structures of the body that are the result of congenital defects, developmental abnormalities, trauma, infection, tumors or disease. While reconstructive surgery is most often undertaken to regain normal motor function or prevent current or future health problems, aesthetics is also considered by the surgical team.
Several of the most common congenital birth defects can be treated by a plastic surgeon operating as an individual, or as a part of a multi-disciplinary team. The most common pediatric birth defects requiring plastic surgeon involvement include:
Cleft lip and/or palate - Babies born with the defect will have opening in the vicinity of the upper lip. The size of the opening reaches anywhere from a small notch to near towards the base of the nostril, in which it would either involve one or both sides of the lip. Worldwide, clefts are estimated to affect 1 in every 700-1000 live births. Roughly 25% of cleft lip and palate cases are inherited from parents, with the other 75% believed to be the cause of a combination of lifestyle and chance factors.
Syndactyly / Polydactyly – The most common of congenital malformations affecting limbs. It is believed that Syndactyly, exhibits in variation, in which digits can be fused either partially or across its entire length, or as simple as only being connected superficially by skin. It affects 1 in every 2,000 – 3,000 live births. Polydactyly is the presence of extra fingers or toes at birth, and is believed to affect somewhere around 2 out of every 1,000 live births. However, it is believed that many cases are so minor that they are taken care of shortly after birth and not reported, so actual statistics may be higher.
Positional Plagiocephaly – IN 1992, to decrease the incidence of SIDS, the American Academy of Pediatrics initiated the "Back to Sleep" campaign, which recommended that babies be put to sleep on their backs. While this almost halved the number of SIDS deaths, the campaign appeared to also help raise plagiocephaly incidence fivefold, to roughly one in sixty live births. Plagiocephaly is simply the flattening of one area of the skull, generally one babies tend to favor as they lie. While treatment is often as simply as repositioning the baby during sleep, in more pronounced cases helmet therapy may be put to use. In most cases, plagiocephaly is quite minor and easily resolved, with many more pediatric plastic surgeons becoming familiar with helmet therapy for more advanced cases.
Craniosynostosis – Much less common, but potentially much more serious than plagiocephaly is craniosynostosis. Craniosynostosis is a congenital abnormality originating from the central nervous system in which one or more of the fibrous joints in the skull close prematurely. This fusion often requires surgical intervention to reconstruct the skull (see craniofacial surgery) either to bring it back to its normal position or to give it a more natural shape. It is believed that craniosynostosis occurs in 1 out of 1,800 to 2,200 live births, and is often a side effect of an associated syndrome.
== Cosmetic plastic surgery ==
Cosmetic plastic surgery is defined as a surgical procedure undertaken to improve the physical appearance and self-esteem of a patient. These procedures are usually elective.
While the majority of pediatric plastic surgery procedures done are reconstructive; there are those performed for cosmetic purposes. The most common procedures done for cosmetic benefit in children include:
Breast augmentation
Male breast reduction
Ear surgery as a result of microtia
Rhinoplasty
Out of all procedures, nose reshaping generally has the most cases on an annual basis (4,313 procedures in 1996). However, children make up only 9% of the total caseload for all nose reshaping. On the opposite end of the spectrum, children requiring ear surgery accounted for 2,470 procedures in 1996, a total of 34% of all total ear surgeries.
While many of these procedures are done for purely cosmetic benefit, many plastic surgeons work on these features (giving them a more normal appearance), while performing a surgery to improve function as the result of a congenital deformity.
== Multi-disciplinary emphasis ==
With the unique challenges created in the field of plastic surgery, an increasingly popular trend has been to utilize the multi-disciplinary team approach in treatment.
Common conditions involving team treatment include:
Breast problems - Includes gynecomastia (male breast development), macromastia (excessively large breasts), tuberous defects, and breast asymmetry. Often, children with breast conditions develop physical problems, as well as psychological side effects. With this knowledge, current multi-disciplinary clinics have arisen including specialists from plastic surgery, nutrition, adolescent medicine, psychology, gynecology, and social work.
Head, Neck, and Skullbase Tumors – Includes angiofibroma, desmoid tumors, fibrosarcomas, hemangiomas, lymphomas and lymphatic malformations, and neuroblastoma. While the bulk of procedures may be left up to neurosurgeons, otolaryngology, and maxillofacial surgery, a multidisaplinary approach is also crucial to minimize scars and maintain a somewhat normal shape and function.
Cleft lip and palate – In cleft lip and palate cases, not are there only hampering physical side effects manifested in the under developed lip and palate, there are also a host of other potential complications. For this reason, CLP children are cared for by a team that may include plastic surgeons or oral and maxillofacial surgeons, speech pathologists, audiologists, densits, orthodontists, and genetics professionals if there is an associated syndrome.
Craniofacial anomalies - Includes craniosynostosis, plagiocephaly, and syndromes associated with these defects. In cases of craniosynostosis where surgical intervention is necessary, the involvement of a team of multi-disciplinary professionals is of utmost importance. Team members often come from departments of plastic surgery, oral and maxillofacial surgery, neurosurgery, audiology, dentistry, orthodontics, and speech and language pathology. These professionals often assist not only in operational procedures, but in developing coordinated care plans for the child throughout their life.
Vascular anomalies – vascular malformations, hemangiomas, and rare vascular tumors. Not only do vascular anomalies have often prominent interior bodily effects; they manifest themselves physically as well. For this reason, the involvement of multiple specialties in coordinating care is of utmost importance. Specialists involve in vascular anomalies and hemangioma care often hail from the disciplines of general surgery, vascular anomalies research, plastic surgery, dermatology, cardiology, hematology/oncology, neurology/neurosurgery, maxillofacial surgery, and otolaryngology. The child needs treatment not only to minimize the physical side effects of a hemangioma or vascular anomalies, but also help in finding out why the tumor is present (if it is in fact a tumor), and developing a course of treatment if necessary.
== References == | Wikipedia/Pediatric_plastic_surgery |
Spectral imaging is an umbrella term for energy-resolved X-ray imaging in medicine. The technique makes use of the energy dependence of X-ray attenuation to either increase the contrast-to-noise ratio, or to provide quantitative image data and reduce image artefacts by so-called material decomposition. Dual-energy imaging, i.e. imaging at two energy levels, is a special case of spectral imaging and is still the most widely used terminology, but the terms "spectral imaging" and "spectral CT" have been coined to acknowledge the fact that photon-counting detectors have the potential for measurements at a larger number of energy levels.
== Background ==
The first medical application of spectral imaging appeared in 1953 when B. Jacobson at the Karolinska University Hospital, inspired by X-ray absorption spectroscopy, presented a method called "dichromography" to measure the concentration of iodine in X-ray images. In the 70's, spectral computed tomography (CT) with exposures at two different voltage levels was proposed by G.N. Hounsfield in his landmark CT paper. The technology evolved rapidly during the 70's and 80's, but technical limitations, such as motion artifacts, for long held back widespread clinical use.
In recent years, however, two fields of technological breakthrough have spurred a renewed interest in energy-resolved imaging. Firstly, single-scan energy-resolved CT was introduced for routine clinical use in 2006 and is now available by several major manufacturers, which has resulted in a large and expanding number of clinical applications. Secondly, energy-resolving photon-counting detectors start to become available for clinical practice; the first commercial photon-counting system was introduced for mammography in 2003, and CT systems are at the verge of being feasible for routine clinical use.
== Spectral image acquisition ==
An energy-resolved imaging system probes the object at two or more photon energy levels. In a generic imaging system, the projected signal in a detector element at energy level
Ω
∈
{
E
1
,
E
2
,
E
3
,
…
}
{\textstyle \Omega \in \{E_{1},E_{2},E_{3},\ldots \}}
is
where
q
{\textstyle q}
is the number of incident photons,
Φ
{\textstyle \Phi }
is the normalized incident energy spectrum, and
Γ
{\textstyle \Gamma }
is the detector response function. Linear attenuation coefficients and integrated thicknesses for materials that make up the object are denoted
μ
{\textstyle \mu }
and
t
{\textstyle t}
(attenuation according to Lambert–Beers law). Two conceivable ways of acquiring spectral information are to either vary
q
×
Φ
{\textstyle q\times \Phi }
with
Ω
{\textstyle \Omega }
, or to have
Ω
{\textstyle \Omega }
-specific
Γ
{\textstyle \Gamma }
, here denoted incidence-based and detection-based methods, respectively.
Most elements appearing naturally in human bodies are of low atomic number and lack absorption edges in the diagnostic X-ray energy range. The two dominating X-ray interaction effects are then Compton scattering and the photo-electric effect, which can be assumed to be smooth and with separable and independent material and energy dependences. The linear attenuation coefficients can hence be expanded as
In contrast-enhanced imaging, high-atomic-number contrast agents with K absorption edges in the diagnostic energy range may be present in the body. K-edge energies are material specific, which means that the energy dependence of the photo-electric effect is no longer separable from the material properties, and an additional term can be added to Eq. (2) according to
where
a
K
{\textstyle a_{K}}
and
f
K
{\textstyle f_{K}}
are the material coefficient and energy dependency of contrast-agent material
K
{\textstyle K}
.
== Energy weighting ==
Summing the energy bins in Eq. (1) (
n
=
∑
n
Ω
{\textstyle n=\sum n_{\Omega }}
) yields a conventional non-energy-resolved image, but because X-ray contrast varies with energy, a weighted sum (
n
=
∑
w
Ω
×
n
Ω
{\textstyle n=\sum w_{\Omega }\times n_{\Omega }}
) optimizes the contrast-to-noise-ratio (CNR) and enables a higher CNR at a constant patient dose or a lower dose at a constant CNR. The benefit of energy weighting is highest where the photo-electric effect dominates and lower in high-energy regions dominated by Compton scattering (with weaker energy dependence).
Energy weighting was pioneered by Tapiovaara and Wagner and has subsequently been refined for projection imaging and CT with CNR improvements ranging from a few percent up to tenth of percent for heavier elements and an ideal CT detector. An example with a realistic detector was presented by Berglund et al. who modified a photon-counting mammography system and raised the CNR of clinical images by 2.2–5.2%.
== Material decomposition ==
Equation (1) can be treated as a system of equations with material thicknesses as unknowns, a technique broadly referred to as material decomposition. System properties and linear attenuation coefficients need to be known, either explicitly (by modelling) or implicitly (by calibration). In CT, implementing material decomposition post reconstruction (image-based decomposition) does not require coinciding projection data, but the decomposed images may suffer from beam-hardening artefacts because the reconstruction algorithm is generally non-reversible. Applying material decomposition directly in projection space instead (projection-based decomposition), can in principle eliminate beam-hardening artefacts because the decomposed projections are quantitative, but the technique requires coinciding projection data such as from a detection-based method.
In the absence of K-edge contrast agents and any other information about the object (e.g. thickness), the limited number of independent energy dependences according to Eq. (2) means that the system of equations can only be solved for two unknowns, and measurements at two energies (
|
Ω
|
=
2
{\textstyle |\Omega |=2}
) are necessary and sufficient for a unique solution of
t
1
{\textstyle t_{1}}
and
t
2
{\textstyle t_{2}}
. Materials 1 and 2 are referred to as basis materials and are assumed to make up the object; any other material present in the object will be represented by a linear combination of the two basis materials.
Material-decomposed images can be used to differentiate between healthy and malignant tissue, such as micro calcifications in the breast, ribs and pulmonary nodules, cysts, solid tumors and normal breast tissue, posttraumatic bone bruises (bone marrow edema) and the bone itself, different types of renal calculi (stones), and gout in the joints. The technique can also be used to characterize healthy tissue, such as the composition of breast tissue (an independent risk factor for breast cancer) and bone-mineral density (an independent risk factor for fractures and all-cause mortality). Finally, virtual autopsies with spectral imaging can facilitate detection and characterization of bullets, knife tips, glass or shell fragments etc.
The basis-material representation can be readily converted to images showing the amounts of photoelectric and Compton interactions by invoking Eq. (2), and to images of effective-atomic-number and electron density distributions. As the basis-material representation is sufficient to describe the linear attenuation of the object, it is possible to calculate virtual monochromatic images, which is useful for optimizing the CNR to a certain imaging task, analogous to energy weighting. For instance, the CNR between grey and white brain matter is maximized at medium energies, whereas artefacts caused by photon starvation are minimized at higher virtual energies.
== K-edge imaging ==
In contrast-enhanced imaging, additional unknowns may be added to the system of equations according to Eq. (3) if one or several K absorption edges are present in the imaged energy range, a technique often referred to as K-edge imaging. With one K-edge contrast agent, measurements at three energies (
|
Ω
|
=
3
{\textstyle |\Omega |=3}
) are necessary and sufficient for a unique solution, two contrast agents can be differentiated with four energy bins (
|
Ω
|
=
4
{\textstyle |\Omega |=4}
), etc. K-edge imaging can be used to either enhance and quantify, or to suppress a contrast agent.
Enhancement of contrast agents can be used for improved detection and diagnosis of tumors, which exhibit increased retention of contrast agents. Further, differentiation between iodine and calcium is often challenging in conventional CT, but energy-resolved imaging can facilitate many procedures by, for instance, suppressing bone contrast and improving characterization of atherosclerotic plaque. Suppression of contrast agents is employed in so-called virtual unenhanced or virtual non-contrast (VNC) images. VNC images are free from iodine staining (contrast-agent residuals), can save dose to the patient by reducing the need for an additional non-contrast acquisition, can improve radiotherapy dose calculations from CT images, and can help in distinguishing between contrast agent and foreign objects.
Most studies of contrast-enhanced spectral imaging have used iodine, which is a well-established contrast agent, but the K edge of iodine at 33.2 keV is not optimal for all applications and some patients are hypersensitive to iodine. Other contrast agents have therefore been proposed, such as gadolinium (K edge at 50.2 keV), nanoparticle silver (K edge at 25.5 keV), zirconium (K edge at 18.0 keV), and gold (K edge at 80.7 keV). Some contrast agents can be targeted, which opens up possibilities for molecular imaging, and using several contrast agents with different K-edge energies in combination with photon-counting detectors with a corresponding number of energy thresholds enable multi-agent imaging.
== Technologies and methods ==
Incidence-based methods obtain spectral information by acquiring several images at different tube voltage settings, possibly in combination with different filtering. Temporal differences between the exposures (e.g. patient motion, variation in contrast-agent concentration) for long limited practical implementations, but dual-source CT and subsequently rapid kV switching have now virtually eliminated the time between exposures. Splitting the incident radiation of a scanning system into two beams with different filtration is another way to quasi-simultaneously acquire data at two energy levels.
Detection-based methods instead obtain spectral information by splitting the spectrum after interaction in the object. So-called sandwich detectors consist of two (or more) detector layers, where the top layer preferentially detects low-energy photons and the bottom layer detects a harder spectrum. Detection-based methods enable projection-based material decomposition because the two energy levels measured by the detector represent identical ray paths. Further, spectral information is available from every scan, which has work-flow advantages.
The currently most advanced detection-based method is based on photon-counting detectors. As opposed to conventional detectors, which integrate all photon interactions over the exposure time, photon-counting detectors are fast enough to register and measure the energy of single photon events. Hence, the number of energy bins and the spectral separation are not determined by physical properties of the system (detector layers, source / filtration etc.), but by the detector electronics, which increases efficiency and the degrees of freedom, and enable elimination of electronic noise. The first commercial photon-counting application was the MicroDose mammography system, introduced by Sectra Mamea in 2003 (later acquired by Philips), and spectral imaging was launched on this platform in 2013.
The MicroDose system was based on silicon strip detectors, a technology that has subsequently been refined for CT with up to eight energy bins. Silicon as sensor material benefit from high charge-collection efficiency, ready availability of high-quality high-purity silicon crystals, and established methods for test and assembly. The relatively low photo-electric cross section can be compensated for by arranging the silicon wafers edge on, which also enables depth segments. Cadmium telluride (CdTe) and cadmium–zinc telluride (CZT) are also being investigated as sensor materials. The higher atomic number of these materials result in a higher photo-electric cross section, which is advantageous, but the higher fluorescent yield degrades spectral response and induces cross talk. Manufacturing of macro-sized crystals of these materials have so far posed practical challenges and leads to charge trapping and long-term polarization effects (build-up of space charge). Other solid-state materials, such as gallium arsenide and mercuric iodide, as well as gas detectors, are currently quite far from clinical implementation.
The main intrinsic challenge of photon-counting detectors for medical imaging is pulse pileup, which results in lost counts and reduced energy resolution because several pulses are counted as one. Pileup will always be present in photon-counting detectors because of the Poisson distribution of incident photons, but detector speeds are now so high that acceptable pileup levels at CT count rates begin to come within reach.
== See also ==
Photon-counting mammography
Photon-counting computed tomography
== References == | Wikipedia/Spectral_imaging_(radiography) |
Digital radiography is a form of radiography that uses x-ray–sensitive plates to directly capture data during the patient examination, immediately transferring it to a computer system without the use of an intermediate cassette. Advantages include time efficiency through bypassing chemical processing and the ability to digitally transfer and enhance images. Also, less radiation can be used to produce an image of similar contrast to conventional radiography.
Instead of X-ray film, digital radiography uses a digital image capture device. This gives advantages of immediate image preview and availability; elimination of costly film processing steps; a wider dynamic range, which makes it more forgiving for over- and under-exposure; as well as the ability to apply special image processing techniques that enhance overall display quality of the image.
== Detectors ==
=== Flat panel detectors ===
Flat panel detectors (FPDs) are the most common kind of direct digital detectors. They are classified in two main categories:
1. Indirect FPDs Amorphous silicon (a-Si) is the most common material of commercial FPDs. Combining a-Si detectors with a scintillator in the detector’s outer layer, which is made from caesium iodide (CsI) or gadolinium oxysulfide (Gd2O2S), converts X-rays to light. Because of this conversion the a-Si detector is considered an indirect imaging device. The light is channeled through the a-Si photodiode layer where it is converted to a digital output signal. The digital signal is then read out by thin film transistors (TFTs) or fiber-coupled CCDs.
2. Direct FPDs. Amorphous selenium (a-Se) FPDs are known as “direct” detectors because X-ray photons are converted directly into charge. The outer layer of the flat panel in this design is typically a high-voltage bias electrode. X-ray photons create electron-hole pairs in a-Se, and the transit of these electrons and holes depends on the potential of the bias voltage charge. As the holes are replaced with electrons, the resultant charge pattern in the selenium layer is read out by a TFT array, active matrix array, electrometer probes or microplasma line addressing.
=== Other direct digital detectors ===
Detectors based on CMOS and charge-coupled device (CCD) have also been developed, but despite lower costs compared to FPDs of some systems, bulky designs and worse image quality have precluded widespread adoption.
A high-density line-scan solid state detector is composed of a photostimulable barium fluorobromide doped with europium (BaFBr:Eu) or caesium bromide (CsBr) phosphor. The phosphor detector records the X-ray energy during exposure and is scanned by a laser diode to excite the stored energy which is released and read out by a digital image capture array of a CCD.
=== Phosphor plate radiography ===
Phosphor plate radiography resembles the old analogue system of a light sensitive film sandwiched between two x-ray sensitive screens, the difference being the analogue film has been replaced by an imaging plate with photostimulable phosphor (PSP), which records the image to be read by an image reading device, which transfers the image usually to a picture archiving and communication system (PACS). It is also called photostimulable phosphor (PSP) plate-based radiography or computed radiography (not to be confused with computed tomography which uses computer processing to convert multiple projectional radiographies to a 3D image).
After X-ray exposure the plate (sheet) is placed in a special scanner where the latent image is retrieved point by point and digitized, using laser light scanning. The digitized images are stored and displayed on the computer screen. Phosphor plate radiography has been described as having an advantage of fitting within any pre-existing equipment without modification because it replaces the existing film; however, it includes extra costs for the scanner and replacement of scratched plates.
Initially phosphor plate radiography was the system of choice; early DR systems were prohibitively expensive (each cassette costs £40-£50K), and as the 'technology was being taken to the patient', prone to damage. Since there is no physical printout, and after the readout process a digital image is obtained, CR has been known as an indirect digital technology, bridging the gap between x-ray film and fully digital detectors.
== Industrial usage ==
=== Security ===
Digital radiography (DR) has existed in various forms (for example, CCD and amorphous Silicon imagers) in the security X-ray inspection field for over 20 years and is steadily replacing the use of film for inspection X-rays in the security and nondestructive testing (NDT) fields. DR has opened a window of opportunity for the security NDT industry due to several key advantages including excellent image quality, high POD (probability of detection), portability, environmental friendliness and immediate imaging.
=== Materials ===
Nondestructive testing of materials is vital in fields such as aerospace and electronics where integrity of materials is vital for safety and cost reasons. Advantages of digital technologies include the ability to provide results in real time.
== History ==
=== Key developments ===
== See also ==
Dental radiography
Fluoroscopy
X-ray detectors
== References == | Wikipedia/Digital_radiography |
Projectional radiography, also known as conventional radiography, is a form of radiography and medical imaging that produces two-dimensional images by X-ray radiation. The image acquisition is generally performed by radiographers, and the images are often examined by radiologists. Both the procedure and any resultant images are often simply called 'X-ray'. Plain radiography or roentgenography generally refers to projectional radiography (without the use of more advanced techniques such as computed tomography that can generate 3D-images). Plain radiography can also refer to radiography without a radiocontrast agent or radiography that generates single static images, as contrasted to fluoroscopy, which are technically also projectional.
== Equipment ==
=== X-ray generator ===
Projectional radiographs generally use X-rays created by X-ray generators, which generate X-rays from X-ray tubes.
=== Grid ===
An anti-scatter grid may be placed between the patient and the detector to reduce the quantity of scattered x-rays that reach the detector. This improves the contrast resolution of the image, but also increases radiation exposure for the patient.
=== Detector ===
Detectors can be divided into two major categories: imaging detectors (such as photographic plates and X-ray film (photographic film), now mostly replaced by various digitizing devices like image plates or flat panel detectors) and dose measurement devices (such as ionization chambers, Geiger counters, and dosimeters used to measure the local radiation exposure, dose, and/or dose rate, for example, for verifying that radiation protection equipment and procedures are effective on an ongoing basis).
=== Shielding ===
Lead is the main material used by radiography personnel for shielding against scattered X-rays.
== Image properties ==
Projectional radiography relies on the characteristics of X-ray radiation (quantity and quality of the beam) and knowledge of how it interacts with human tissue to create diagnostic images. X-rays are a form of ionizing radiation, meaning it has sufficient energy to potentially remove electrons from an atom, thus giving it a charge and making it an ion.
=== X-ray attenuation ===
When an exposure is made, X-ray radiation exits the tube as what is known as the primary beam. When the primary beam passes through the body, some of the radiation is absorbed in a process known as attenuation. Anatomy that is denser has a higher rate of attenuation than anatomy that is less dense, so bone will absorb more X-rays than soft tissue. What remains of the primary beam after attenuation is known as the remnant beam. The remnant beam is responsible for exposing the image receptor. Areas on the image receptor that receive the most radiation (portions of the remnant beam experiencing the least attenuation) will be more heavily exposed, and therefore will be processed as being darker. Conversely, areas on the image receptor that receive the least radiation (portions of the remnant beam experience the most attenuation) will be less exposed and will be processed as being lighter. This is why bone, which is very dense, process as being 'white' on radio graphs, and the lungs, which contain mostly air and is the least dense, shows up as 'black'.
=== Density ===
Radiographic density is the measure of overall darkening of the image. Density is a logarithmic unit that describes the ratio between light hitting the film and light being transmitted through the film. A higher radiographic density represents more opaque areas of the film, and lower density more transparent areas of the film.
With digital imaging, however, density may be referred to as brightness. The brightness of the radiograph in digital imaging is determined by computer software and the monitor on which the image is being viewed.
=== Contrast ===
Contrast is defined as the difference in radiographic density between adjacent portions of the image. The range between black and white on the final radiograph. High contrast, or short-scale contrast, means there is little gray on the radiograph, and there are fewer gray shades between black and white. Low contrast, or long-scale contrast, means there is much gray on the radiograph, and there are many gray shades between black and white.
Closely related to radiographic contrast is the concept of exposure latitude. Exposure latitude is the range of exposures over which the recording medium (image receptor) will respond with a diagnostically useful density; in other words, this is the "flexibility" or "leeway" that a radiographer has when setting his/her exposure factors. Images having a short-scale of contrast will have narrow exposure latitude. Images having long-scale contrast will have a wide exposure latitude; that is, the radiographer will be able to utilize a broader range of technical factors to produce a diagnostic-quality image.
Contrast is determined by the kilovoltage (kV; energy/quality/penetrability) of the x-ray beam and the tissue composition of the body part being radiographed. Selection of look-up tables (LUT) in digital imaging also affects contrast.
Generally speaking, high contrast is necessary for body parts in which bony anatomy is of clinical interest (extremities, bony thorax, etc.). When soft tissue is of interest (ex. abdomen or chest), lower contrast is preferable in order to accurately demonstrate all of the soft tissue tones in these areas.
=== Geometric magnification ===
Geometric magnification results from the detector being farther away from the X-ray source than the object. In this regard, the source-detector distance or SDD is a measurement of the distance between the generator and the detector. Alternative names are source/focus to detector/image-receptor/film (latter used when using X-ray film) distance (SID, FID or FRD).
The estimated radiographic magnification factor (ERMF) is the ratio of the source-detector distance (SDD) over the source-object distance (SOD). The size of the object is given as:
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{\displaystyle Size_{object}={\frac {Size_{projection}}{ERMF}}}
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where Sizeprojection is the size of the projection that the object forms on the detector. On lumbar and chest radiographs, it is anticipated that ERMF is between 1.05 and 1.40. Because of the uncertainty of the true size of objects seen on projectional radiography, their sizes are often compared to other structures within the body, such as dimensions of the vertebrae, or empirically by clinical experience.
The source-detector distance (SDD) is roughly related to the source-object distance (SOD) and the object-detector distance (ODD) by the equation SOD + ODD = SDD.
=== Geometric unsharpness ===
Geometric unsharpness is caused by the X-ray generator not creating X-rays from a single point but rather from an area, as can be measured as the focal spot size. Geometric unsharpness increases proportionally to the focal spot size, as well as the estimated radiographic magnification factor (ERMF).
=== Geometric distortion ===
Organs will have different relative distances to the detector depending on which direction the X-rays come from. For example, chest radiographs are preferably taken with X-rays coming from behind (called a "posteroanterior" or "PA" radiograph). However, in case the patient cannot stand, the radiograph often needs to be taken with the patient lying in a supine position (called a "bedside" radiograph) with the X-rays coming from above ("anteroposterior" or "AP"), and geometric magnification will then cause for example the heart to appear larger than it actually is because it is further away from the detector.
=== Scatter ===
In addition to using an anti-scatter grid, increasing the ODD alone can improve image contrast by decreasing the amount of scattered radiation that reaches the receptor. However, this needs to be weighted against increased geometric unsharpness if the SDD is not also proportionally increased.
== Imaging variations by target tissue ==
Projection radiography uses X-rays in different amounts and strengths depending on what body part is being imaged:
Hard tissues such as bone require a relatively high energy photon source, and typically a tungsten anode is used with a high voltage (50-150 kVp) on a 3-phase or high-frequency machine to generate bremsstrahlung or braking radiation. Bony tissue and metals are denser than the surrounding tissue, and thus by absorbing more of the X-ray photons they prevent the film from getting exposed as much. Wherever dense tissue absorbs or stops the X-rays, the resulting X-ray film is unexposed, and appears translucent blue, whereas the black parts of the film represent lower-density tissues such as fat, skin, and internal organs, which could not stop the X-rays. This is usually used to see bony fractures, foreign objects (such as ingested coins), and used for finding bony pathology such as osteoarthritis, infection (osteomyelitis), cancer (osteosarcoma), as well as growth studies (leg length, achondroplasia, scoliosis, etc.).
Soft tissues are seen with the same machine as for hard tissues, but a "softer" or less-penetrating X-ray beam is used. Tissues commonly imaged include the lungs and heart shadow in a chest X-ray, the air pattern of the bowel in abdominal X-rays, the soft tissues of the neck, the orbits by a skull X-ray before an MRI to check for radiopaque foreign bodies (especially metal), and of course the soft tissue shadows in X-rays of bony injuries are looked at by the radiologist for signs of hidden trauma (for example, the famous "fat pad" sign on a fractured elbow).
== Projectional radiography terminology ==
NOTE: The simplified word 'view' is often used to describe a radiographic projection.
Plain radiography generally refers to projectional radiography (without the use of more advanced techniques such as computed tomography). Plain radiography can also refer to radiography without a radiocontrast agent or radiography that generates single static images, as contrasted to fluoroscopy.
AP - Antero-Posterior
PA - Postero-Anterior
DP - Dorsal-Plantar
Lateral - Projection taken with the central ray perpendicular to the midsagittal plane
Oblique - Projection taken with the central ray at an angle to any of the body planes. Described by the angle of obliquity and the portion of the body the X-ray beam exits; right or left and posterior or anterior. For example, a 45 degree Right Anterior Oblique of the Cervical Spine.
Flexion - Joint is radiographed while in flexion
Extension - Joint is radiographed while in extension
Stress Views - Typically taken of joints with external force applied in a direction that is different from main movement of the joint. Test of stability.
Weight-bearing - Generally with the subject standing up
HBL, HRL, HCR or CTL - Horizontal Beam Lateral, Horizontal Ray Lateral, Horizontal Central Ray, or Cross Table Lateral. Used to obtain a lateral projection usually when patients are unable to move.
Prone - Patient lies on their front
Supine - Patient lies on the back
Decubitus - Patient lying down. Further described by the downside body surface: dorsal (backside down), ventral (frontside down), or lateral (left or right side down).
OM - occipito-mental, an imaginary positioning line extending from the menti (chin) to the occiput (particularly the external occiputal protuberance)
Cranial or Cephalad - Tube angulation towards the head
Caudal - Tube angulation towards the feet
== By target organ or structure ==
=== Breasts ===
Projectional radiography of the breasts is called mammography. This has been used mostly on women to screen for breast cancer, but is also used to view male breasts, and used in conjunction with a radiologist or a surgeon to localise suspicious tissues before a biopsy or a lumpectomy. Breast implants designed to enlarge the breasts reduce the viewing ability of mammography, and require more time for imaging as more views need to be taken. This is because the material used in the implant is very dense compared to breast tissue, and looks white (clear) on the film. The radiation used for mammography tends to be softer (has a lower photon energy) than that used for the harder tissues. Often a tube with a molybdenum anode is used with about 30 000 volts (30 kV), giving a range of X-ray energies of about 15-30 keV. Many of these photons are "characteristic radiation" of a specific energy determined by the atomic structure of the target material (Mo-K radiation).
=== Chest ===
Chest radiographs are used to diagnose many conditions involving the chest wall, including its bones, and also structures contained within the thoracic cavity including the lungs, heart, and great vessels. Conditions commonly identified by chest radiography include pneumonia, pneumothorax, interstitial lung disease, heart failure, bone fracture and hiatal hernia. Typically an erect postero-anterior (PA) projection is the preferred projection. Chest radiographs are also used to screen for job-related lung disease in industries such as mining where workers are exposed to dust.
For some conditions of the chest, radiography is good for screening but poor for diagnosis. When a condition is suspected based on chest radiography, additional imaging of the chest can be obtained to definitively diagnose the condition or to provide evidence in favor of the diagnosis suggested by initial chest radiography. Unless a fractured rib is suspected of being displaced, and therefore likely to cause damage to the lungs and other tissue structures, an X-ray of the chest is not necessary as it will not alter patient management.
=== Abdomen ===
In children, abdominal radiography is indicated in the acute setting in suspected bowel obstruction, gastrointestinal perforation, foreign body in the alimentary tract, suspected abdominal mass and intussusception (latter as part of the differential diagnosis). Yet, CT scan is the best alternative for diagnosing intra-abdominal injury in children. For acute abdominal pain in adults, an abdominal X-ray has a low sensitivity and accuracy in general. Computed tomography provides an overall better surgical strategy planning, and possibly less unnecessary laparotomies. Abdominal X-ray is therefore not recommended for adults presenting in the emergency department with acute abdominal pain.
The standard abdominal X-ray protocol is usually a single anteroposterior projection in supine position. A Kidneys, Ureters, and Bladder projection (KUB) is an anteroposterior abdominal projection that covers the levels of the urinary system, but does not necessarily include the diaphragm.
=== Axial skeleton ===
==== Head ====
Cerebral angiography allows visualization of blood vessels in and around the brain. A contrast agent is injected prior to the radiographs of the head,
Orbital radiography, imaging both left and right eye sockets, generally including the frontal and maxillary sinuses.
Dental radiography uses a small radiation dose with high penetration to view teeth, which are relatively dense. A dentist may examine a painful tooth and gum using X-ray equipment. The machines used are typically single-phase pulsating DC, the oldest and simplest sort. Dental technicians or the dentist may run these machines; radiographers are not required by law to be present. A derivative technique from projectional radiography used in dental radiography is orthopantomography. This is a panoramic imaging technique of the upper and lower jaw using focal plane tomography, where the X-ray generator and X-ray detector are simultaneously moved so as to keep a consistent exposure of only the plane of interest during image acquisition.
Sinus - The standard protocol in the UK is OM with open mouth.
Facial Bones - The standard protocol in the UK is OM and OM 30°.
In case of trauma, the standard UK protocol is to have a CT scan of the skull instead of projectional radiography. A skeletal survey including the skull can be indicated in for example multiple myeloma.
==== Other axial skeleton ====
The spine (that is, the vertebral column. A projectional radiograph of the spine confers an effective dose of approximately 1.5 mSv, comparable to a background radiation equivalent time of 6 months.
Cervical spine: The standard projections in the UK AP and Lateral. Peg projection with trauma only. Obliques and Flexion and Extension on special request. In the US, five or six projections are common; a Lateral, two 45 degree obliques, an AP axial (Cephalad), an AP "Open Mouth" for C1-C2, and Cervicothoracic Lateral (Swimmer's) to better visualize C7-T1 if necessary. Special projections include a Lateral with Flexion and Extension of the cervical spine, an Axial for C1-C2 (Fuchs or Judd method), and an AP Axial (Caudad) for articular pillars.
Thoracic Spine - AP and Lateral in the UK. In the US, an AP and Lateral are basic projections. Obliques 20 degrees from lateral may be ordered to better visualize the zygapophysial joint.
Lumbar Spine - AP and Lateral +/- L5/S1 view in the UK, with obliques and Flexion and Extension requests being rare. In the US, basic projections include an AP, two Obliques, a Lateral, and a Lateral L5-S1 spot to better visualize the L5-S1 interspace. Special projections are AP Right and Left bending, and Laterals with Flexion and Extension.
Pelvis - AP only in the UK, with SIJ projections (prone) on special request.
Sacrum and Coccyx: In the US, if both bones are to be examined separate cephalad and caudad AP axial projections are obtained for the sacrum and coccyx respectively as well as a single Lateral of both bones.
Ribs: In the US, common rib projections are based on the location of the area of interest. These are obtained with shorter wavelengths/higher frequencies/higher levels of radiation than a standard CXR.
Anterior area of interest - a PA chest X-ray, a PA projection of the ribs, and a 45 degree Anterior Oblique with the non-interest side closest to the image receptor.
Posterior area of interest - a PA chest X-ray, an AP projection of the ribs, and a 45 degree Posterior Oblique with the side of interest closest to the image receptor.
Sternum. The standard projections in the UK are PA chest and lateral sternum. In the US, the two basic projections are a 15 to 20 degree Right Anterior Oblique and a Lateral.
Sternoclavicular Joints - Are usually ordered as a single PA and a Right and Left 15 degree Right Anterior Obliques in the US.
=== Shoulders ===
These include:
AP-projection 40° posterior oblique after Grashey
The body has to be rotated about 30 to 45 degrees towards the shoulder to be imaged, and the standing or sitting patient lets the arm hang. This method reveals the joint gap and the vertical alignment towards the socket.
Transaxillary projection
The arm should be abducted 80 to 100 degrees. This method reveals:
The horizontal alignment of the humerus head in respect to the socket, and the lateral clavicle in respect to the acromion.
Lesions of the anterior and posterior socket border or of the tuberculum minus.
The eventual non-closure of the acromial apophysis.
The coraco-humeral interval
Y-projection
The lateral contour of the shoulder should be positioned in front of the film in a way that the longitudinal axis of the scapula continues parallel to the path of the rays. This method reveals:
The horizontal centralization of the humerus head and socket.
The osseous margins of the coraco-acromial arch and hence the supraspinatus outlet canal.
The shape of the acromion
This projection has a low tolerance for errors and accordingly needs proper execution. The Y-projection can be traced back to Wijnblath's 1933 published cavitas-en-face projection.
In the UK, the standard projections of the shoulder are AP and Lateral Scapula or Axillary Projection.
=== Extremities ===
A projectional radiograph of an extremity confers an effective dose of approximately 0.001 mSv, comparable to a background radiation equivalent time of 3 hours.
The standard projection protocols in the UK are:
Clavicle - AP and AP Cranial
Humerus - AP and Lateral
Elbow - AP and Lateral. Radial head projections available on request
Radius and Ulna - AP and Lateral
Wrist - DP and Lateral
Scaphoid - DP with Ulna deviation, Lateral, Oblique and DP with 30° angulation
Hip joint: AP and Lateral.
The Lauenstein projection a form of examination of the hip joint emphasizing the relationship of the femur to the acetabulum. The knee of the affected leg is flexed, and the thigh is drawn up to nearly a right angle. This is also called the frog-leg position.
Applications include X-ray of hip dysplasia.
Hand - DP and Oblique
Fingers - DP and Lateral
Thumb - AP and Lateral
Femur - AP and Lateral
Knee - AP and Lateral. Intra Condular projections on request
Patella - Skyline projection
Tibia and Fibula - AP and Lateral
Ankle - AP/Mortice and Lateral
Calcaneum - Axial and Lateral
Foot / Toes - Dorsoplantar, Oblique and Lateral.
Certain suspected conditions require specific projections. For example, skeletal signs of rickets are seen predominantly at sites of rapid growth, including the proximal humerus, distal radius, distal femur and both the proximal and the distal tibia. Therefore, a skeletal survey for rickets can be accomplished with anteroposterior radiographs of the knees, wrists, and ankles.
== General disease mimics ==
Radiological disease mimics are visual artifacts, normal anatomic structures or harmless variants that may simulate diseases or abnormalities. In projectional radiography, general disease mimics include jewelry, clothes and skin folds. In general medicine a disease mimic shows symptoms and/or signs like those of another.
== See also ==
Medical imaging in pregnancy, including projectional radiography
Radiography
Medical imaging
X-ray
X-ray generator
X-ray detector
Radiographer
Digital radiography
Tomography
Anatomical terms of location
== References ==
== External links ==
Online Radiography Positioning Manual
Nice Guidelines
The Human Skeleton | Wikipedia/Projection_radiography |
Medical ultrasound includes diagnostic techniques (mainly imaging) using ultrasound, as well as therapeutic applications of ultrasound. In diagnosis, it is used to create an image of internal body structures such as tendons, muscles, joints, blood vessels, and internal organs, to measure some characteristics (e.g., distances and velocities) or to generate an informative audible sound. The usage of ultrasound to produce visual images for medicine is called medical ultrasonography or simply sonography, or echography. The practice of examining pregnant women using ultrasound is called obstetric ultrasonography, and was an early development of clinical ultrasonography. The machine used is called an ultrasound machine, a sonograph or an echograph. The visual image formed using this technique is called an ultrasonogram, a sonogram or an echogram.
Ultrasound is composed of sound waves with frequencies greater than 20,000 Hz, which is the approximate upper threshold of human hearing. Ultrasonic images, also known as sonograms, are created by sending pulses of ultrasound into tissue using a probe. The ultrasound pulses echo off tissues with different reflection properties and are returned to the probe which records and displays them as an image.
A general-purpose ultrasonic transducer may be used for most imaging purposes but some situations may require the use of a specialized transducer. Most ultrasound examination is done using a transducer on the surface of the body, but improved visualization is often possible if a transducer can be placed inside the body. For this purpose, special-use transducers, including transvaginal, endorectal, and transesophageal transducers are commonly employed. At the extreme, very small transducers can be mounted on small diameter catheters and placed within blood vessels to image the walls and disease of those vessels.
== Types ==
The imaging mode refers to probe and machine settings that result in specific dimensions of the ultrasound image.
Several modes of ultrasound are used in medical imaging:
A-mode: Amplitude mode refers to the mode in which the amplitude of the transducer voltage is recorded as a function of two-way travel time of an ultrasound pulse. A single pulse is transmitted through the body and scatters back to the same transducer element. The voltage amplitudes recorded correlate linearly to acoustic pressure amplitudes. A-mode is one-dimensional.
B-mode: In brightness mode, an array of transducer elements scans a plane through the body resulting in a two-dimensional image. Each pixel value of the image correlates to voltage amplitude registered from the backscattered signal. The dimensions of B-mode images are voltage as a function of angle and two-way time.
M-mode: In motion mode, A-mode pulses are emitted in succession. The backscattered signal is converted to lines of bright pixels, whose brightness linearly correlates to backscattered voltage amplitudes. Each next line is plotted adjacent to the previous, resulting in an image that looks like a B-mode image. The M-mode image dimensions are however voltage as a function of two-way time and recording time. This mode is an ultrasound analogy to streak video recording in high-speed photography. As moving tissue transitions produce backscattering, this can be used to determine the displacement of specific organ structures, most commonly the heart.
Most machines convert two-way time to imaging depth using as assumed speed of sound of 1540 m/s. As the actual speed of sound varies greatly in different tissue types, an ultrasound image is therefore not a true tomographic representation of the body.
Three-dimensional imaging is done by combining B-mode images, using dedicated rotating or stationary probes. This has also been referred to as C-mode.
An imaging technique refers to a method of signal generation and processing that results in a specific application.
Most imaging techniques are operating in B-mode.
Doppler sonography: This imaging technique makes use of the Doppler effect in detection and measuring moving targets, typically blood.
Harmonic imaging: backscattered signal from tissue is filtered to comprise only frequency content of at least twice the centre frequency of the transmitted ultrasound. Harmonic imaging used for perfusion detection when using ultrasound contrast agents and for the detection of tissue harmonics. Common pulse schemes for the creation of harmonic response without the need of real-time Fourier analysis are pulse inversion and power modulation.
B-flow is an imaging technique that digitally highlights moving reflectors (mainly red blood cells) while suppressing the signals from the surrounding stationary tissue. It aims to visualize flowing blood and surrounding stationary tissues simultaneously. It is thus an alternative or complement to Doppler ultrasonography in visualizing blood flow.
Therapeutic ultrasound aimed at a specific tumor or calculus is not an imaging mode. However, for positioning a treatment probe to focus on a specific region of interest, A-mode and B-mode are typically used, often during treatment.
== Advantages and drawbacks ==
Compared to other medical imaging modalities, ultrasound has several advantages. It provides images in real-time, is portable, and can consequently be brought to the bedside. It is substantially lower in cost than other imaging strategies. Drawbacks include various limits on its field of view, the need for patient cooperation, dependence on patient physique, difficulty imaging structures obscured by bone, air or gases, and the necessity of a skilled operator, usually with professional training.
== Uses ==
Sonography (ultrasonography) is widely used in medicine. It is possible to perform both diagnosis and therapeutic procedures, using ultrasound to guide interventional procedures such as biopsies or to drain collections of fluid, which can be both diagnostic and therapeutic. Sonographers are medical professionals who perform scans which are traditionally interpreted by radiologists, physicians who specialize in the application and interpretation of medical imaging modalities, or by cardiologists in the case of cardiac ultrasonography (echocardiography). Sonography is effective for imaging soft tissues of the body. Superficial structures such as muscle, tendon, testis, breast, thyroid and parathyroid glands, and the neonatal brain are imaged at higher frequencies (7–18 MHz), which provide better linear (axial) and horizontal (lateral) resolution. Deeper structures such as liver and kidney are imaged at lower frequencies (1–6 MHz) with lower axial and lateral resolution as a price of deeper tissue penetration.
=== Anesthesiology ===
In anesthesiology, ultrasound is commonly used to guide the placement of needles when injecting local anesthetic solutions in the proximity of nerves identified within the ultrasound image (nerve block). It is also used for vascular access such as cannulation of large central veins and for difficult arterial cannulation. Transcranial Doppler is frequently used by neuro-anesthesiologists for obtaining information about flow-velocity in the basal cerebral vessels.
=== Angiology (vascular) ===
In angiology or vascular medicine, duplex ultrasound (B Mode imaging combined with Doppler flow measurement) is used to diagnose arterial and venous disease. This is particularly important in potential neurologic problems, where carotid ultrasound is commonly used for assessing blood flow and potential or suspected stenosis in the carotid arteries, while transcranial Doppler is used for imaging flow in the intracerebral arteries.
Intravascular ultrasound (IVUS) uses a specially designed catheter with a miniaturized ultrasound probe attached to its distal end, which is then threaded inside a blood vessel. The proximal end of the catheter is attached to computerized ultrasound equipment and allows the application of ultrasound technology, such as a piezoelectric transducer or capacitive micromachined ultrasonic transducer, to visualize the endothelium of blood vessels in living individuals.
In the case of the common and potentially, serious problem of blood clots in the deep veins of the leg, ultrasound plays a key diagnostic role, while ultrasonography of chronic venous insufficiency of the legs focuses on more superficial veins to assist with planning of suitable interventions to relieve symptoms or improve cosmetics.
=== Cardiology (heart) ===
Echocardiography is an essential tool in cardiology, assisting in evaluation of heart valve function, such as stenosis or insufficiency, strength of cardiac muscle contraction, and hypertrophy or dilatation of the main chambers. (ventricle and atrium)
=== Emergency medicine ===
Point of care ultrasound has many applications in emergency medicine. These include differentiating cardiac from pulmonary causes of acute breathlessness, and the Focused Assessment with Sonography for Trauma (FAST) exam, extended to include assessment for significant hemoperitoneum or pericardial tamponade after trauma (EFAST). Other uses include assisting with differentiating causes of abdominal pain such as gallstones and kidney stones. Emergency Medicine Residency Programs have a substantial history of promoting the use of bedside ultrasound during physician training.
=== Gastroenterology/Colorectal surgery ===
Both abdominal and endoanal ultrasound are frequently used in gastroenterology and colorectal surgery. In abdominal sonography, the major organs of the abdomen such as the pancreas, aorta, inferior vena cava, liver, gall bladder, bile ducts, kidneys, and spleen may be imaged. However, sound waves may be blocked by gas in the bowel and attenuated to differing degrees by fat, sometimes limiting diagnostic capabilities. The appendix can sometimes be seen when inflamed (e.g.: appendicitis) and ultrasound is the initial imaging choice, avoiding radiation if possible, although it frequently needs to be followed by other imaging methods such as CT. Endoanal ultrasound is used particularly in the investigation of anorectal symptoms such as fecal incontinence or obstructed defecation. It images the immediate perianal anatomy and is able to detect occult defects such as tearing of the anal sphincter.
=== Hepatology ===
Ultrasonography of liver tumors allows for both detection and characterization.
Ultrasound imaging studies are often obtained during the evaluation process of Fatty liver disease. Ultrasonography reveals a "bright" liver with increased echogenicity. Pocket-sized ultrasound devices might be used as point-of-care screening tools to diagnose liver steatosis.
=== Gynecology and obstetrics ===
Gynecologic ultrasonography examines female pelvic organs (specifically the uterus, ovaries, and fallopian tubes) as well as the bladder, adnexa, and pouch of Douglas. It uses transducers designed for approaches through the lower abdominal wall, curvilinear and sector, and specialty transducers such as transvaginal ultrasound.
Obstetrical sonography was originally developed in the late 1950s and 1960s by Sir Ian Donald and is commonly used during pregnancy to check the development and presentation of the fetus. It can be used to identify many conditions that could be potentially harmful to the mother and/or baby possibly remaining undiagnosed or with delayed diagnosis in the absence of sonography. It is currently believed that the risk of delayed diagnosis is greater than the small risk, if any, associated with undergoing an ultrasound scan. However, its use for non-medical purposes such as fetal "keepsake" videos and photos is discouraged.
Obstetric ultrasound is primarily used to:
Date the pregnancy (gestational age)
Confirm fetal viability
Determine location of fetus, intrauterine vs ectopic
Check the location of the placenta in relation to the cervix
Check for the number of fetuses (multiple pregnancy)
Check for major physical abnormalities.
Assess fetal growth (for evidence of intrauterine growth restriction (IUGR))
Check for fetal movement and heartbeat.
Determine the sex of the baby
According to the European Committee of Medical Ultrasound Safety (ECMUS)
Ultrasonic examinations should only be performed by competent personnel who are trained and updated in safety matters. Ultrasound produces heating, pressure changes and mechanical disturbances in tissue. Diagnostic levels of ultrasound can produce temperature rises that are hazardous to sensitive organs and the embryo/fetus. Biological effects of non-thermal origin have been reported in animals but, to date, no such effects have been demonstrated in humans, except when a micro-bubble contrast agent is present.Nonetheless, care should be taken to use low power settings and avoid pulsed wave scanning of the fetal brain unless specifically indicated in high risk pregnancies.
Figures released for the period 2005–2006 by the UK Government (Department of Health) show that non-obstetric ultrasound examinations constituted more than 65% of the total number of ultrasound scans conducted.
=== Hemodynamics (blood circulation) ===
Blood velocity can be measured in various blood vessels, such as middle cerebral artery or descending aorta, by relatively inexpensive and low risk ultrasound Doppler probes attached to portable monitors. These provide non-invasive or transcutaneous (non-piercing) minimal invasive blood flow assessment. Common examples are transcranial Doppler, esophageal Doppler and suprasternal Doppler.
=== Otolaryngology (head and neck) ===
Most structures of the neck, including the thyroid and parathyroid glands, lymph nodes, and salivary glands, are well-visualized by high-frequency ultrasound with exceptional anatomic detail. Ultrasound is the preferred imaging modality for thyroid tumors and lesions, and its use is important in the evaluation, preoperative planning, and postoperative surveillance of patients with thyroid cancer. Many other benign and malignant conditions in the head and neck can be differentiated, evaluated, and managed with the help of diagnostic ultrasound and ultrasound-guided procedures.
=== Neonatology ===
In neonatology, transcranial Doppler can be used for basic assessment of intracerebral structural abnormalities, suspected hemorrhage, ventriculomegaly or hydrocephalus and anoxic insults (periventricular leukomalacia). It can be performed through the soft spots in the skull of a newborn infant (Fontanelle) until these completely close at about 1 year of age by which time they have formed a virtually impenetrable acoustic barrier to ultrasound. The most common site for cranial ultrasound is the anterior fontanelle. The smaller the fontanelle, the more the image is compromised.
Lung ultrasound has been found to be useful in diagnosing common neonatal respiratory diseases such as transient tachypnea of the newborn, respiratory distress syndrome, congenital pneumonia, meconium aspiration syndrome, and pneumothorax. A neonatal lung ultrasound score, first described by Brat et al., has been found to highly correlate with oxygenation in the newborn.
=== Ophthalmology (eyes) ===
In ophthalmology and optometry, there are two major forms of eye exam using ultrasound:
A-scan ultrasound biometry, is commonly referred to as an A-scan (amplitude scan). A-mode provides data on the length of the eye, which is a major determinant in common sight disorders, especially for determining the power of an intraocular lens after cataract extraction.
B-scan ultrasonography, or B-scan-Brightness scan, is a B-mode scan that produces a cross-sectional view of the eye and the orbit. It is an essential tool in ophthalmology for diagnosing and managing a wide array of conditions affecting the posterior segment of the eye.It is non invasive and uses frequency 10–15 MHz. It is often used in conjunction with other imaging techniques (like OCT or fluorescein angiography) for a more comprehensive evaluation of ocular conditions.
=== Pulmonology (lungs) ===
Ultrasound is used to assess the lungs in a variety of settings including critical care, emergency medicine, trauma surgery, as well as general medicine. This imaging modality is used at the bedside or examination table to evaluate a number of different lung abnormalities as well as to guide procedures such as thoracentesis, (drainage of pleural fluid (effusion)), needle aspiration biopsy, and catheter placement. Although air present in the lungs does not allow good penetration of ultrasound waves, interpretation of specific artifacts created on the lung surface can be used to detect abnormalities.
==== Lung ultrasound basics ====
The Normal Lung Surface: The lung surface is composed of visceral and parietal pleura. These two surfaces are typically pushed together and make up the pleural line, which is the basis of lung (or pleural) ultrasound. This line is visible less than a centimeter below the rib line in most adults. On ultrasound, it is visualized as a hyperechoic (bright white) horizontal line if the ultrasound probe is applied perpendicularly to the skin.
Artifacts: Lung ultrasound relies on artifacts, which would otherwise be considered a hindrance in imaging. Air blocks the ultrasound beam and thus visualizing healthy lung tissue itself with this mode of imaging is not practical. Consequently, physicians and sonographers have learned to recognize patterns that ultrasound beams create when imaging healthy versus diseased lung tissue. Three commonly seen and utilized artifacts in lung ultrasound include lung sliding, A-lines, and B-lines.
§ Lung Sliding: The presence of lung sliding, which indicates the shimmering of the pleural line that occurs with movement of the visceral and parietal pleura against one another with respiration (sometimes described as 'ants marching'), is the most important finding in normal aerated lung. Lung sliding indicates both that the lung is present at the chest wall and that the lung is functioning.
§ A-lines: When the ultrasound beam makes contact with the pleural line, it is reflected back creating a bright white horizontal line. The subsequent reverberation artifacts that appear as equally spaced horizontal lines deep to the pleura are A-lines. Ultimately, A-lines are a reflection of the ultrasound beam from the pleura with the space between A-lines corresponding to the distance between the parietal pleura and the skin surface. A-lines indicate the presence of air, which means that these artifacts can be present in normal healthy lung (and also in patients with pneumothorax).
§ B-lines: B-lines are also reverberation artifacts. They are visualized as hyperechoic vertical lines extending from the pleura to the edge of the ultrasound screen. These lines are sharply defined and laser-like and typically do not fade as they progress down the screen. A few B-lines that move along with the sliding pleura can be seen in normal lung due to acoustic impedance differences between water and air. However, excessive B-lines (three or more) are abnormal and are typically indicative of underlying lung pathology.
==== Lung pathology assessed with ultrasound ====
Pulmonary edema: Lung ultrasound has been shown to be very sensitive for the detection of pulmonary edema. It allows for improvement in diagnosis and management of critically ill patients, particularly when used in combination with echocardiography. The sonographic feature that is present in pulmonary edema is multiple B-lines. B-lines can occur in a healthy lung; however, the presence of 3 or more in the anterior or lateral lung regions is always abnormal. In pulmonary edema, B-lines indicate an increase in the amount of water contained in the lungs outside of the pulmonary vasculature. B-lines can also be present in a number of other conditions including pneumonia, pulmonary contusion, and lung infarction. Additionally, it is important to note that there are multiple types of interactions between the pleural surface and the ultrasound wave that can generate artifacts with some similarity to B-lines but which do not have pathologic significance.
Pneumothorax: In clinical settings when pneumothorax is suspected, lung ultrasound can aid in diagnosis. In pneumothorax, air is present between the two layers of the pleura and lung sliding on ultrasound is therefore absent. The negative predictive value for lung sliding on ultrasound is reported as 99.2–100% – briefly, if lung sliding is present, a pneumothorax is effectively ruled out. The absence of lung sliding, however, is not necessarily specific for pneumothorax as there are other conditions that also cause this finding including acute respiratory distress syndrome, lung consolidations, pleural adhesions, and pulmonary fibrosis.
Pleural effusion: Lung ultrasound is a cost-effective, safe, and non-invasive imaging method that can aid in the prompt visualization and diagnosis of pleural effusions. Effusions can be diagnosed by a combination of physical exam, percussion, and auscultation of the chest. However, these exam techniques can be complicated by a variety of factors including the presence of mechanical ventilation, obesity, or patient positioning, all of which reduce the sensitivity of the physical exam. Consequently, lung ultrasound can be an additional tool to augment plain chest Xray and chest CT. Pleural effusions on ultrasound appear as structural images within the thorax rather than an artifact. They will typically have four distinct borders including the pleural line, two rib shadows, and a deep border. In critically ill patients with pleural effusion, ultrasound may guide procedures including needle insertion, thoracentesis, and chest-tube insertion.
Lung cancer staging: In pulmonology, endobronchial ultrasound (EBUS) probes are applied to standard flexible endoscopic probes and used by pulmonologists to allow for direct visualization of endobronchial lesions and lymph nodes prior to transbronchial needle aspiration. Among its many uses, EBUS aids in lung cancer staging by allowing for lymph node sampling without the need for major surgery.
COVID-19: Lung ultrasound has proved useful in the diagnosis of COVID-19 especially in cases where other investigations are not available.
=== Urinary tract ===
Ultrasound is routinely used in urology to determine the amount of fluid retained in a patient's bladder. In a pelvic sonogram, images include the uterus and ovaries or urinary bladder in females. In males, a sonogram will provide information about the bladder, prostate, or testicles (for example to urgently distinguish epididymitis from testicular torsion). In young males, it is used to distinguish more benign testicular masses (varicocele or hydrocele) from testicular cancer, which is curable but must be treated to preserve health and fertility. There are two methods of performing pelvic sonography – externally or internally. The internal pelvic sonogram is performed either transvaginally (in a woman) or transrectally (in a man). Sonographic imaging of the pelvic floor can produce important diagnostic information regarding the precise relationship of abnormal structures with other pelvic organs and it represents a useful hint to treat patients with symptoms related to pelvic prolapse, double incontinence and obstructed defecation. It is also used to diagnose and, at higher frequencies, to treat (break up) kidney stones or kidney crystals (nephrolithiasis).
=== Penis and scrotum ===
Scrotal ultrasonography is used in the evaluation of testicular pain, and can help identify solid masses.
Ultrasound is an excellent method for the study of the penis, such as indicated in trauma, priapism, erectile dysfunction or suspected Peyronie's disease.
=== Musculoskeletal ===
Musculoskeletal ultrasound is used to examine tendons, muscles, nerves, ligaments, soft tissue masses, and bone surfaces.
It is helpful in diagnosing ligament sprains, muscles strains and joint pathology. It is an alternative or supplement to x-ray imaging in detecting fractures of the wrist, elbow and shoulder for patients up to 12 years (Fracture sonography).
Quantitative ultrasound is an adjunct musculoskeletal test for myopathic disease in children; estimates of lean body mass in adults; proxy measures of muscle quality (i.e., tissue composition) in older adults with sarcopenia
Ultrasound can also be used for needle guidance in muscle or joint injections, as in ultrasound-guided hip joint injection.
=== Kidneys ===
In nephrology, ultrasonography of the kidneys is essential in the diagnosis and management of kidney-related diseases. The kidneys are easily examined, and most pathological changes are distinguishable with ultrasound. It is an accessible, versatile, relatively economic, and fast aid for decision-making in patients with renal symptoms and for guidance in renal intervention. Using B-mode imaging, assessment of renal anatomy is easily performed, and US is often used as image guidance for renal interventions. Furthermore, novel applications in renal US have been introduced with contrast-enhanced ultrasound (CEUS), elastography and fusion imaging. However, renal US has certain limitations, and other modalities, such as CT (CECT) and MRI, should be considered for supplementary imaging in assessing renal disease.
=== Venous access ===
Intravenous access, for the collection of blood samples to assist in diagnosis or laboratory investigation including blood culture, or for administration of intravenous fluids for fluid maintenance of replacement or blood transfusion in sicker patients, is a common medical procedure. The need for intravenous access occurs in the outpatient laboratory, in the inpatient hospital units, and most critically in the Emergency Room and Intensive Care Unit. In many situations, intravenous access may be required repeatedly or over a significant time period. In these latter circumstances, a needle with an overlying catheter is introduced into the vein and the catheter is then inserted securely into the vein while the needle is withdrawn.
The chosen veins are most frequently selected from the arm, but in challenging situations, a deeper vein from the neck (external jugular vein) or upper arm (subclavian vein) may need to be used.
There are many reasons why the selection of a suitable vein may be problematic.
These include, but are not limited to, obesity, previous injury to veins from inflammatory reaction to previous 'blood draws', previous injury to veins from recreational drug use.
In these challenging situations, the insertion of a catheter into a vein has been greatly assisted by the use of ultrasound. The ultrasound unit may be 'cart-based' or 'handheld' using a linear transducer with a frequency of 10 to 15 megahertz. In most circumstances, choice of vein will be limited by the requirement that the vein is within 1.5 cms. from the skin surface.
The transducer may be placed longitudinally or transversely over the chosen vein.
Ultrasound training for intravenous cannulation is offered in most ultrasound training programs.
== Mechanism ==
The creation of an image from sound has three steps – transmitting a sound wave, receiving echoes, and interpreting those echoes.
=== Producing a sound wave ===
A sound wave is typically produced by a piezoelectric transducer encased in a plastic housing. Strong, short electrical pulses from the ultrasound machine drive the transducer at the desired frequency. The frequencies can vary between 1 and 18 MHz, though frequencies up to 50–100 megahertz have been used experimentally in a technique known as biomicroscopy in special regions, such as the anterior chamber of the eye.
Older technology transducers focused their beam with physical lenses. Contemporary technology transducers use digital antenna array techniques (piezoelectric elements in the transducer produce echoes at different times) to enable the ultrasound machine to change the direction and depth of focus. Near the transducer, the width of the ultrasound beam almost equals to the width of the transducer, after reaching a distance from the transducer (near zone length or Fresnel zone), the beam width narrows to half of the transducer width, and after that the width increases (far zone length or Fraunhofer's zone), where the lateral resolution decreases. Therefore, the wider the transducer width and the higher the frequency of ultrasound, the longer the Fresnel zone, and the lateral resolution can be maintained at a greater depth from the transducer. Ultrasound waves travel in pulses. Therefore, a shorter pulse length requires higher bandwidth (greater number of frequencies) to constitute the ultrasound pulse.
As stated, the sound is focused either by the shape of the transducer, a lens in front of the transducer, or a complex set of control pulses from the ultrasound scanner, in the beamforming or spatial filtering technique. This focusing produces an arc-shaped sound wave from the face of the transducer. The wave travels into the body and comes into focus at a desired depth.
Materials on the face of the transducer enable the sound to be transmitted efficiently into the body (often a rubbery coating, a form of impedance matching). In addition, a water-based gel is placed between the patient's skin and the probe to facilitate ultrasound transmission into the body. This is because air causes total reflection of ultrasound; impeding the transmission of ultrasound into the body.
The sound wave is partially reflected from the layers between different tissues or scattered from smaller structures. Specifically, sound is reflected anywhere where there are acoustic impedance changes in the body: e.g. blood cells in blood plasma, small structures in organs, etc. Some of the reflections return to the transducer.
=== Receiving the echoes ===
The return of the sound wave to the transducer results in the same process as sending the sound wave, in reverse. The returned sound wave vibrates the transducer and the transducer turns the vibrations into electrical pulses that travel to the ultrasonic scanner where they are processed and transformed into a digital image.
=== Forming the image ===
To make an image, the ultrasound scanner must determine two characteristics from each received echo:
How long it took the echo to be received from when the sound was transmitted. (Time and distance are equivalent.)
How strong the echo was.
Once the ultrasonic scanner determines these two, it can locate which pixel in the image to illuminate and with what intensity.
Transforming the received signal into a digital image may be explained by using a blank spreadsheet as an analogy. First picture a long, flat transducer at the top of the sheet. Send pulses down the 'columns' of the spreadsheet (A, B, C, etc.). Listen at each column for any return echoes. When an echo is heard, note how long it took for the echo to return. The longer the wait, the deeper the row (1,2,3, etc.). The strength of the echo determines the brightness setting for that cell (white for a strong echo, black for a weak echo, and varying shades of grey for everything in between.) When all the echoes are recorded on the sheet, a greyscale image has been accomplished.
In modern ultrasound systems, images are derived from the combined reception of echoes by multiple elements, rather than a single one. These elements in the transducer array work together to receive signals, a process essential for optimizing the ultrasonic beam's focus and producing detailed images. One predominant method for this is "delay-and-sum" beamforming. The time delay applied to each element is calculated based on the geometrical relationship between the imaging point, the transducer, and receiver positions. By integrating these time-adjusted signals, the system pinpoints focus onto specific tissue regions, enhancing image resolution and clarity. The utilization of multiple element reception combined with the delay-and-sum principles underpins the high-quality images characteristic of contemporary ultrasound scans.
=== Displaying the image ===
Images from the ultrasound scanner are transferred and displayed using the DICOM standard. Normally, very little post processing is applied.
== Sound in the body ==
Ultrasonography (sonography) uses a probe containing multiple acoustic transducers to send pulses of sound into a material. Whenever a sound wave encounters a material with a different density (acoustical impedance), some of the sound wave is scattered but part is reflected back to the probe and is detected as an echo. The time it takes for the echo to travel back to the probe is measured and used to calculate the depth of the tissue interface causing the echo. The greater the difference between acoustic impedances, the larger the echo is. If the pulse hits gases or solids, the density difference is so great that most of the acoustic energy is reflected and it becomes impossible to progress further.
The frequencies used for medical imaging are generally in the range of 1 to 18 MHz Higher frequencies have a correspondingly smaller wavelength, and can be used to make more detailed sonograms. However, the attenuation of the sound wave is increased at higher frequencies, so penetration of deeper tissues necessitates a lower frequency (3–5 MHz).
Penetrating deep into the body with sonography is difficult. Some acoustic energy is lost each time an echo is formed, but most of it (approximately
0.5
dB
cm depth
⋅
MHz
{\displaystyle \textstyle 0.5{\frac {\mbox{dB}}{{\mbox{cm depth}}\cdot {\mbox{MHz}}}}}
) is lost from acoustic absorption. (See Acoustic attenuation for further details on modeling of acoustic attenuation and absorption.)
The speed of sound varies as it travels through different materials, and is dependent on the acoustical impedance of the material. However, the sonographic instrument assumes that the acoustic velocity is constant at 1540 m/s. An effect of this assumption is that in a real body with non-uniform tissues, the beam becomes somewhat de-focused and image resolution is reduced.
To generate a 2-D image, the ultrasonic beam is swept. A transducer may be swept mechanically by rotating or swinging or a 1-D phased array transducer may be used to sweep the beam electronically. The received data is processed and used to construct the image. The image is then a 2-D representation of the slice into the body.
3-D images can be generated by acquiring a series of adjacent 2-D images. Commonly a specialized probe that mechanically scans a conventional 2-D image transducer is used. However, since the mechanical scanning is slow, it is difficult to make 3D images of moving tissues. Recently, 2-D phased array transducers that can sweep the beam in 3-D have been developed. These can image faster and can even be used to make live 3-D images of a beating heart.
Doppler ultrasonography is used to study blood flow and muscle motion. The different detected speeds are represented in color for ease of interpretation, for example leaky heart valves: the leak shows up as a flash of unique color. Colors may alternatively be used to represent the amplitudes of the received echoes.
== Expansions ==
An additional expansion of ultrasound is bi-planar ultrasound, in which the probe has two 2D planes perpendicular to each other, providing more efficient localization and detection. Furthermore, an omniplane probe can rotate 180° to obtain multiple images. In 3D ultrasound, many 2D planes are digitally added together to create a 3-dimensional image of the object.
=== Doppler ultrasonography ===
Doppler ultrasonography employs the Doppler effect to assess whether structures (usually blood) are moving towards or away from the probe, and their relative velocity. By calculating the frequency shift of a particular sample volume, flow in an artery or a jet of blood flow over a heart valve, its speed and direction can be determined and visualized, as an example. Color Doppler is the measurement of velocity by color scale. Color Doppler images are generally combined with gray scale (B-mode) images to display duplex ultrasonography images. Uses include:
Doppler echocardiography is the use of Doppler ultrasonography to examine the heart. An echocardiogram can, within certain limits, produce accurate assessment of the direction of blood flow and the velocity of blood and cardiac tissue at any arbitrary point using the Doppler effect. Velocity measurements allow assessment of cardiac valve areas and function, abnormal communications between the left and right side of the heart, leaking of blood through the valves (valvular regurgitation), and calculation of the cardiac output and E/A ratio (a measure of diastolic dysfunction). Contrast-enhanced ultrasound using gas-filled microbubble contrast media can be used to improve velocity or other flow-related measurements of interest.
Transcranial Doppler (TCD) and transcranial color Doppler (TCCD), measure the velocity of blood flow through the brain's blood vessels through the cranium. They are useful in the diagnosis of emboli, stenosis, vasospasm from a subarachnoid hemorrhage (bleeding from a ruptured aneurysm), and other problems.
Doppler fetal monitors use the Doppler effect to detect the fetal heartbeat during prenatal care. These are hand-held, and some models also display the heart rate in beats per minute (BPM). Use of this monitor is sometimes known as Doppler auscultation. The Doppler fetal monitor is commonly referred to simply as a Doppler or fetal Doppler and provides information similar to that provided by a fetal stethoscope.
=== Contrast ultrasonography (ultrasound contrast imaging) ===
A contrast medium for medical ultrasonography is a formulation of encapsulated gaseous microbubbles to increase echogenicity of blood, discovered by Dr. Raymond Gramiak in 1968 and named contrast-enhanced ultrasound. This contrast medical imaging modality is used throughout the world, for echocardiography in particular in the United States and for ultrasound radiology in Europe and Asia.
Microbubbles-based contrast media is administered intravenously into the patient blood stream during the ultrasonography examination. Due to their size, the microbubbles remain confined in blood vessels without extravasating towards the interstitial fluid. An ultrasound contrast media is therefore purely intravascular, making it an ideal agent to image organ microvasculature for diagnostic purposes. A typical clinical use of contrast ultrasonography is detection of a hypervascular metastatic tumor, which exhibits a contrast uptake (kinetics of microbubbles concentration in blood circulation) faster than healthy biological tissue surrounding the tumor. Other clinical applications using contrast exist, as in echocardiography to improve delineation of left ventricle for visualizing contractibility of heart muscle after a myocardial infarction. Finally, applications in quantitative perfusion (relative measurement of blood flow) have emerged for identifying early patient response to anti-cancerous drug treatment (methodology and clinical study by Dr. Nathalie Lassau in 2011), enabling the best oncological therapeutic options to be determined.
In oncological practice of medical contrast ultrasonography, clinicians use 'parametric imaging of vascular signatures' invented by Dr. Nicolas Rognin in 2010. This method is conceived as a cancer aided diagnostic tool, facilitating characterization of a suspicious tumor (malignant versus benign) in an organ. This method is based on medical computational science to analyze a time sequence of ultrasound contrast images, a digital video recorded in real-time during patient examination. Two consecutive signal processing steps are applied to each pixel of the tumor:
calculation of a vascular signature (contrast uptake difference with respect to healthy tissue surrounding the tumor);
automatic classification of the vascular signature into a unique parameter, the latter coded in one of the four following colors:
green for continuous hyper-enhancement (contrast uptake higher than healthy tissue one),
blue for continuous hypo-enhancement (contrast uptake lower than healthy tissue one),
red for fast hyper-enhancement (contrast uptake before healthy tissue one) or
yellow for fast hypo-enhancement (contrast uptake after healthy tissue one).
Once signal processing in each pixel is completed, a color spatial map of the parameter is displayed on a computer monitor, summarizing all vascular information of the tumor in a single image called a parametric image (see last figure of press article as clinical examples). This parametric image is interpreted by clinicians based on predominant colorization of the tumor: red indicates a suspicion of malignancy (risk of cancer), green or yellow – a high probability of benignity. In the first case (suspicion of malignant tumor), the clinician typically prescribes a biopsy to confirm the diagnostic or a CT scan examination as a second opinion. In the second case (quasi-certain of benign tumor), only a follow-up is needed with a contrast ultrasonography examination a few months later. The main clinical benefits are to avoid a systemic biopsy (with inherent risks of invasive procedures) of benign tumors or a CT scan examination exposing the patient to X-ray radiation. The parametric imaging of vascular signatures method proved to be effective in humans for characterization of tumors in the liver. In a cancer screening context, this method might be potentially applicable to other organs such as breast or prostate.
=== Molecular ultrasonography (ultrasound molecular imaging) ===
The current future of contrast ultrasonography is in molecular imaging with potential clinical applications expected in cancer screening to detect malignant tumors at their earliest stage of appearance. Molecular ultrasonography (or ultrasound molecular imaging) uses targeted microbubbles originally designed by Dr Alexander Klibanov in 1997; such targeted microbubbles specifically bind or adhere to tumoral microvessels by targeting biomolecular cancer expression (overexpression of certain biomolecules that occurs during neo-angiogenesis or inflammation in malignant tumors). As a result, a few minutes after their injection in blood circulation, the targeted microbubbles accumulate in the malignant tumor; facilitating its localization in a unique ultrasound contrast image. In 2013, the very first exploratory clinical trial in humans for prostate cancer was completed at Amsterdam in the Netherlands by Dr. Hessel Wijkstra.
In molecular ultrasonography, the technique of acoustic radiation force (also used for shear wave elastography) is applied in order to literally push the targeted microbubbles towards microvessels wall; first demonstrated by Dr. Paul Dayton in 1999. This allows maximization of binding to the malignant tumor; the targeted microbubbles being in more direct contact with cancerous biomolecules expressed at the inner surface of tumoral microvessels. At the stage of scientific preclinical research, the technique of acoustic radiation force was implemented as a prototype in clinical ultrasound systems and validated in vivo in 2D and 3D imaging modes.
=== Elastography (ultrasound elasticity imaging) ===
Ultrasound is also used for elastography, which is a relatively new imaging modality that maps the elastic properties of soft tissue. This modality emerged in the last two decades. Elastography is useful in medical diagnoses as it can discern healthy from unhealthy tissue for specific organs/growths. For example, cancerous tumors will often be harder than the surrounding tissue, and diseased livers are stiffer than healthy ones.
There are many ultrasound elastography techniques.
=== Interventional ultrasonography ===
Interventional ultrasonography involves biopsy, emptying fluids, intrauterine Blood transfusion (Hemolytic disease of the newborn).
Thyroid cysts: High frequency thyroid ultrasound (HFUS) can be used to treat several gland conditions. The recurrent thyroid cyst that was usually treated in the past with surgery, can be treated effectively by a new procedure called percutaneous ethanol injection, or PEI. With ultrasound guided placement of a 25 gauge needle within the cyst, and after evacuation of the cyst fluid, about 50% of the cyst volume is injected back into the cavity, under strict operator visualization of the needle tip. The procedure is 80% successful in reducing the cyst to minute size.
Metastatic thyroid cancer neck lymph nodes: HFUS may also be used to treat metastatic thyroid cancer neck lymph nodes that occur in patients who either refuse, or are no longer candidates, for surgery. Small amounts of ethanol are injected under ultrasound guided needle placement. A power doppler blood flow study is done prior to injection. The blood flow can be destroyed and the node rendered inactive. Power doppler visualized blood flow can be eradicated, and there may be a drop in the cancer blood marker test, thyroglobulin, TG, as the node become non-functional. Another interventional use for HFUS is to mark a cancer node prior to surgery to help locate the node cluster at the surgery. A minute amount of methylene dye is injected, under careful ultrasound guided placement of the needle on the anterior surface, but not in the node. The dye will be evident to the thyroid surgeon when opening the neck. A similar localization procedure with methylene blue, can be done to locate parathyroid adenomas.
Joint injections can be guided by medical ultrasound, such as in ultrasound-guided hip joint injections.
=== Compression ultrasonography ===
Compression ultrasonography is when the probe is pressed against the skin. This can bring the target structure closer to the probe, increasing spatial resolution of it. Comparison of the shape of the target structure before and after compression can aid in diagnosis.
It is used in ultrasonography of deep venous thrombosis, wherein absence of vein compressibility is a strong indicator of thrombosis. Compression ultrasonography has both high sensitivity and specificity for detecting proximal deep vein thrombosis in symptomatic patients. Results are not reliable when the patient is asymptomatic, for example in high risk postoperative orthopedic patients.
=== Panoramic ultrasonography ===
Panoramic ultrasonography is the digital stitching of multiple ultrasound images into a broader one. It can display an entire abnormality and show its relationship to nearby structures on a single image.
=== Multiparametric ultrasonography ===
Multiparametric ultrasonography (mpUSS) combines multiple ultrasound techniques to produce a composite result. For example, one study combined B-mode, colour Doppler, real-time elastography, and contrast-enhanced ultrasound, achieving an accuracy similar to that of multiparametric MRI.
=== Speed-of-Sound Imaging ===
Speed-of-sound (SoS) imaging aims to find the spatial distribution of the SoS within the tissue. The idea is to find relative delay measurements for different transmission events and solve the limited-angle tomographic reconstruction problem using delay measurements and transmission geometry. Compared to shear-wave elastography, SoS imaging has better ex-vivo tissue differentiation for benign and malignant tumors.
== Attributes ==
As with all imaging modalities, ultrasonography has positive and negative attributes.
=== Strengths ===
Muscle, soft tissue, and bone surfaces are imaged very well including the delineation of interfaces between solid and fluid-filled spaces.
"Live" images can be dynamically selected, permitting diagnosis and documentation often rapidly. Live images also permit ultrasound-guided biopsies or injections, which can be cumbersome with other imaging modalities.
Organ structure can be demonstrated.
There are no known long-term side effects when used according to guidelines, and discomfort is minimal.
Ability to image local variations in the mechanical properties of soft tissue.
Equipment is widely available and comparatively flexible.
Small, easily carried scanners are available which permit bedside examinations.
Transducers have become relatively inexpensive compared to other modes of investigation, such as computed X-ray tomography, DEXA or magnetic resonance imaging.
Spatial resolution is better in high frequency ultrasound transducers than most other imaging modalities.
Use of an ultrasound research interface can offer a relatively inexpensive, real-time, and flexible method for capturing data required for specific research purposes of tissue characterization and development of new image processing techniques.
=== Weaknesses ===
Sonographic devices have trouble penetrating bone. For example, sonography of the adult brain is currently very limited.
Sonography performs very poorly when there is gas between the transducer and the organ of interest, due to the extreme differences in acoustic impedance. For example, overlying gas in the gastrointestinal tract often makes ultrasound scanning of the pancreas difficult. Lung imaging however can be useful in demarcating pleural effusions, detecting heart failure and pneumonia.
Even in the absence of bone or air, the depth penetration of ultrasound may be limited depending on the frequency of imaging. Consequently, there might be difficulties imaging structures deep in the body, especially in obese patients.
Image quality and accuracy of diagnosis is limited with obese patients and overlying subcutaneous fat attenuates the sound beam. A lower frequency transducer is required with subsequent lower resolution.
The method is operator-dependent. Skill and experience is needed to acquire good-quality images and make accurate diagnoses.
There is no scout image as there is with CT and MRI. Once an image has been acquired there is no exact way to tell which part of the body was imaged.
80% of sonographers experience Repetitive Strain Injuries (RSI) or so-called Work-Related Musculoskeletal Disorders (WMSD) because of bad ergonomic positions.
== Risks and side-effects ==
Ultrasonography is generally considered safe imaging, with the World Health Organizations stating:
"Diagnostic ultrasound is recognized as a safe, effective, and highly flexible imaging modality capable of providing clinically relevant information about most parts of the body in a rapid and cost-effective fashion".
Diagnostic ultrasound studies of the fetus are generally considered to be safe during pregnancy. However, this diagnostic procedure should be performed only when there is a valid medical indication, and the lowest possible ultrasonic exposure setting should be used to gain the necessary diagnostic information under the "as low as reasonably practicable" or ALARP principle.
Although there is no evidence that ultrasound could be harmful to the fetus, medical authorities typically strongly discourage the promotion, selling, or leasing of ultrasound equipment for making "keepsake fetal videos".
=== Studies on the safety of ultrasound ===
A meta-analysis of several ultrasonography studies published in 2000 found no statistically significant harmful effects from ultrasonography. It was noted that there is a lack of data on long-term substantive outcomes such as neurodevelopment.
A study at the Yale School of Medicine published in 2006 found a small but significant correlation between prolonged and frequent use of ultrasound and abnormal neuronal migration in mice.
A study performed in Sweden in 2001 has shown that subtle effects of neurological damage linked to ultrasound were implicated by an increased incidence in left-handedness in boys (a marker for brain problems when not hereditary) and speech delays.
The above findings, however, were not confirmed in a follow-up study.
A later study, however, performed on a larger sample of 8865 children, has established a statistically significant, albeit weak association of ultrasonography exposure and being non-right handed later in life.
== Regulation ==
Diagnostic and therapeutic ultrasound equipment is regulated in the US by the Food and Drug Administration, and worldwide by other national regulatory agencies. The FDA limits acoustic output using several metrics; generally, other agencies accept the FDA-established guidelines.
Currently, New Mexico, Oregon, and North Dakota are the only US states that regulate diagnostic medical sonographers. Certification examinations for sonographers are available in the US from three organizations: the American Registry for Diagnostic Medical Sonography, Cardiovascular Credentialing International and the American Registry of Radiologic Technologists.
The primary regulated metrics are Mechanical Index (MI), a metric associated with the cavitation bio-effect, and Thermal Index (TI) a metric associated with the tissue heating bio-effect. The FDA requires that the machine not exceed established limits, which are reasonably conservative in an effort to maintain diagnostic ultrasound as a safe imaging modality. This requires self-regulation on the part of the manufacturer in terms of machine calibration.
Ultrasound-based pre-natal care and sex screening technologies were launched in India in the 1980s. With concerns about its misuse for sex-selective abortion, the Government of India passed the Pre-natal Diagnostic Techniques Act (PNDT) in 1994 to distinguish and regulate legal and illegal uses of ultrasound equipment. The law was further amended as the Pre-Conception and Pre-natal Diagnostic Techniques (Regulation and Prevention of Misuse) (PCPNDT) Act in 2004 to deter and punish prenatal sex screening and sex selective abortion. It is currently illegal and a punishable crime in India to determine or disclose the sex of a fetus using ultrasound equipment.
== Use in other animals ==
Ultrasound is also a valuable tool in veterinary medicine, offering the same non-invasive imaging that helps in the diagnosis and monitoring of conditions in animals.
== History ==
After the French physicist Pierre Curie's discovery of piezoelectricity in 1880, ultrasonic waves could be deliberately generated for industry. In 1940, the American acoustical physicist Floyd Firestone devised the first ultrasonic echo imaging device, the Supersonic Reflectoscope, to detect internal flaws in metal castings. In 1941, Austrian neurologist Karl Theo Dussik, in collaboration with his brother, Friedrich, a physicist, was likely the first person to image the human body ultrasonically, outlining the ventricles of a human brain. Ultrasonic energy was first applied to the human body for medical purposes by Dr George Ludwig at the Naval Medical Research Institute, Bethesda, Maryland, in the late 1940s. English-born physicist John Wild (1914–2009) first used ultrasound to assess the thickness of bowel tissue as early as 1949; he has been described as the "father of medical ultrasound". Subsequent advances took place concurrently in several countries but it was not until 1961 that David Robinson and George Kossoff's work at the Australian Department of Health resulted in the first commercially practical water bath ultrasonic scanner. In 1963 Meyerdirk & Wright launched production of the first commercial, hand-held, articulated arm, compound contact B-mode scanner, which made ultrasound generally available for medical use.
=== France ===
Léandre Pourcelot, a researcher and teacher at INSA (Institut National des Sciences Appliquées), Lyon, co-published a report in 1965 at the Académie des sciences, "Effet Doppler et mesure du débit sanguin" ("Doppler effect and measure of the blood flow"), the basis of his design of a Doppler flow meter in 1967.
=== Scotland ===
Parallel developments in Glasgow, Scotland by Professor Ian Donald and colleagues at the Glasgow Royal Maternity Hospital (GRMH) led to the first diagnostic applications of the technique. Donald was an obstetrician with a self-confessed "childish interest in machines, electronic and otherwise", who, having treated the wife of one of the company's directors, was invited to visit the Research Department of boilermakers Babcock & Wilcox at Renfrew. He adapted their industrial ultrasound equipment to conduct experiments on various anatomical specimens and assess their ultrasonic characteristics. Together with the medical physicist Tom Brown. and fellow obstetrician John MacVicar, Donald refined the equipment to enable differentiation of pathology in live volunteer patients. These findings were reported in The Lancet on 7 June 1958 as "Investigation of Abdominal Masses by Pulsed Ultrasound" – possibly one of the most important papers published in the field of diagnostic medical imaging.
At GRMH, Professor Donald and James Willocks then refined their techniques to obstetric applications including fetal head measurement to assess the size and growth of the fetus. With the opening of the new Queen Mother's Hospital in Yorkhill in 1964, it became possible to improve these methods even further. Stuart Campbell's pioneering work on fetal cephalometry led to it acquiring long-term status as the definitive method of study of foetal growth. As the technical quality of the scans was further developed, it soon became possible to study pregnancy from start to finish and diagnose its many complications such as multiple pregnancy, fetal abnormality and placenta praevia. Diagnostic ultrasound has since been imported into practically every other area of medicine.
=== Sweden ===
Medical ultrasonography was used in 1953 at Lund University by cardiologist Inge Edler and Gustav Ludwig Hertz's son Carl Hellmuth Hertz, who was then a graduate student at the university's department of nuclear physics.
Edler had asked Hertz if it was possible to use radar to look into the body, but Hertz said this was impossible. However, he said, it might be possible to use ultrasonography. Hertz was familiar with using ultrasonic reflectoscopes of the American acoustical physicist Floyd Firestone's invention for nondestructive materials testing, and together Edler and Hertz developed the idea of applying this methodology in medicine.
The first successful measurement of heart activity was made on October 29, 1953, using a device borrowed from the ship construction company Kockums in Malmö. On December 16 the same year, the method was applied to generate an echo-encephalogram (ultrasonic probe of the brain). Edler and Hertz published their findings in 1954.
=== United States ===
In 1962, after about two years of work, Joseph Holmes, William Wright, and Ralph Meyerdirk developed the first compound contact B-mode scanner. Their work had been supported by U.S. Public Health Services and the University of Colorado. Wright and Meyerdirk left the university to form Physionic Engineering Inc., which launched the first commercial hand-held articulated arm compound contact B-mode scanner in 1963. This was the start of the most popular design in the history of ultrasound scanners.
In the late 1960s Gene Strandness and the bio-engineering group at the University of Washington conducted research on Doppler ultrasound as a diagnostic tool for vascular disease. Eventually, they developed technologies to use duplex imaging, or Doppler in conjunction with B-mode scanning, to view vascular structures in real time while also providing hemodynamic information.
The first demonstration of color Doppler was by Geoff Stevenson, who was involved in the early developments and medical use of Doppler shifted ultrasonic energy.
== Manufacturers ==
Major manufacturers of Medical Ultrasound Devices and Equipment are:
Canon Medical Systems Corporation
Esaote
GE Healthcare
Fujifilm
Mindray Medical International Limited
Koninklijke Philips N.V.
Samsung Medison
Siemens Healthineers
== Gallery ==
== See also ==
== Explanatory notes ==
== References ==
== External links ==
About the discovery of medical ultrasonography on ob-ultrasound.net
History of medical sonography (ultrasound) on ob-ultrasound.net | Wikipedia/Ultrasonography |
Radiographers, also known as radiology technologists, radiologic technologists, diagnostic radiographers and medical radiation technologists, are healthcare professionals who specialise in the imaging of human anatomy for the diagnosis and treatment of pathology. Radiographers are sometimes popularly known as x-ray technologists, though this is misleading because while x-rays were the earliest form of medical imaging, the field also includes magnetic resonance imaging and other technologies that do not use x-rays. In countries that use the title radiologic technologist, these professionals are often informally referred to as techs in the clinical environment; this phrase has emerged in popular culture such as television programmes. The term radiographer can also refer to a therapeutic radiographer, also known as a radiation therapist.
Radiographers are allied health professionals who work in both public healthcare and private healthcare and can be physically located in any setting where appropriate diagnostic equipment is located, most frequently in hospitals. The practice varies from country to country and can even vary between hospitals in the same country.
Radiographers are represented by a variety of organizations worldwide, including the International Society of Radiographers and Radiological Technologists which aims to give direction to the profession as a whole through collaboration with national representative bodies.
== History ==
For the first three decades of medical imaging's existence (1897 to the 1930s), there was no standardized differentiation between the roles that we now differentiate as radiologic technologist (a technician in an allied health profession who obtains the images) versus radiologist (a physician who interprets them). By the 1930s and 1940s, as it became increasingly apparent that proper interpretation of the images required not only a physician but also one who was specifically trained and experienced in doing so, the differentiation between the roles was formalized. Simultaneously, it also became increasingly true that just as a radiologic technologist cannot do the radiologist's job, the radiologist also cannot do the radiologic technologist's job, as it requires some knowledge, skills, experience, and certifications that are specific to it.
Radiography's origins and fluoroscopy's origins can both be traced to 8 November 1895, when German physics professor Wilhelm Röntgen discovered the X-ray and noted that, while it could pass through human tissue, it could not pass through bone or metal. Röntgen referred to the radiation as "X", to indicate that it was an unknown type of radiation. He received the first Nobel Prize in Physics for his discovery.
There are conflicting accounts of his discovery because Röntgen had his lab notes burned after his death, but this is a likely reconstruction by his biographers: Röntgen was investigating cathode rays using a fluorescent screen painted with barium platinocyanide and a Crookes tube which he had wrapped in black cardboard to shield its fluorescent glow. He noticed a faint green glow from the screen, about 1 metre away. Röntgen realized some invisible rays coming from the tube were passing through the cardboard to make the screen glow: they were passing through an opaque object to affect the film behind it.
Röntgen discovered X-rays' medical use when he made a picture of his wife's hand on a photographic plate formed due to X-rays. The photograph of his wife's hand was the first ever photograph of a human body part using X-rays. When she saw the picture, she said, "I have seen my death."
The first use of X-rays under clinical conditions was by John Hall-Edwards in Birmingham, England on 11 January 1896, when he radiographed a needle stuck in the hand of an associate. On 14 February 1896, Hall-Edwards also became the first to use X-rays in a surgical operation.
The United States saw its first medical X-ray obtained using a discharge tube of Ivan Pulyui's design. In January 1896, on reading of Röntgen's discovery, Frank Austin of Dartmouth College tested all of the discharge tubes in the physics laboratory and found that only the Pulyui tube produced X-rays. This was a result of Pulyui's inclusion of an oblique "target" of mica, used for holding samples of fluorescent material, within the tube. On 3 February 1896 Gilman Frost, professor of medicine at the college, and his brother Edwin Frost, professor of physics, exposed the wrist of Eddie McCarthy, whom Gilman had treated some weeks earlier for a fracture, to the X-rays and collected the resulting image of the broken bone on gelatin photographic plates obtained from Howard Langill, a local photographer also interested in Röntgen's work.
X-rays were put to diagnostic use very early; for example, Alan Archibald Campbell-Swinton opened a radiographic laboratory in the United Kingdom in 1896, before the dangers of ionizing radiation were discovered. Indeed, Marie Curie pushed for radiography to be used to treat wounded soldiers in World War I. Initially, many kinds of staff conducted radiography in hospitals, including physicists, photographers, physicians, nurses, and engineers. The medical speciality of radiology grew up over many years around the new technology. When new diagnostic tests were developed, it was natural for the radiographers to be trained in and to adopt this new technology. Radiographers now perform fluoroscopy, computed tomography, mammography, ultrasound, nuclear medicine and magnetic resonance imaging as well. Although a nonspecialist dictionary might define radiography quite narrowly as "taking X-ray images", this has long been only part of the work of "X-ray Departments", Radiographers, and Radiologists. Initially, radiographs were known as roentgenograms, while Skiagrapher (from the Ancient Greek words for "shadow" and "writer") was used until about 1918 to mean Radiographer.
The history of magnetic resonance imaging includes many researchers who have discovered NMR and described its underlying physics, but it is regarded to be invented by Paul C. Lauterbur in September 1971; he published the theory behind it in March 1973. The factors leading to image contrast (differences in tissue relaxation time values) had been described nearly 20 years earlier by Erik Odeblad (doctor and scientist) and Gunnar Lindström.
In 1950, spin echoes and free induction decay were first detected by Erwin Hahn and in 1952, Herman Carr produced a one-dimensional NMR spectrum as reported in his Harvard PhD thesis. In the Soviet Union, Vladislav Ivanov filed (in 1960) a document with the USSR State Committee for Inventions and Discovery at Leningrad for a Magnetic Resonance Imaging device, although this was not approved until the 1970s.
By 1959, Jay Singer had studied blood flow by NMR relaxation time measurements of blood in living humans. Such measurements were not introduced into common medical practice until the mid-1980s, although a patent for a whole-body NMR machine to measure blood flow in the human body was already filed by Alexander Ganssen in early 1967.
In the 1960s and 1970s the results of a very large amount of work on relaxation, diffusion, and chemical exchange of water in cells and tissues of various types appeared in the scientific literature. In 1967, Ligon reported the measurement of NMR relaxation of water in the arms of living human subjects. In 1968, Jackson and Langham published the first NMR signals from a living animal.
== Role in healthcare ==
A radiographer uses their expertise and knowledge of patient care, physics, human anatomy, physiology, pathology and radiology to assess patients, develop optimum radiological techniques and evaluate the resulting radiographic media.
This branch of healthcare is extremely varied, especially between different countries, and as a result radiographers in one country often have a completely different role to that of radiographers in another. However, the base responsibilities of the radiographer are summarised below:
Autonomy as a professional
Accountability as a professional
Contribute to and participate in continuing professional development
Enforcement of radiation protection (There is a duty of care to patients, colleagues and any lay persons that may be irradiated.)
Justification of radiographic examinations
Patient care
Production of diagnostic media
Safe, efficient and correct use of diagnostic equipment
Supervise students and assistants
On a basic level, radiographers do not generally interpret diagnostic media, rather they evaluate media and make a decision about its diagnostic effectiveness. In order to make this evaluation radiographers must have a comprehensive but not necessarily exhaustive knowledge of pathology and radiographic appearances; it is for this reason that radiographers often do not interpret or diagnose without further training. Notwithstanding, it is now becoming more common that radiographers have an extended and expanded clinical role, this includes a role in initial radiological diagnosis, diagnosis consultation and what subsequent investigations to conduct. It is not uncommon for radiographers to now conduct procedures which would have previously been undertaken by a cardiologist, urologist, radiologist or oncologist autonomously.
Contrary to what could be inferred, radiographers conduct and contribute to investigations which are not necessarily radiological in nature, e.g. sonography and magnetic resonance imaging.
Radiographers often have opportunities to enter military service due to their role in healthcare. As with most other occupations in the medical field many radiographers have rotating shifts that include night duties.
=== Career pathways ===
Radiography is a deeply diverse profession with many different modalities and specialities. It is not uncommon for radiographers to be specialised in more than one modality and even have expertise of interventional procedures themselves; however this depends on the country in which they operate. As a result of this the typical career pathway for a radiographer is hard to summarise. Upon qualifying it is common for radiographers to focus solely on plain film radiography before specialising in any one chosen modality. After a number of years in the profession, non-imaging based roles often become open and radiographers may then move into these positions.
==== Imaging modalities ====
Generally, imaging modalities are all diagnostic, all have the potential to be used therapeutically in order to deliver an intervention. Modalities (or specialities) include but are not limited to:
1Prefixes such as pediatric, geriatric, trauma are routinely placed used in conjunction with professional titles.
2This list of technologies is not exhaustive.
==== Non-imaging modalities ====
Non-imaging modalities vary, and are often undertaken in addition to imaging modalities. They commonly include:
Academia – Education role.
Clinical Management – Clinical managerial role which can be varied; may include managing audits, rotas, department budgets, etc.
Clinical Research – Research role.
Medical Physics – Multidisciplinary role ensuring the correct calibration of and most efficient use of diagnostic equipment.
PACS Management – Managerial role concerned with maintaining and supervising appropriate and correct use of the RIS and PACS systems.
Radiation Protection – A managerial role concerned with monitoring the level of ionising radiation absorbed by anyone who comes into contact with ionising radiation at their site.
Reporting Radiography – A clinical role involved with interpretation of radiographs and various other radiological media for diagnosis.
== Education and role variation ==
Education varies worldwide due to legal limitations on scope of practice.
=== Belgium ===
The profession of diagnostic radiographer is called "medical imaging technologist", it is a regulated healthcare profession. A diploma of a specific professional Bachelor is a requirement for registration and recognition.
Since 2 December 2014, everyone who works at a Medical Imaging department, is obliged to be in possession of the recognition and the visa issued by the Ministry of Health (a professional identity card that is considered a license)
To practice a health care profession with a foreign diploma from within the EEA or equivalent in the EEA, it is necessary to request the recognition for the profession from Government of Flanders (Agency of Care and Health).
It is possible to request the recognition if:
The person have a diploma of their healthcare profession and want to practice their profession in Belgium.
The person have obtained their degree in one of the countries of the European Economic Area (EEA) or Switzerland.
Or the person's diploma is equivalent in a country of the EEA and they are a European national.
=== Germany ===
In Germany radiographers either take a 3-year full-time professional training or a 5-year part-time professional training before they qualify as a 'Medizinischer Technologe für Radiologie (MTR)' (eng. medical technologist for radiology).
Similar to other countries, they work within the areas of radiography diagnostics (CT scans, magnetic resonance imaging, radiography, digital subtraction angiography), radiation therapy, radiation dosimeters and nuclear medicine.
The job profile is in high demand, with almost half of hospitals struggling to fill MTR positions in 2019. MTR trainees primarily aim for positions in diagnostic and interventional radiology.
=== Ireland ===
Radiographers in the Republic of Ireland (ROI) must be registered with CORU before they can practice in the Republic of Ireland. Student radiographers training in the ROI will typically study for 4 years on an approved bachelor's degree program; currently degree programs only exist at University College Dublin.
Applicants must have either an approved qualification, a schedule 3 qualification, an appropriate letter of recommendation/accreditation or another qualification which is deemed 'suitably relevant' by registration board in order to successfully fulfil the vocational education requirements to become a Radiographer in the ROI. Applications for registration with qualifications outside of this are considered on an individual basis; typically this includes most international applicants.
The professional body representing Radiographers in the ROI is the Irish Institute of Radiography and Radiation Therapy (IIRRT).
To practice as a Radiographer or Radiation Therapist in Ireland, one must register with CORU as of 31 October 2015. CORU is Ireland's multi-profession health regulator. Set up under the Health and Social Care Professionals Act 2005, CORU is used to protect the public by promoting high standards of professional conduct, education, training and competence through statutory registration of health and social care professionals. If a radiographer commences clinical practice without registration then they may be prosecuted with a fine or an imprisonment of up to six months.
=== Malta ===
Radiography is a regulated profession in Malta and anyone wanting to practice Diagnostic or Therapeutic Radiography would need to obtain state registration in order to be licensed as a Radiographer, obtained from the Council for Professions Complementary to Medicine (CPCM).
In Malta, in order for an individual to become a Radiographer he/she first has to follow a course offered by the University of Malta. The course is BSc (Hons) Radiography and its duration is of four years. On completion of the course, the graduate will have the conditions to be eligible for registration with the council for professions complementary to Medicine
A foreign radiographer can work in Malta should the necessary documentation and competencies have been obtained and presented. Radiographers working on Malta should abide by the rules of the host country and title of radiographer will be used.
An application form has to be filled along with the necessary authenticated copies of several documents. The application form includes the insertion of personal details of the individual along with the description of qualifications and the university which granted the qualifications. The individual has to declare whether he or she is registered with another Health Care Profession Register in Malta.
Below is a list of the documents needed for a professional to register with the council:
Application Form
Original or authenticated copies of the following documents (English versions): a. Birth and marriage (if applicable) certificates.
Identification document such as ID or Passport.
Recent Police Conduct certificate.
Professional Document Diploma/Degree.
Letters of Reference in English.
A detailed transcript of Theoretical and Practical Training and Studies in hours associated with the Profession and in relation with the profession syllabus performed by their Institution being the university/College. This has to be endorsed in the original format by the Head/Registrar of their Institution being the university/College.
A recent (six months) verification certificate of current registration and good standing with the council the person are registered with.
A secure English Language test (SELT) for foreign applicants.
Curriculum Vitae in English.
In cases where the professional qualification acquired was not obtained from an Accredited Institution in Malta, a letter is to be submitted, issued from the Malta Qualifications Recognition Information Centre (MQRIC), certifying that the Institution from where the qualification was obtained is equivalently accredited and indicate the level of qualification in accordance to the Malta Qualifications Framework.
For applicants from the European Economic Area countries, once the application is submitted, it will follow the regulations established on the Directive 2005/36/EC on the recognition of qualifications between member states. In these cases, the professional document and theoretical and practical training are required to be equivalent to the requirements of Malta, i.e. An EQF Level 6 Bachelor's Degree with an equivalent syllabus to that of the University of Malta and their course is no more than one year shorter. Should the radiographer have a substantial difference between their professional qualifications and those required by CPCM, the radiographer has the right to provide further evidence of competence (including professional experience or CPD), otherwise, the CPCM board should offer the applicant the possibility to do an aptitude test or adaptation period (as chosen by the applicant). A Flow chart explaining this procedure for EEA applicants can be found on the government's website.
=== Nepal ===
As a developing country, the health care sector in Federal Democratic Republic of Nepal has very limited resources meaning radiological services are rather limited.
Nepal is still struggling to improve and manage conventional radiological examinations. Radiological Services in Nepal commenced in 1923 at Military Hospital by Dr. Rana and Dr Asta Bahadur Shrestha. The first health related training program began in 1933 at the Nepal Rajkiya Ayurved School; the Civil Medical School was later established in 1934. Radiological education in Nepal started in 1923 in a 64 bedded Military Hospital, Tri-ChandraElectro-Medical Institute. The post graduate (MSc) program in physics at TU began in 1965 with only Nuclear Physics specialization. In 1972, the Institute of Medicine (IOM) which is affiliated with TU started the Proficiency Certificate Level (PCL) Radiography course however this has since stopped.
Radiotherapy was first introduced at Maternity Hospital in 1976 utilising radium needle treatment. CT and Nuclear Medicine was introduced in 1988 at Bir Hospital. The Radiotherapy unit with Tele Cobalt-60 machine was established at Bir Hospital in 1991.
Nepal became a member of IAEA in 2008. Since 2008 onwards diploma level radiography courses have been conducted across the country by the Council for Technical Education and Vocational Training (CTEVT) and other affiliated institutions.
In Nepal there are 125 vocational health training institutes however only 15 are conducting radiological technological education. Bachelor level radiography education is taught in two universities & one college whereas master level radiography course is taught
in one where another university is in pipeline. Until recently, therapeutic radiography courses have not been taught in Nepal;
radiation therapists are predominantly trained abroad.
The Nepal Health Professional Council (NHPC) is the legislative body for registering, accrediting, developing & enforcing quality assurance of Health Professionals, including Radiographers, in Nepal.
=== The Netherlands ===
==== The Quality Register Paramedics ====
Until 1997, radiographers were required to register the Evidence of Competence at the Chief of Medical Inspections. This was mandatory under the Law on Paramedic professions. After innovate the law of Individual Health Care Professions (BIG), the registration requirements for radiographers were cancelled. A voluntary register has been set up in consultation with the Health Care Inspectorate: the Paramedics Quality Register.
The Paramedics Quality Register comes from the BIG. The purpose of the Paramedics Quality Register is to guarantee the quality of professional practice. Through the registration and re-registration (once in five years) it becomes visible for patients, health insurers etc. that the registered radiographer professional is and remains competent in the field of professional practice. Despite the fact that the quality register is not compulsory according to the law, many hospitals are obliged to do it. The hospitals are obliged to provide good quality care. Health insurers also attach great value to the Paramedics Quality Register because they are also required to provide good care.
==== Enrollment ====
Radiographers who are in possession of a valid Certificate of Competence, diploma of certificate and endorse the code of professional conduct of the professional association, can be enroll in the Paramedics historical register.
The official registration of the radiographer satisfies the educational requirements in the General Administrative Order (AMvB) ex. art. 34 BIG and the quality requirements of the professional group. On the basis of which is carried out radiographer is mentioned in the Diplomaregister Paramedici and / or the Quality Register Paramedics. By registration, the radiographer continues to be traced by, for example, the Health Care Inspectorate (IGZ) and the professional associations. Other organizations also intend the Quality Register Paramedics.
==== Re-enrollment ====
To be in the Paramedics Quality Register the radiographer need to request re-registration every five years. The first period of five years is determined on the basis of the diploma date. In case of re-registration, the radiographer must meet the requirements for that period. The start date of the period station local quality criteria. The quality criteria are set every five years by the Paramedics Quality Register, paramedical professional associations. To ensure that the requirements for the patient and the client-oriented exercises and expertise-enhancing activities are safeguarded for the quality of the professional practice. The quality criteria are set up in such a way that paramedics can meet the quality requirements with the set range of expertise-enhancing activities.
=== Nigeria ===
In Nigeria, these professionals are generally referred to as Radiographers or Medical Radiographers to differentiate them from Industrial Radiographers. Radiographers must complete a 5-year undergraduate BSc and a compulsory one year paid internship program in a hospital after graduation before attaining a full licensing by the Radiographers Registration Board of Nigeria. The board also registers Radiotherapists who have undergone the initial 5-year Radiography program before proceeding to the Radiotherapy training.
Radiographers in Nigeria have been striving to extend their practice to include radiographic interpretation and Ultrasound services. They are also on the verge of adopting an official professional title of "Radr" or "Rr" As of 2015.
Radiographers in Nigeria normally proceed for a Masters programme and a PhD programme in the profession.
There is a recent rise in the number of radiographers available in the country unlike the situation of shortage between 2000 – 2010.
In a typical Nigerian Teaching Hospital, radiographers do not undertake sonography examinations, this is left for the radiologists, who, in some areas, have gradually improved their relationship with the radiographers in providing services in other radiographic units. The radiologist is also in charge of specific Fluoroscopic cases where the radiographer assists only with positioning and image acquisition.
Allied Health Unions (such as 'JOHESU' and 'NUAHP') that Radiographers are members of (with Nurses, Pharmacists, Physiotherapists, Laboratory Scientists, etc.), have over the years gone on strike actions to force the Nigerian government to improve their allowances/salaries in the government owned hospitals. These strikes (when it is not a response on its own) often trigger a response from the Nigerian Medical Association who will also table some requests for the medical doctors.
Apart from monetary issues, these professional bodies are also in loggerheads over non-doctors requesting to be given top administrative roles in government owned hospitals. Many radiographers, however, do not particularly involve themselves in these movements as working in a private establishment is more lucrative.
Some Radiographers in Nigeria are also keen on setting up a "Department of Radiography" in the government owned hospitals which will not be under the Head of the Radiology Department. Some hospitals however have an understanding between the Radiology head (a Radiologist) and the Chief Radiographer where all radiographers are directly answerable to their Chief, and not the HOD.
=== Saudi Arabia ===
X-Ray Technicians (فني اشعة) in Saudi Arabia must successfully undertake a degree level program at a recognised higher-level education institution in Nursing before undertaking further study in radiographic imaging at university for typically 2 to 3 years; this must include a year's experience in a hospital. Upon completion, graduates are qualified X-Ray Technicians and can commence clinical practice.
=== United Kingdom ===
The SCoR is the professional body and union for UK radiographers. In the United Kingdom, there is ambiguity in the use of the term Radiographer as this does not differentiate between Therapeutic Radiographers (also known as Radiotherapists) and Diagnostic Radiographers. As a result, all of these titles are protected titles within the United Kingdom and can not be used by any persons who has not undertaken formal study and registered with the Health and Care Professions Council (HCPC). In order to practise Radiography in the United Kingdom candidates must now successfully obtain a pass in a degree level programme from an accredited institution. Degrees are offered by universities across the UK and last for at least 3 years in England, Wales and Northern Ireland; and 4 years in Scotland. Student Diagnostic Radiographers spend a significant amount of time working at various hospitals affiliated with their university during their studies to meet the requirement for registration with the HCPC.
They specialise in the acquisition of radiographs of General Practitioner referred (GP) patients, Outpatients, Emergency Department (ED) referred patients and Inpatients. They conduct mobile X-rays on wards and in other departments where patients are too critical to be moved and work as part of the operating team in mainly Orthopaedic and Urology cases, offering surgeons live radiographic imaging. Once qualified, Diagnostic Radiographers are able to acquire X-rays without supervision and work as part of the imaging team. They will have basic head examination qualifications in CT and even basic experience of MRI, Ultrasound and Nuclear Medicine.
Diagnostic Radiographers can specialise in-house or through a university course as a postgraduate in CT, MRI, Ultrasound or Nuclear Medicine with opportunities to gain an MSc or PhD in their field. Diagnostic Radiographers in the UK are also taking on roles that were typically only undertaken by the Radiologist (a medical doctor who specialised in interpreting X-rays), Urologist or Cardiologist in the past. This extended practice includes various interventional procedures not excluding barium enemas, barium meals/swallows, peripheral angioplasties, nerve root injections, central line insertions and many other procedures.
The professional body and workers union for Radiographers in the United Kingdom is the Society and College of Radiographers (SCoR). The union has been heavily involved in extending practice of Radiographers in the United Kingdom and has helped expand the role of the Radiographer greatly.
==== Expanded practice ====
Radiographers are now able to write reports and diagnose pathologies and/or conditions seen on differing diagnostic media after completing a HCPC and SCoR accredited university course; completing a course in this modality allows the Radiographer to become a reporting Radiographer in their chosen specialty.
Diagnostic Radiographers are able to become supplementary prescribers which allows them the capacity to prescribe medications in partnership with an independent prescriber (a doctor or a dentist); the supplementary prescriber is to implement an agreed Clinical Management Plan for an individual patient with that patient's agreement. An accredited university course must be undertaken before this role extension is annotated onto a HCPC registrant's record. It is thought that in the future Diagnostic Radiographers in will gain independent prescribing rights, however this is currently limited by their restricted and varied scope of practice. In 2016, the introduction of independent prescribing right was agreed for Therapeutic Radiographers after a consultation by the Medicines and Healthcare products Regulatory Agency (MHRA)
=== United States ===
In the United States, these professionals are known as Radiologic Technologists. Formal training programs in radiography range in length that leads to a certificate, an associate or a bachelor's degree. The American Registry of Radiologic Technologists (ARRT), the primary credentialing organisation for Radiologic Technologists in the United States, requires that candidates for ARRT Certification Exams must have an associate degree at minimum as of January, 2015, effectively ending non-degree granting diploma programs. Accreditation is primarily through The Joint Review Committee on Education in Radiologic Technology (JRCERT), the only agency recognised by the United States Department of Education and the Council for Higher Education Accreditation to grant accreditation to both traditional and online programs in Radiography, Radiation Therapy, Magnetic Resonance Imaging, and Medical Dosimetry. An online page where prospective students can check the accreditation of programs is maintained by JRCERT.
Radiologic Technology students study anatomy, physiology, physics, radiopharmacology, pathology, biology, research, nursing, medical imaging, diagnosis, radiologic instrumentation, emergency medical procedures, medical imaging techniques, patient care, medical ethics and general chemistry. Schooling also includes significant amounts of documented practicum supervised by Registered Technologists in various clinical settings where the classroom theory is translated to practical knowledge and real world experience. The change from Film to Digital imaging has changed training as film quality assurance and quality control is largely obsolete. The role of computer workstations to produce synthetic images for Radiologists has steadily increased the need for computer skills as has electronic medical record software.
After primary training and licensure, continuing education is required to maintain licensure and certification with the ARRT, who sets the accepted national guidelines. The ARRT requires 24 Units of accredited continuing education every two years and the laws and the regulations of most states accept this standard. Continuing formal education or the passing of an advanced practice speciality exam may also be accepted for continuing education credit. The American Society of Radiologic Technologists (ASRT), a professional association for people in Medical Imaging and Therapy, offers members and others continuing education materials in various media that meet the requirements of the ARRT for continuing education. Additional requirements are set forth for technologists who specialise in mammography by the US FDA.
==== Expanded practice ====
A new and evolving career for Radiologic Technologists is that of the Registered Radiologist Assistant (RRA) who is an experienced technologist (a type of Physician Assistant) who has completed additional education, training, and has passed exams to function as radiologist extenders. A list of the 9 currently accredited RRA programs is maintained by the ARRT and can be accessed online. Candidates for the RRA certification must possess a bachelor's degree at minimum.
Registered Radiologist Assistant (RRA), a new advanced practice radiographer career path in the United States for experienced technologists. RRAs do not interpret studies in the manner of the reporting radiographer. The role has been accepted by the American College of Radiology (ACR).
== Risks ==
Epidemiological studies indicate that Radiographers employed before 1950 are at increased risk of leukemia and skin cancer, most likely due to the lack of use of radiation monitoring and shielding. The relationship between radiation and cancer was found to correlate with women who were in the menopausal stages of their lives. In today's workplace, radiation exposure is monitored very closely and cancer cases in technologists has been found to have decreased tremendously due to the current prevention methods.
Ionising radiation, used in a variety of imaging procedures, can damage cells. Lead shields are used on the patient and by the Radiographer to reduce exposure by shielding areas that do not need to be imaged from the radiation source. While lead is highly toxic, the shields used in medical imaging are coated to prevent lead exposure and are regularly tested for integrity.
Radiographers who develop x-ray films are exposed to the various chemical hazards such as sulfur dioxide, glutaraldehyde, and acetic acid. These agents can cause asthma and other health issues.
Theoretically, the strong static magnetic fields of MRI scanners can cause physiological changes. After a human neural cell culture was exposed to a static magnetic field for 15 minutes, changes in cell morphology occurred along with some modifications in the physiological functions of those cells. However, these effects have not yet been independently replicated or confirmed, and this particular study was performed in vitro.
Ultrasound imaging can deform cells in the imaging field, if those cells are in a fluid. However, this effect is not sufficient to damage the cells.
As with any allied health professional, exposure to infectious diseases is likely, and use of Personal Protective Equipment (PPE) and infection control precautions must be employed to reduce the risk of infection. Those with family health histories reported feeling increased amount of stress due to concern of bringing infectious diseases home.
In 2016, 59% of technologists surveyed reported that being overworked lead to risking medical error and threatening patient safety. Being overworked also led to depersonalization due to the emotional drain it takes on technologists' mental health, also putting patients at risk.
Due to constantly maneuvering heavy patients, technologists are at risk for work related injuries from the strain it puts on their bodies. Most technologists who develop a work related injury, later report having more work related injuries.
== References ==
== External links ==
CORU
Irish Institute of Radiography and Radiation Therapy (IIRRT)
International Society of Radiographers and Radiologic Technologists (ISRRT) | Wikipedia/Radiographer |
Industrial computed tomography (CT) scanning is any computer-aided tomographic process, usually X-ray computed tomography, that uses irradiation to produce three-dimensional internal and external representations of a scanned object. Industrial CT scanning has been used in many areas of industry for internal inspection of components. Some of the key uses for industrial CT scanning have been flaw detection, failure analysis, metrology, assembly analysis and reverse engineering applications. Just as in medical imaging, industrial imaging includes both nontomographic radiography (industrial radiography) and computed tomographic radiography (computed tomography).
== Types of scanners ==
Line beam scanning is the traditional process of industrial CT scanning. X-rays are produced and the beam is collimated to create a line. The X-ray line beam is then translated across the part and data is collected by the detector. The data is then reconstructed to create a 3-D volume rendering of the part.
In cone beam scanning, the part to be scanned is placed on a rotary table. As the part rotates, the cone of X-rays produce a large number of 2D images that are collected by the detector. The 2D images are then processed to create a 3D volume rendering of the external and internal geometries of the part.
== History ==
Industrial CT scanning technology was introduced in 1972 with the invention of the CT scanner for medical imaging by Godfrey Hounsfield. The invention earned him a Nobel Prize in medicine, which he shared with Allan McLeod Cormack. Many advances in CT scanning have allowed for its use in the industrial field for metrology in addition to the visual inspection primarily used in the medical field (medical CT scan).
== Analysis and inspection techniques ==
Various inspection uses and techniques include part-to-CAD comparisons, part-to-part comparisons, assembly and defect analysis, void analysis, wall thickness analysis, and generation of CAD data. The CAD data can be used for reverse engineering, geometric dimensioning and tolerance analysis, and production part approval.
=== Assembly ===
One of the most recognized forms of analysis using CT is for assembly, or visual analysis. CT scanning provides views inside components in their functioning position, without disassembly. Some software programs for industrial CT scanning allow for measurements to be taken from the CT dataset volume rendering. These measurements are useful for determining the clearances between assembled parts or the dimension of an individual feature.
=== Void, crack and defect detection ===
Traditionally, determining defects, voids and cracks within an object would require destructive testing. CT scanning can detect internal features and flaws displaying this information in 3D without destroying the part. Industrial CT scanning (3D X-ray) is used to detect flaws inside a part such as porosity, an inclusion, or a crack. It has been also used to detect the origin and propagation of damages in concrete.
Metal casting and moulded plastic components are typically prone to porosity because of cooling processes, transitions between thick and thin walls, and material properties. Void analysis can be used to locate, measure, and analyze voids inside plastic or metal components.
=== Geometric dimensioning and tolerancing analysis ===
Traditionally, without destructive testing, full metrology has only been performed on the exterior dimensions of components, such as with a coordinate-measuring machine (CMM) or with a vision system to map exterior surfaces. Internal inspection methods would require using a 2D X-ray of the component or the use of destructive testing. Industrial CT scanning allows for full non-destructive metrology. With unlimited geometrical complexity, 3D printing allows for complex internal features to be created with no impact on cost, such features are not accessible using traditional CMM. The first 3D printed artefact that is optimised for characterisation of form using computed tomography CT
=== Image-based finite element methods ===
Image-based finite element method converts the 3D image data from X-ray computed tomography directly into meshes for finite element analysis. Benefits of this method include modelling complex geometries (e.g. composite materials) or accurately modelling "as manufactured" components at the micro-scale.
== Trends and Developments ==
The industrial computed tomography market is forecast to reach a size of USD 773.45 million to USD 1,116.5 million between 2029 and 2030. Regional trends show that strong market growth is expected, particularly in the Asia-Pacific region, but also in North America and Europe, due to strict safety regulations and preventive maintenance of industrial equipment. Growth is being driven primarily by the ongoing development of CT devices and services that enable precise and non-destructive testing of components. Innovations such as the use of artificial intelligence for automated fault analyses and the development of mobile CT systems are expanding the possibilities.
== Developments for Forensic Science ==
Computed Tomography (CT) has become an increasingly valuable tool in forensic science, particularly in conducting virtual autopsies. Unlike traditional autopsies, which require invasive procedures, CT scans allow for non-invasive internal examinations of the body, producing detailed 3D images of bones, organs, and soft tissues. This technology is especially useful for detecting fractures, foreign objects (such as bullets or shrapnel), gas embolisms, and signs of trauma that may not be immediately visible externally. CT scans can preserve forensic evidence more effectively and are particularly beneficial in cases involving mass disasters, decomposition, or cultural and religious objections to dissection. Furthermore, digital imaging from CT can be stored and reviewed multiple times, aiding both legal investigations and educational purposes. Overall, CT has enhanced the accuracy, efficiency, and accessibility of post-mortem examinations in forensic contexts.
=== List of uses of CT scanning in Forensic Science ===
Sources:
Virtual Autopsies (Virtopsies)
Non-invasive internal examinations of deceased individuals.
Detection of Fractures
Identification of skull, rib, and other skeletal fractures, especially those not visible externally.
Visualization of Foreign Objects
Location and analysis of bullets, shrapnel, or other embedded materials.
Assessment of Trauma
Differentiation between antemortem (before death) and postmortem (after death) injuries.
Analysis of Gas Embolisms
Identification of air or gas in blood vessels, which may indicate drowning, decompression sickness, or medical malpractice.
Age Estimation
Evaluation of skeletal maturity and dental development in unidentified remains.
Facial Reconstruction Support
High-resolution skull imaging for reconstructing a face digitally.
Identification of Pathologies
Detection of diseases, infections, or chronic conditions that may relate to cause of death.
Documentation and Archiving
Permanent, revisitable digital records of body condition and evidence.
Comparison with Antemortem Data
Matching postmortem CT scans with medical imaging from a person’s lifetime for identification.
Explosion and Blast Injury Analysis
Assessment of internal damage patterns caused by high-pressure events.
Burn Victim Analysis
Examining internal structures in severely burned bodies when traditional autopsy is limited.
Decomposition Studies
Monitoring changes in tissues and gases during the decomposition process.
Cultural/Religious Sensitivity
Alternative to invasive autopsies when cutting open a body is not permitted.
Mass Disaster Victim Identification
Efficient imaging of multiple bodies for quick identification and trauma assessment.
== See also ==
CT scan
Industrial radiography
Cone beam computed tomography, applications in quality control and metrology.
PCB reverse engineering, an application of industrial CT to image printed circuit boards non-destructively.
== References == | Wikipedia/Industrial_computed_tomography |
Physiology (; from Ancient Greek φύσις (phúsis) 'nature, origin' and -λογία (-logía) 'study of') is the scientific study of functions and mechanisms in a living system. As a subdiscipline of biology, physiology focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out chemical and physical functions in a living system. According to the classes of organisms, the field can be divided into medical physiology, animal physiology, plant physiology, cell physiology, and comparative physiology.
Central to physiological functioning are biophysical and biochemical processes, homeostatic control mechanisms, and communication between cells. Physiological state is the condition of normal function. In contrast, pathological state refers to abnormal conditions, including human diseases.
The Nobel Prize in Physiology or Medicine is awarded by the Royal Swedish Academy of Sciences for exceptional scientific achievements in physiology related to the field of medicine.
== Foundations ==
Because physiology focuses on the functions and mechanisms of living organisms at all levels, from the molecular and cellular level to the level of whole organisms and populations, its foundations span a range of key disciplines:
Anatomy is the study of the structure and organization of living organisms, from the microscopic level of cells and tissues to the macroscopic level of organs and systems. Anatomical knowledge is important in physiology because the structure and function of an organism are often dictated by one another.
Biochemistry is the study of the chemical processes and substances that occur within living organisms. Knowledge of biochemistry provides the foundation for understanding cellular and molecular processes that are essential to the functioning of organisms.
Biophysics is the study of the physical properties of living organisms and their interactions with their environment. It helps to explain how organisms sense and respond to different stimuli, such as light, sound, and temperature, and how they maintain homeostasis, or a stable internal environment.
Genetics is the study of heredity and the variation of traits within and between populations. It provides insights into the genetic basis of physiological processes and the ways in which genes interact with the environment to influence an organism's phenotype.
Evolutionary biology is the study of the processes that have led to the diversity of life on Earth. It helps to explain the origin and adaptive significance of physiological processes and the ways in which organisms have evolved to cope with their environment.
== Subdisciplines ==
There are many ways to categorize the subdisciplines of physiology:
based on the taxa studied: human physiology, animal physiology, plant physiology, microbial physiology, viral physiology
based on the level of organization: cell physiology, molecular physiology, systems physiology, organismal physiology, ecological physiology, integrative physiology
based on the process that causes physiological variation: developmental physiology, environmental physiology, evolutionary physiology
based on the ultimate goals of the research: applied physiology (e.g., medical physiology), non-applied (e.g., comparative physiology)
=== Subdisciplines by level of organisation ===
==== Cell physiology ====
Although there are differences between animal, plant, and microbial cells, the basic physiological functions of cells can be divided into the processes of cell division, cell signaling, cell growth, and cell metabolism.
=== Subdisciplines by taxa ===
==== Plant physiology ====
Plant physiology is a subdiscipline of botany concerned with the functioning of plants. Closely related fields include plant morphology, plant ecology, phytochemistry, cell biology, genetics, biophysics, and molecular biology. Fundamental processes of plant physiology include photosynthesis, respiration, plant nutrition, tropisms, nastic movements, photoperiodism, photomorphogenesis, circadian rhythms, seed germination, dormancy, and stomata function and transpiration. Absorption of water by roots, production of food in the leaves, and growth of shoots towards light are examples of plant physiology.
==== Animal physiology ====
==== Human physiology ====
Human physiology is the study of how the human body's systems and functions work together to maintain a stable internal environment. It includes the study of the nervous, endocrine, cardiovascular, respiratory, digestive, and urinary systems, as well as cellular and exercise physiology. Understanding human physiology is essential for diagnosing and treating health conditions and promoting overall wellbeing.
It seeks to understand the mechanisms that work to keep the human body alive and functioning, through scientific enquiry into the nature of mechanical, physical, and biochemical functions of humans, their organs, and the cells of which they are composed. The principal level of focus of physiology is at the level of organs and systems within systems. The endocrine and nervous systems play major roles in the reception and transmission of signals that integrate function in animals. Homeostasis is a major aspect with regard to such interactions within plants as well as animals. The biological basis of the study of physiology, integration refers to the overlap of many functions of the systems of the human body, as well as its accompanied form. It is achieved through communication that occurs in a variety of ways, both electrical and chemical.
Changes in physiology can impact the mental functions of individuals. Examples of this would be the effects of certain medications or toxic levels of substances. Change in behavior as a result of these substances is often used to assess the health of individuals.
Much of the foundation of knowledge in human physiology was provided by animal experimentation. Due to the frequent connection between form and function, physiology and anatomy are intrinsically linked and are studied in tandem as part of a medical curriculum.
=== Subdisciplines by research objective ===
==== Comparative physiology ====
Involving evolutionary physiology and environmental physiology, comparative physiology considers the diversity of functional characteristics across organisms.
== History ==
=== The classical era ===
The study of human physiology as a medical field originates in classical Greece, at the time of Hippocrates (late 5th century BC). Outside of Western tradition, early forms of physiology or anatomy can be reconstructed as having been present at around the same time in China, India and elsewhere. Hippocrates incorporated the theory of humorism, which consisted of four basic substances: earth, water, air and fire. Each substance is known for having a corresponding humor: black bile, phlegm, blood, and yellow bile, respectively. Hippocrates also noted some emotional connections to the four humors, on which Galen would later expand. The critical thinking of Aristotle and his emphasis on the relationship between structure and function marked the beginning of physiology in Ancient Greece. Like Hippocrates, Aristotle took to the humoral theory of disease, which also consisted of four primary qualities in life: hot, cold, wet and dry. Galen (c. 130–200 AD) was the first to use experiments to probe the functions of the body. Unlike Hippocrates, Galen argued that humoral imbalances can be located in specific organs, including the entire body. His modification of this theory better equipped doctors to make more precise diagnoses. Galen also played off of Hippocrates' idea that emotions were also tied to the humors, and added the notion of temperaments: sanguine corresponds with blood; phlegmatic is tied to phlegm; yellow bile is connected to choleric; and black bile corresponds with melancholy. Galen also saw the human body consisting of three connected systems: the brain and nerves, which are responsible for thoughts and sensations; the heart and arteries, which give life; and the liver and veins, which can be attributed to nutrition and growth. Galen was also the founder of experimental physiology. And for the next 1,400 years, Galenic physiology was a powerful and influential tool in medicine.
=== Early modern period ===
Jean Fernel (1497–1558), a French physician, introduced the term "physiology". Galen, Ibn al-Nafis, Michael Servetus, Realdo Colombo, Amato Lusitano and William Harvey, are credited as making important discoveries in the circulation of the blood. Santorio Santorio in 1610s was the first to use a device to measure the pulse rate (the pulsilogium), and a thermoscope to measure temperature.
In 1791 Luigi Galvani described the role of electricity in the nerves of dissected frogs. In 1811, César Julien Jean Legallois studied respiration in animal dissection and lesions and found the center of respiration in the medulla oblongata. In the same year, Charles Bell finished work on what would later become known as the Bell–Magendie law, which compared functional differences between dorsal and ventral roots of the spinal cord. In 1824, François Magendie described the sensory roots and produced the first evidence of the cerebellum's role in equilibration to complete the Bell–Magendie law.
In the 1820s, the French physiologist Henri Milne-Edwards introduced the notion of physiological division of labor, which allowed to "compare and study living things as if they were machines created by the industry of man." Inspired in the work of Adam Smith, Milne-Edwards wrote that the "body of all living beings, whether animal or plant, resembles a factory ... where the organs, comparable to workers, work incessantly to produce the phenomena that constitute the life of the individual." In more differentiated organisms, the functional labor could be apportioned between different instruments or systems (called by him as appareils).
In 1858, Joseph Lister studied the cause of blood coagulation and inflammation that resulted after previous injuries and surgical wounds. He later discovered and implemented antiseptics in the operating room, and as a result, decreased the death rate from surgery by a substantial amount.
The Physiological Society was founded in London in 1876 as a dining club. The American Physiological Society (APS) is a nonprofit organization that was founded in 1887. The Society is, "devoted to fostering education, scientific research, and dissemination of information in the physiological sciences."
In 1891, Ivan Pavlov performed research on "conditional responses" that involved dogs' saliva production in response to a bell and visual stimuli.
In the 19th century, physiological knowledge began to accumulate at a rapid rate, in particular with the 1838 appearance of the Cell theory of Matthias Schleiden and Theodor Schwann. It radically stated that organisms are made up of units called cells. Claude Bernard's (1813–1878) further discoveries ultimately led to his concept of milieu interieur (internal environment), which would later be taken up and championed as "homeostasis" by American physiologist Walter B. Cannon in 1929. By homeostasis, Cannon meant "the maintenance of steady states in the body and the physiological processes through which they are regulated." In other words, the body's ability to regulate its internal environment. William Beaumont was the first American to utilize the practical application of physiology.
Nineteenth-century physiologists such as Michael Foster, Max Verworn, and Alfred Binet, based on Haeckel's ideas, elaborated what came to be called "general physiology", a unified science of life based on the cell actions, later renamed in the 20th century as cell biology.
=== Late modern period ===
In the 20th century, biologists became interested in how organisms other than human beings function, eventually spawning the fields of comparative physiology and ecophysiology. Major figures in these fields include Knut Schmidt-Nielsen and George Bartholomew. Most recently, evolutionary physiology has become a distinct subdiscipline.
In 1920, August Krogh won the Nobel Prize for discovering how, in capillaries, blood flow is regulated.
In 1954, Andrew Huxley and Hugh Huxley, alongside their research team, discovered the sliding filaments in skeletal muscle, known today as the sliding filament theory.
Recently, there have been intense debates about the vitality of physiology as a discipline (Is it dead or alive?). If physiology is perhaps less visible nowadays than during the golden age of the 19th century, it is in large part because the field has given birth to some of the most active domains of today's biological sciences, such as neuroscience, endocrinology, and immunology. Furthermore, physiology is still often seen as an integrative discipline, which can put together into a coherent framework data coming from various different domains.
== Notable physiologists ==
=== Women in physiology ===
Initially, women were largely excluded from official involvement in any physiological society. The American Physiological Society, for example, was founded in 1887 and included only men in its ranks. In 1902, the American Physiological Society elected Ida Hyde as the first female member of the society. Hyde, a representative of the American Association of University Women, a global non-profit organization that advances equity for women and girls in education, attempted to promote gender equality in every aspect of science and medicine.
Soon thereafter, in 1913, J.S. Haldane proposed that women be allowed to formally join The Physiological Society, which had been founded in 1876. On 3 July 1915, six women were officially admitted: Florence Buchanan, Winifred Cullis, Ruth Skelton, Sarah C. M. Sowton, Constance Leetham Terry, and Enid M. Tribe. The centenary of the election of women was celebrated in 2015 with the publication of the book "Women Physiologists: Centenary Celebrations And Beyond For The Physiological Society." (ISBN 978-0-9933410-0-7)
Prominent women physiologists include:
Bodil Schmidt-Nielsen, the first woman president of the American Physiological Society in 1975.
Gerty Cori, along with her husband Carl Cori, received the Nobel Prize in Physiology or Medicine in 1947 for their discovery of the phosphate-containing form of glucose known as glycogen, as well as its function within eukaryotic metabolic mechanisms for energy production. Moreover, they discovered the Cori cycle, also known as the Lactic acid cycle, which describes how muscle tissue converts glycogen into lactic acid via lactic acid fermentation.
Barbara McClintock was rewarded the 1983 Nobel Prize in Physiology or Medicine for the discovery of genetic transposition. McClintock is the only female recipient who has won an unshared Nobel Prize.
Gertrude Elion, along with George Hitchings and Sir James Black, received the Nobel Prize for Physiology or Medicine in 1988 for their development of drugs employed in the treatment of several major diseases, such as leukemia, some autoimmune disorders, gout, malaria, and viral herpes.
Linda B. Buck, along with Richard Axel, received the Nobel Prize in Physiology or Medicine in 2004 for their discovery of odorant receptors and the complex organization of the olfactory system.
Françoise Barré-Sinoussi, along with Luc Montagnier, received the Nobel Prize in Physiology or Medicine in 2008 for their work on the identification of the Human Immunodeficiency Virus (HIV), the cause of Acquired Immunodeficiency Syndrome (AIDS).
Elizabeth Blackburn, along with Carol W. Greider and Jack W. Szostak, was awarded the 2009 Nobel Prize for Physiology or Medicine for the discovery of the genetic composition and function of telomeres and the enzyme called telomerase.
== See also ==
== References ==
== Bibliography ==
Human physiology
Hall, John (2011). Guyton and Hall textbook of medical physiology (12th ed.). Philadelphia, Pa.: Saunders/Elsevier. ISBN 978-1-4160-4574-8.
Widmaier, E.P., Raff, H., Strang, K.T. Vander's Human Physiology. 11th Edition, McGraw-Hill, 2009.
Marieb, E.N. Essentials of Human Anatomy and Physiology. 10th Edition, Benjamin Cummings, 2012.
Animal physiology
Hill, R.W., Wyse, G.A., Anderson, M. Animal Physiology, 3rd ed. Sinauer Associates, Sunderland, 2012.
Moyes, C.D., Schulte, P.M. Principles of Animal Physiology, second edition. Pearson/Benjamin Cummings. Boston, MA, 2008.
Randall, D., Burggren, W., and French, K. Eckert Animal Physiology: Mechanism and Adaptation, 5th Edition. W.H. Freeman and Company, 2002.
Schmidt-Nielsen, K. Animal Physiology: Adaptation and Environment. Cambridge & New York: Cambridge University Press, 1997.
Withers, P.C. Comparative animal physiology. Saunders College Publishing, New York, 1992.
Plant physiology
Larcher, W. Physiological plant ecology (4th ed.). Springer, 2001.
Salisbury, F.B, Ross, C.W. Plant physiology. Brooks/Cole Pub Co., 1992
Taiz, L., Zieger, E. Plant Physiology (5th ed.), Sunderland, Massachusetts: Sinauer, 2010.
Fungal physiology
Griffin, D.H. Fungal Physiology, Second Edition. Wiley-Liss, New York, 1994.
Protistan physiology
Levandowsky, M. Physiological Adaptations of Protists. In: Cell physiology sourcebook: essentials of membrane biophysics. Amsterdam; Boston: Elsevier/AP, 2012.
Levandowski, M., Hutner, S.H. (eds). Biochemistry and physiology of protozoa. Volumes 1, 2, and 3. Academic Press: New York, NY, 1979; 2nd ed.
Laybourn-Parry J. A Functional Biology of Free-Living Protozoa. Berkeley, California: University of California Press; 1984.
Algal physiology
Lobban, C.S., Harrison, P.J. Seaweed ecology and physiology. Cambridge University Press, 1997.
Stewart, W. D. P. (ed.). Algal Physiology and Biochemistry. Blackwell Scientific Publications, Oxford, 1974.
Bacterial physiology
El-Sharoud, W. (ed.). Bacterial Physiology: A Molecular Approach. Springer-Verlag, Berlin-Heidelberg, 2008.
Kim, B.H., Gadd, M.G. Bacterial Physiology and Metabolism. Cambridge, 2008.
Moat, A.G., Foster, J.W., Spector, M.P. Microbial Physiology, 4th ed. Wiley-Liss, Inc. New York, NY, 2002.
== External links ==
The dictionary definition of physiology at Wiktionary
Works on the topic Physiology at Wikisource
Media related to Physiology at Wikimedia Commons
physiologyINFO.org – public information site sponsored by the American Physiological Society | Wikipedia/physiology |
Clinical physiology is an academic discipline within the medical sciences and a clinical medical specialty for physicians in the health care systems of Sweden, Denmark, Portugal and Finland. Clinical physiology is characterized as a branch of physiology that uses a functional approach to understand the pathophysiology of a disease.
== Overview ==
As a specialty for medical doctors, clinical physiology is a diagnostic specialty in which patients are subjected to specialized tests for the functions of the heart, blood vessels, lungs, kidneys and gastrointestinal tract, and other organs. Testing methods include evaluation of electrical activity (e.g. electrocardiogram of the heart), blood pressure (e.g. ankle brachial pressure index), and air flow (e.g. pulmonary function testing using spirometry). In addition, Clinical Physiologists measure movements, velocities, and metabolic processes through imaging techniques such as ultrasound, echocardiography, magnetic resonance imaging (MRI), x-ray computed tomography (CT), and nuclear medicine scanners (e.g. single photon emission computed tomography (SPECT) and positron emission tomography (PET) with and without CT or MRI).
== History ==
The field of clinical physiology was originally founded by Professor Torgny Sjöstrand in Sweden, and it continues to make its way around the world in other hospitals and academic environments. Sjöstrand was the first to establish departments for clinical physiology separate from those of physiology, during his work at the Karolinska Hospital in Stockholm. Along with Sjöstrand, another influential name in clinical physiology was P.K Anokhin. Anohkin heavily contributed to the branch of physiology where he worked diligently to use his theories of functional systems to solve medical mysteries amongst his patients.
In Sweden, clinical physiology was originally a discipline on its own, however, between 2008 and 2015, clinical physiology was categorized as a sub-discipline of radiology. For this reason, those pursuing a career in clinical physiology had to first become registered and certified radiologists before becoming clinical physiologists. Since 2015, clinical physiology has been a separate discipline, independent of radiology.
== Role ==
Human physiology is the study of bodily functions. Clinical physiology examinations typically involve assessments of such functions as opposed to assessments of structures and anatomy. The specialty encompasses the development of new physiological tests for medical diagnostics. Using equipments to measure, monitor and record patients proves very helpful for patients in many hospitals. Moreover, it is helpful to doctors, making it possible for patients to be diagnosed correctly. Some Clinical Physiology departments perform tests from related medical specialties including nuclear medicine, clinical neurophysiology, and radiology. In the health care systems of countries that lack this specialty, the tests performed in clinical physiology are often performed by the various organ-specific specialties in internal medicine, such as cardiology, pulmonology, nephrology, and others.
In Australia, the United Kingdom, and many other commonwealth and European countries, clinical physiology is not a medical specialty for physicians. It is individually a non-medical allied health profession - scientist, physiologist or technologist - who may practice as a cardiac scientist, vascular scientist, respiratory scientist, sleep scientist or in Ophthalmic and Vision Science as an Ophthalmic Science Practitioner (UK). These professionals also aid in the diagnosis of disease and manage patients, with an emphasis on understanding physiological and pathophysiological pathways. Disciplines within clinical physiology field include audiologists, cardiac physiologists, gastro-intestinal physiologists, neurophysiologists, respiratory physiologists, and sleep physiologists.
== References ==
== External links ==
Scandinavian Society of Clinical Physiology and Nuclear Medicine (SSCPNM) http://www.sscpnm.com/
The official journal of the SSCPNM: Clinical Physiology and Functional Imaging http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1475-097X | Wikipedia/Clinical_physiology |
Pulmonary function testing (PFT) is a complete evaluation of the respiratory system including patient history, physical examinations, and tests of pulmonary function. The primary purpose of pulmonary function testing is to identify the severity of pulmonary impairment. Pulmonary function testing has diagnostic and therapeutic roles and helps clinicians answer some general questions about patients with lung disease. PFTs are normally performed by a pulmonary function technologist, respiratory therapist, respiratory physiologist, physiotherapist, pulmonologist, or general practitioner.
== Indications ==
Pulmonary function testing is a diagnostic and management tool used for a variety of reasons, such as:
Diagnose lung disease.
Monitor the effect of chronic diseases like asthma, chronic obstructive lung disease, or cystic fibrosis.
Detect early changes in lung function.
Identify narrowing in the airways.
Evaluate airway bronchodilator reactivity.
Show if environmental factors have harmed the lungs
Preoperative testing
=== Neuromuscular disorders ===
Pulmonary function testing in patients with neuromuscular disorders helps to evaluate the respiratory status of patients at the time of diagnosis, monitor their progress and course, evaluate them for possible surgery, and gives an overall idea of the prognosis.
Duchenne muscular dystrophy is associated with gradual loss of muscle function over time. Involvement of respiratory muscles results in poor ability to cough and decreased ability to breathe well and leads to collapse of part or all of the lung leading to impaired gas exchange and an overall insufficiency in lung strength.
== Tests ==
=== Spirometry ===
Spirometry includes tests of pulmonary mechanics – measurements of FVC, FEV1, FEF values, forced inspiratory flow rates (FIFs), and MVV. Measuring pulmonary mechanics assesses the ability of the lungs to move huge volumes of air quickly through the airways to identify airway obstruction.
The measurements taken by the spirometry device are used to generate a pneumotachograph that can help to assess lung conditions such as: asthma, pulmonary fibrosis, cystic fibrosis, and chronic obstructive pulmonary disease. Physicians may also use the test results to diagnose bronchial hyperresponsiveness to exercise, cold air, or pharmaceutical agents.
==== Helium dilution ====
The helium dilution technique for measuring lung volumes uses a closed, rebreathing circuit. This technique is based on the assumptions that a known volume and concentration of helium in air begin in the closed spirometer, that the patient has no helium in their lungs, and that an equilibration of helium can occur between the spirometer and the lungs.
==== Nitrogen washout ====
The nitrogen washout technique uses a non-rebreathing open circuit. The technique is based on the assumptions that the nitrogen concentration in the lungs is 78% and in equilibrium with the atmosphere, that the patient inhales 100% oxygen and that the oxygen replaces all of the nitrogen in the lungs.
=== Plethysmography ===
The plethysmography technique applies Boyle's law and uses measurements of volume and pressure changes to determine total lung volume, assuming temperature is constant.
There are four lung volumes and four lung capacities. A lung's capacity consists of two or more lung volumes. The lung volumes are tidal volume (VT), inspiratory reserve volume (IRV), expiratory reserve volume (ERV), and residual volume (RV). The four lung capacities are total lung capacity (TLC), inspiratory capacity (IC), functional residual capacity (FRC) and vital capacity (VC).
=== Maximal respiratory pressures ===
Measurement of maximal inspiratory and expiratory pressures is indicated whenever there is an unexplained decrease in vital capacity or respiratory muscle weakness is suspected clinically. Maximal inspiratory pressure (MIP) is the maximal pressure that can be produced by the patient trying to inhale through a blocked mouthpiece. Maximal expiratory pressure (MEP) is the maximal pressure measured during forced expiration (with cheeks bulging) through a blocked mouthpiece after a full inhalation. Repeated measurements of MIP and MEP are useful in following the course of patients with neuromuscular disorders.
=== Diffusing capacity ===
Measurement of the single-breath diffusing capacity for carbon monoxide (DLCO) is a fast and safe tool in the evaluation of both restrictive and obstructive lung disease.
=== Bronchodilator responsiveness ===
When a patient has an obstructive defect, a bronchodilator test is given to evaluate if airway constriction is reversible with a short acting beta-agonist. This is defined as an increase of ≥12% and ≥200 mL in the FEV1 or FVC.
=== Oxygen desaturation during exercise ===
The six-minute walk test is a good index of physical function and therapeutic response in patients with a chronic lung disease, such as COPD or idiopathic pulmonary fibrosis.
=== Arterial blood gases ===
Arterial blood gases (ABGs) are a helpful measurement in pulmonary function testing in selected patients. The primary role of measuring ABGs in individuals that are healthy and stable is to confirm hypoventilation when it is suspected on the basis of medical history, such as respiratory muscle weakness or advanced COPD.
ABGs also provide a more detailed assessment of the severity of hypoxemia in patients who have low normal oxyhemoglobin saturation.
== Risks ==
Pulmonary function testing is a safe procedure; however, there is cause for concern regarding untoward reactions and the value of the test data should be weighed against potential hazards. Some complications include dizziness, shortness of breath, coughing, pneumothorax, and inducing an asthma attack.
== Contraindications ==
There are some indications against a pulmonary function test being done. These include a recent heart attack, stroke, head injury, an aneurysm, or confusion.
== Technique ==
=== Preparation ===
Subjects have measurements of height and weight taken before spirometry to determine what their predicted values should be. Additionally, a history of smoking, recent illness, and medications is taken.
=== Quality control ===
In order for the forced vital capacity to be considered accurate it has to be conducted three times where the peak is sharp in the flow-volume curve and the exhalation time is longer than 6 seconds.
Repeatability of the PFT is determined by comparing the values of forced vital capacity (FVC) and forced expiratory volume at 1 second (FEV1). The difference between the highest values of two FVCs need to be within 5% or 150 mL. When the FVC is less than 1.0 L, the difference between the highest two values must be within 100 mL. Lastly, the difference between the two highest values of FEV1 should also be within 150 mL. The highest FVC and FEV1 may be used from each different test. Until the results of three tests meet the criteria of reproducibility, the test can be repeated up to eight times. If it is still not possible to get accurate results, the best three tests are used.
== Clinical significance ==
Changes in lung volumes and capacities from normal are generally consistent with the pattern of lung impairment.
Spirometry is required for a diagnosis of COPD.
== Interpretation of tests ==
Professional societies such as the American Thoracic Society and the European Respiratory Society have published guidelines regarding the conduct and interpretation of pulmonary function testing to ensure standardization and uniformity in performance of tests. The interpretation of tests depends on comparing the patients values to published normals from previous studies. Deviation from guidelines can result in false-positive or false negative test results, even though only a small minority of pulmonary function laboratories followed published guidelines for spirometry, lung volumes and diffusing capacity in 2012.
=== COPD ===
The Global Initiative for Chronic Obstructive Lung Disease provides guidelines for the diagnosis, severity, and management of COPD. To determine obstruction in a patient's lungs, the post-bronchodilator FEV1/FVC needs to be <0.7. Then, the FEV1 percentage of predicted result is used to determine the degree of obstruction where the lower the percent the worse the obstruction.
=== Maximum respiratory pressures ===
Several calculations are needed for what a normal maximum inspiratory (MIP) and expiratory pressure (MEP) is. For males this found by:
M
I
P
=
120
−
(
0.41
×
a
g
e
)
{\displaystyle MIP=120-(0.41\times age)}
and
M
E
P
=
174
−
(
0.83
×
a
g
e
)
{\displaystyle MEP=174-(0.83\times age)}
To find the lower limit of what is acceptable in males the equations are:
M
I
P
L
L
N
=
62
−
(
0.15
×
a
g
e
)
{\displaystyle MIP_{LLN}=62-(0.15\times age)}
and
M
E
P
L
L
N
=
117
−
(
0.83
×
a
g
e
)
{\displaystyle MEP_{LLN}=117-(0.83\times age)}
For females, the equations are slightly different. For the normal values this is used:
M
I
P
=
108
−
(
0.61
×
a
g
e
)
{\displaystyle MIP=108-(0.61\times age)}
and
M
E
P
=
131
−
(
0.86
×
a
g
e
)
{\displaystyle MEP=131-(0.86\times age)}
For find the lower limit of what it should be without impairment this form of the equations is used:
M
I
P
L
L
N
=
62
−
(
0.50
×
a
g
e
)
{\displaystyle MIP_{LLN}=62-(0.50\times age)}
and
M
E
P
L
L
N
=
95
−
(
0.57
×
a
g
e
)
{\displaystyle MEP_{LLN}=95-(0.57\times age)}
where
M
I
P
{\displaystyle MIP}
= maximum inspiratory pressure in cmH20
M
E
P
{\displaystyle MEP}
= maximum expiratory pressure in cmH20
M
I
P
L
L
N
{\displaystyle MIP_{LLN}}
= maximum inspiratory pressure lower limit of normal in cmH20
M
E
P
L
L
N
{\displaystyle MEP_{LLN}}
= maximum expiratory pressure lower limit of normal in cmH20
a
g
e
{\displaystyle age}
= the patient's age in years
== References == | Wikipedia/Pulmonary_function_testing |
Immunology is a branch of biology and medicine that covers the study of immune systems in all organisms.
Immunology charts, measures, and contextualizes the physiological functioning of the immune system in states of both health and diseases; malfunctions of the immune system in immunological disorders (such as autoimmune diseases, hypersensitivities, immune deficiency, and transplant rejection); and the physical, chemical, and physiological characteristics of the components of the immune system in vitro, in situ, and in vivo. Immunology has applications in numerous disciplines of medicine, particularly in the fields of organ transplantation, oncology, rheumatology, virology, bacteriology, parasitology, psychiatry, and dermatology.
The term was coined by Russian biologist Ilya Ilyich Mechnikov, who advanced studies on immunology and received the Nobel Prize for his work in 1908 with Paul Ehrlich "in recognition of their work on immunity". He pinned small thorns into starfish larvae and noticed unusual cells surrounding the thorns. This was the active response of the body trying to maintain its integrity. It was Mechnikov who first observed the phenomenon of phagocytosis, in which the body defends itself against a foreign body. Ehrlich accustomed mice to the poisonous ricin and abrin. After feeding them with small but increasing dosages of ricin he ascertained that they had become "ricin-proof". Ehrlich interpreted this as immunization and observed that it was abruptly initiated after a few days and was still in existence after several months.
Prior to the designation of immunity, from the etymological root immunis, which is Latin for 'exempt', early physicians characterized organs that would later be proven as essential components of the immune system. The important lymphoid organs of the immune system are the thymus, bone marrow, and chief lymphatic tissues such as spleen, tonsils, lymph vessels, lymph nodes, adenoids, and liver. However, many components of the immune system are cellular in nature, and not associated with specific organs, but rather embedded or circulating in various tissues located throughout the body.
== Classical immunology ==
Classical immunology ties in with the fields of epidemiology and medicine. It studies the relationship between the body systems, pathogens, and immunity. The earliest written mention of immunity can be traced back to the plague of Athens in 430 BCE. Thucydides noted that people who had recovered from a previous bout of the disease could nurse the sick without contracting the illness a second time. Many other ancient societies have references to this phenomenon, but it was not until the 19th and 20th centuries before the concept developed into scientific theory.
The study of the molecular and cellular components that comprise the immune system, including their function and interaction, is the central science of immunology. The immune system has been divided into a more primitive innate immune system and, in vertebrates, an acquired or adaptive immune system. The latter is further divided into humoral (or antibody) and cell-mediated components.
The immune system has the capability of self and non-self-recognition. An antigen is a substance that ignites the immune response. The cells involved in recognizing the antigen are Lymphocytes. Once they recognize, they secrete antibodies. Antibodies are proteins that neutralize the disease-causing microorganisms. Antibodies do not directly kill pathogens, but instead, identify antigens as targets for destruction by other immune cells such as phagocytes or NK cells.
The (antibody) response is defined as the interaction between antibodies and antigens. Antibodies are specific proteins released from a certain class of immune cells known as B lymphocytes, while antigens are defined as anything that elicits the generation of antibodies (antibody generators). Immunology rests on an understanding of the properties of these two biological entities and the cellular response to both.
It is now getting clear that the immune responses contribute to the development of many common disorders not traditionally viewed as immunologic, including metabolic, cardiovascular, cancer, and neurodegenerative conditions like Alzheimer's disease. Besides, there are direct implications of the immune system in the infectious diseases (tuberculosis, malaria, hepatitis, pneumonia, dysentery, and helminth infestations) as well. Hence, research in the field of immunology is of prime importance for the advancements in the fields of modern medicine, biomedical research, and biotechnology.
== Diagnostic immunology ==
The specificity of the bond between antibody and antigen has made the antibody an excellent tool for the detection of substances by a variety of diagnostic techniques. Antibodies specific for a desired antigen can be conjugated with an isotopic (radio) or fluorescent label or with a color-forming enzyme in order to detect it. However, the similarity between some antigens can lead to false positives and other errors in such tests by antibodies cross-reacting with antigens that are not exact matches.
== Immunotherapy ==
The use of immune system components or antigens to treat a disease or disorder is known as immunotherapy. Immunotherapy is most commonly used to treat allergies, autoimmune disorders such as Crohn's disease, Hashimoto's thyroiditis and rheumatoid arthritis, and certain cancers. Immunotherapy is also often used for patients who are immunosuppressed (such as those with HIV) and people with other immune deficiencies.
This includes regulating factors such as IL-2, IL-10, GM-CSF B, IFN-α.
== Clinical immunology ==
Clinical immunology is the study of diseases caused by disorders of the immune system (failure, aberrant action, and malignant growth of the cellular elements of the system). It also involves diseases of other systems, where immune reactions play a part in the pathology and clinical features.
The diseases caused by disorders of the immune system fall into two broad categories:
immunodeficiency, in which parts of the immune system fail to provide an adequate response (examples include chronic granulomatous disease and primary immune diseases);
autoimmunity, in which the immune system attacks its own host's body (examples include systemic lupus erythematosus, rheumatoid arthritis, Hashimoto's disease and myasthenia gravis).
Other immune system disorders include various hypersensitivities (such as in asthma and other allergies) that respond inappropriately to otherwise harmless compounds.
The most well-known disease that affects the immune system itself is AIDS, an immunodeficiency characterized by the suppression of CD4+ ("helper") T cells, dendritic cells and macrophages by the human immunodeficiency virus (HIV).
Clinical immunologists also study ways to prevent the immune system's attempts to destroy allografts (transplant rejection).
Clinical immunology and allergy is usually a subspecialty of internal medicine or pediatrics. Fellows in Clinical Immunology are typically exposed to many of the different aspects of the specialty and treat allergic conditions, primary immunodeficiencies and systemic autoimmune and autoinflammatory conditions. As part of their training fellows may do additional rotations in rheumatology, pulmonology, otorhinolaryngology, dermatology and the immunologic lab.
=== Clinical and pathology immunology ===
When health conditions worsen to emergency status, portions of immune system organs, including the thymus, spleen, bone marrow, lymph nodes, and other lymphatic tissues, can be surgically excised for examination while patients are still alive.
== Theoretical immunology ==
Immunology is strongly experimental in everyday practice but is also characterized by an ongoing theoretical attitude. Many theories have been suggested in immunology from the end of the nineteenth century up to the present time. The end of the 19th century and the beginning of the 20th century saw a battle between "cellular" and "humoral" theories of immunity. According to the cellular theory of immunity, represented in particular by Elie Metchnikoff, it was cells – more precisely, phagocytes – that were responsible for immune responses. In contrast, the humoral theory of immunity, held by Robert Koch and Emil von Behring, among others, stated that the active immune agents were soluble components (molecules) found in the organism's "humors" rather than its cells.
In the mid-1950s, Macfarlane Burnet, inspired by a suggestion made by Niels Jerne, formulated the clonal selection theory (CST) of immunity. On the basis of CST, Burnet developed a theory of how an immune response is triggered according to the self/nonself distinction: "self" constituents (constituents of the body) do not trigger destructive immune responses, while "nonself" entities (e.g., pathogens, an allograft) trigger a destructive immune response. The theory was later modified to reflect new discoveries regarding histocompatibility or the complex "two-signal" activation of T cells. The self/nonself theory of immunity and the self/nonself vocabulary have been criticized, but remain very influential.
More recently, several theoretical frameworks have been suggested in immunology, including "autopoietic" views, "cognitive immune" views, the "danger model" (or "danger theory"), and the "discontinuity" theory. The danger model, suggested by Polly Matzinger and colleagues, has been very influential, arousing many comments and discussions.
== Developmental immunology ==
The body's capability to react to antigens depends on a person's age, antigen type, maternal factors and the area where the antigen is presented. Neonates are said to be in a state of physiological immunodeficiency, because both their innate and adaptive immunological responses are greatly suppressed. Once born, a child's immune system responds favorably to protein antigens while not as well to glycoproteins and polysaccharides. In fact, many of the infections acquired by neonates are caused by low virulence organisms like Staphylococcus and Pseudomonas. In neonates, opsonic activity and the ability to activate the complement cascade is very limited. For example, the mean level of C3 in a newborn is approximately 65% of that found in the adult. Phagocytic activity is also greatly impaired in newborns. This is due to lower opsonic activity, as well as diminished up-regulation of integrin and selectin receptors, which limit the ability of neutrophils to interact with adhesion molecules in the endothelium. Their monocytes are slow and have a reduced ATP production, which also limits the newborn's phagocytic activity. Although, the number of total lymphocytes is significantly higher than in adults, the cellular and humoral immunity is also impaired. Antigen-presenting cells in newborns have a reduced capability to activate T cells. Also, T cells of a newborn proliferate poorly and produce very small amounts of cytokines like IL-2, IL-4, IL-5, IL-12, and IFN-g which limits their capacity to activate the humoral response as well as the phagocitic activity of macrophage. B cells develop early during gestation but are not fully active.
Maternal factors also play a role in the body's immune response. At birth, most of the immunoglobulin present is maternal IgG. These antibodies are transferred from the placenta to the fetus using the FcRn (neonatal Fc receptor). Because IgM, IgD, IgE and IgA do not cross the placenta, they are almost undetectable at birth. Some IgA is provided by breast milk. These passively-acquired antibodies can protect the newborn for up to 18 months, but their response is usually short-lived and of low affinity. These antibodies can also produce a negative response. If a child is exposed to the antibody for a particular antigen before being exposed to the antigen itself then the child will produce a dampened response. Passively acquired maternal antibodies can suppress the antibody response to active immunization. Similarly, the response of T-cells to vaccination differs in children compared to adults, and vaccines that induce Th1 responses in adults do not readily elicit these same responses in neonates. Between six and nine months after birth, a child's immune system begins to respond more strongly to glycoproteins, but there is usually no marked improvement in their response to polysaccharides until they are at least one year old. This can be the reason for distinct time frames found in vaccination schedules.
During adolescence, the human body undergoes various physical, physiological and immunological changes triggered and mediated by hormones, of which the most significant in females is 17-β-estradiol (an estrogen) and, in males, is testosterone. Estradiol usually begins to act around the age of 10 and testosterone some months later. There is evidence that these steroids not only act directly on the primary and secondary sexual characteristics but also have an effect on the development and regulation of the immune system, including an increased risk in developing pubescent and post-pubescent autoimmunity. There is also some evidence that cell surface receptors on B cells and macrophages may detect sex hormones in the system.
The female sex hormone 17-β-estradiol has been shown to regulate the level of immunological response, while some male androgens such as testosterone seem to suppress the stress response to infection. Other androgens, however, such as DHEA, increase immune response. As in females, the male sex hormones seem to have more control of the immune system during puberty and post-puberty than during the rest of a male's adult life.
Physical changes during puberty such as thymic involution also affect immunological response.
== Ecoimmunology and behavioural immunity ==
Ecoimmunology, or ecological immunology, explores the relationship between the immune system of an organism and its social, biotic and abiotic environment.
More recent ecoimmunological research has focused on host pathogen defences traditionally considered "non-immunological", such as pathogen avoidance, self-medication, symbiont-mediated defenses, and fecundity trade-offs. Behavioural immunity, a phrase coined by Mark Schaller, specifically refers to psychological pathogen avoidance drivers, such as disgust aroused by stimuli encountered around pathogen-infected individuals, such as the smell of vomit. More broadly, "behavioural" ecological immunity has been demonstrated in multiple species. For example, the Monarch butterfly often lays its eggs on certain toxic milkweed species when infected with parasites. These toxins reduce parasite growth in the offspring of the infected Monarch. However, when uninfected Monarch butterflies are forced to feed only on these toxic plants, they suffer a fitness cost as reduced lifespan relative to other uninfected Monarch butterflies. This indicates that laying eggs on toxic plants is a costly behaviour in Monarchs which has probably evolved to reduce the severity of parasite infection.
Symbiont-mediated defenses are also heritable across host generations, despite a non-genetic direct basis for the transmission. Aphids, for example, rely on several different symbionts for defense from key parasites, and can vertically transmit their symbionts from parent to offspring. Therefore, a symbiont that successfully confers protection from a parasite is more likely to be passed to the host offspring, allowing coevolution with parasites attacking the host in a way similar to traditional immunity.
The preserved immune tissues of extinct species, such as the thylacine (Thylacine cynocephalus), can also provide insights into their biology.
== Cancer immunology ==
The study of the interaction of the immune system with cancer cells can lead to diagnostic tests and therapies with which to find and fight cancer. The immunology concerned with physiological reaction characteristic of the immune state. Inflammation is an immune response that has been observed in many types of cancers.
== Reproductive immunology ==
This area of the immunology is devoted to the study of immunological aspects of the reproductive process including fetus acceptance. The term has also been used by fertility clinics to address fertility problems, recurrent miscarriages, premature deliveries and dangerous complications such as pre-eclampsia.
== See also ==
List of immunologists
Immunomics
International Reviews of Immunology
Outline of immunology
History of immunology
Osteoimmunology
== References ==
== External links ==
Media related to Immunology at Wikimedia Commons
American Association of Immunologists
British Society for Immunology
Federation of Clinical Immunology Societies | Wikipedia/immunology |
Apolipoprotein C-III also known as apo-CIII, and apolipoprotein C3, is a protein that in humans is encoded by the APOC3 gene. Apo-CIII is secreted by the liver as well as the small intestine, and is found on triglyceride-rich lipoproteins such as chylomicrons, very low density lipoprotein (VLDL), and remnant cholesterol.
== Structure ==
ApoC-III is a relatively small protein containing 79 amino acids that can be glycosylated at threonine-74. The most abundant glycoforms are characterized by an O-linked disaccharide galactose linked to N-acetylgalactosamine (Gal–GalNAc), further modified with up to two sialic acid residues. Less abundant glycoforms are characterized by more complex and fucosylated glycan moieties.
== Function ==
APOC3 inhibits lipoprotein lipase and hepatic lipase; it is thought to inhibit hepatic uptake of triglyceride-rich particles. The APOA1, APOC3 and APOA4 genes are closely linked in both rat and human genomes. The A-I and A-IV genes are transcribed from the same strand, while the A-1 and C-III genes are convergently transcribed. An increase in apoC-III levels induces the development of hypertriglyceridemia.
Recent evidence suggests an intracellular role for Apo-CIII in promoting the assembly and secretion of triglyceride-rich VLDL particles from hepatic cells under lipid-rich conditions. However, two naturally occurring point mutations in human apoC3 coding sequence, namely Ala23Thr and Lys58Glu have been shown to abolish the intracellular assembly and secretion of triglyceride-rich VLDL particles from hepatic cells.
== Clinical significance ==
Overexpression of Apo-CIII in humans contributes to atherosclerosis. Two novel susceptibility haplotypes (specifically, P2-S2-X1 and P1-S2-X1) have been discovered in ApoAI-CIII-AIV gene cluster on chromosome 11q23; these confer approximately threefold higher risk of coronary heart disease in normal as well as non-insulin diabetes mellitus. In persons with type 2 diabetes, elevated plasma Apo-CIII is associated with higher plasma triglycerides and greater coronary artery calcification (a measure of subclinical atherosclerosis).
Apo-CIII delays the catabolism of triglyceride rich particles. HDL cholesterol particles that bear Apo-CIII are associated with increased, rather than decreased, risk for coronary heart disease.
Elevations of Apo-CIII associated with single-nucleotide polymorphisms found in genetic variation studies may predispose patients to non-alcoholic fatty liver disease, although the association has been questioned and may be specific to certain ethnicities or to people without central obesity.
Antisense oligonucleotides that bind APOC3 mRNA and prevent its translation have been found to reduce episodes of acute pancreatitis in people with familial chylomicronemia syndrome and lower their triglyceride levels in blood. Adverse effects include thrombocytopenia, which may be prevented by targeting hepatocellular APOC3 expression with a chemically modified oligonucleotide.
== Interactive pathway map ==
Click on genes, proteins and metabolites below to link to respective articles.
== Apolipoprotein CIII and HDL ==
Apolipoprotein CIII is also found on HDL particles. Formation of APOCIII-containing HDL is not a matter of simple binding of APOCII to pre-existing HDL particles but requires the lipid transported ABCA1 in a fashion similar to APOA1-containing HDL. Accumulation of APOCIII on HDL is important for the maintenance of plasma triglyceride homeostasis since it prevents excessive amount of APOCIII on VLDL and other triglyceride rich lipoproteins, thus preventing APOCIII-mediated inhibition of LpL and the subsequent hydrolysis of plasma triglycerides. This may explain the hypertriglyceridemia associated with ABCA1-deficiency in patients with Tangier's disease.
== References ==
== External links ==
Apolipoprotein+C-III at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
Human APOC3 genome location and APOC3 gene details page in the UCSC Genome Browser.
== Further reading == | Wikipedia/Apolipoprotein_C3 |
Hashimoto's thyroiditis, also known as chronic lymphocytic thyroiditis, Hashimoto's disease and autoimmune thyroiditis, is an autoimmune disease in which the thyroid gland is gradually destroyed.
Early on, symptoms may not be noticed. Over time, the thyroid may enlarge, forming a painless goiter. Most people eventually develop hypothyroidism with accompanying weight gain, fatigue, constipation, hair loss, and general pains. After many years the thyroid typically shrinks in size. Potential complications include thyroid lymphoma. Further complications of hypothyroidism can include high cholesterol, heart disease, heart failure, high blood pressure, myxedema, and potential problems in pregnancy.
Hashimoto's thyroiditis is thought to be due to a combination of genetic and environmental factors. Risk factors include a family history of the condition and having another autoimmune disease. Diagnosis is confirmed with blood tests for TSH, Thyroxine (T4), antithyroid autoantibodies, and ultrasound. Other conditions that can produce similar symptoms include Graves' disease and nontoxic nodular goiter.
Hashimoto's is typically not treated unless there is hypothyroidism, or the presence of a goiter, when it may be treated with levothyroxine. Those affected should avoid eating large amounts of iodine; however, sufficient iodine is required especially during pregnancy. Surgery is rarely required to treat the goiter.
Hashimoto's thyroiditis has a global prevalence of 7.5%, and varies greatly by region. The highest rate is in Africa, and the lowest in Asia. In the US white people are affected more often than black. It is more common in low to middle income groups. Females are more susceptible with a 17.5% rate of prevalence compared to 6% in males. It is the most common cause of hypothyroidism in developed countries. It typically begins between the ages of 30 and 50. Rates of the disease have increased. It was first described by the Japanese physician Hakaru Hashimoto in 1912. Studies in 1956 discovered that it was an autoimmune disorder.
== Signs and symptoms ==
=== Signs ===
In the early stages of autoimmune thyroiditis, patients may have normal thyroid hormone levels and no goiter or a small one. Enlargement of the thyroid is due to lymphocytic infiltration and fibrosis. Early on, thyroid autoantibodies in the blood may be the only indication of Hashimoto’s disease. They are thought to be the secondary products of the T cell-mediated destruction of the gland.
As lymphocytic infiltration progresses, patients may exhibit signs of hypothyroidism in multiple bodily systems, including, but not limited to, a larger goiter, weight gain, cold intolerance, fatigue, myxedema, constipation, menstrual disturbances, pale or dry skin, and dry, brittle hair, depression, and ataxia. Extended thyroid hormone deficiency may lead to muscle fibre changes, resulting in muscle weakness, muscle pain, stiffness, and rarely, pseudohypertrophy. Patients with goiters who have had autoimmune thyroiditis for many years might see their goiter shrink in the later stages of the disease due to destruction of the thyroid. Graves disease may occur before or after the development of autoimmune thyroiditis.
While rare, more serious complications of the hypothyroidism resulting from autoimmune thyroiditis are pericardial effusion, pleural effusion, both of which require further medical attention, and myxedema coma, which is an endocrine emergency.
=== Symptoms ===
Many symptoms are attributed to the development of Hashimoto's thyroiditis. Symptoms can include: fatigue, weight gain, pale or puffy face, feeling cold, joint and muscle pain, constipation, dry and thinning hair, heavy menstrual flow or irregular periods, depression, a slowed heart rate, problems getting pregnant, miscarriages, and myopathy. Some patients in the early stage of the disease may experience symptoms of hyperthyroidism due to the release of thyroid hormones from intermittent thyroid destruction (also called "destructive thyrotoxicosis"). In non-medical settings, the term "flare" is used to refer to a sudden exacerbation of symptoms, whether hyper or hypo.
While most symptoms are attributed to hypothyroidism, similar symptoms are observed in Hashimoto's patients with normal thyroid hormone levels. According to one study, these symptoms may include lower quality of life, and issues of the "digestive system (abdominal distension, constipation and diarrhea), endocrine system (chilliness, gain weight and facial edema), neuropsychiatric system (forgetfulness, anxiety, depressed, fatigue, insomnia, irritability, and indifferent [sic]) and mucocutaneous system (dry skin, pruritus, and hair loss)."
== Causes ==
The causes of Hashimoto's thyroiditis are complex. Around 80% of the risk of developing an autoimmune thyroid disorder is due to genetic factors, while the remaining 20% is related to environmental factors (such as iodine, drugs, infection, stress, radiation).
=== Genetics ===
Thyroid autoimmunity can be familial. Many patients report a family history of autoimmune thyroiditis or Graves' disease. The strong genetic component is borne out in studies on monozygotic twins, with a concordance of 38–55%, with an even higher concordance of circulating thyroid antibodies not in relation to clinical presentation (up to 80% in monozygotic twins). Neither result was seen to a similar degree in dizygotic twins, offering strong favour for high genetic etiology.
The genes implicated vary in different ethnic groups and the impact of these genes on the disease differs significantly among people from different ethnic groups. A gene that has a large effect in one ethnic group's risk of developing Hashimoto's thyroiditis might have a much smaller effect in another ethnic group.
The incidence of autoimmune thyroid disorders is increased in people with chromosomal disorders, including Turner, Down, and Klinefelter syndromes.
==== HLA genes ====
The first gene locus associated with autoimmune thyroid disease was the major histocompatibility complex (MHC) region on chromosome 6p21. It encodes human leukocyte antigens (HLAs). Specific HLA alleles have a higher affinity to auto-antigenic thyroidal peptides and can contribute to autoimmune thyroid disease development. Specifically, in Hashimoto's disease, aberrant expression of HLA II on thyrocytes has been demonstrated. They can present thyroid autoantigens and initiate autoimmune thyroid disease. Susceptibility alleles are not consistent in Hashimoto's disease. In Caucasians, various alleles are reported to be associated with the disease, including DR3, DR5, and DQ7.
==== CTLA-4 genes ====
CTLA-4 is the second major immune-regulatory gene related to autoimmune thyroid disease. CTLA-4 gene polymorphisms may contribute to the reduced inhibition of T-cell proliferation and increase susceptibility to autoimmune response. CTLA-4 is a major thyroid autoantibody susceptibility gene. A linkage of the CTLA-4 region to the presence of thyroid autoantibodies was demonstrated by a whole-genome linkage analysis. CTLA-4 was confirmed as the main locus for thyroid autoantibodies.
==== PTPN22 gene ====
PTPN22 is the most recently identified immune-regulatory gene associated with autoimmune thyroid disease. It is located on chromosome 1p13 and expressed in lymphocytes. It acts as a negative regulator of T-cell activation. Mutation in this gene is a risk factor for many autoimmune diseases. Weaker T-cell signaling may lead to impaired thymic deletion of autoreactive T cells, and increased PTPN22 function may result in inhibition of regulatory T cells, which protect against autoimmunity.
==== Immune-related genes ====
IFN-γ promotes cell-mediated cytotoxicity against thyroid mutations causing increased production of IFN-γ were associated with the severity of hypothyroidism. Severe hypothyroidism is associated with mutations leading to lower production of IL-4 (Th2 cytokine suppressing cell-mediated autoimmunity), lower secretion of TGF-β (inhibitor of cytokine production), and mutations of FOXP3, an essential regulatory factor for the regulatory T cells (Tregs) development. Development of Hashimoto's disease was associated with mutation of the gene for TNF-α (stimulator of the IFN-γ production), causing its higher concentration.
=== Existential (endogenous environmental) ===
==== Sex ====
Study of healthy Danish twins divided to three groups (monozygotic and dizygotic same sex, and opposite sex twin pairs) estimated that genetic contribution to thyroid peroxidase antibodies susceptibility was 61% in males and 72% in females, and contribution to thyroglobulin antibodies susceptibility was 39% in males and 75% in females.
The high female predominance in thyroid autoimmunity may be associated with the X chromosome. It contains sex and immune-related genes responsible for immune tolerance.
A higher incidence of thyroid autoimmunity was reported in patients with a higher rate of X-chromosome monosomy in peripheral white blood cells. Another potential mechanism might be skewed X-chromosome inactivation.
==== Pregnancy ====
In one population study, two or more births were a risk factor for developing autoimmune hypothyroidism in pre-menopausal women.
=== Environmental ===
==== Medications ====
Certain medications or drugs have been associated with altering and interfering with thyroid function. There are two main mechanisms of interference:
Altering thyroid hormone serum transfer proteins. Estrogen, tamoxifen, heroin, methadone, clofibrate, 5-fluorouracil, mitotane, and perphenazine all increase thyroid binding globulin (TBG) concentration. Androgens, anabolic steroids such as danazol, glucocorticoids, and slow release nicotinic acid all decrease TBG concentrations. Furosemide, fenoflenac, mefenamic acid, salicylates, phenytoin, diazepam, sulphonylureas, free fatty acids, and heparin all interfere with thyroid hormone binding to TBG and/or transthyretin.
Altering extra-thryoidal metabolism of thyroid hormone. Propylthiouracil, glucocorticoids, propranolol, iondinated contrast agents, amiodarone, and clomipramine all inhibit conversion of T4 and T3. Phenobarbital, rifampin, phenytoin and carbamazepine all increase hepatic metabolism. Finally, cholestryamine, colestipol, aluminium hydroxide, ferrous sulphate, and sucralfate are all drugs that decrease T4 absorption or enhance excretion.
==== Iodine ====
Both excessive and insufficient iodine intake has been implicated in developing antithyroid antibodies. Thyroid autoantibodies are found to be more prevalent in geographical areas after increasing iodine levels. Several mechanisms by which excessive iodine may promote thyroid autoimmunity have been proposed:
Via thyroglobulin iodination: Iodine exposure leads to higher iodination of thyroglobulin, increasing its immunogenicity by creating new iodine-containing epitopes or exposing cryptic epitopes.
Via thyrocyte damage: Iodine exposure has been shown to increase the level of reactive oxygen species. They enhance the expression of the intracellular adhesion molecule-1 on the thyrocytes, which could attract the immuno-competent cells into the thyroid gland. Iodine also promotes thyrocyte apoptosis.
Via immune cell behaviour: Iodine has an influence on immune cells.
==== Comorbidities ====
Comorbid autoimmune diseases are a risk factor for developing Hashimoto's thyroiditis, and the opposite is also true. Another thyroid disease closely associated with Hashimoto's thyroiditis is Graves' disease. Autoimmune diseases affecting other organs most commonly associated with Hashimoto's thyroiditis include celiac disease, type 1 diabetes, vitiligo, alopecia, Addison disease, Sjogren's syndrome, and rheumatoid arthritis Autoimmune thyroiditis has also been seen in patients with autoimmune polyendocrine syndromes type 1 and 2.
==== Other ====
Other environmental factors include selenium deficiency, infectious diseases such as hepatitis C, rubella, and possibly Covid-19, toxins, dietary factors, radiation exposure, and gut dysbiosis.
== Mechanism ==
The pathophysiology of autoimmune thyroiditis is not well understood. However, once the disease is established, its core processes have been observed:
Hashimoto's thyroiditis is a T-lymphocyte mediated attack on the thyroid gland. T helper 1 cells trigger macrophages and cytotoxic lymphocytes to destroy thyroid follicular cells, while T helper 2 cells stimulate the excessive production of B cells and plasma cells which generate antibodies against the thyroid antigens, leading to thyroiditis. The three major antibodies are: Thyroid peroxidase Antibodies (TPOAb), Thyroglobulin Antibodies (TgAb), and Thyroid stimulating hormone receptor Antibodies (TRAb), with TPOAb and TgAb being most commonly implicated in Hashimotos. They are hypothesized to develop as a result of thyroid damage, where T-lymphocytes are sensitized to residual thyroid peroxidase and thyroglobulin, rather than as the initial cause of thyroid damage. However, they may exacerbate further thyroid destruction by binding the complement system and triggering apoptosis of thyroid cells. TPO antibody levels may correlate with the degree of lymphocyte infiltration of the thyroid.
Gross morphological changes within the thyroid are seen in the general enlargement, which is far more locally nodular and irregular than more diffuse patterns (such as that of hyperthyroidism). While the capsule is intact and the gland itself is still distinct from surrounding tissue, microscopic examination can provide a more revealing indication of the level of damage. Hypothyroidism is caused by replacement of follicular cells with parenchymatous tissue.
Partial regeneration of the thyroid tissue can occur, but this has not been observed to normalise hormonal levels.
=== Pathology ===
Gross pathology of a thyroid with autoimmune thyroiditis may show an symmetrically enlarged thyroid. It is often paler in color, in comparison to normal thyroid tissue which is reddish-brown.
Microscopic examination (histology) will show lymphocytes (including plasma B-cells) diffusely infiltrating the parenchyma. The lymphocytes are predominately T-lymphocytes with a representation of both CD4+ and CD8+ cells. The plasma cells are polyclonal, with present germinal centers resembling the structure of a lymph node (also called secondary lymphoid follicles, not to be confused with the normally present colloid-filled follicles that constitute the thyroid).
In late stages of the disease, the thyroid may be atrophic. Colloid-filled follicles shrink and the cuboidal cells that usually line the follicles become Hürthle cells. Fibrous tissue may be found throughout the affected thyroid as well. Severe thyroid atrophy presents often with denser fibrotic bands of collagen that remains within the confines of the thyroid capsule.
Generally, pathological findings of the thyroid are related to the amount of existing thyroid function — the more infiltration and fibrosis, the less likely a patient will have normal thyroid function. A rare but serious complication is thyroid lymphoma, generally the B-cell type, non-Hodgkin lymphoma.
== Diagnosis ==
=== Tests ===
==== Physical exam ====
Physicians will often start by assessing reported symptoms and performing a thorough physical exam, including a neck exam. Patients may have a "firm, bumpy, symmetric, painless goiter", however, up to 10% of patients may have an atrophied thyroid.
==== Antithyroid antibodies tests ====
Tests for antibodies against thyroid peroxidase, thyroglobulin, and thyrotropin receptors can detect autoimmune processes against the thyroid. 90% of hashimoto's patients have elevated levels of thyroid peroxidase antibodies. However, seronegative (without circulating autoantibodies) thyroiditis is also possible. There may be circulating antibodies before the onset of any symptoms.
==== Ultrasound ====
An ultrasound may be useful in detecting Hashimoto thyroiditis, especially in those with seronegative thyroiditis, or when patients have normal laboratory values but symptoms of autoimmune thyroiditis. Key features detected in the ultrasound of a person with Hashimoto's thyroiditis include "echogenicity, heterogeneity, hypervascularity, and presence of small cysts." Images obtained with ultrasound can evaluate the size of the thyroid, reveal the presence of nodules, or provide clues to the diagnosis of other thyroid conditions.
==== Nuclear medicine ====
Nuclear imaging showing thyroid uptake can also be helpful in diagnosing thyroid function, particularly differential diagnosis.
==== TSH levels test ====
Elevated Thyroid-stimulating hormone (TSH) levels may indicate hypothyroidism (underpeforming thyroid). Hypothyroidism is a common symptom and potential indication of Hashimoto's disease. As blood levels of thyroid hormones fall due to hypothyroidism, the anterior pituitary gland increases production of TSH, which stimulates increased production of thyroid hormones in the thyroid. The elevation is usually a marked increase over the normal range. TSH is the preferred initial test of thyroid function as it has a higher sensitivity to changes in thyroid status than free T4.
Biotin can cause this test to read "falsely low". Time of day can affect the results of this test; TSH peaks early in the morning and slumps in the late afternoon to early evening, with "a variation in TSH by a mean of between 0.95 mIU/mL to 2.0 mIU/mL". Hypothyroidism is diagnosed more often in samples taken soon after waking.
==== T3 or T4 levels test ====
These tests detect levels of two thyroid hormones: Thyroxine (T4) and Tri-iodothyronine (T3). Low levels of these hormones (hypothyroidism) may indicate autoimmune damage to the thyroid due to Hashimoto's, while elevated levels may indicate an attack of destructive thyrotoxicosis. Hashimotos with normal levels is possible however.
Free or total levels can be measured. Typically, Free T4 is the preferred test for hypothyroidism, as Free T3 immunoassay tests are less reliable at detecting low levels of thyroid hormone, and they are more susceptible to interference. Both immunoassay tests of Free T4 and Free T3 may overestimate concentrations, particularly at low thyroid hormone levels, which is why results are typically read in conjunction with TSH, a more sensitive measure. LC-MSMS assays are rarer, but they are "highly specific, sensitive, precise, and can detect hormones found in low concentrations."
==== Muscle Biopsy ====
Muscle biopsy is not necessary for diagnosis of myopathy due to hypothyroid muscle fibre changes, however it may reveal confirmatory features.
== Treatment ==
There is no cure for Hashimoto's Thyroiditis. There is currently no known way to stop auto-immune lymphocytes infiltrating the thyroid or to stimulate regeneration of thyroid tissue. However, the condition can be managed.
=== Managing hormone levels ===
Hypothyroidism caused by Hashimoto's thyroiditis is treated with thyroid hormone replacement agents such as levothyroxine (LT4), liothyronine (LT3), or desiccated thyroid extract (T4+T3). In most cases, the treatment needs to be taken for the rest of the person's life.
The standard of care is levothyroxine (LT4) therapy, which is an oral medication identical in molecular structure to endogenous thyroxine (T4). Levothyroxine sodium has a sodium salt added to increase the gastrointestinal absorption of levothyroxine. Levothyroxine has the benefits of a long half-life leading to stable thyroid hormone levels, ease of monitoring, excellent safety and efficacy record, and usefulness in pregnancy as it can cross the fetal blood-brain barrier.
Levothyroxine dosing to normalise TSH is based on the amount of residual endogenous thyroid function and the patient’s weight, particularly lean body mass. The dose can be adjusted based upon each patient, for example, the dose may be lowered for elderly patients or patients with certain cardiac conditions, but is increased in pregnant patients. It is administered on a consistent schedule. Levothyroxine may be dosed daily or weekly, however weekly dosing may be associated with higher TSH levels, elevated thyroid hormone levels, and transient "echocardiographic changes in some patients following 2-4 h of thyroxine intake".
Some patients elect combination therapy with both levothyroxine and liothyronine (which is identical in molecular structure to tri-iodothyronine) however studies of combination therapy are limited, and five meta-analyses/reviews "suggested no clear advantage of the combination therapy." However, subgroup analysis found that patients who remain the most symptomatic while taking levothyroxine may benefit from therapy containing liothyronine.
There is a lack of evidence around the benefits, long-term effects and side effects of desiccated thyroid extract. It is no longer recommended for the treatment of hypothyroidism.
==== Side Effects ====
Side effects of thyroid replacement therapy are associated with "inadequate or excessive doses." Symptoms to watch for include, but are not limited to, anxiety, tremor, weight loss, heat sensitivity, diarrhea, and shortness of breath. More worrisome symptoms include atrial fibrillation and bone density loss. Long term over-treatment is associated with increased mortality and dementia.
==== Monitoring ====
Thyroid Stimulating Hormone (TSH) is the laboratory value of choice for monitoring response to treatment with levothyroxine. When treatment is first initiated, TSH levels may be monitored as often as a frequency of every 6–8 weeks. Each time the dose is adjusted, TSH levels may be measured at that frequency until the correct dose is determined. Once titrated to a proper dose, TSH levels will be monitored yearly. The target level for TSH is the subject of debate, with factors like age, sex, individual needs and special circumstances such as pregnancy being considered. Recent studies suggest that adjusting therapy based on thyroid hormone levels (T4 and/or T3) may be important.
Monitoring liothyronine treatment or combination treatment can be challenging. Liothyronine can suppress TSH to a greater extent than levothyroxine. Short-acting Liothyronine's short half-life can result in large fluctuations of free T3 over the course of 24 hours.
Patients may have to adjust their dosage several times over the course of the disease. Endogenous thyroid hormone levels may fluctuate, particularly early in the disease. Patients may sometimes develop hyperthyroidism, even after long-term treatment. This can be due to a number of factors including acute attacks of destructive thyrotoxicosis (autoimmune attacks on the thyroid resulting in rises in thyroid hormone levels as thyroid hormones leak out of the damaged tissues). This is usually followed by hypothyroidism.
==== Reverse T3 ====
Measuring reverse tri-iodothyronine (rT3) is often mentioned in the lay (non-medical) press as a possible marker to inform T4 or T3 therapy, "however, there is currently no evidence to support this application" as of 2023. Although cited in the lay press as a possible competitor to T3, it is unlikely that rT3 causes hypothyroid symptoms by out-competing T3 for thyroid hormone receptors, as it has a binding affinity 200 times weaker. It is also unlikely that rT3 causes poor T4 to T3 conversion; despite being demonstrated in vivo to have the potential to inhibit DIO-mediated T4 to T3 conversion, this is considered improbable at normal body hormone concentrations.
=== Persistent Symptoms ===
Multiple studies have demonstrated persistent symptoms in Hashimoto's patients with normal thyroid hormone levels (euthyroid) and an estimated 10%-15% of patients treated with levothyroxine monotherapy are dissatisfied due to persistent symptoms of hypothyroidism. Several different hypothesised causes are discussed in the medical literature:
==== Low tissue tri-iodothyronine (T3) hypothesis ====
Peripheral tissue T4 to T3 conversion may be inadequate: Some patients on LT4 monotherapy may have blood T3 levels low or below the normal range, and/or may have local T3 deficiency in some tissues. Although both molecules can have biological effects, thyroxine (T4) is considered the "storage form" of thyroid hormone with much less effect, while tri-iodothyronine (T3) is considered the active form used by body tissues. Thus the body must convert thyroxine into tri-iodothyronine. Tri-iodothyronine is produced primarily by conversion in the liver, kidney, skeletal muscle and pituitary gland.
Adequate conversion requires sufficient levels of the micronutrients zinc, selenium, iron, and possibly vitamin A. Conversion rates may decline with age. Since deiodinase type 2 is necessary for T4 to T3 conversion in some peripheral tissues, "patients with DIO2 gene polymorphisms may have variable peripheral T3 availability", leading to localised hypothyroidism in some tissues. The Thr92Ala DIO2 polymorphism is present in 12–36% of the population.
For the latter patients, levothyroxine monotherapy may not be sufficient and patients may have improvement on combination therapy of T4 and T3. As standard immunoassay tests can overestimate blood T4 and T3 levels, Ultrafiltration LC-MSMS T4 and T3 tests may help to identify patients who would benefit from additional T3.
==== Inadequate markers hypothesis ====
There is ongoing debate about how to define euthyroidism and whether TSH is its best indicator. TSH may be useful to detect poor thyroid output and may reflect the state of thyroid hormones in the hypothalamic-pituitary-thyroid axis, but not the presence of hormones in other body tissues. As a result, LT4 monotherapy may not result in a "truly biochemically euthyroid state." Patients may express a preference for "low normal or below normal TSH values" and/or T4 and T3 monitoring. The monitoring of other biomarkers that reflect the action of thyroid hormone on tissues has also been proposed.
As immunoassay Free T3 and Free T4 tests can overestimate levels, particularly at low thyroid hormone levels, hypothyroidism may be undertreated. LC-MSMS tests may provide more reliable measures.
==== Extra-thyroidal effects of autoimmunity hypothesis ====
It is hypothesised that autoimmunity may play some role in euthyroid symptoms. Hypothesised mechanisms include the proposal that TPO-antibody-producing lymphocytes may travel out of the thyroid to other tissue, creating symptoms and inflammation due to cross-reaction, or "the inflammatory nature of [...] persistently increased circulating cytokine levels." Multiple studies find that antibodies coincide with symptoms even in euthyroid patients, and higher levels are associated with increased symptoms, however "the found association does not prove a causality". No treatment currently exists for Hashimoto's autoimmunity, although observed wellbeing improvements after surgical thyroid removal are hypothesised to be due to removing the autoimmune stimulus.
==== Physical and psychosocial co-morbidities hypothesis ====
It is hypothesised that euthyroid symptoms may not be due to Hashimoto's or hypothyroidism, but some other "physical and psychosocial co-morbidities".
=== Improving wellbeing ===
Some patients may perceive improved wellbeing while in thyrotoxicosis, however overtreatment has risks (known risks for levothyroxine and unknown risks for liothyronine). One study demonstrated surgical thyroid removal may substantially improve fatigue and wellbeing, see Surgery considerations, below.
=== Reducing antibodies ===
It is not established that reducing antithyroid antibodies in Hashimoto's has benefits. A systematic review and meta-analysis of selenium trials found that while selenium reduces TPO antibodies, there was a lack of evidence of effects on "disease remission, progression, lowered levothyroxine dose or improved quality of life".
Selenium, vitamin D, and metformin can reduce thyroid peroxidase antibodies. There is preliminary evidence that levothyroxine, aloe vera juice and black cumin seed may reduce thyroid peroxidase antibodies. Metformin can reduce thyroglobulin antibodies. It is not established that a gluten-free diet can reduce antibodies when there is no comorbid coeliac disease. Gluten-free diets have been shown in several studies to reduce antibodies, and in other studies to have no effect, however there were significant confounding issues in these studies, including not ruling out comorbid coeliac disease.
One study found surgical thyroid removal can substantially reduce anti-thyroid antibody levels, see Surgery considerations, below.
=== Surgery considerations ===
Surgery is not the initial treatment of choice for autoimmune disease, and uncomplicated Hashimoto's thyroiditis is not an indication for thyroidectomy. Patients generally may discuss surgery with their doctor if they are experiencing significant pressure symptoms, or cosmetic concerns, or have nodules present on ultrasound. One well-conducted study of patients with troublesome general symptoms and with anti-thyroperoxidase (anti-TPO) levels greater than 1000 IU/ml (normal <100 IU/ml) showed that total thyroidectomy caused the symptoms to resolve and median anti-thyroid peroxidase levels to reduce from 2232 to 152 IU/mL, but post-operative complications were higher than expected: infection (4.1%), permanent hypoparathyroidism (4.1%) and recurrent laryngeal nerve injury (5.5%).
=== Other ===
Zinc may increase free T3 levels. A small pilot study found Ashwagandha Root may increase T3 and T4 levels, however, there's a lack of strong evidence of this benefit and Ashwagandha has a potential to cause adrenal insufficiency.
As of 2022, there has been only one study of low-dose naltrexone in Hashimoto's, which did not demonstrate efficacy, therefore nothing supports its use; Removing dairy products in those without lactose intolerance has not been found to be supported. While soy isoflavones have the potential to theoretically affect T3 and T4 production, studies in those with sufficient iodine find no effect.
== Prognosis ==
Overt, symptomatic thyroid dysfunction is the most common complication, with about 5% of people with subclinical hypothyroidism and chronic autoimmune thyroiditis progressing to thyroid failure every year. Transient periods of thyrotoxicosis (over-activity of the thyroid) sometimes occur, and rarely the illness may progress to full hyperthyroid Graves' disease with active orbitopathy (bulging, inflamed eyes).
Rare cases of fibrous autoimmune thyroiditis present with severe shortness of breath and difficulty swallowing, resembling aggressive thyroid tumors, but such symptoms always improve with surgery or corticosteroid therapy. Although primary thyroid B-cell lymphoma affects fewer than one in 1000 persons, it is more likely to affect those with long-standing autoimmune thyroiditis, as there is a 67- to 80-fold increased risk of developing primary thyroid lymphoma in patients with Hashimoto's thyroiditis.
Myopathy as a result of muscle fibre changes due to thyroid hormone deficiency may take months or years of thyroid hormone treatment to resolve.
=== Anti-thyroid antibodies ===
Thyroid peroxidase antibodies typically (but not always) decline in patients treated with levothyroxine, with decreases varying between 10% and 90% after a follow-up of 6 to 24 months. One study of patients treated with levothyroxine observed that 35 out of 38 patients (92%) had declines in thyroid peroxidase antibody levels over five years, lowering by 70% on average. 6 of the 38 patients (16%) had thyroid peroxidase antibody levels return to normal.
=== Children ===
Many children diagnosed with Hashimoto's disease will experience the same progressive course of the disease that adults do. However, of children who develop anti-thyroid antibodies and hypothyroidism, up to 50% are later observed to have normal antibodies and thyroid hormone levels. One case of true remission has been observed in a 12-year-old girl. Her thyroid was observed via ultrasound to progress from early inflammation to severe end-stage Hashimoto's thyroiditis with hypothyroidism, and then return to "almost normal with only minimal features of inflammation" and euthyroidism.
== Epidemiology ==
Hashimoto's Disease is estimated to affect 2% of the world's population. About 1.0 to 1.5 in 1000 people have this disease at any time.
=== Sex ===
Anyone may develop this disease, but it occurs between 8 and 15 times more often in women than in men. Some research suggests a connection to the role of the placenta as an explanation for the sex difference. Other research suggests the difference in prevalence amongst genders is due to the effects of sex hormones.
=== High iodine consumption ===
Autoimmune thyroiditis has a higher prevalence in societies that have a higher intake of iodine in their diet, such as the United States and Japan, and among people who are genetically susceptible. It is the most common cause of hypothyroidism in areas of sufficient iodine. Also, the rate of lymphocytic infiltration increased in areas where the iodine intake was once low, but increased due to iodine supplementation.
Iodine deficiency disorder is combated using an increase in iodine in a person's diet. When a dramatic change occurs in a person's diet, they become more at-risk of developing hypothyroidism and other thyroid disorders. Treating iodine deficiency disorder with high salt intakes should be done carefully and cautiously as risk for Hashimoto's may increase.
=== Geographic influence of dietary trends ===
Geography plays a large role in which regions have access to diets with low or high iodine. Iodine levels in both water and salt should be heavily monitored in order to protect at-risk populations from developing hypothyroidism. Geographic trends of hypothyroidism vary across the world as different places have different ways of defining disease and reporting cases. Populations that are spread out or defined poorly may skew data in unexpected ways.
=== North America ===
Hashimoto's thyroiditis may affect up to 5% of the United States' population. Hashimoto's thyroiditis disorder is thought to be the most common cause of primary hypothyroidism in North America.
=== Age ===
Hashimoto's thyroiditis can occur at any age, including children, but more commonly appears in middle age, particularly for men. Incidence peaks in the fifth decade of life, but patients are usually diagnosed between age 30–50. The highest prevalence from one study was found in the elderly members of the community. It has been shown that the prevalence of positive tests for thyroid antibodies increases with age, "with a frequency as high as 33 percent in women 70 years old or older."
=== Race ===
The prevalence of Hashimoto's varies geographically. The highest rate is in Africa, and the lowest in Asia. In the US, the African-American population experiences it less commonly but has greater associated mortality.
=== Autoimmune diseases ===
Those that already have an autoimmune disease are at greater risk of developing Hashimoto's as the diseases generally coexist with each other. See Causes > Comorbidities, above.
=== Secular trends ===
The secular trends of hypothyroidism reveal how the disease has changed over the course of time given changes in technology and treatment options. Even though ultrasound technology and treatment options have improved, the incidence of hypothyroidism has increased according to data focused on the US and Europe. Between 1993 and 2001, per 1000 women, the disease was found varying between 3.9 and 4.89. Between 1994 and 2001, per 1000 men, the disease increased from 0.65 to 1.01.
== History ==
Also known as Hashimoto's disease, Hashimoto's thyroiditis is named after Japanese physician Hakaru Hashimoto (1881−1934) of the medical school at Kyushu University, who first described the symptoms of persons with struma lymphomatosa, an intense infiltration of lymphocytes within the thyroid, in 1912 in the German journal called Archiv für Klinische Chirurgie. This paper was made up of 30 pages and 5 illustrations all describing the histological changes in the thyroid tissue. Furthermore, all results in his first study were collected from four women. These results explained the pathological characteristics observed in these women especially the infiltration of lymphocyte and plasma cells as well as the formation of lymphoid follicles with germinal centers, fibrosis, degenerated thyroid epithelial cells and leukocytes in the lumen. He described these traits to be histologically similar to those of Mikulic's disease. As mentioned above, once he discovered these traits in this new disease, he named the disease struma lymphomatosa. This disease emphasized the lymphocyte infiltration and formation of the lymphoid follicles with germinal centers, neither of which had ever been previously reported.
Despite Dr. Hashimoto's discovery and publication, the disease was not recognized as distinct from Reidel's thyroiditis, which was a common disease at that time in Europe. Although many other articles were reported and published by other researchers, Hashimoto's struma lymphomatosa was only recognized as an early phase of Reidel's thyroiditis in the early 1900s. It was not until 1931 that the disease was recognized as a disease in its own right, when researchers Allen Graham et al. from Cleveland reported its symptoms and presentation in the same detailed manner as Hashimoto.
In 1956, Drs. Rose and Witebsky were able to demonstrate how immunization of certain rodents with extracts of other rodents' thyroid resembled the disease Hakaru and other researchers were trying to describe. These doctors were also able to describe anti-thyroglobulin antibodies in blood serum samples from these same animals.
Later on in the same year, researchers from the Middlesex Hospital in London were able to perform human experiments on patients who presented with similar symptoms. They purified anti-thyroglobulin antibody from their serum and were able to conclude that these sick patients had an immunological reaction to human thyroglobulin. From this data, it was proposed that Hashimoto's struma could be an autoimmune disease of the thyroid gland: "Following these discoveries, the concept of organ-specific autoimmune disease was established and HT recognized as one such disease."
Following this recognition, the same researchers from Middlesex Hospital published an article in 1962 in The Lancet that included a portrait of Hakaru Hashimoto. The disease became more well known from that moment, and Hashimoto's disease started to appear more frequently in textbooks.
== Pregnancy ==
=== Conception ===
It is recommended that hypothyroidism be treated with levothyoxine before conception, to prevent adverse effects on the course of the pregnancy and on the development of the child. In IVF, embryo transfer is improved when hypothyroidism is treated.
=== Pregnancy ===
The Endocrine Society recommends screening in pregnant women who are considered high-risk for thyroid autoimmune disease. Universal screening for thyroid diseases during pregnancy is controversial, however, one study "supports the potential benefit of universal screening". Pregnant women may have antithyroid antibodies (5%–14% of pregnancies), poor thyroid function resulting in hypothyroidism, or both. Each is associated with risks:
==== Anti-thyroid antibodies in pregnancy ====
The presence of Thyroid peroxidase antibodies at the outset of pregnancy are associated with a greater risk to the mother of hypothyroidism and thyroid impairment in the first year after delivery.
The presence of antibodies is also associated with "a 2 to 4-fold increase in the risk of recurrent miscarriages, and 2 to 3-fold increased risk of preterm birth", however the reason why is unclear. Thyroid peroxidase antibodies are speculated to indicate other autoimmune processes against the placental-fetal unit.
Levothyroxine treatment in euthyroid women with thyroid autoimmunity does not significantly impact the relative risk of miscarriage and preterm delivery, or outcomes with live birth. "Therefore, no strong recommendations regarding the therapy in such scenarios could be made, but consideration on a case-by-case basis might be implemented."
==== Hypothyroidism in pregnancy. ====
Women who have low thyroid function that has not been stabilized are at greater risk of complications for both parent and child. Risks to the mother include gestational hypertension including preeclampsia and eclampsia, gestational diabetes, placental abruption, and postpartum hemorrhage. Risks to the infant include miscarriage, preterm delivery, low birth weight, neonatal respiratory distress, hydrocephalus, hypospadias, fetal death, infant intensive care unit admission, and neurodevelopmental delays (lower child IQ, language delay or global developmental delay).
Successful pregnancy outcomes are improved when hypothyroidism is treated. Levothyroxine treatment may be considered at lower TSH levels in pregnancy than in standard treatment. Liothyronine does not cross the fetal blood-brain barrier, so liothyronine (T3) only or liothyronine + levothyroxine (T3 + T4) therapy is not indicated in pregnancy.
Close cooperation between the endocrinologist and obstetrician benefits the woman and the infant.
==== Immune changes during pregnancy ====
Hormonal changes and trophoblast expression of key immunomodulatory molecules lead to immunosuppression and fetal tolerance. The main players in regulation of the immune response are Tregs. Both cell-mediated and humoral immune responses are attenuated, resulting in immune tolerance and suppression of autoimmunity. It has been reported that during pregnancy, levels of thyroid peroxidase and thyroglobulin antibodies decrease.
=== Postpartum ===
Thyroid peroxidase antibodies testing is recommended for women who have ever been pregnant regardless of pregnancy outcome. "[P]revious pregnancy plays a major role in development of autoimmune overt hypothyroidism in premenopausal women, and the number of previous pregnancies should be taken into account when evaluating the risk of hypothyroidism in a young women [sic]."
Postpartum thyroiditis can occur in women with Hashimoto's. In healthy women, Postpartum thyroiditis can occur up to 1 year after delivery and should be differentiated from Hashimoto's thyroiditis as it is treated differently.
After giving birth, Tregs rapidly decrease and immune responses are re-established. It may lead to the occurrence or aggravation of autoimmune thyroid disease. In up to 50% of females with thyroid peroxidase antibodies in the early pregnancy, thyroid autoimmunity in the postpartum period exacerbates in the form of postpartum thyroiditis. Higher secretion of IFN-γ and IL-4, and lower plasma cortisol concentration during pregnancy has been reported in females with postpartum thyroiditis than in healthy females. It indicates that weaker immunosuppression during pregnancy could contribute to the postpartum thyroid dysfunction.
=== Fetal microchimerism ===
Several years after the delivery, the chimeric male cells can be detected in the maternal peripheral blood, thyroid, lung, skin, or lymph nodes. The fetal immune cells in the maternal thyroid gland may become activated and act as a trigger that may initiate or exaggerate the autoimmune thyroid disease. In Hashimoto's disease patients, fetal microchimeric cells were detected in thyroid in significantly higher numbers than in healthy females.
== Other animals ==
Hashimoto's disease is known to occur in chickens, rats, mice, dogs, and marmosets, but Graves' disease does not.
== See also ==
Hashimoto's encephalopathy
Myxedematous psychosis
Hashitoxicosis
Hoffmann Syndrome
== References == | Wikipedia/Hashimoto's_disease |
In immunology, clonal selection theory explains the functions of cells of the immune system (lymphocytes) in response to specific antigens invading the body. The concept was introduced by Australian doctor Frank Macfarlane Burnet in 1957, in an attempt to explain the great diversity of antibodies formed during initiation of the immune response. The theory has become the widely accepted model for how the human immune system responds to infection and how certain types of B and T lymphocytes are selected for destruction of specific antigens.
The theory states that in a pre-existing group of lymphocytes (both B and T cells), a specific antigen activates (i.e. selects) only its counter-specific cell, which then induces that particular cell to multiply, producing identical clones for antibody production. This activation occurs in secondary lymphoid organs such as the spleen and the lymph nodes. In short, the theory is an explanation of the mechanism for the generation of diversity of antibody specificity. The first experimental evidence came in 1958, when Gustav Nossal and Joshua Lederberg showed that one B cell always produces only one antibody. The idea turned out to be the foundation of molecular immunology, especially in adaptive immunity.
== Postulates ==
The clonal selection theory can be summarised with the following four tenets:
Each lymphocyte bears a single type of receptor with a unique specificity (generated by V(D)J recombination).
Receptor occupation is required for cell activation.
The differentiated effector cells derived from an activated lymphocyte bear receptors of identical specificity as the parent cell.
Those lymphocytes bearing receptors for self molecules (i.e., endogenous antigens produced within the body) are destroyed at an early stage.
== Early work ==
In 1900, Paul Ehrlich proposed the so-called "side chain theory" of antibody production. According to it, certain cells exhibit on their surface different "side chains" (i.e. membrane-bound antibodies) able to react with different antigens. When an antigen is present, it binds to a matching side chain. Then the cell stops producing all other side chains and starts intensive synthesis and secretion of the antigen-binding side chain as a soluble antibody. Though distinct from clonal selection, Ehrlich's idea was a selection theory far more accurate than the instructive theories that dominated immunology in the next decades.
In 1955, Danish immunologist Niels Jerne put forward a hypothesis that there is already a vast array of soluble antibodies in the serum prior to any infection. The entrance of an antigen into the body results in the selection of only one type of antibody to match it. This supposedly occurred by certain cells phagocytosing the immune complexes and somehow replicating the antibody structure to produce more of it.
In 1957, David W. Talmage hypothesized that antigens bind to antibodies on the surface of antibody-producing cells and "only those cells are selected for multiplication whose synthesized product has affinity for the antigen". The key difference from Ehrlich's theory was that every cell was presumed to synthesize only one sort of antibody. After antigen binding the cell proliferates, forming clones with identical antibodies.
=== Burnet's clonal selection theory ===
Later in 1957, Australian immunologist Frank Macfarlane Burnet published a paper titled "A modification of Jerne's theory of antibody production using the concept of clonal selection" in the rather obscure Australian Journal of Science. In it Burnet expanded the ideas of Talmage and named the resulting theory the "clonal selection theory". He further formalised the theory in his 1959 book The Clonal Selection Theory of Acquired Immunity. He explained immunological memory as the cloning of two types of lymphocyte. One clone acts immediately to combat infection whilst the other is longer lasting, remaining in the immune system for a long time and causing immunity to that antigen. According to Burnet's hypothesis, among antibodies are molecules that can probably correspond with varying degrees of precision to all, or virtually all, the antigenic determinants that occur in biological material other than those characteristic of the body itself. Each type of pattern is a specific product of a clone of lymphocytes and it is the essence of the hypothesis that each cell automatically has available on its surface representative reactive sites equivalent to those of the globulin they produce. When an antigen enters the blood or tissue fluids it is assumed that it will attach to the surface of any lymphocyte carrying reactive sites that correspond to one of its antigenic determinants. Then the cell is activated and undergoes proliferation to produce a variety of descendants. In this way, preferential proliferation is initiated of all those clones whose reactive sites correspond to the antigenic determinants on the antigens present in the body. The descendants are capable of active liberation of soluble antibody and lymphocytes, the same functions as the parental forms.
In 1958, Gustav Nossal and Joshua Lederberg showed that one B cell always produces only one antibody, which was the first direct evidence supporting the clonal selection theory.
== Theories supported by clonal selection ==
Burnet and Peter Medawar worked together on understanding immunological tolerance, a phenomenon also explained by clonal selection. This is the organism's ability to tolerate the introduction of cells prior to the development of an immune response as long as it occurs early in the organism's development. There are a vast number of lymphocytes occurring in the immune system, ranging from cells that tolerate self tissue to cells that do not. However, only cells tolerant of self tissue survive the embryonic stage.If non-self tissue is introduced, lymphocytes that develop are the ones that include the non-self tissues as self tissue.
In 1959, Burnet proposed that under certain circumstances, tissues could be successfully transplanted into foreign recipients. This work has led to a much greater understanding of the immune system and also great advances in tissue transplantation. Burnet and Medawar shared the Nobel Prize in Physiology or Medicine in 1960.
In 1974, Niels Kaj Jerne proposed that the immune system functions as a network that is regulated via interactions between the variable parts of lymphocytes and their secreted molecules. Immune network theory is firmly based on the concept of clonal selection. Jerne won the Nobel Prize in Physiology or Medicine in 1984, largely for his contributions to immune network theory.
== See also ==
Adaptive immune system
Clonal selection algorithm
Universal Darwinism
== References ==
== Further reading ==
Podolsky, Alfred I. Tauber; Scott H. (1997). The Generation of Diversity : Clonal Selection Theory and the Rise of Molecular Immunology (1st paperback ed.). Cambridge, Massachusetts: Harvard Univ. Press. ISBN 0-674-00182-6.{{cite book}}: CS1 maint: multiple names: authors list (link)
"Biology in Context - The Spectrum of Life" Authors, Peter Aubusson, Eileen Kennedy.
Forsdyke D.R. (1995). "The Origins of the Clonal Selection Theory of Immunity". FASEB Journal. 9 (2): 164–66. doi:10.1096/fasebj.9.2.7781918. PMID 7781918. S2CID 38467403.
== External links ==
Animation of clonal selection Archived 6 July 2011 at the Wayback Machine from the Walter & Elisa Hall institute. | Wikipedia/Clonal_selection_theory |
The danger model of the immune system proposes that it differentiates between components that are capable of causing damage, rather than distinguishing between self and non-self.
== History of immunologic models ==
The first major immunologic model was the Self/Non-self Model proposed by Macfarlane Burnet and Frank Fenner in 1949 with later refinement by Burnet. It theorizes that the immune system distinguishes between self, which is tolerated, and non-self, which is attacked and destroyed. According to this theory, the chief cell of the immune system is the B cell, activated by recognizing non-self structures. Later research showed that B cell activation is reliant on CD4+ T helper cells and a co-stimulatory signal from an antigen-presenting cell (APC). Because APCs are not antigen-specific, capable of processing self structures, Charles Janeway proposed the Infectious Non-self Model in 1989. Janeway's theory involved APCs being activated by pattern recognition receptors (PRRs) that recognize evolutionarily conserved pathogen-associated molecular patterns (PAMPs) as infectious non-self, whereas PRRs are not activated by non-infectious self. However, neither of these models are sufficient to explain non-cytopathic viral infections, graft rejection, or anti-tumor immunity.
== Danger model ==
In 1994, Polly Matzinger formulated the danger model, theorizing that the immune system identifies threats to initiate an immune response based on the presence of pathogens and/or alarm signals from cells under stress. When injured or stressed, tissues typically undergo non-silent types of cell death, such as necrosis or pyroptosis, releasing danger signals like DNA, RNA, heat shock proteins (Hsps), hyaluronic acid, serum amyloid A protein, ATP, uric acid, and cytokines like interferon-α, interleukin-1β, and CD40L for detection by dendritic cells. In comparison, neoplastic tumors do not induce significant immune responses because controlled apoptosis degrades most danger signals, preventing the detection and destruction of malignant cells.
Matzinger's work emphasizes that bodily tissues are the drivers of immunity, providing alarm signals on the location and extent of damage to minimize collateral damage. The adaptive immune system relies on the innate immune system using its antigen-presenting cells to activate B and T lymphocytes for specific antibodies, exemplified by low dendritic cell counts resulting in common variable immunodeficiency (CVID). For example, gut cells secrete transforming growth factor beta (TGF-β) during bacterial invasions to stimulate B cell production of Immunoglobulin A (IgA). Similarly, 30-40% of the liver's T cells are Type I Natural Killer T (NTK) cells, providing Interleukin 4 (IL-4) for an organ-specific response of driving naïve CD4+ T cells to become Type 2 Helper T cells, as opposed to Type 1.
== Damage-associated molecular pattern (DAMP) model ==
Whereas the danger model proposes non-silent cell death releasing intracellular contents and/or expressing unique signalling proteins to stimulate an immune response, the damage-associated molecular pattern (DAMP) model theorizes that the immune system responds to exposed hydrophobic regions of biological molecules. In 2004, Seung-Yong Seong and Matzinger argued that as cellular damage causes denaturing and protein misfolding, exposed hydrophobic regions aggregate into clumps for improved binding to immune receptors.
== Pattern Recognition Receptors (PRRs) ==
Pattern Recognition Receptors (PRRs) are a family of surface receptors on antigen-presenting cells that includes toll-like receptors (TLRs), nucleotide oligomerization domain (NOD)-like receptors, retinoic acid inducible gene-I (RIG-I)-like receptors and C-type lectin-like receptors (CLRs). They recognize alarmins, a category that includes both DAMPs and PAMPs, to process their antigenic regions for presentation to T helper cells.
== References == | Wikipedia/Danger_model |
The term abdominal surgery broadly covers surgical procedures that involve opening the abdomen (laparotomy). Surgery of each abdominal organ is dealt with separately in connection with the description of that organ (see stomach, kidney, liver, etc.) Diseases affecting the abdominal cavity are dealt with generally under their own names.
== Types ==
The most common abdominal surgeries are described below.
Appendectomy: surgical opening of the abdominal cavity and removal of the appendix. Typically performed as definitive treatment for appendicitis, although sometimes the appendix is prophylactically removed incidental to another abdominal procedure.
Caesarean section (also known as C-section): a surgical procedure in which one or more incisions are made through a mother's abdomen (laparotomy) and uterus (hysterotomy) to deliver one or more babies, or, rarely, to remove a dead fetus.
Inguinal hernia surgery: the repair of an inguinal hernia.
Exploratory laparotomy: the opening of the abdominal cavity for direct examination of its contents; for example, to locate a source of bleeding or trauma. It may or may not be followed by repair or removal of the primary problem.
Laparoscopy: a minimally invasive approach to abdominal surgery where rigid tubes are inserted through small incisions into the abdominal cavity. The tubes allow introduction of a small camera, surgical instruments, and gases into the cavity for direct or indirect visualization and treatment of the abdomen. The abdomen is inflated with carbon dioxide gas to facilitate visualization and, often, a small video camera is used to show the procedure on a monitor in the operating room. The surgeon manipulates instruments within the abdominal cavity to perform procedures such as cholecystectomy (gallbladder removal), the most common laparoscopic procedure. The laparoscopic method speeds recovery time and reduces blood loss and infection as compared to the traditional "open" method.
== Complications ==
Complications of abdominal surgery include, but are not limited to:
Adhesions (also called scar tissue): complications of postoperative adhesion formation are frequent, they have a large negative effect on patients’ health, and increase workload in clinical practice
Bleeding
Infection
Paralytic ileus: short-term paralysis of the bowel
Perioperative mortality, any death occurring within 30 days after surgery
Shock
Sterile technique, aseptic post-operative care, antibiotics, use of the WHO Surgical Safety Checklist, and vigilant post-operative monitoring greatly reduce the risk of these complications. Planned surgery performed under sterile conditions is much less risky than that performed under emergency or unsterile conditions. The contents of the bowel are unsterile, and thus leakage of bowel contents, as from trauma, substantially increases the risk of infection.
Globally, there are few studies comparing perioperative mortality following abdominal surgery across different health systems. One major prospective study of 10,745 adult patients undergoing emergency laparotomy from 357 centres in 58 high-, middle-, and low-income countries found that mortality is three times higher in low- compared with high-HDI countries even when adjusted for prognostic factors. In this study the overall global mortality rate was 1.6 percent at 24 hours (high 1.1 percent, middle 1.9 percent, low 3.4 percent), increasing to 5.4 percent by 30 days (high 4.5 percent, middle 6.0 percent, low 8.6 percent). Of the 578 patients who died, 404 (69.9 percent) did so between 24 hours and 30 days following surgery (high 74.2 percent, middle 68.8 percent, low 60.5 percent). Patient safety factors were suggested to play an important role, with use of the WHO Surgical Safety Checklist associated with reduced mortality at 30 days.
Taking a similar approach, a unique global study of 1,409 children undergoing emergency laparotomy from 253 centres in 43 countries showed that adjusted mortality in children following surgery may be as high as 7 times greater in low-HDI and middle-HDI countries compared with high-HDI countries, translating to 40 excess deaths per 1,000 procedures performed in these settings. Internationally, the most common operations performed were appendectomy, small bowel resection, pyloromyotomy and correction of intussusception. After adjustment for patient and hospital risk factors, child mortality at 30 days was significantly higher in low-HDI (adjusted OR 7.14 (95% CI 2.52 to 20.23)) and middle-HDI (4.42 (1.44 to 13.56)) countries compared with high-HDI countries.
Absorption of drugs administered orally was shown to be significantly affected following abdominal surgery.
There is low-certainty evidence that there is no difference between using scalpel and electrosurgery in infection rates during major abdominal surgeries.
== See also ==
Abdominoplasty
ASA physical status classification system or perioperative physical fitness
Diabetes
General surgery
Laparotomy
Low-fiber/low-residue diet
Perioperative mortality
== References == | Wikipedia/Abdominal_surgery |
General Surgery is a Swedish goregrind group known as one of the earliest Carcass clones. Their 1991 debut Necrology was released by Relapse Records and would be General Surgery's only material released until 2001, when the group recorded one track for the Carcass tribute album, Requiems of Revulsion. However, in 2003, General Surgery reformed and released a split album with The County Medical Examiners and have since released a collection of demos, two split 7-inches, a 2005 demo, a split album with Butcher ABC, and two full-length albums.
== Members ==
=== Current members ===
Joacim Carlsson – guitar (1989–1990, 2007–present)
Andreas "Adde" Mitroulis – drums, vocals (2002–present)
Andreas Eriksson – bass, vocals (2002–2004, 2007–present)
Erik Sahlström – vocals (2007–present)
Urban "Ubbe" Skytt – guitar (2015–present)
=== Former members ===
Jonas Derouche – guitar (1988–1989)
Grant McWilliams – bass, vocals (1988–1989, 1990)
Richard Cabeza – vocals (1988–1990, 1999–2002)
Matti Kärki – bass, drums, vocals (1988–1990)
Mats Nordrup – drums (1988–1990)
Anders Jakobson – drums (1999–2000)
Erik Thyselius – drums (2000–2001)
Chris Barkensjö – drums (2001–2002)
Glenn Sykes – bass (2004–2006)
Johan Wallin – guitar, vocals (2006–2011)
Tobias Sillman – guitar (2012–2015)
=== Timeline ===
== Discography ==
=== Full length albums ===
2006 - Left Hand Pathology (Listenable Records)
2009 - Corpus In Extremis: Analysing Necrocriticism (Listenable Records)
=== EPs ===
1991 - Necrology (Relapse Records)
2012 - Like an Ever Flying Limb (Relapse Records)
2021 - Lay Down and Be Counted (Self-released)
=== Demos ===
1990 - Errosive Offals
1990 - Pestisferous Anthropophagia
1990 - Internecine Prurience
2005 - Demo 2005
=== Split albums ===
2003 - General Surgery/The County Medical Examiners (Razorback Records)
2003 - Relapse Singles Series Vol. 2 (Relapse Records)
2004 - General Surgery/Filth (Bones Brigade Records)
2004 - General Surgery/Machetazo (Escorbuto Recordings/Goryfied Productions)
2009 - General Surgery/Butcher ABC (Obliteration Records/Living Dead Society)
=== Compilation albums ===
2001 - Requiems of Revulsion (Necropolis Records)
2004 - Demos (Nuclear Abominations Records)
2012 - A Collection of Depravation (Relapse Records)
== References ==
== External links ==
Official General Surgery website
General Surgery at MySpace | Wikipedia/General_Surgery_(band) |
Organ transplantation is a medical procedure in which an organ is removed from one body and placed in the body of a recipient, to replace a damaged or missing organ. The donor and recipient may be at the same location, or organs may be transported from a donor site to another location. Organs and/or tissues that are transplanted within the same person's body are called autografts. Transplants that are recently performed between two subjects of the same species are called allografts. Allografts can either be from a living or cadaveric source.
Organs that have been successfully transplanted include the heart, kidneys, liver, lungs, pancreas, intestine, thymus and uterus. Tissues include bones, tendons (both referred to as musculoskeletal grafts), corneae, skin, heart valves, nerves and veins. Worldwide, the kidneys are the most commonly transplanted organs, followed by the liver and then the heart. J. Hartwell Harrison performed the first organ removal for transplant in 1954 as part of the first kidney transplant. Corneae and musculoskeletal grafts are the most commonly transplanted tissues; these outnumber organ transplants by more than tenfold.
Organ donors may be living, brain-dead, or deceased due to circulatory death. Tissue can be recovered from donors who die from either circulatory or brain death, for up to 24 hours after the cessation of heartbeat. Unlike organs, most tissues (with the exception of corneas) can be preserved and stored for up to five years, meaning they can be "banked.". Transplantation raises a number of bioethical issues, including the definition of death, when and how consent should be given for an organ to be transplanted, and payment for organs for transplantation. Other ethical issues include transplantation tourism (medical tourism) and more broadly the socio-economic context in which organ procurement or transplantation may occur. A particular problem is organ trafficking. There is also the ethical issue of not holding out false hope to patients.
Transplantation medicine is one of the most challenging and complex areas of modern medicine. Some of the key areas for medical management are the problems of transplant rejection, during which the body has an immune response to the transplanted organ, possibly leading to transplant failure and the need to immediately remove the organ from the recipient. When possible, transplant rejection can be reduced through serotyping to determine the most appropriate donor-recipient match and through the use of immunosuppressant drugs.
== Types of transplant ==
=== Autograft ===
Autografts are the transplant of tissue to the same person. Sometimes this is done with surplus tissue, tissue that can regenerate, or tissues more desperately needed elsewhere (examples include skin grafts, vein extraction for CABG, etc.). Sometimes an autograft is done to remove the tissue and then treat it or the person before returning it (examples include stem cell autograft and storing blood in advance of surgery). In a rotationplasty, a distal joint is used to replace a more proximal one; typically a foot or ankle joint is used to replace a knee joint. The person's foot is severed and reversed, the knee removed, and the tibia joined with the femur.
=== Allograft and allotransplantation ===
An allograft is a transplant of an organ or tissue between two genetically non-identical members of the same species. Most human tissue and organ transplants are allografts. Due to the genetic difference between the organ and the recipient, the recipient's immune system will identify the organ as foreign and attempt to destroy it, causing transplant rejection. The risk of transplant rejection can be estimated by measuring the panel-reactive antibody level.
==== Isograft ====
An isograft is a subset of allograft in which organs or tissues are transplanted from a donor to a genetically identical recipient (such as an identical twin). Isografts are differentiated from other types of transplants because while they are anatomically identical to allografts, they do not trigger an immune response.
=== Xenograft and xenotransplantation ===
A xenograft is a transplant of organs or tissue from one species to another. An example is porcine heart valve transplant, which is quite common and successful. Another example is attempted piscine–primate (fish to non-human primate) transplant of pancreatic islets. The latter research study was intended to pave the way for potential human use if successful. However, xenotransplantation is often an extremely dangerous type of transplant because of the increased risk of non-functional compatibility, rejection, and disease carried in the tissue. In the opposite direction, attempts are being made to devise a way to transplant human fetal hearts and kidneys into animals for future transplantation into human patients to address the shortage of donor organs.
=== Domino transplants ===
In people with cystic fibrosis (CF), where both lungs need to be replaced, it is a technically easier operation with a higher rate of success to replace both the heart and lungs of the recipient with those of the donor. As the recipient's original heart is usually healthy, it can then be transplanted into a second recipient in need of a heart transplant, thus making the person with CF a living heart donor.
In a 2016 case at Stanford Medical Center, a woman who was needing a heart-lung transplant had cystic fibrosis which had led to one lung expanding and the other shrinking, thereby displacing her heart. The second patient who in turn received her heart was a woman with right ventricular dysplasia which had led to a dangerously abnormal rhythm. The dual operations required three surgical teams, including one to remove the heart and lungs from a recently deceased initial donor. The two living recipients did well and had an opportunity to meet six weeks after their simultaneous operations.
Another example of this situation occurs with a special form of liver transplant in which the recipient has familial amyloid polyneuropathy, a disease where the liver slowly produces a protein that damages other organs. The recipient's liver can then be transplanted into an older person for whom the effects of the disease will not necessarily contribute significantly to mortality.
This term also refers to a series of living donor transplants in which one donor donates to the highest recipient on the waiting list and the transplant center utilizes that donation to facilitate multiple transplants. These other transplants are otherwise impossible due to blood type or antibody barriers to transplantation. The "Good Samaritan" kidney is transplanted into one of the other recipients, whose donor in turn donates his or her kidney to an unrelated recipient. This method allows all organ recipients to get a transplant even if their living donor is not a match for them. This further benefits people below any of these recipients on waiting lists, as they move closer to the top of the list for a deceased-donor organ. Johns Hopkins Hospital in Baltimore and Northwestern University's Northwestern Memorial Hospital have received significant attention for pioneering transplants of this kind. In February 2012, the last link in a record 60-person domino chain of 30 kidney transplants was completed.
In May 2023, New York Presbyterian Morgan Stanley Children's Hospital performed the first domino heart transplantation in a baby, eventually saving two baby girls.
=== ABO-incompatible transplants ===
Because very young children (generally under 12 months, but often as old as 24 months) do not have a well-developed immune system, it is possible for them to receive organs from otherwise incompatible donors. This is known as ABO-incompatible (ABOi) transplantation. Graft survival and people's mortality are approximately the same between ABOi and ABO-compatible (ABOc) recipients. While focus has been on infant heart transplants, the principles generally apply to other forms of solid organ transplantation.
The most important factors are that the recipient not have produced isohemagglutinins, and that they have low levels of T cell-independent antigens. United Network for Organ Sharing (UNOS) regulations allow for ABOi transplantation in children under two years of age if isohemagglutinin titers are 1:4 or below, and if there is no matching ABOc recipient. Studies have shown that the period under which a recipient may undergo ABOi transplantation may be prolonged by exposure to nonself A and B antigens. Furthermore, should the recipient (for example, type B-positive with a type AB-positive graft) require eventual retransplantation, the recipient may receive a new organ of either blood type.
Limited success has been achieved in ABO-incompatible heart transplants in adults, though this requires that the adult recipients have low levels of anti-A or anti-B antibodies. Renal transplantation is more successful, with similar long-term graft survival rates to ABOc transplants.
=== Transplantation in obese individuals ===
Until recently, people with obesity were not considered appropriate candidate donors for renal transplantation. In 2009, the physicians at the University of Illinois Medical Center performed the first robotic renal transplantation in an obese recipient and have continued to transplant people with a body mass index over 35 using robotic surgery. As of January 2014, over 100 people who would otherwise have been turned down because of their weight have successfully been transplanted.
=== Impact of Human Herpesvirus 6 (HHV-6) Reactivation on Pediatric Liver Transplantation ===
Human herpesvirus 6 (HHV-6) reactivation emerges as a notable concern in pediatric liver transplantation, potentially influencing both graft and recipient health. HHV-6, prevalent in a substantial portion of the population, can manifest in liver transplant recipients with inherited chromosomally integrated HHV-6 (iciHHV-6), predisposing them to heightened risks of complications such as graft-versus-host disease and allograft rejections. Recent case studies underscore the significance of HHV-6 reactivation, demonstrating its ability to infect liver grafts and impact recipient outcomes. Clinical management involves early detection, targeted antiviral therapy, and vigilant monitoring post-transplantation, with future research aimed at optimizing preventive measures and therapeutic interventions to mitigate the impact of HHV-6 reactivation on pediatric liver transplant outcomes.
== Organs and tissues transplanted ==
=== Eye ===
Eyeball (First successful transplantation of a non-functional eye was performed in 2024)
=== Chest ===
Heart (deceased-donor only; porcine xenograft attempted)
Lung (deceased-donor and living-related lung transplantation)
Thymus
Pulmonary Artery: First succesfull main pulmonary artery transplantation to extend Thymus cancer treatment possibility was performed in Switzerland at Ente Ospedaliero Cantonale in 2023
=== Abdomen ===
Kidney (deceased-donor and living-donor; porcine xenograft attempted)
Liver (deceased-donor, which enables donation of a whole liver; and living-donor, where each donor can provide up to 70% of a liver)
Pancreas (deceased-donor only; a very severe type of diabetes ensues if a live person's entire pancreas is removed)
Intestine (deceased-donor and living-donor; normally refers to the small intestine)
Stomach (deceased-donor only)
Uterus (deceased-donor only)
Testis (deceased-donor and living-donor)
Penis (deceased-donor only)
=== Tissues, cells and fluids ===
Hand (deceased-donor only), see first recipient Clint Hallam
Cornea (deceased-donor only) see the ophthalmologist Eduard Zirm
Skin, including face replant (autograft) and face transplant (extremely rare)
Islets of Langerhans (pancreas islet cells) (deceased-donor and living-donor)
Bone marrow or adult stem cell (living-donor and autograft)
Blood transfusion, whole blood or fractionated blood products (living-donor and autograft)
Blood vessels (autograft and deceased-donor)
Heart valve (deceased-donor, living-donor and xenograft [porcine/bovine])
Bone (deceased-donor and living-donor)
== Indications for transplantation ==
Kidney transplantation is becoming increasingly common and is the preferred treatment for end-stage renal failure.
Liver transplantation is the only curative therapy for end-stage liver disease, and the liver is the second most frequently transplanted solid organ.
Pancreatic transplantation is a complex surgical procedure performed in patients with severe chronic diabetes, often in association with renal transplantation.
Heart transplantation is increasingly performed in patients with end-stage heart failure, most often related to ischemic and non-ischemic cardiomyopathies.
== Complications ==
The main complications are procedural complications, infection, acute rejection, cardiac allograft vasculopathy and malignancy.
Non-vascular and vascular complications can occur in the initial post-transplant phase and at later stages. Overall postoperative complications after kidney transplantation occur in approximately 12% to 25% of kidney transplant patients.
Following a transplant, recipients will be given lab draws, ultrasounds, and other tests to see if the transplanted organ is being accepted.
== Types of donor ==
Organ donors may be living or may have died of brain death or circulatory death. Most deceased donors are those who have been pronounced brain dead. Brain dead means the cessation of brain function, typically after receiving an injury (either traumatic or pathological) to the brain, or otherwise cutting off blood circulation to the brain (drowning, suffocation, etc.). Breathing is maintained via artificial sources, which, in turn, maintains heartbeat. Once brain death has been declared, the person can be considered for organ donation. Criteria for brain death vary. Because less than 3% of all deaths in the US are the result of brain death, the overwhelming majority of deaths are ineligible for organ donation, resulting in severe shortages. It is important to note currently that patients that have been pronounced brain dead are one of the most common and ideal donors, since often these donors are young and healthy, thus leading to high quality organs.
Organ donation is possible after cardiac death in some situations, primarily when the person is severely brain-injured and not expected to survive without artificial breathing and mechanical support. Independent of any decision to donate, a person's next-of-kin may decide to end artificial support. If the person is expected to expire within a short period of time after support is withdrawn, arrangements can be made to withdraw that support in an operating room to allow quick recovery of the organs after circulatory death has occurred.
Tissues may be recovered from donors who die of either brain or circulatory death. In general, tissues may be recovered from donors up to 24 hours past the cessation of heartbeat. In contrast to organs, most tissues (with the exception of corneas) can be preserved and stored for up to five years, meaning they can be "banked." Also, more than 60 grafts may be obtained from a single tissue donor. Because of these three factors – the ability to recover from a non-heart-beating donor, the ability to bank tissue, and the number of grafts available from each donor – tissue transplants are much more common than organ transplants. The American Association of Tissue Banks estimates that more than one million tissue transplants take place in the United States each year.
=== Living donor ===
In living donors, the donor remains alive and donates a renewable tissue, cell, or fluid (e.g., blood, skin), or donates an organ or part of an organ in which the remaining organ can regenerate or take on the workload of the rest of the organ (primarily single kidney donation, partial donation of liver, lung lobe, small bowel). Regenerative medicine may one day allow for laboratory-grown organs, using person's own cells via stem cells, or healthy cells extracted from the failing organs.
=== Deceased donor ===
Deceased donors (formerly cadaveric) are people who have been declared brain-dead and whose organs are kept viable by ventilators or other mechanical mechanisms until they can be excised for transplantation. Apart from brainstem-dead donors, who have formed the majority of deceased donors for the last 20 years, there is increasing use of after-circulatory-death donors (formerly non-heart-beating donors) to increase the potential pool of donors as demand for transplants continues to grow. Prior to the legal recognition of brain death in the 1980s, all deceased organ donors had died of circulatory death. These organs have inferior outcomes to organs from a brain-dead donor. For instance, patients who underwent liver transplantation using donation-after-circulatory-death allografts have been shown to have significantly lower graft survival than those from donation-after-brain-death allografts due to biliary complications and primary nonfunction in liver transplantation. However, given the scarcity of suitable organs and the number of people who die waiting, any potentially suitable organ must be considered. Jurisdictions with medically assisted suicide may co-ordinate organ donations from that source.
== Allocation of organs ==
In most countries there is a shortage of suitable organs for transplantation. Countries often have formal systems in place to manage the process of determining who is an organ donor and in what order organ recipients receive available organs.
The overwhelming majority of deceased-donor organs in the United States are allocated by federal contract to the Organ Procurement and Transplantation Network, held since it was created by the Organ Transplant Act of 1984 by the United Network for Organ Sharing, or UNOS. (UNOS does not handle donor cornea tissue; corneal donor tissue is usually handled by multiple eye banks with guidance from the Eye Bank Association of America (EBAA) and Food and Drug Administration (FDA). Individual regional organ procurement organizations, all members of the Organ Procurement and Transplantation Network, are responsible for the identification of suitable donors and collection of the donated organs. UNOS then allocates organs based on the method considered most fair by the leadership in the field. The allocation methodology varies somewhat by organ, and changes periodically. For example, liver allocation is based partially on MELD score (Model of End-Stage Liver Disease), an empirical score based on lab values indicative of the sickness of the person from liver disease. In 1984, the National Organ Transplant Act (NOTA) was passed; it gave way to the Organ Procurement and Transplantation Network, which maintains the organ registry and ensures equitable allocation of organs. The Scientific Registry of Transplant Recipients was also established to conduct ongoing studies into the evaluation and clinical status of organ transplants. In 2000 the Children's Health Act passed and required NOTA to consider special issues around pediatric patients and organ allocation.
An example of "line jumping" occurred in 2003 at Duke University when doctors attempted to correct an initially incorrect transplant. An American teenager received a heart-lung donation with the wrong blood type for her. She then received a second transplant even though she was then in such poor physical shape that she normally would not be considered a good candidate for a transplant.
In an April 2008 article in The Guardian, Steven Tsui, the head of the transplant team at Papworth Hospital in the UK, is quoted in raising the ethical issue of not holding out false hope. He stated, "Conventionally we would say if people's life expectancy was a year or less we would consider them a candidate for a heart transplant. But we also have to manage expectations. If we know that in an average year we will do 30 heart transplants, there is no point putting 60 people on our waiting list, because we know half of them will die and it's not right to give them false hope."
Experiencing somewhat increased popularity, but still very rare, is directed or targeted donation, in which the family of a deceased donor (often honoring the wishes of the deceased) requests an organ be given to a specific person, subverting the allocation system. In the United States, there are various lengths of waiting times due to the different availabilities of organs in different UNOS regions. In other countries such as the UK, only medical factors and the position on the waiting list can affect who receives the organ.
One of the more publicized cases of this type was the 1994 Chester and Patti Szuber transplant. This was the first time that a parent had received a heart donated by one of their own children. Although the decision to accept the heart from his recently killed child was not an easy decision, the Szuber family agreed that giving Patti's heart to her father would have been something that she would have wanted.
Access to organ transplantation is one reason for the growth of medical tourism.
== Reasons for donation and ethical issues ==
=== Living related donors ===
Living related donors donate to family members or friends in whom they have an emotional investment. The risk of surgery is offset by the psychological benefit of not losing someone related to them, or not seeing them suffer the ill effects of waiting on a list.
==== Paired exchange ====
A "paired-exchange" is a technique of matching willing living donors to compatible recipients using serotyping. For example, a spouse may be willing to donate a kidney to their partner but cannot since there is not a biological match. The willing spouse's kidney is donated to a matching recipient who also has an incompatible but willing spouse. The second donor must match the first recipient to complete the pair exchange. Typically the surgeries are scheduled simultaneously in case one of the donors decides to back out and the couples are kept anonymous from each other until after the transplant. Paired-donor exchange, led by work in the New England Program for Kidney Exchange as well as at Johns Hopkins University and the Ohio organ procurement organizations, may more efficiently allocate organs and lead to more transplants.
Paired exchange programs were popularized in the New England Journal of Medicine article "Ethics of a paired-kidney-exchange program" in 1997 by L.F. Ross. It was also proposed by Felix T. Rapport in 1986 as part of his initial proposals for live-donor transplants "The case for a living emotionally related international kidney donor exchange registry" in Transplant Proceedings. A paired exchange is the simplest case of a much larger exchange registry program where willing donors are matched with any number of compatible recipients. Transplant exchange programs have been suggested as early as 1970: "A cooperative kidney typing and exchange program."
The first pair exchange transplant in the US was in 2001 at Johns Hopkins Hospital. The first complex multihospital kidney exchange involving 12 people was performed in February 2009 by The Johns Hopkins Hospital, Barnes-Jewish Hospital in St. Louis and Integris Baptist Medical Center in Oklahoma City. Another 12-person multihospital kidney exchange was performed four weeks later by Saint Barnabas Medical Center in Livingston, New Jersey, Newark Beth Israel Medical Center and New York-Presbyterian Hospital. Surgical teams led by Johns Hopkins continue to pioneer this field with more complex chains of exchange, such as an eight-way multihospital kidney exchange. In December 2009, a 13 organ 13 recipient matched kidney exchange took place, coordinated through Georgetown University Hospital and Washington Hospital Center, Washington, DC.
=== Good Samaritan ===
Good Samaritan or "altruistic" donation is giving a donation to someone that has no prior affiliation with the donor. The idea of altruistic donation is to give with no interest of personal gain, it is out of pure selflessness. On the other hand, the current allocation system does not assess a donor's motive, so altruistic donation is not a requirement. Some people choose to do this out of a personal need to donate. Some donate to the next person on the list; others use some method of choosing a recipient based on criteria important to them. Websites are being developed that facilitate such donation. Over half of the members of the Jesus Christians, an Australian religious group, have donated kidneys in such a fashion.
=== Financial compensation ===
Monetary compensation for organ donors, in the form of reimbursement for out-of-pocket expenses, has been legalised in Australia, and strictly only in the case of kidney transplant in the case of Singapore (minimal reimbursement is offered in the case of other forms of organ harvesting by Singapore). Kidney disease organizations in both countries have expressed their support.
In compensated donation, donors get money or other compensation in exchange for their organs. This practice is common in some parts of the world, whether legal or not, and is one of the many factors driving medical tourism.
In the illegal black market the donors may not get sufficient after-operation care, the price of a kidney may be above $160,000, middlemen take most of the money, the operation is more dangerous to both the donor and receiver, and the receiver often gets hepatitis or HIV. In legal markets of Iran the price of a kidney is $2,000 to $4,000.
An article by Gary Becker and Julio Elias on "Introducing Incentives in the market for Live and Cadaveric Organ Donations" said that a free market could help solve the problem of a scarcity in organ transplants. Their economic modeling was able to estimate the price tag for human kidneys ($15,000) and human livers ($32,000).
In the United States, The National Organ Transplant Act of 1984 made organ sales illegal. In the United Kingdom, the Human Organ Transplants Act 1989 first made organ sales illegal, and has been superseded by the Human Tissue Act 2004. In 2007, two major European conferences recommended against the sale of organs. Recent development of websites and personal advertisements for organs among listed candidates has raised the stakes when it comes to the selling of organs, and have also sparked significant ethical debates over directed donation, "good-Samaritan" donation, and the current US organ allocation policy. Bioethicist Jacob M. Appel has argued that organ solicitation on billboards and the internet may actually increase the overall supply of organs.
In an experimental survey, Elias, Lacetera and Macis (2019) find that preferences for compensation for kidney donors have strong moral foundations; participants in the experiment especially reject direct payments by patients, which they find would violate principles of fairness.
Many countries have different approaches to organ donation such as the opt-out approach and many advertisements of organ donors, encouraging people to donate. Although these laws have been implemented in a certain country they are not forced upon everyone as it is an individual decision.
Two books, Kidney for Sale By Owner by Mark Cherry (Georgetown University Press, 2005) and Stakes and Kidneys: Why Markets in Human Body Parts are Morally Imperative by James Stacey Taylor:
(Ashgate Press, 2005), advocate using markets to increase the supply of organs available for transplantation.
In a 2004 journal article economist Alex Tabarrok argues that allowing organ sales, and elimination of organ donor lists will increase supply, lower costs and diminish social anxiety towards organ markets.
Iran has had a legal market for kidneys since 1988. The donor is paid approximately US$1200 by the government and also usually receives additional funds from either the recipient or local charities. The Economist and the Ayn Rand Institute approve and advocate a legal market elsewhere. They argued that if 0.06% of Americans between 19 and 65 were to sell one kidney, the national waiting list would disappear (which, the Economist wrote, happened in Iran). The Economist argued that donating kidneys is no more risky than surrogate motherhood, which can be done legally for pay in most countries.
In Pakistan, 40 percent to 50 percent of the residents of some villages have only one kidney because they have sold the other for a transplant into a wealthy person, probably from another country, said Dr. Farhat Moazam of Pakistan, at a World Health Organization conference. Pakistani donors are offered $2,500 for a kidney but receive only about half of that because middlemen take so much. In Chennai, southern India, poor fishermen and their families sold kidneys after their livelihoods were destroyed by the Indian Ocean tsunami on 26 December 2004. About 100 people, mostly women, sold their kidneys for 40,000–60,000 rupees ($900–1,350). Thilakavathy Agatheesh, 30, who sold a kidney in May 2005 for 40,000 rupees said, "I used to earn some money selling fish but now the post-surgery stomach cramps prevent me from going to work." Most kidney sellers say that selling their kidney was a mistake.
In Cyprus in 2010, police closed a fertility clinic under charges of trafficking in human eggs. The Petra Clinic, as it was known locally, brought in women from Ukraine and Russia for egg harvesting and sold the genetic material to foreign fertility tourists. This sort of reproductive trafficking violates laws in the European Union. In 2010, Scott Carney reported for the Pulitzer Center on Crisis Reporting and the magazine Fast Company explored illicit fertility networks in Spain, the United States and Israel.
=== Forced donation ===
There have been concerns that certain authorities are harvesting organs from people deemed undesirable, such as prison populations. The World Medical Association stated that prisoners and other individuals in custody are not in a position to give consent freely, and therefore their organs must not be used for transplantation.
According to former Chinese Deputy Minister of Health, Huang Jiefu, the practice of transplanting organs from executed prisoners is still occurring as of February 2017. World Journal reported Huang had admitted approximately 95% of all organs used for transplantation are from executed prisoners. The lack of a public organ donation program in China is used as a justification for this practice. In July 2006, the Kilgour-Matas report stated, "the source of 41,500 transplants for the six-year period 2000 to 2005 is unexplained" and "we believe that there has been and continues today to be large scale organ seizures from unwilling Falun Gong practitioners". Investigative journalist Ethan Gutmann estimates 65,000 Falun Gong practitioners were killed for their organs from 2000 to 2008. However 2016 reports updated the death toll of the 15-year period since the persecution of Falun Gong began putting the death toll at 150,000 to 1.5 million. In December 2006, after not getting assurances from the Chinese government about allegations relating to Chinese prisoners, the two major organ transplant hospitals in Queensland, Australia stopped transplantation training for Chinese surgeons and banned joint research programs into organ transplantation with China.
In May 2008, two United Nations Special Rapporteurs reiterated their requests for "the Chinese government to fully explain the allegation of taking vital organs from Falun Gong practitioners and the source of organs for the sudden increase in organ transplants that has been going on in China since the year 2000". People in other parts of the world are responding to this availability of organs, and a number of individuals (including US and Japanese citizens) have elected to travel to China or India as medical tourists to receive organ transplants which may have been sourced in what might be considered elsewhere to be unethical manner.
== Organ transplantation by region ==
Some estimates of the number of transplants performed in various regions of the world have been derived from the Global Burden of Disease Study.
According to the Council of Europe, Spain through the Spanish Transplant Organization shows the highest worldwide rate of 35.1 donors per million population in 2005 and 33.8 in 2006. In 2011, it was 35.3.
In addition to the citizens waiting for organ transplants in the US and other developed nations, there are long waiting lists in the rest of the world. More than 2 million people need organ transplants in China, 50,000 waiting in Latin America (90% of whom are waiting for kidneys), as well as thousands more in the less documented continent of Africa. Donor bases vary in developing nations.
In Latin America the donor rate is 40–100 per million per year, similar to that of developed countries. However, in Uruguay, Cuba, and Chile, 90% of organ transplants came from cadaveric donors. Cadaveric donors represent 35% of donors in Saudi Arabia.
There is continuous effort to increase the utilization of cadaveric donors in Asia. However, the popularity of living, single kidney donors in India yields a cadaveric donor prevalence of less than 1 per million population. India has a very low donation rate, as compared to the world average, despite the fact, that it ranks third among the countries with largest transplantation activities.
Traditionally, Muslims believe body desecration in life or death to be forbidden, and thus many reject organ transplant. However most Muslim authorities nowadays accept the practice if another life will be saved. As an example, it may be assumed in countries such as Singapore with a cosmopolitan populace that includes Muslims, a special Majlis Ugama Islam Singapura governing body is formed to look after the interests of Singapore's Muslim community over issues that includes their burial arrangements.
Organ transplantation in Singapore is generally overseen by the National Organ Transplant Unit of the Ministry of Health (Singapore). Due to a diversity in mindsets and religious viewpoints, while Muslims on this island are generally not expected to donate their organs even upon death, youth in Singapore are educated on the Human Organ Transplant Act at the age of 18, which is around the age of military conscription. The Organ Donor Registry maintains two types of information, firstly people of Singapore that donate their organs or bodies for transplantation, research or education upon their death, under the Medical (Therapy, Education and Research) Act (MTERA), and secondly people that object to the removal of kidneys, liver, heart and corneas upon death for the purpose of transplantation, under the Human Organ Transplant Act (HOTA). The Live On social awareness movement is also formed to educate Singaporeans on organ donation.
Organ transplantation in China has taken place since the 1960s, and China has one of the largest transplant programmes in the world, peaking at over 13,000 transplants a year by 2004. Organ donation, however, is against Chinese tradition and culture, and involuntary organ donation is illegal under Chinese law. China's transplant programme attracted the attention of international news media in the 1990s due to ethical concerns about the organs and tissue removed from the corpses of executed criminals being commercially traded. In 2006 it became clear that about 41,500 organs had been sourced from Falun Gong practitioners in China since 2000.
With regard to organ transplantation in Israel, there is a severe organ shortage due to religious objections by some rabbis who oppose all organ donations and others who advocate that a rabbi participate in all decision making regarding a particular donor. One-third of all heart transplants performed on Israelis are done in China; others are done in Europe. Dr. Jacob Lavee, head of the heart-transplant unit, Sheba Medical Center, Tel Aviv, believes that "transplant tourism" is unethical and Israeli insurers should not pay for it. The organization HODS (Halachic Organ Donor Society) is working to increase knowledge and participation in organ donation among Jews throughout the world.
Transplantation rates also differ based on race, sex, and income. A study done with people beginning long term dialysis showed that the sociodemographic barriers to renal transplantation present themselves even before patients are on the transplant list. For example, different groups express definite interest and complete pretransplant workup at different rates. Previous efforts to create fair transplantation policies had focused on people currently on the transplantation waiting list.
In the United States, nearly 35,000 organ transplants were done in 2017, a 3.4 percent increase over 2016. About 18 percent of these were from living donors – people who gave one kidney or a part of their liver to someone else. But 115,000 Americans remain on waiting lists for organ transplants. By September 2022, the US had reached one million organ transplants overall.
== History ==
Successful human allotransplants have a relatively long history of operative skills that were present long before the necessities for post-operative survival were discovered. Rejection and the side effects of preventing rejection (especially infection and nephropathy) were, are, and may always be the key problem.
Several apocryphal accounts of transplants exist well prior to the scientific understanding and advancements that would be necessary for them to have actually occurred. The Chinese physician Pien Chi'ao reportedly exchanged hearts between a man of strong spirit but weak will with one of a man of weak spirit but strong will in an attempt to achieve balance in each man. Roman Catholic accounts report the 3rd-century saints Damian and Cosmas as replacing the gangrenous or cancerous leg of the Roman deacon Justinian with the leg of a recently deceased Ethiopian. Most accounts have the saints performing the transplant in the 4th century, many decades after their deaths; some accounts have them only instructing living surgeons who performed the procedure.
The more likely accounts of early transplants deal with skin transplantation. The first reasonable account is of the Indian surgeon Sushruta in the 2nd century BC, who used autografted skin transplantation in nose reconstruction, a rhinoplasty. Success or failure of these procedures is not well documented. Centuries later, the Italian surgeon Gasparo Tagliacozzi performed successful skin autografts; he also failed consistently with allografts, offering the first suggestion of rejection centuries before that mechanism could possibly be understood. He attributed it to the "force and power of individuality" in his 1596 work De Curtorum Chirurgia per Insitionem.
The first successful corneal allograft transplant was performed in 1837 in a gazelle model; the first successful human corneal transplant, a keratoplastic operation, was performed by Eduard Zirm at Olomouc Eye Clinic, now in the Czech Republic, in 1905.
The first transplant in the modern sense – the implantation of organ tissue in order to replace an organ function – was a thyroid transplant in 1883. It was performed by the Swiss surgeon and later Nobel laureate Theodor Kocher. In the preceding decades Kocher had perfected the removal of excess thyroid tissue in cases of goiter to an extent that he was able to remove the whole organ without the person dying from the operation. Kocher carried out the total removal of the organ in some cases as a measure to prevent recurrent goiter. By 1883, the surgeon noticed that the complete removal of the organ leads to a complex of particular symptoms that we today have learned to associate with a lack of thyroid hormone. Kocher reversed these symptoms by implanting thyroid tissue to these people and thus performed the first organ transplant. In the following years Kocher and other surgeons used thyroid transplantation also to treat thyroid deficiency that appeared spontaneously, without a preceding organ removal.
Thyroid transplantation became the model for a whole new therapeutic strategy: organ transplantation. After the example of the thyroid, other organs were transplanted in the decades around 1900. Some of these transplants were done in animals for purposes of research, where organ removal and transplantation became a successful strategy of investigating the function of organs. Kocher was awarded his Nobel Prize in 1909 for the discovery of the function of the thyroid gland. At the same time, organs were also transplanted for treating diseases in humans. The thyroid gland became the model for transplants of adrenal and parathyroid glands, pancreas, ovary, testicles and kidney. By 1900, the idea that one can successfully treat internal diseases by replacing a failed organ through transplantation had been generally accepted. Pioneering work in the surgical technique of transplantation was made in the early 1900s by the French surgeon Alexis Carrel, with Charles Guthrie, with the transplantation of arteries or veins. Their skillful anastomosis operations and the new suturing techniques laid the groundwork for later transplant surgery and won Carrel the 1912 Nobel Prize in Physiology or Medicine. From 1902, Carrel performed transplant experiments on dogs. Surgically successful in moving kidneys, hearts, and spleens, he was one of the first to identify the problem of rejection, which remained insurmountable for decades. The discovery of transplant immunity by the German surgeon Georg Schöne, various strategies of matching donor and recipient, and the use of different agents for immune suppression did not result in substantial improvement so that organ transplantation was largely abandoned after WWI.
In 1954, the first ever successful transplant of any organ was done at the Brigham & Women's Hospital in Boston. The surgery was performed by American surgeon Dr. Joseph Murray, who received the Nobel Prize in Medicine for his work. The success of this transplant was mostly due to the family relation between the recipient, a Richard Herrick of Maine, and his donor and identical twin brother Ronald. Richard Herrick was in the Navy and became severely ill with acute renal failure. His brother Ronald donated his kidney to Richard, and Richard lived on for another eight years. Prior to this case, transplant recipients did not survive for more than thirty days. Their close family relation meant there was no need for anti-rejection medications, which was not known until this time, so the case shed light on the cause of rejection and of possible anti-rejection medicine.
Major steps in skin transplantation occurred during the First World War, notably in the work of Harold Gillies at Aldershot, United Kingdom. Among his advances was the tubed pedicle graft, which maintained a flesh connection from the donor site until the graft established its own blood flow. Gillies' assistant, Archibald McIndoe, carried on the work into the Second World War as reconstructive surgery. In 1962, the first successful replantation surgery was performed – re-attaching a severed limb and restoring (limited) function and feeling.
Transplant of a single gonad (testis) from a living donor was carried out in early July 1926 in Zaječar, Serbia, by a Russian émigré surgeon Dr. Peter Vasil'evič Kolesnikov. The donor was a convicted murderer, one Ilija Krajan, whose death sentence was commuted to 20 years imprisonment, and he was led to believe that it was done because he had donated his testis to an elderly medical doctor. Both the donor and the receiver survived, but charges were brought in a court of law by the public prosecutor against Dr. Kolesnikov, not for performing the operation, but for lying to the donor.
The first attempted human deceased-donor transplant was performed by the Ukrainian surgeon Yurii Voronoy in the 1930s; but failed due to ischemia. Joseph Murray and J. Hartwell Harrison performed the first successful transplant, a kidney transplant between identical twins, in 1954, because no immunosuppression was necessary for genetically identical individuals.
In the late 1940s British surgeon Peter Medawar, working for the National Institute for Medical Research, improved the understanding of rejection. Identifying the immune reactions in 1951, Medawar suggested that immunosuppressive drugs could be used. Cortisone had been recently discovered and the more effective azathioprine was identified in 1959, but it was not until the discovery of cyclosporine in 1970 that transplant surgery found a sufficiently powerful immunosuppressive.
There was a successful deceased-donor lung transplant into an emphysema and lung cancer patient in June 1963 by James Hardy at the University of Mississippi Medical Center in Jackson, Mississippi. The patient John Russell survived for eighteen days before dying of kidney failure.
Thomas Starzl of Denver attempted a liver transplant in the same year, but he was not successful until 1967.
In the early 1960s and prior to long-term dialysis becoming available, Keith Reemtsma and his colleagues at Tulane University in New Orleans attempted transplants of chimpanzee kidneys into 13 human patients. Most of these patients only lived one to two months. However, in 1964, a 23-year-old woman lived for nine months and even returned to her job as a school teacher until she suddenly collapsed and died. It was assumed that she died from an acute electrolyte disturbance. At autopsy, the kidneys had not been rejected nor was there any other obvious cause of death. One source states this patient died from pneumonia. Tom Starzl and his team in Colorado used baboon kidneys with six human patients who lived one or two months, but with no longer term survivors. Others in the United States and France had limited experiences.
The heart was a major prize for transplant surgeons. But over and above rejection issues, the heart deteriorates within minutes of death, so any operation would have to be performed at great speed. The development of the heart-lung machine was also needed. Lung pioneer James Hardy was prepared to attempt a human heart transplant in 1964, but when a premature failure of comatose Boyd Rush's heart caught Hardy with no human donor, he used a chimpanzee heart, which beat in his patient's chest for approximately one hour and then failed. The first partial success was achieved on 3 December 1967, when Christiaan Barnard of Cape Town, South Africa, performed the world's first human-to-human heart transplant with patient Louis Washkansky as the recipient. Washkansky survived for eighteen days amid what many saw as a distasteful publicity circus. The media interest prompted a spate of heart transplants. Over a hundred were performed in 1968–1969, but almost all the people died within 60 days. Barnard's second patient, Philip Blaiberg, lived for 19 months.
It was the advent of cyclosporine that altered transplants from research surgery to life-saving treatment. In 1968 surgical pioneer Denton Cooley performed 17 transplants, including the first heart-lung transplant. Fourteen of his patients were dead within six months. By 1984 two-thirds of all heart transplant patients survived for five years or more. With organ transplants becoming commonplace, limited only by donors, surgeons moved on to riskier fields, including multiple-organ transplants on humans and whole-body transplant research on animals. On 9 March 1981, the first successful heart-lung transplant took place at Stanford University Hospital. The head surgeon, Bruce Reitz, credited the patient's recovery to cyclosporine.
As the rising success rate of transplants and modern immunosuppression make transplants more common, the need for more organs has become critical. Transplants from living donors, especially relatives, have become increasingly common. Additionally, there is substantive research into xenotransplantation, or transgenic organs; although these forms of transplant are not yet being used in humans, clinical trials involving the use of specific cell types have been conducted with promising results, such as using porcine islets of Langerhans to treat type 1 diabetes. However, there are still many problems that would need to be solved before they would be feasible options in people requiring transplants.
Recently, researchers have been looking into means of reducing the general burden of immunosuppression. Common approaches include avoidance of steroids, reduced exposure to calcineurin inhibitors, increased coverance of vaccination for Vaccine-preventable disease and other means of weaning drugs based on patient outcome and function. While short-term outcomes appear promising, long-term outcomes are still unknown, and in general, reduced immunosuppression increases the risk of rejection and decreases the risk of infection. The risk of early rejection is increased if corticosteroid immunosuppression are avoided or withdrawn after renal transplantation.
Many other new drugs are under development for transplantation.
The emerging field of regenerative medicine promises to solve the problem of organ transplant rejection by regrowing organs in the lab, using person's own cells (stem cells or healthy cells extracted from the donor site).
=== Timeline of transplants ===
1869: First skin autograft-transplantation by Carl Bunger, who documented the first modern successful skin graft on a person. Bunger repaired a person's nose destroyed by syphilis by grafting flesh from the inner thigh to the nose, in a method reminiscent of the Sushrutha.
1905: First successful cornea transplant by Eduard Zirm (Czech Republic)
1908: First skin allograft-transplantation of skin from a donor to a recipient (Switzerland)
1931: First uterus transplantation (Lili Elbe).
1950: First successful kidney transplant by Dr. Richard H. Lawler (Chicago, US)
1954: First living related kidney transplant (identical twins) (US)
1954: Brazil's first successful corneal transplant, the first liver (Brazil)
1955: First heart valve allograft into descending aorta (Canada)
1963: First successful lung transplant by James D. Hardy with patient living 18 days (US)
1964: James D. Hardy attempts heart transplant using chimpanzee heart (US)
1964: Human patient lived nine months with chimpanzee kidneys, twelve other human patients only lived one to two months, Keith Reemtsma and team (New Orleans, US)
1965: Spain's first successful kidney transplant at Hospital Clinic de Barcelona, Catalonia, Spain, by a surgeon team led by Josep Maria Gil-Vernet and Antoni Caralps. The patient, a woman, had a very long life since the procedure.
1965: Australia's first successful (living) kidney transplant (Queen Elizabeth Hospital, SA, Australia)
1966: First successful pancreas transplant by Richard C. Lillehei and William Kelly (Minnesota, US)
1967: First successful liver transplant by Thomas Starzl (Denver, US)
1967: First successful heart transplant by Christiaan Barnard (Cape Town, South Africa)
1978 Use of ciclosporin in clinical renal transplants
1981 Use of monoclonal antibodies to lymphocytes in organ grafting
1981: First successful heart/lung transplant by Bruce Reitz (Stanford, US)
1983: First successful lung lobe transplant by Joel Cooper at the Toronto General Hospital (Toronto, Canada)
1984: First successful double organ transplant by Thomas Starzl and Henry T. Bahnson (Pittsburgh, US)
1986: First successful double-lung transplant (Ann Harrison) by Joel Cooper at the Toronto General Hospital (Toronto, Canada)
1990: First successful adult segmental living-related liver transplant by Mehmet Haberal (Ankara, Turkey)
1992: First successful combined liver-kidney transplantation from a living-related donor by Mehmet Haberal (Ankara, Turkey)
1995: First successful laparoscopic live-donor nephrectomy by Lloyd Ratner and Louis Kavoussi (Baltimore, US)
1997: First successful allogeneic vascularized transplantation of a fresh and perfused human knee joint by Gunther O. Hofmann
1997: Illinois' first living donor kidney-pancreas transplant and first robotic living donor pancreatectomy in the US. University of Illinois Medical Center
1998: First successful live-donor partial pancreas transplant by David Sutherland (Minnesota, US)
1998: First successful hand transplant by Dr. Jean-Michel Dubernard (Lyon, France)
1998: United States' first adult-to-adult living donor liver transplant University of Illinois Medical Center
1999: First successful tissue engineered bladder transplanted by Anthony Atala (Boston Children's Hospital, US)
2000: First robotic donor nephrectomy for a living-donor kidney transplant in the world University of Illinois Medical Center
2004: First liver and small bowel transplants from same living donor into same recipient in the world University of Illinois Medical Center
2005: First successful ovarian transplant by Dr. P. N. Mhatre (Wadia Hospital, Mumbai, India)
2005: First successful partial face transplant (France)
2005: First robotic hepatectomy in the United States University of Illinois Medical Center
2006: Illinois' first paired donation for ABO incompatible kidney transplant University of Illinois Medical Center
2006: First jaw transplant to combine donor jaw with bone marrow from the patient, by Eric M. Genden (Mount Sinai Hospital, New York City, US)
2006: First successful human penis transplant (later reversed after 15 days due to 44-year-old recipient's wife's psychological rejection) (Guangzhou, China)
2008: First successful complete full double arm transplant by Edgar Biemer, Christoph Höhnke and Manfred Stangl (Technical University of Munich, Germany)
2008: First baby born from transplanted ovary. The transplant was carried out by Dr Sherman Silber at the Infertility Centre of St Louis in Missouri. The donor is her twin sister.
2008: First transplant of a human windpipe using a patient's own stem cells, by Paolo Macchiarini (Barcelona, Spain)
2008: First successful transplantation of near total area (80%) of face, (including palate, nose, cheeks, and eyelid) by Maria Siemionow (Cleveland Clinic, US)
2009: Worlds' first robotic kidney transplant in an obese patient University of Illinois Medical Center
2010: First full facial transplant by Dr. Joan Pere Barret and team (Hospital Universitari Vall d'Hebron on 26 July 2010, in Barcelona, Spain)
2011: First double leg transplant by Dr. Cavadas and team (Valencia's Hospital, La Fe, Spain)
2012: First simultaneous robotic bariatric surgery (sleeve gastrectomy) and kidney transplantation (university of Illinois at Chicago). (1). (2)
2012: First Robotic Alloparathyroid transplant. University of Illinois Chicago
2013: First successful entire face transplantation as an urgent life-saving surgery at Maria Skłodowska-Curie Institute of Oncology branch in Gliwice, Poland.
2014: First successful uterine transplant resulting in live birth (Sweden)
2014: First successful penis transplant. (South Africa)
2014: First neonatal organ transplant. (UK)
2018: Skin gun invented, which takes a small amount of healthy skin to be grown in a lab, then is sprayed onto burnt skin. This way skin will heal in days instead of months and will not scar.
2019: First drone delivery of a donated kidney, that was then successfully transplanted into a patient. (US)
2021: First transplant of both arms and shoulders performed on an Icelandic patient at the Édouard Herriot Hospital. (FR)
2022: First successful heart transplant from a pig to a human patient. (US) The recipient later died as the pig's heart was infected with porcine cytomegalovirus.
2023: First main pulmonary artery transplant to extend cancer treatment possibility by Prof. Stefano Cafarotti and team (Ente Ospedaliero Cantonale, Lugano - Switzerland)
2025: First human bladder transplant (US)
== Society and culture ==
=== Success rates ===
Since 2000, there have been approximately 2,200 lung transplants performed each year worldwide. From 2000 to 2006, the median survival period for lung transplant patients has been 5.5 years.
=== Comparative costs ===
In China, a kidney transplant operation runs for around $70,000, liver for $160,000, and heart for $120,000.
=== Safety ===
In the United States, tissue transplants are regulated by the US Food and Drug Administration (FDA) which sets strict regulations on the safety of the transplants, primarily aimed at the prevention of the spread of communicable disease. Regulations include criteria for donor screening and testing as well as strict regulations on the processing and distribution of tissue grafts. Organ transplants are not regulated by the FDA. It is essential that the HLA complexes of both the donor and recipient be as closely matched as possible to prevent graft rejection.
In November 2007, the CDC reported the first-ever case of HIV and Hepatitis C being simultaneously transferred through an organ transplant. The donor was a 38-year-old male, considered "high-risk" by donation organizations, and his organs transmitted HIV and Hepatitis C to four organ recipients. Experts say that the reason the diseases did not show up on screening tests is probably because they were contracted within three weeks before the donor's death, so antibodies would not have existed in high enough numbers to detect. The crisis has caused many to call for more sensitive screening tests, which could pick up antibodies sooner. Currently, the screens cannot detect the small number of antibodies produced in HIV infections within the last 90 days or Hepatitis C infections within the last 18–21 days before a donation is made.
Nucleic acid testing is now being done by many organ procurement organizations and is able to detect HIV and hepatitis C directly within seven to ten days of exposure to the virus.
=== Transplant laws ===
Both developing and developed countries have forged various policies to try to increase the safety and availability of organ transplants to their citizens. However, whilst potential recipients in developing countries may mirror their more developed counterparts in desperation, potential donors in developing countries do not. The Indian government has had difficulty tracking the flourishing organ black market in their country, but in recent times it has amended its organ transplant law to make punishment more stringent for commercial dealings in organs. It has also included new clauses in the law to support deceased organ donation, such as making it mandatory to request for organ donation in case of brain death. Other countries victimized by illegal organ trade have also implemented legislative reactions. Moldova has made international adoption illegal in fear of organ traffickers. China has made selling of organs illegal as of July 2006 and claims that all prisoner organ donors have filed consent. However, doctors in other countries, such as the United Kingdom, have accused China of abusing its high capital punishment rate. Despite these efforts, illegal organ trafficking continues to thrive and can be attributed to corruption in healthcare systems, which has been traced as high up as the doctors themselves in China and Ukraine, and the blind eye economically strained governments and health care programs must sometimes turn to organ trafficking. Some organs are also shipped to Uganda and the Netherlands. This was a main product in the triangular trade in 1934.
Starting on 1 May 2007, doctors involved in commercial trade of organs will face fines and suspensions in China. Only a few certified hospitals will be allowed to perform organ transplants in order to curb illegal transplants. Harvesting organs without donor's consent was also deemed a crime.
On 27 June 2008, Indonesian, Sulaiman Damanik, 26, pleaded guilty in Singapore court for sale of his kidney to CK Tang's executive chair, Tang Wee Sung, 55, for 150 million rupiah (S$22,200). The Transplant Ethics Committee must approve living donor kidney transplants. Organ trading is banned in Singapore and in many other countries to prevent the exploitation of "poor and socially disadvantaged donors who are unable to make informed choices and suffer potential medical risks." Toni, 27, the other accused, donated a kidney to an Indonesian patient in March, alleging he was the patient's adopted son, and was paid 186 million rupiah (US$20,200). Upon sentence, both would suffer each, 12 months in jail or 10,000 Singapore dollars (US$7,600) fine.
In an article appearing in the April 2004 issue of Econ Journal Watch, economist Alex Tabarrok examined the impact of direct consent laws on transplant organ availability. Tabarrok found that social pressures resisting the use of transplant organs decreased over time as the opportunity of individual decisions increased. Tabarrok concluded his study suggesting that gradual elimination of organ donation restrictions and move to a free market in organ sales will increase supply of organs and encourage broader social acceptance of organ donation as a practice.
In the United States 24 states have no law preventing discrimination against potential organ recipients based on cognitive ability, including children. A 2008 study found that of the transplant centers surveyed in those states 85 percent considered disability when deciding transplant list and forty four percent would deny an organ transplant to a child with a neurodevelopmental disability.
=== Ethical concerns ===
The existence and distribution of organ transplantation procedures in developing countries, while almost always beneficial to those receiving them, raise many ethical concerns. Both the source and method of obtaining the organ to transplant are major ethical issues to consider, as well as the notion of distributive justice. The World Health Organization argues that transplantations promote health, but the notion of "transplantation tourism" has the potential to violate human rights or exploit the poor, to have unintended health consequences, and to provide unequal access to services, all of which ultimately may cause harm. Regardless of the "gift of life", in the context of developing countries, this might be coercive. The practice of coercion could be considered exploitative of the poor population, violating basic human rights according to Articles 3 and 4 of the Universal Declaration of Human Rights. There is also a powerful opposing view, that trade in organs, if properly and effectively regulated to ensure that the seller is fully informed of all the consequences of donation, is a mutually beneficial transaction between two consenting adults, and that prohibiting it would itself be a violation of Articles 3 and 29 of the Universal Declaration of Human Rights.
Even within developed countries there is concern that enthusiasm for increasing the supply of organs may trample on respect for the right to life. The question is made even more complicated by the fact that the "irreversibility" criterion for legal death cannot be adequately defined and can easily change with changing technology.
=== Artificial organ transplantation ===
Surgeons, notably Paolo Macchiarini, in Sweden performed the first implantation of a synthetic trachea in July 2011, for a 36-year-old patient who had cancer. Stem cells taken from the patient's hip were treated with growth factors and incubated on a plastic replica of his natural trachea.
According to information uncovered by the Swedish documentary "Dokument Inifrån: Experimenten" (Swedish: "Documents from the Inside: The Experiments") the patient, Andemariam went on to develop an increasingly terrible and eventually bloody cough to dying, incubated, in the hospital. At that point, determined by autopsy, 90% of the synthetic windpipe had come loose. He allegedly made several trips to see Macchiarini for his complications, and at one point had surgery again to have his synthetic windpipe replaced, but Macchiarini was notoriously difficult to get an appointment with. According to the autopsy, the old synthetic windpipe did not appear to have been replaced.
Macchiarini's academic credentials have been called into question and he has recently been accused of alleged research misconduct.
Left ventricular assist devices are often used as a "bridge" to provide additional time while a patient waits for a transplant. For example, former US vice-president Dick Cheney had such a device implanted in 2010 and then 20 months later received a heart transplant in 2012. In year 2012, about 3,000 ventricular assist devices were inserted in the United States, as compared to approximately 2,500 heart transplants. The use of airbags in cars as well as greater use of helmets by bicyclists and skiers has reduced the number of persons with fatal head injuries, which is a common source of donors hearts.
== Research ==
An early-stage medical laboratory and research company, called Organovo, designs and develops functional, three dimensional human tissue for medical research and therapeutic applications. The company utilizes its NovoGen MMX Bioprinter for 3D bioprinting. Organovo anticipates that the bioprinting of human tissues will accelerate the preclinical drug testing and discovery process, enabling treatments to be created more quickly and at lower cost. Additionally, Organovo has long-term expectations that this technology could be suitable for surgical therapy and transplantation.
A further area of active research is concerned with improving and assessing organs during their preservation. Various techniques have emerged which show great promise, most of which involve perfusing the organ under either hypothermic (4–10 °C) or normothermic (37 °C) conditions. All of these add additional cost and logistical complexity to the organ retrieval, preservation and transplant process, but early results suggest it may well be worth it. Hypothermic perfusion is in clinical use for transplantation of kidneys and liver whilst normothermic perfusion has been used effectively in the heart, lung, liver and, less so, in the kidney.
Another area of research being explored is the use of genetically engineered animals for transplants. Similar to human organ donors, scientists have developed a genetically engineered pig with the aim of reducing rejection to pig organs by human patients. This is currently at the basic research stage, but shows great promise in alleviating the long waiting lists for organ transplants and the number of people in need of transplants outweighs the amount of organs donated. Trials are being done to prevent the pig organ transplant to enter a clinical trial phase until the potential disease transfer from pigs to humans can be safely and satisfactorily managed (Isola & Gordon, 1991).
== Negative effects of transplantation ==
In 2021, the National Academies of Sciences, Engineering, and Medicine published a report titled Exploring the State of the Science of Solid Organ Transplantation and Disability which discussed quality of life after transplantation. In the chapter about pediatric transplantation, Nitika Gupta, Eyal Shemesh, George Mazariegos, Dorry Segev, and other researchers discuss outcomes in young transplant recipients. Pediatric intestine transplant recipients have poor long-term outcomes with 15% requiring retransplant within 5 years of receiving their first transplant and 40-60% experiencing transplant failure after 10 years.
Pediatric transplant recipients frequently have mental and behavioral problems. As many as one in three adolescent transplant recipients are nonadherenant to their medication regimens. Adolescent kidney recipients are more likely to be diagnosed with mental disorders such as depression and anxiety following transplantation, living with their parents and experiencing unemployment as adults, and having poor grades in school. They were also more likely to commit suicide and abuse substances. Dr. Clifford Chin explains his opinion that rather than being a cure, heart transplantation creates a chronic illness with a plethora of adverse side effects, such as developmental delay, limited ability to participate in everyday activities, and impaired cognitive function, which may suggest an arrested development, but hepatologist Saeed Mohammad later explains how lack of proper oxygen levels may effect intellectual ability following the transplant.
Saeed Mohammad also discussed the correlation between developmental milestones and pediatric transplantation in general. He considers pediatric transplant recipients to be chronically ill, even though the transplants cured their illnesses. He explains how children who had received transplants are often underestimated, but also points out that immunosuppressive therapy can affect brain development.
Patients who had received liver transplants between the ages of eleven and seventeen had lower survival rates than compared to those who had received liver transplants when they were under five years old, especially if they had their transplant between the ages of sixteen and seventeen. Nitika Gupta, a pediatric hepatologist, points out that teenagers' brains are still forming and developing, which can have critical effects on patients.
It should be pointed out that the researchers refer to pediatric transplant recipients as chronically ill, special needs, and affected by chronic health conditions, though transplantation is a medical operation, rather than a diagnosable condition.
In young liver transplant recipients, nonadherence was more common in girls, patients living in single-parent homes, and patients nineteen and older.
== Myths ==
There are myths that transplantation, regardless of organ, leads to infertility, obsessive-compulsive disorder, and avoidance. In reality, females can often get pregnant, and most patients don't experience avoidant behavior.
== See also ==
Artificial organ
Beating heart cadaver
Blood transfusion
Laboratory-grown organ
Organ donation
Regenerative medicine
Transplant rejection
Xenotransplantation
== References ==
Isola, L. M., & Gordon, J. W. (1991). Transgenic animals: a new era in developmental biology and medicine. Biotechnology (Reading, Mass.), 16, 3–20.
== Further reading ==
World Health Organization (2008). Human organ and tissue transplantation (PDF). Geneva / New York: WHO. p. 13. Retrieved 24 December 2013.
== External links ==
Organ Transplant survival rates from the Scientific Registry of Transplant Recipients
The short film A Science of Miracles (2009) is available for free viewing and download at the Internet Archive.
"Overcoming the Rejection Factor: MUSC's First Organ Transplant" online exhibit at Waring Historical Library | Wikipedia/Transplant_surgery |
Apolipoprotein C-III also known as apo-CIII, and apolipoprotein C3, is a protein that in humans is encoded by the APOC3 gene. Apo-CIII is secreted by the liver as well as the small intestine, and is found on triglyceride-rich lipoproteins such as chylomicrons, very low density lipoprotein (VLDL), and remnant cholesterol.
== Structure ==
ApoC-III is a relatively small protein containing 79 amino acids that can be glycosylated at threonine-74. The most abundant glycoforms are characterized by an O-linked disaccharide galactose linked to N-acetylgalactosamine (Gal–GalNAc), further modified with up to two sialic acid residues. Less abundant glycoforms are characterized by more complex and fucosylated glycan moieties.
== Function ==
APOC3 inhibits lipoprotein lipase and hepatic lipase; it is thought to inhibit hepatic uptake of triglyceride-rich particles. The APOA1, APOC3 and APOA4 genes are closely linked in both rat and human genomes. The A-I and A-IV genes are transcribed from the same strand, while the A-1 and C-III genes are convergently transcribed. An increase in apoC-III levels induces the development of hypertriglyceridemia.
Recent evidence suggests an intracellular role for Apo-CIII in promoting the assembly and secretion of triglyceride-rich VLDL particles from hepatic cells under lipid-rich conditions. However, two naturally occurring point mutations in human apoC3 coding sequence, namely Ala23Thr and Lys58Glu have been shown to abolish the intracellular assembly and secretion of triglyceride-rich VLDL particles from hepatic cells.
== Clinical significance ==
Overexpression of Apo-CIII in humans contributes to atherosclerosis. Two novel susceptibility haplotypes (specifically, P2-S2-X1 and P1-S2-X1) have been discovered in ApoAI-CIII-AIV gene cluster on chromosome 11q23; these confer approximately threefold higher risk of coronary heart disease in normal as well as non-insulin diabetes mellitus. In persons with type 2 diabetes, elevated plasma Apo-CIII is associated with higher plasma triglycerides and greater coronary artery calcification (a measure of subclinical atherosclerosis).
Apo-CIII delays the catabolism of triglyceride rich particles. HDL cholesterol particles that bear Apo-CIII are associated with increased, rather than decreased, risk for coronary heart disease.
Elevations of Apo-CIII associated with single-nucleotide polymorphisms found in genetic variation studies may predispose patients to non-alcoholic fatty liver disease, although the association has been questioned and may be specific to certain ethnicities or to people without central obesity.
Antisense oligonucleotides that bind APOC3 mRNA and prevent its translation have been found to reduce episodes of acute pancreatitis in people with familial chylomicronemia syndrome and lower their triglyceride levels in blood. Adverse effects include thrombocytopenia, which may be prevented by targeting hepatocellular APOC3 expression with a chemically modified oligonucleotide.
== Interactive pathway map ==
Click on genes, proteins and metabolites below to link to respective articles.
== Apolipoprotein CIII and HDL ==
Apolipoprotein CIII is also found on HDL particles. Formation of APOCIII-containing HDL is not a matter of simple binding of APOCII to pre-existing HDL particles but requires the lipid transported ABCA1 in a fashion similar to APOA1-containing HDL. Accumulation of APOCIII on HDL is important for the maintenance of plasma triglyceride homeostasis since it prevents excessive amount of APOCIII on VLDL and other triglyceride rich lipoproteins, thus preventing APOCIII-mediated inhibition of LpL and the subsequent hydrolysis of plasma triglycerides. This may explain the hypertriglyceridemia associated with ABCA1-deficiency in patients with Tangier's disease.
== References ==
== External links ==
Apolipoprotein+C-III at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
Human APOC3 genome location and APOC3 gene details page in the UCSC Genome Browser.
== Further reading == | Wikipedia/Apolipoprotein_C-III |
Orthognathic surgery (), also known as corrective jaw surgery or simply jaw surgery, is surgery designed to correct conditions of the jaw and lower face related to structure, growth, airway issues including sleep apnea, TMJ disorders, malocclusion problems primarily arising from skeletal disharmonies, and other orthodontic dental bite problems that cannot be treated easily with braces, as well as the broad range of facial imbalances, disharmonies, asymmetries, and malproportions where correction may be considered to improve facial aesthetics and self-esteem.
The origins of orthognathic surgery belong in oral surgery, and the basic operations related to the surgical removal of impacted or displaced teeth – especially where indicated by orthodontics to enhance dental treatments of malocclusion and dental crowding. One of the first published cases of orthognathic surgery was the one from Dr. Simon P. Hullihen in 1849.
Originally coined by Harold Hargis, it was more widely popularised first in Germany and then most famously by Hugo Obwegeser who developed the bilateral sagittal split osteotomy (BSSO). This surgery is also used to treat congenital conditions such as cleft palate. Typically surgery is performed via the mouth, where jaw bone is cut, moved, modified, and realigned to correct malocclusion or dentofacial deformity. The word "osteotomy" means the division of bone by means of a surgical cut.
The "jaw osteotomy", either to the upper jaw or lower jaw (and usually both) allows (typically) an oral and maxillofacial surgeon to surgically align an arch of teeth, or the segment of a dental arch with its associated jawbone, relative to other segments of the dental arches. Working with orthodontists, the coordination of dental arches has primarily been directed to create a working occlusion. As such, orthognathic surgery is seen a secondary procedure supporting a more fundamental orthodontic objective.
It is only recently, and especially with the evolution of oral and maxillofacial surgery in establishing itself as a primary medical specialty – as opposed to its long term status as a dental speciality – that orthognathic surgery has increasingly emerged as a primary treatment for obstructive sleep apnoea, as well as for primary facial proportionality or symmetry correction.
The primary use of surgery to correct jaw disproportion or malocclusion is rare in most countries due to private health insurance and public hospital funding and health access issues. A small number of mostly heavily socialist funded countries report that jaw correction procedures occur in some form or other in about 5% of a general population, but this figure would be at the extreme end of service presenting with dentofacial deformities like maxillary prognathisms, mandibular prognathisms, open bites, difficulty chewing, difficulty swallowing, temporomandibular joint dysfunction pains, excessive wear of the teeth, and receding chins.
Increasingly, as people are more able to self-fund surgery, 3D facial diagnostic and design systems have emerged, as well as new operations that enable for a broad range of jaw correction procedures that have become readily accessible; in particularly in private maxillofacial surgical practice. These procedures include IMDO, SARME, GenioPaully, custom BIMAX, and custom PEEK procedures. These procedures are replacing the traditional role of certain orthognathic surgery operations that have for decades served wholly and primarily orthodontic or dental purposes. Another development in the field is the new index called the index of orthognathic functional treatment need (IOFTN) that detects patients with the greatest need for orthognathic surgery as a part of their comprehensive treatment. IOFTN has been validated internationally and detected over 90% of patients with greatest need for orthognathic surgery.
== Medical uses ==
It is estimated that nearly 5% of the UK or US population present with dentofacial deformities that are not amenable to orthodontic treatment requiring orthognathic surgery as a part of their definitive treatment. Orthognathic surgery can be used to correct:
Gross jaw discrepancies (anteroposterior, vertical, or transverse discrepancies)
Skeletofacial discrepancies associated with documented sleep apnea, airway defects, and soft tissue discrepancies
Skeletofacial discrepancies associated with documented temporomandibular joint pathology
A disproportionately grown upper or lower jaw causes dentofacial deformities. Chewing becomes problematic, and may also cause pain due to straining of the jaw muscle and bone. Deformities range from micrognathia, which is when the mandible does not grow far forward enough (over bite), and when the mandible grows too much, causing an under bite; all of which are uncomfortable. Also, a total maxilla osteotomy is used to treat the "long face syndrome", known as the skeptical open bite, idiopathic long face, hyper divergent face, total maxillary alveolar hyperplasia, and vertical maxillary excess. Prior to surgery, surgeons should take x-rays of the patient's jaw to determine the deformity, and to make a plan of procedures. Mandible osteotomies, or corrective jaw surgeries, benefit individuals who have difficulty chewing, swallowing, TMJ pains, excessive wear of the teeth, open bites, overbites, underbites, or a receding chin. The deformities listed above can be perfected by an osteotomy surgery of either the maxilla or mandible (whichever the deformity calls for), which is performed by an oral surgeon who is specialized in the working with both the upper and lower jaws. Orthognathic surgery is also available as a very successful treatment (90–100%) for obstructive sleep apnea.
Cleft lip and palate
Orthognathic surgery is a well established and widely used treatment option for insufficient growth of the maxilla in patients with an orofacial cleft. There is some debate regarding the timing of orthognathic procedures, to maximise the potential for natural growth of the facial skeleton. Patient reported aesthetic outcomes of orthognathic surgery for cleft lip and palate appear to be of overall satisfaction, despite complications that may arise. A potentially significant long-term outcome of orthognathic surgery is impaired maxillary growth, due to scar tissue formation. A 2013 systematic review comparing traditional orthognathic surgery with maxillary distraction osteogenesis found that the evidence was of low quality; it appeared that both procedures might be effective, but suggested distraction osteogenesis might reduce the incidence of long-term relapse. The most common causes of cleft lip and palate are genetic and environmental factors. Clefts are known to occur due to folic acid deficiency, iron and iodine deficiency
== Risks ==
Although infrequent, there can be complications such as bleeding, swelling, infection, nausea and vomiting. Infection rates of up to 7% are reported after orthognathic surgery; antibiotic prophylaxis reduces the risk of surgical site infections when the antibiotics are given during surgery and continued for longer than a day after the operation.
There can also be some post operative facial numbness due to nerve damage. Diagnostics for nerve damage consist of: brush-stroke directional discrimination (BSD), touch detection threshold (TD), warm/cold (W/C) and sharp/blunt discrimination (S/B), electrophysiological tests (mental nerve blink reflex (BR), nerve conduction study (NCS), and cold (CDT) and warm (WDT) detection thresholds. The inferior alveolar nerve, which is a branch of the mandibular nerve, must be identified during surgery and worked around carefully in order to minimize nerve damage. The numbness may be either temporary, or more rarely, permanent. Recovery from the nerve damage typically occurs within three months after repair. Some 3D movements are considered riskier than other ones, such as maxillary impaction.
== Surgery ==
Orthognathic surgery is performed by maxillofacial or an oral surgeon or a plastic surgeon in collaboration with an orthodontist. It often includes braces before and after surgery, and retainers after the final removal of braces. Orthognathic surgery is often needed after reconstruction of cleft palate or other major craniofacial anomalies. Careful coordination between the surgeon and orthodontist is essential to ensure that the teeth will fit correctly after the surgery.
== Planning ==
Planning for the surgery usually involves input from a multidisciplinary team, including oral and maxillofacial surgeons, orthodontists, and occasionally a speech and language therapist. Although it depends on the reason for surgery, working with a speech and language therapist in advance can help minimize potential relapse. The surgery usually results in a noticeable change in the patient's face; a psychological assessment is occasionally required to assess patient's need for surgery and its predicted effect on the patient.
Radiographs and photographs are taken to help in the planning. There is also advanced software that can predict the shape of the patient's face after surgery, which is useful for the planning and also explaining the surgery to the patient and the patient's family. Great care needs to be taken during the planning phase to maximize airway patency.
Orthodontics are a critical component of orthognathic surgery. Traditionally the presurgical orthodontic phase can take as long as one year and undertaken with conventional metal braces. However, these days new approaches and paradigms exist including surgery-first And using clear aligner orthodontia (like Invisalign)
=== Sagittal split osteotomy ===
This procedure is used to correct mandible retrusion and mandibular prognathism (over and under bite).
First, a horizontal cut is made on the inner side of the ramus mandibulae, extending anterally to the anterior portion of the ascending ramus. The cut is then made inferiorly on the ascending ramus to the descending ramus, extending to the lateral border of the mandible in the area between the first and second molar. At this time, a vertical cut is made extending inferior to the body of the mandible, to the inferior border of the mandible.
All cuts are made into the middle of the bone, where bone marrow is present. Then, a chisel is inserted into the pre existing cuts and tapped gently in all areas to split the mandible of the left and right side. From here, the mandible can be moved either forwards or backwards. If sliding backwards, the distal segment must be trimmed to provide room in order to slide the mandible backwards. Lastly, the jaw is stabilized using stabilizing screws that are inserted extra-orally. The jaw is then wired shut for approximately 4–5 weeks.
=== Genioplasty osteotomy (intra-oral) ===
This procedure is used for the advancement (movement forward) or retraction (movement backwards) of the chin.
First, incisions are made from the first bicuspid to the first bicuspid, exposing the mandible. Then, soft tissue of the mandible is detached from the bone; done by stripping attaching tissues. A horizontal incision is then made inferior to the first bicuspids, bilaterally, where bone cuts (osteotomies) are made vertically inferior, extending to the inferior border of the mandible, thereby detaching the bony segments of the mandible. The bony segments are stabilized with titanium plates; no fixation (binding of the jaw) necessary. If advancement is indicated for the chin, there are inert products available to implant onto the mandible, utilizing titanium screws, bypassing bone cuts.
=== Rapid palatal expansion osteotomy ===
When a patient has a constricted (oval shape) maxilla, but normal mandible, many orthodontists request a rapid palatal expansion.
This consists of the surgeon making horizontal cuts on the lateral board of the maxilla, extending anterally to the inferior border of the nasal cavity. At this time, a chisel designed for the nasal septum is utilized to detach the maxilla from the cranial base. Then, a pterygoid chisel, which is a curved chisel, is used on the left and right side of the maxilla to detach the pterygoid palates. Care must be taken as to not injure the inferior palatine artery. Prior to the procedure, the orthodontist has an orthopedic appliance attached to the maxilla teeth, bilaterally, extending over the palate with an attachment so the surgeon may use a hex-like screw to place into the device to push from anterior to posterior to start spreading the bony segments. The expansion of the maxilla may take up to eight weeks with the surgeon advancing the expander hex lock, sideways (← →), once a week.
== Post operation ==
After orthognathic surgery, patients are often required to adhere to an all-liquid diet for a time. Weight loss due to lack of appetite and the liquid diet is common. Normal recovery time can range from a few weeks for minor surgery, to up to a year for more complicated surgery. For some surgeries, pain may be minimal due to minor nerve damage and lack of feeling. Doctors will prescribe pain medication and prophylactic antibiotics to the patient. There is often a large amount of swelling around the jaw area, and in some cases bruising. Most of the swelling will disappear in the first few weeks, but some may remain for a few months.
== Recovery ==
All dentofacial osteotomies require an initial healing time of 2–6 weeks with secondary healing (complete bony union and bone remodeling) taking an additional 2–4 months. The jaw is sometimes immobilized (movement restricted by wires or elastics) for approximately 1–4 weeks. However, the jaw will still require two to three months for proper healing. Lastly, if screws were inserted in the jaw, bone will typically grow over them during the two to three month healing period. Patients also may not drive or operate vehicles or large machinery during the consumption of painkillers, which are typically taken for six to eight days after the surgery, depending on the pain experienced. Immediately after surgery, patients must adhere to certain infection preventing instructions such as daily cleaning, and the consumption of antibiotics. Cleaning of the mouth should always be done regardless of surgery to ensure healthy, strong teeth. Patients are able to return to work 2–6 weeks after the surgery, but must follow the specific rules for recovery for ~8 weeks.
== History ==
Mandible and maxilla osteotomies date to the 1940s. They were used to correct dentofacial deformities like a malocclusion, and a prognathism. Advances have been made in the procedures, and in the anesthesia used. In 1985, mandible and maxilla osteotomies were effectively used to correct more extreme deformities like receding chins, and to relieve pain from temporomandibular joint disorder (TMJ).
Prior to 1991, some patients undergoing a dentofacial osteotomy still had third molars (wisdom teeth), and had them removed during surgery. An extensive study done by Dr. M Lacy and Dr. R Colcleugh, was used to identify threats of combining the two surgeries used 83 patients from the time span of 1987 and 1991. Patients were reviewed, and divided into two groups; those who had, and those who did not have their third molars extracted during the dentofacial Osteotomy. The study showed that 73% of patients developed an infection of the hardware inserted into the jaw when having their third molars removed during an osteotomy. The data indicated that getting the osteotomy and the third molar extraction at the same time highly increases the chances of infection development.
Advances in the surgical techniques allow surgeons to perform the surgery under local anesthesia with assistance from intravenous sedation. Dr. Raffaini introduced this technique in 2002 after a four-year study done with local anesthesia and assistance from intravenous sedation. Prior to this, surgeons would fully sedate patients, hospitalizing them shortly after the surgery for a 2–3 day recovery, specifically from the anesthesia. Advancements allow surgeons to expand the use of an osteotomy on more parts of the jaws with faster recovery time, less pain, and no hospitalization, making the surgery more effective with respect to time and recovery.
The procedure, which is strictly used for a mandibular (jaw) deformity and mobilization, has advanced from similar, very effective procedures performed since 1985. The original mandible and maxilla osteotomy procedure still remains almost unchanged, as it is the simplest and still the most effective for dentofacial deformity correction.
== See also ==
Oral and maxillofacial surgery
Dental braces
Oral and maxillofacial pathology
Le Fort osteotomy
== References == | Wikipedia/Orthognathic_surgery |
Mesotherapy (from Greek mesos, "middle", and therapy from Greek therapeia) is a form of alternative medicine which involves intradermal or subcutaneous injections of pharmaceutical preparations, enzymes, hormones, plant extracts, vitamins, and/or other ingredients such as hyaluronic acid. It has no proven clinical efficacy and poor scientific backing. Mesotherapy injections allegedly target adipose fat cells, apparently by inducing lipolysis, rupture and cell death among adipocytes. The stated aim of mesotherapy is to provide the skin with essential nutrients, hydration, and other beneficial compounds to rejuvenate and revitalize its appearance.
The effects of the treatment may vary depending on the individual.
Pressurized mesotherapy is a needle-free method that uses an accelerated jet of air to insert the ingredients into the skin tissue. A study on the effect of using a lipolytic substance inserted with needles compared to pressurized injection showed significant fat layer reduction for both methods but even better results with the pressurized injection system.
== Usage ==
In the United States, deoxycholic acid, under the brand name Kybella, is approved by the Food and Drug Administration for reducing moderate-to-severe fat below the chin. When injected into submental fat, deoxycholic acid helps destroy adipocytes (fat cells), which are metabolized by the body over the course of several months. Deoxycholic acid has not been approved for injection elsewhere in the body.
There is no conclusive research proof that any chemical compounds work to target adipose (fat cells) specifically. Cell lysis, resulting from the detergent action of deoxycholic acid, may account for any clinical effect.
== History ==
Michel Pistor (1924–2003) performed clinical research and founded the field of mesotherapy.
The French press coined the term mesotherapy in 1958. The French Académie Nationale de Médecine recognized mesotherapy as a specialty of medicine in 1987. The French Society of Mesotherapy recognizes its use as treatment for various conditions but makes no mention of its use in plastic surgery. Popular throughout European countries and South America, mesotherapy is practiced by approximately 18,000 physicians worldwide.
== Market Trends ==
The global mesotherapy market is projected to grow from approximately US$664 million in 2024 to over US$1.3 billion by 2031, with a compound annual growth rate (CAGR) of 10.4% between 2025 and 2031.
The increasing demand for non-invasive aesthetic procedures, such as skin rejuvenation, fat reduction, and hair restoration, is a key driver of this growth. Advancements in mesotherapy technologies—such as no-needle and automated injection systems—have improved treatment precision, patient comfort, and safety. These innovations have made mesotherapy more accessible to dermatologists and cosmetic professionals worldwide.
In addition, the rising influence of social media and celebrity endorsements has contributed to the popularity of cosmetic procedures, particularly among younger demographics. Regional markets in North America and Europe currently dominate, while countries in Asia-Pacific, including China, India, and South Korea, are experiencing rapid growth due to changing beauty standards, increasing urbanization, and higher disposable incomes.
The development of customized mesotherapy cocktails containing hyaluronic acid, peptides, and vitamins has also expanded treatment capabilities. These formulations target a range of skin concerns, including aging, pigmentation, and hair loss.
== Criticism ==
Physicians have expressed concern over the efficacy of mesotherapy, arguing that the treatment hasn't been studied enough to make a determination. Mesotherapy for the treatment of cosmetic conditions hasn't been the subject of standard clinical trials; however, the procedure has been studied for pain relief for several ailments, such as tendonitis, tendon calcification, dental procedures, cancer, cervicobrachialgia, arthritis, lymphedema, and venous stasis.
Despite the lack of clinical trials, there have been case studies and medical papers written on mesotherapy as a cosmetic treatment.
Rod Rohrich, M.D., chairman of the Department of Plastic Surgery at the University of Texas Southwestern Medical Center is quoted as saying: "There is simply no data, no science and no information, to my knowledge, that mesotherapy works." The American Society of Plastic Surgeons issued a position statement not endorsing mesotherapy.
In the United States, the FDA cannot control the act of practitioners injecting various mixtures into patient's bodies, because this practice falls under the jurisdiction of state medical boards.
Robin Ashinoff, speaking for the American Academy of Dermatology, wrote "A simple injection is giving people false hope. Everybody's looking for a quick fix. But there is no quick fix for fat or fat deposits or for cellulite." The American Society for Dermatologic Surgery informed its members in February 2005 that "further study is warranted before this technique can be endorsed."
"No one says exactly what they put into the (syringe)," said Naomi Lawrence, a derma-surgeon at the University of Medicine and Dentistry of New Jersey. "One drug they often use, phosphatidylcholine, is unpredictable and causes extreme inflammation and swelling where injected. It is not a benign drug."
Mesotherapy is currently banned in a number of South American countries. Even Brazil, which tends to be less strict than the US in drug approvals, has banned the drug for these purposes.
In Australia, an alternative therapy salon was investigated by the Health Department after several clients developed skin abscesses on the calves, buttocks, thighs, abdomen, shoulders, face and neck after undergoing mesotherapy, with one patient also developing a mycobacterial infection.
Following undesirable effects observed on several patients of a French practitioner, an official ratification was published in France in April 2011 to ban mesotherapy as a method for removing fat deposits. This ban was canceled in June 2011 by the French Council of State because the investigation proved that these undesirable effects weren't due to mesotherapy itself, but were due to unhygienic conditions.
== Clinical studies ==
In a prospective study, 10 patients underwent four sessions of facial mesotherapy using multivitamins at monthly intervals. This study found that there was no clinically relevant benefit for skin rejuvenation.
Deoxycholic acid received FDA approval as an injectable to dissolve submental fat June 2015. This was based on the results of a phase III randomized trial of 2600 patients in which 68.2% of patients showed a response by measurement of the fat deposit; 81% had mild temporary adverse reactions of bruising, swelling, pain, numbness, erythema, and firmness around the treated area.
== References ==
== External links ==
American Board of Aesthetic Mesotherapy
French Society of Mesotherapy
Professional Board of Mesotherapy Atlanta Archived 2016-03-25 at the Wayback Machine | Wikipedia/Mesotherapy |
Pediatric surgery is a subspecialty of surgery involving the surgery of fetuses, infants, children, adolescents, and young adults.
== History ==
Pediatric surgery arose in the middle of the 1879 century as the surgical care of birth defects required novel techniques and methods, and became more commonly based at children's hospitals. One of the sites of this innovation was the Children's Hospital of Philadelphia. Beginning in the 1940s under the surgical leadership of C. Everett Koop, newer techniques for endotracheal anesthesia of infants allowed surgical repair of previously untreatable birth defects. By the late 1970s, the infant death rate from several major congenital malformation syndromes had been reduced to near zero.
== Specialties ==
Subspecialties of pediatric surgery itself include: neonatal surgery and fetal surgery.
Other areas of surgery also have pediatric specialties of their own that require further training during the residencies and in a fellowship: pediatric cardiothoracic (surgery on the child's heart and/or lungs, including heart and/or lung transplantation), pediatric nephrological surgery (surgery on the child's kidneys and ureters, including renal, or kidney, transplantation), pediatric neurosurgery (surgery on the child's brain, central nervous system, spinal cord, and peripheral nerves), pediatric urological surgery (surgery on the child's urinary bladder and other structures below the kidney necessary for ejaculation), pediatric emergency surgery, surgery involving fetuses or embryos (overlapping with obstetric/gynecological surgery, neonatology, and maternal-fetal medicine), surgery involving adolescents or young adults, pediatric hepatological (liver) and gastrointestinal (stomach and intestines) surgery (including liver and intestinal transplantation in children), pediatric orthopedic surgery (muscle and bone surgery in children), pediatric plastic and reconstructive surgery (such as for burns, or for congenital defects like cleft palate not involving the major organs), and pediatric oncological (childhood cancer) surgery.
== Conditions ==
Common pediatric diseases that may require pediatric surgery include:
Congenital malformations: lymphangioma, cleft lip and palate, esophageal atresia and tracheoesophageal fistula, hypertrophic pyloric stenosis, intestinal atresia, necrotizing enterocolitis, meconium plugs, Hirschsprung's disease, Anorectal Malformations, Undescended Testes (Cryptorchidism), intestinal malrotation, Biliary Atresia, Pelviureteric Junction Obstruction
Abdominal wall defects: Omphalocele, Gastroschisis, Hernias
Chest wall deformities: Pectus Excavatum
Childhood tumors: like Neuroblastoma, Wilms' tumor, Rhabdomyosarcoma, ATRT, Liver tumors, Teratomas, kidney tumors:
Separation of conjoined twins
Disorders of Sexual Development
== See Related Syndromes ==
VACTERL Association
Apert Syndrome
CHARGE Syndrome
Currarino Syndrome
Pierre Robin Sequence
Prune Belly Syndrome
== See also ==
William E. Ladd; known as the father of pediatric surgery.
Lewis Spitz; Emeritus Nuffield Professor of Paediatric Surgery. Spitz was awarded Denis Browne Gold Medal, Rehbein Medal and the American Ladd Medal.
Robert Edward Gross; president of the American Association for Thoracic Surgery, a member of the National Academy of Sciences and a fellow of the American Academy of Arts and Sciences. He was also awarded the Denis Browne Gold Medal and the American Ladd Medal for his contributions in Pediatric Surgery research.
Morio Kasai; best known for the procedure that came to bear his name. He received the William E. Ladd Medal from the American Academy of Pediatrics, the Denis Browne Gold Medal from the British Association of Paediatric Surgeons and the Asahi Prize from the national newspaper known as the Asahi Shimbun.
== Associations of Pediatric Surgery ==
European Paediatric Surgeons’ Association: EUPSA
World Federation of Associations of Pediatric Surgeons: WOFAPS
American Pediatric Surgical Association: APSA
British Association of Paediatric Surgeons: BAPS
Deutsche Gesellschaft für Kinderchirurgie: German Association of Paediatric Surgeons (DKH)
Pan-African Paediatric Surgical Association: PAPSA
== References == | Wikipedia/Paediatric_surgery |
Cold compression therapy, also known as hilotherapy, combines two of the principles of rest, ice, compression, elevation to reduce pain and swelling from a sports or activity injury to soft tissues and is recommended by orthopedic surgeons following surgery. The therapy is especially useful for sprains, strains, pulled muscles and pulled ligaments.
== Cold compression ==
Cold compression is a combination of cryotherapy and static compression, commonly used for the treatment of pain and inflammation after acute injury or surgical procedures.
Cryotherapy, the use of ice or cold in a therapeutic setting, has become one of the most common treatments in orthopedic medicine. The primary reason for using cryotherapy in acute injury management is to lower the temperature of the injured tissue, which reduces the tissue's metabolic rate and helps the tissue to survive the period following the injury. It is well documented that metabolic rate decreases by application of cryotherapy.
A study done found that current literature on the use of cryotherapy on acute ankle sprains has insufficient evidence for the efficacy.
Static compression is often used in conjunction with cryotherapy for the care of acute injuries. To date, the primary reason for using compression is to increase external pressure on the tissue to prevent edema formation (swelling). This occurs by hindering fluid loss from the vessels in the injured area, making it more difficult for fluids to accumulate. Ice with compression is significantly colder than ice alone due to improved skin contact and increased tissue density caused by extended static compression. Tissue reaches its lowest temperature faster and the tissue maintains its cool even after treatment ends.
Compression therapy has been used in deep venous thrombosis prevention, wound care, as well as managing edema. Literature suggests that compression therapy use for perioperative ankle fractures will be beneficial for edema reduction and therefore, will probably be beneficial for pain and ankle joint mobility as well. Post operative arthroscopic surgeries also shows significant recovery with cold compression.
It has been studied following facial surgery where it has been found to decrease pain and swelling on day two or three. In athletes, cryotherapy has its greatest effect on recovery by using it within the first 24 hours of exercise or injury. Cryotherapy has also been shown that it can increase joint flexibility. It is unclear if it affects the risk of bruising.
== Devices ==
Continuous cold therapy devices (also called ice machines) which circulate ice water through a pad are currently the subject of class action lawsuits for skin and tissue damage caused by excessive cooling or icing time and lack of temperature control. Reported injuries range from frostbite to severe tissue damage resulting in amputation.
Studies have shown that the body activates the hunting reaction after only 10 minutes of cryotherapy, at temperatures less than 9.5 °C (49 °F). The hunting response is a cycle of vasoconstriction (decreased blood flow), then vasodilation (increased blood flow) that increases the delivery of oxygen and nutrient rich blood to the tissue. Studies show a debate whether cold should be used or not for faster recovery. Increased blood flow can slow cell death, limit tissue damage and aid in the removal of cellular debris and waste products. Under normal circumstances the hunting reaction would be essential to tissue health but only serves to increase pain, inflammation and cell death as excess blood is forced into the area.
== Wraps ==
Cold compression wraps using either re-freezable ice or gel are a much safer product, as such products do not exceed the cooling or icing time recommended by the established medical community.
Many of the ice wraps available use adjustable elastic straps to aid in compression over the injured areas. More advanced single-use wraps have guidelines to indicate how the bandage should be applied in order to achieve optimum compression required for an acute injury.
Most ice wraps that use ice, have a built-in protective layer, so ice is not applied directly to the skin, which can result in a burn to the area, sometimes known as a "cryoburn".
== See also ==
Achilles tendinitis
Dermatitis
Plantar fasciitis
Repetitive strain injury
Rotator cuff
Sprain
Strain (injury)
Tennis elbow
Torn rotator cuff
== References ==
Works cited | Wikipedia/Hilotherapy |
Oral and maxillofacial surgery (OMFS) is a surgical specialty focusing on reconstructive surgery of the face, facial trauma surgery, the mouth, head and neck, and jaws, as well as facial plastic surgery including cleft lip and cleft palate surgery.
== Specialty ==
An oral and maxillofacial surgeon is a specialist surgeon who treats the entire craniomaxillofacial complex: anatomical area of the mouth, jaws, face, and skull, head and neck as well as associated structures. Depending upon the national jurisdiction, oral and maxillofacial surgery may require a degree in medicine, dentistry or both.
=== United States ===
In the U.S., oral and maxillofacial surgeons, whether possessing a single or dual degree, may further specialise after residency, undergoing additional one or two year sub-specialty oral and maxillofacial surgery fellowship training in the following areas:
Cosmetic facial surgery, including eyelid (blepharoplasty), nose (rhinoplasty), facial lift, brow lift, and laser resurfacing
Cranio-maxillofacial trauma, including zygomatic (cheek bone), orbital (eye socket), mandibular and nasal fractures as well as facial soft tissue lacerations and penetrating neck injuries
Craniofacial surgery/paediatric maxillofacial surgery, including cleft lip and palate surgery and trans-cranial craniofacial surgery including Fronto-Orbital Advancement and Remodelling (FOAR) and total vault remodelling
Head and neck cancer and microvascular reconstruction free flap surgery
Maxillofacial regeneration, which is re-formation of the facial region by advanced stem cell technique
=== United Kingdom and Europe ===
In countries such as the UK and most of Europe, it is recognised as a specialty of medicine with a degree in medicine and an additional degree in dentistry being compulsory. The scope of practice is mainly head and neck cancer, microvascular reconstruction, craniofacial surgery and cranio-maxillofacial trauma, skin cancer, facial deformity, cleft lip and palate, craniofacial surgery, TMJ surgery and cosmetic facial surgery.
In the UK, maxillofacial surgery is a specialty of the Royal College of Surgeons of England, Royal College of Surgeons of Edinburgh. Intercollegiate Board Certification is provided through the JCIE, and is the same as plastic surgery, ENT, general surgery, orthopaedics, paediatric surgery, neurosurgery and cardiothoracic surgery.
The FRCS (Fellowship of the Royal College of Surgeons) is the specialist exam at the end of surgical training, and is required to work as a Consultant Surgeon in maxillofacial surgery.
In the EU, OMFS is defined within Directive 2005/36 on professional qualifications (updated 2021). The two OMFS specialties are 'dual degree' dental, oral, and maxillofacial surgery (DOMFS) and 'single medical degree' maxillofacial surgery (MFS). In some cases a dental degree may be required to enter specialty training but in all cases the medical degree must be obtained before starting OMFS specialty training.
In Poland, maxillofacial surgery has always been dominated by dentists and still the majority of current OMFS trainees are dental graduates.
Since 2019, Norway switched from dual degree requirement for maxillofacial surgery to medical degree only. Similarly, Sweden has started several maxillofacial surgery training programs for medical graduates.
=== Canada and Asia ===
In Asia, oral and maxillofacial surgery is also recognized as a dental specialty and requires a degree in dentistry prior to surgical residency training. The Canadian model is the same as the model used in the United States of America.
=== Pakistan ===
In Pakistan, OMFS is recognized as a specialty of dentistry which requires FCPS from CPSP after 4 years BDS degree and a one-year housejob. The candidate has to pass FCPS-1 in order to commence their training followed by PGMI Exam (not in all cases).
=== India ===
Oral and maxillofacial surgery, also known as OMFS, is a branch recognized by DCI (Dental Council of India). Becoming a maxillofacial surgeon requires a five-year dental degree followed by three years of post-graduate specialisation. Oral and maxillofacial surgery includes the treatment of complex dental surgery, including wisdom tooth removal, dental implant, craniomaxillofacial trauma, orofacial pain (trigeminal neuralgia) and jaw joint pain (temporomandibular disorder) management, jaw joint replacement for ankylosis and deformed jaw joint cases, Lefort-3 distraction for craniosynostosis case, jaw tumour and cyst removal surgery, head and neck cancer, facial aesthetic like rhinoplasty, eye and ear plastic surgery, facial cosmetic surgery, microvascular surgery, and cleft and craniomaxillofacial surgery. A maxillofacial surgeon is considered one of the required members of an emergency team. Almost 20-25% of trauma patients usually have sustained facial trauma, and that needs urgent opinion and primary management that can be better managed by maxillofacial experts.
=== Australia and New Zealand ===
In Australia and New Zealand, oral and maxillofacial surgery is recognised as both a specialty of medicine and dentistry. Degrees in both medicine and dentistry are compulsory prior to being accepted for surgical training. The scope of practice is broad and there is the ability to undertake subspecialty fellowships in areas such as head and neck surgery and microvascular reconstruction.
=== Globally ===
In other countries, oral and maxillofacial surgery as a specialty exists but under different forms, as the work is sometimes performed by a single or dual qualified specialist depending on each country's regulations and training opportunities available. In several countries, oral and maxillofacial surgery is a specialty recognized by a professional association, as is the case with the Dental Council of India, American Dental Association, Royal College of Surgeons of England, Royal College of Surgeons of Edinburgh, Royal College of Dentists of Canada, Royal Australasian College of Surgeons and Brazilian Federal Council of Odontology (CFO).
== Regulation in the United States ==
Oral and maxillofacial surgery is an internationally recognized surgical specialty. Oral and maxillofacial surgery is formally designated as either a medical, dental or dual (medical and dental) specialty.
In the United States, oral and maxillofacial surgery is a recognised surgical specialty, formally designated as a dental specialty. A professional dental degree is required, a qualification in medicine may be undertaken optionally during residency training. In this respect, oral and maxillofacial surgery is sui generis among surgical specialties. Board certification in the U.S. is governed by the American Board of Oral and Maxillofacial Surgery (ABOMS). Oral and maxillofacial surgery is among the fourteen surgical specialties recognized by the American College of Surgeons. Oral and maxillofacial surgeons in the United States, whether single or dual degree, may become Fellows of the American College of Surgeons, "FACS" (Fellow, American College of Surgeons).
The American Association of Oral and Maxillofacial Surgeons (AAOMS) is the chief professional organization representing the roughly 9,000 oral and maxillofacial surgeons in the United States. The American Association of Oral and Maxillofacial Surgeons publishes the peer-reviewed Journal of Oral and Maxillofacial Surgery.
== Surgical procedures ==
Globally, treatments may be performed on the craniomaxillofacial complex: mouth, jaws, face, neck, and skull, and include:
Cosmetic surgery of the head and neck: (rhytidectomy/facelift, browlift, blepharoplasty/Asian blepharoplasty, otoplasty, rhinoplasty, septoplasty, cheek augmentation, chin augmentation, genioplasty, oculoplastics, neck liposuction, hair transplantation, lip enhancement, injectable cosmetic treatments like botox, fillers, platelet rich plasma, stem cells, chemical peel, mesotherapy.
Orthognathic surgery, surgical treatment/correction of dentofacial deformity as well as management of facial trauma, and sleep apnea
Oncology head and neck surgery with free flap microvascular reconstruction
Cutanous malignancy/skin cancer surgery of head and neck surgery skin grafts and local flaps
Diagnosis and treatment of:
benign pathology (cysts, tumors etc.)
malignant pathology (oral & head and neck cancer) with (ablative and reconstructive surgery, microsurgery)
cutaneous malignancy (skin cancer), lip reconstruction
congenital craniofacial malformations such as cleft lip and palate and cranial vault malformations such as craniosynostosis, (craniofacial surgery)
chronic facial pain disorders
temporomandibular joint (TMJ) disorders
Orthognathic (literally "straight jaw") reconstructive surgery, orthognathic surgery, maxillomandibular advancement, surgical correction of facial asymmetry.
soft and hard tissue trauma of the oral and maxillofacial region (jaw fractures, cheek bone fractures, nasal fractures, LeFort fracture, skull fractures and eye socket fractures).
Dentoalveolar surgery (surgery to remove impacted teeth, difficult tooth extractions, extractions on medically compromised patients, bone grafting or preprosthetic surgery to provide better anatomy for the placement of implants, dentures, or other dental prostheses)
Surgery to insert osseointegrated (bone fused) dental implants and maxillofacial implants for attaching craniofacial prostheses and bone anchored hearing aids.
== Occupation ==
Oral and maxillofacial surgery is intellectually and physically demanding and is among the most highly compensated surgical specialties in the United States with a 2008 average annual income of $568,968.
The popularity of oral and maxillofacial surgery as a career for persons whose first degree was medicine, not dentistry, seems to be increasing. At least one program (University of Alabama at Birmingham) exists that allows highly qualified candidates whose first degree is in medicine to earn the required dental degree, so as to qualify for entrance into oral and maxillofacial residency training programs and ultimately achieve board eligibility and certification in the surgical specialty.
== Education and training ==
In the UK, oral and maxillofacial surgery is one of the ten medical specialties, requiring MRCS and FRCS examinations.
In mainland Europe, its status, including whether or not oral surgery, maxillofacial surgery, and stomatology are considered separate specialties, varies by country. The required qualifications (medical degree, dental degree, or both, as well as the required internship and residency programs) also vary.
In the US, Australia and South Africa, oral and maxillofacial surgery is one of the ten dental specialties recognised by the American Dental Association, Royal College of Dentists of Canada, and the Royal Australasian College of Dental Surgeons. Oral and maxillofacial surgery requires four to six years of further formal university training after dental school (i.e., DDS, BDent, DMD, or BDS).
Residency training programs are either four or six years in duration. In the United States, four-year residency programs grant a certificate of specialty training in oral and maxillofacial surgery. Six-year programs granting an optional MD degree emerged in the early 1990s in the United States. Typically, six-year residency programs grant the specialty certificate and an additional degree such as a medical degree (e.g., MD, DO, MBBS, MBChB) or research degree (e.g., MS, MSc, MPhil, MDS, MSD, MDSc, DClinDent, DSc, DMSc, PhD). Both four– and six–year graduates are designated US "board eligible" and those who earn "board certification" are diplomats. Approximately 50% of the training programs in the US and 66% of Canadian training programs are "dual-degree." The typical length of education and training, in post-secondary school is 12 to 14 years. Beyond these years, some sub-specialise, adding an additional 1-2 year fellowship.
The typical training program for an oral and maxillofacial surgeon is:
2–4 years of undergraduate study (BS, BA, or equivalent degrees)
4 years dental study (DMD, BDent, DDS or BDS)
4–6 years residency training – Some programs integrate an additional degree such as a master's degree (MS, MDS, MSc, MClinDent, MScDent, MDent), doctoral degree (PhD, DMSc, DClinDent, DSc), or medical degree (e.g., MBBS, MD, DO, MBChB, MDCM)
After completion of surgical training most undertake final specialty examinations: US: "Board Certified (ABOMS)", Australia/NZ: FRACDS, or Canada: "FRCDC"
Some colleges offer membership or fellowships in oral/maxillofacial surgery: MOralSurg RCS, M(OMS) RCPS, FFD RCSI, FEBOS, FACOMS, FFD RCS, FAMS, FCDSHK, FCMFOS (SA)
Both single and dual qualified oral and maxillofacial surgeons may obtain fellowship with the American College of Surgeons (FACS).
=== Surgical sub-specialty fellowship training ===
In addition, single and dual-qualified graduates of oral and maxillofacial surgery training programs can pursue post-residency sub-specialty fellowships, typically 1–2 years in length, in the following areas:
Head and neck cancer – microvascular reconstruction
Cosmetic facial surgery (facelift, rhinoplasty, etc.)
Craniofacial surgery and pediatric maxillofacial surgery (cleft lip and palate repair, surgery for craniosynostosis, etc.)
Cranio-maxillofacial trauma (soft tissue and skeletal injuries to the face, head and neck)
== Charities ==
Several notable philanthropic organizations provide humanitarian oral and maxillofacial surgery globally. Smile Train was created in 1998 by Charles Wang focusing on childhood facial deformity. Operation Smile focuses on correcting cleft lips and palates in children. AboutFace, created by Paul Stanley, of the rock band KISS, who was born with a facial deformity, focuses on craniofacial disfiguration.
== See also ==
== References ==
== External links ==
International Association of Oral and Maxillofacial Surgeons
British Association of Oral and Maxillofacial Surgeons
American College of Surgeons
American Association of Oral and Maxillofacial Surgeons
American Board of Oral and Maxillofacial Surgeons
Journal of Oral and Maxillofacial Surgery | Wikipedia/Oral_and_Maxillofacial_Surgery |
An imperforate anus or anorectal malformations (ARMs) are birth defects in which the rectum is malformed. ARMs are a spectrum of different congenital anomalies which vary from fairly minor lesions to complex anomalies. The cause of ARMs is unknown; the genetic basis of these anomalies is very complex because of their anatomical variability. In 8% of patients, genetic factors are clearly associated with ARMs. Anorectal malformation in Currarino syndrome represents the only association for which the gene HLXB9 has been identified.
== Types ==
There are other forms of anorectal malformations though imperforate anus is most common. Other variants include cloacal malformation, rectal atresia, rectal stenosis, and anterior ectopic anus. This form is more commonly seen in females and presents with constipation.
== Presentation ==
There are several forms of imperforate anus and anorectal malformations. The new classification is in relation of the type of associated fistula.
The Wingspread classification was in low and high anomalies:
A low lesion, in which the colon remains close to the skin. In this case, there may be a stenosis (narrowing) of the anus, or the anus may be missing altogether, with the rectum ending in a blind pouch.
A high lesion, in which the colon is higher up in the pelvis and there is a fistula connecting the rectum and the bladder, urethra or the vagina.
A persistent cloaca (from the term cloaca, an analogous orifice in birds, reptiles and amphibians), in which the rectum, vagina and urinary tract are joined into a single channel.
Imperforate anus is usually present along with other birth defects—spinal problems, heart problems, tracheoesophageal fistula, esophageal atresia, renal anomalies and limb anomalies are among the possibilities, collectively being called the VACTERL association.
=== Associated anomalies ===
Imperforate anus is associated with an increased incidence of some other specific anomalies as well, together being called the VACTERL association.
Other entities associated with an imperforate anus are trisomies 18 and 21, the cat-eye syndrome (partial trisomy or tetrasomy of a maternally derived chromosome 22), Baller–Gerold syndrome, Currarino syndrome, caudal regression syndrome, FG syndrome, Johanson–Blizzard syndrome, McKusick–Kaufman syndrome, Pallister–Hall syndrome, short rib–polydactyly syndrome type 1, Townes–Brocks syndrome, 13q deletion syndrome, urorectal septum malformation sequence and the OEIS complex (omphalocele, exstrophy of the cloaca, imperforate anus, spinal defects).
== Diagnosis ==
When an infant is born with an anorectal malformation, it is usually detected quickly as it is a very obvious defect. Doctors will then determine the type of birth defect the child was born with and whether or not there are any associated malformations. Determining the presence of any associated defects during the newborn period in order to treat them early may avoid further sequelae. There are two main categories of anorectal malformations: those that require a protective colostomy and those that do not. The decision to open a colostomy is usually taken within the first 24 hours of birth.
Sonography can be used to determine the type of imperforate anus.
== Treatment ==
Imperforate anus usually requires immediate surgery to open a passage for feces unless a fistula can be relied on until corrective surgery takes place. Depending on the severity of the imperforate, it is treated either with a perineal anoplasty or with a colostomy.
While many surgical techniques to definitively repair anorectal malformations have been described, the posterior sagittal approach (PSARP) has become the most popular. It involves dissection of the perineum without entry into the abdomen and 90% of defects in boys can be repaired this way.
== Prognosis ==
With a high lesion, many children have problems controlling bowel function and most also become constipated. With a low lesion, children generally have good bowel control, but they may still become constipated. For children who have a poor outcome for continence and constipation from the initial surgery, further surgery to better establish the angle between the anus and the rectum may improve continence and, for those with a large rectum, surgery to remove that dilated segment may significantly improve the bowel control for the patient. An antegrade enema mechanism can be established by joining the appendix to the skin (Malone stoma); however, establishing more normal anatomy is the priority.
== Epidemiology ==
Imperforate anus has an estimated incidence of 1 in 5,000 births. It affects boys and girls with similar frequency. However, imperforate anus will present as the low version 90% of the time in females and 50% of the time in males.
Imperforate anus is an occasional complication of sacrococcygeal teratoma.
== History ==
Seventh-century Byzantine physician Paulus Aegineta described a surgical treatment for imperforate anus for the first time. Tenth-century Persian physician Haly Abbas was the first to highlight preserving the sphincter muscles throughout the surgery and the prevention of strictures with a stent. He reported the use of wine for wound care in this surgery. Some reports of children surviving this surgery are available from the early medieval Islamic era.
== References ==
== External links ==
Medline Plus Medical Encyclopedia: Imperforate anus | Wikipedia/Imperforate_anus |
Cataract surgery, also called lens replacement surgery, is the removal of the natural lens of the eye that has developed a cataract, an opaque or cloudy area. The eye's natural lens is usually replaced with an artificial intraocular lens (IOL) implant.
Over time, metabolic changes of the crystalline lens fibres lead to the development of a cataract, causing impairment or loss of vision. Some infants are born with congenital cataracts, and environmental factors may lead to cataract formation. Early symptoms may include strong glare from lights and small light sources at night and reduced visual acuity at low light levels.
During cataract surgery, the cloudy natural lens is removed from the posterior chamber, either by emulsification in place or by cutting it out. An IOL is usually implanted in its place (PCIOL), or less frequently in front of the chamber, to restore useful focus. Cataract surgery is generally performed by an ophthalmologist in an out-patient setting at a surgical centre or hospital. Local anaesthesia is normally used; the procedure is usually quick and causes little or no pain and minor discomfort. Recovery sufficient for most daily activities usually takes place in days, and full recovery takes about a month.
Well over 90% of operations are successful in restoring useful vision, and there is a low complication rate. Day care, high-volume, minimally invasive, small-incision phacoemulsification with quick post-operative recovery has become the standard of care in cataract surgery in the developed world. Manual small incision cataract surgery (MSICS), which is considerably more economical in time, capital equipment, and consumables, and provides comparable results, is popular in the developing world. Both procedures have a low risk of serious complications, and are the definitive treatment for vision impairment due to lens opacification.
== Uses ==
Cataract surgery is the most common application of lens removal surgery, and is usually associated with lens replacement. It is used to remove the natural lens of the eye when it has developed a cataract, a cloudy area in the lens that causes visual impairment. Cataracts usually develop slowly and can affect one or both eyes. Early symptoms may include faded colours, blurred or double vision, halos around lights, sensitivity to glare from bright lights, and night blindness. Total blindness is the end result. The procedure is normally elective, but lens removal may be part of trauma surgery in cases where the eye is severely injured. The lens is usually replaced by an intraocular implant when this is reasonably practicable, as removal of the lens also removes the ability of the eye to focus at any distance.
Cataracts most commonly occur due to aging, but may also be caused by trauma or radiation exposure, be present since birth, or may develop as a complication of eye surgery intended to solve other health problems. Cataracts form when clumps of proteins or yellow-brown pigment accumulate in the lens, which reduces transmission of light to the retina at the back of the eye. Cataracts can be diagnosed via an eye examination.
Early symptoms of cataract may be improved by wearing appropriate glasses; if this does not help, cataract surgery is the only effective treatment. Surgery with implants generally results in better vision and an improved quality of life: however, the procedure is not readily available in many countries.
== Techniques ==
Two main classes of cataract surgical procedures are currently in common use throughout the world: phacoemulsification, and extracapsular cataract extraction. Intracapsular cataract extraction has been superseded where the facilities for surgery under a microscope are available except for cases where the lens capsule cannot be retained, and couching is no longer used in mainstream medicine.
In phacoemulsification (phaco), the natural lens is fragmented by an ultrasonic probe and removed by suction. A more recent and less common variation of this, femtosecond laser-assisted phacoemulsification surgery, uses a laser to make the corneal incision, execute the capsulotomy, which provides access to the lens, and initiate lens fragmentation, which reduces energy requirements for phacoemulsification. The small incision size used in phacoemulsification generally allows for sutureless incision closure.
In extracapsular cataract extraction (ECCE), and its variation manual small incision cataract surgery (MSICS), the lens is removed from its capsule and manually extracted from the eye, either whole or after being split into a small number of substantial pieces. The basic version of ECCE uses a larger incision of 10–12 mm (0.39–0.47 in) and usually requires stitches. This requirement led to the variation known as MSICS, which does not usually need stitches as the incision should be self sealing under internal pressure due to its geometry.
Comparative trials of MSICS against phaco in dense cataracts have found no significant difference in outcomes, although MSICS had shorter operating times and significantly lower costs. MSICS has been prioritized as the method of choice in developing countries, because it provides high-quality outcomes with less surgically-induced astigmatism than standard ECCE, no suture-related problems, quick rehabilitation, and fewer post-operative visits. MSICS is generally easy and fast to learn for the surgeon, cost-effective and applicable to almost all types of cataract. ECCE using a large incision has largely become a contingency procedure to deal with complications during surgery and for managing cataracts expected to be difficult extractions.
In most surgeries, an IOL is inserted. Foldable lenses are generally used for the 2–3 mm (0.08–0.12 in) phaco incision, while non-foldable lenses can be placed through the larger extracapsular incision.
Intracapsular cataract extraction (ICCE) is the removal of the lens and the surrounding lens capsule in one piece. The procedure has a relatively high rate of complications in comparison to techniques in which the capsule is retained in place, due to the large incision required, pressure placed on the vitreous body when removing the encapsulated lens, and the removal of the barrier between the chambers of the eye, allowing easier migration of vitreous into the anterior chamber. It has therefore been largely superseded and is rarely performed in countries where operating microscopes and high-technology equipment are readily available. After lens removal by ICCE, an intraocular lens implant can be placed in either the anterior chamber or sutured into the ciliary sulcus. Cryoextraction is a technique used in ICCE to extract the lens using a cryoprobe, the refrigerated tip of which adheres to the tissue of the lens at the contact point by freezing with a cryogenic substance such as liquid nitrogen, facilitating its removal. Cryoextraction may still be used for the removal of subluxated (partially dislocated) lenses.
Couching is the earliest documented form of cataract surgery. It involves dislodging the lens of the eye, removing the cataract from the optical axis, but leaving it inside the eye. The lens is not replaced and the eye cannot focus at any distance.
Phacoemulsification is the most commonly performed cataract procedure in the developed world, but the high capital and maintenance costs of a phacoemulsification machine and of the associated disposable equipment, have made ECCE and MSICS the most commonly performed procedures in developing countries. Cataract surgery is commonly done as an out-patient or day-care procedure, which is less expensive than hospitalisation and an overnight stay, and day surgery has similar medical outcomes.
== Pre-operative evaluation ==
An eye examination or pre-operative evaluation is done to confirm the presence of a cataract and to determine the patient's suitability for surgery:
The degree of reduction of vision due largely to the cataract is evaluated. While the existence of other sight-threatening diseases, such as age-related macular degeneration or glaucoma, does not preclude cataract surgery, less improvement may be expected in their presence.
In cases of uncontrolled glaucoma, a combined cataract-glaucoma procedure (phaco-trabeculectomy) can be planned and performed.
The pupil is checked for dilation using eyedrops; if they do not provide a satisfactory result, injected intracameral mydriatics have been shown to be safe and effective for surgery and fast acting. If pharmacologic pupil dilation is insufficient, procedures for mechanical pupil dilatation may be needed during the surgery.
People with retinal detachment may be scheduled for a combined vitreo-retinal procedure, along with IOL implantation.
People taking tamsulosin (Flomax), a common drug for enlarged prostate, are prone to developing a surgical complication known as intraoperative floppy iris syndrome (IFIS), which requires appropriate management to avoid posterior capsule rupture.
A Cochrane Review of three randomized clinical trials, including over 21,500 cataract surgeries, examined whether routine pre-operative medical testing resulted in a reduction of adverse events during surgery. Results showed performing pre-operative medical testing did not result in a reduction of risk of intra-operative or post-operative medical adverse events, compared to surgeries with no or limited pre-operative testing.
Infants with congenital cataracts are more likely to have post-operative inflammation problems, and their eyes grow rapidly and unpredictably, making it challenging to select and fit a posterior chamber IOL in infants younger than seven months that will give satisfactory results later in childhood. A second surgery may be required later.
=== Contraindications ===
Contraindications to cataract surgery include cataracts that do not cause visual impairment and medical conditions that predict a high risk of unsatisfactory surgical outcomes. such as:
Poor general health or a serious medical condition.
Surgery will not provide better visual function.
Advanced macular degeneration
Detached retina.
Advanced diabetes that has affected the retina.
An infection of the eyes or nearby that could cause endophthalmitis, so should be treated before cataract surgery.
The person does not want surgery.
Functional vision can be provided by glasses or other visual aids which is sufficient for the person's requirements.
Corneal diseases such as glaucoma may be a relative contraindication.
=== Selection of intraocular lenses ===
After the removal of a cataract, an intraocular lens is usually implanted to replace the damaged natural lens. A foldable IOL may be implanted through a 1.8 to 2.8 mm (0.071 to 0.110 in) incision, whereas a rigid poly(methyl methacrylate) (PMMA) lens requires a larger cut. Foldable IOLs are made of silicone, hydrophobic, or hydrophilic acrylic material of appropriate refractive power and are inserted with a special tool. The IOL is inserted through the incision, usually into the capsular bag from which the cataract was removed (in-the-bag implantation). Sometimes, a sulcus implantation—in front of the capsular bag, but behind the iris—may be required because of posterior capsular tears or zonular dialysis (inadequate support for the capsular bag). This requires an IOL with different refractive power because of the placement further forward on the optical axis.
The appropriate refractive power of the IOL is selected, much like a spectacle or contact lens prescription, to provide the desired refractive outcome. Pre-operative measurements, including corneal curvature, axial length, and white-to-white measurements are used to estimate the required power of the IOL. These methods include several formulae and free online calculators which use similar input data. A history of LASIK surgery, which alters corneal curvature, requires different calculations to take this into account.
Monofocal IOLs provide accurately focused vision at one distance only; far, intermediate, or near. People who are fitted with these lenses may need to wear glasses or contact lenses while reading or using a computer. These lenses usually have uniform spherical curvature.
Other designs of multifocal intraocular lens that focus light from distant and near objects, working with similar effect to bifocal or trifocal eyeglasses, are also available. Pre-operative patient selection and good counselling is necessary to avoid unrealistic expectations and post-operative patient dissatisfaction, and possibly a requirement to replace the lens. Acceptability of these lenses has improved, and studies have shown good results in patients selected for expected compatibility.
Cataract surgery may be performed to correct vision problems on both eyes. If both eyes are suitable, people are usually advised to consider monovision. This procedure involves inserting an IOL providing near vision into one eye, while using one that provides distance vision for the other eye. Although most people can adjust to having monofocal IOLs with differing focal length, some cannot compensate and may experience blurred vision at both near and far distances. An IOL optimised for distance vision may be combined with an IOL that optimises intermediate vision, instead of near vision, as a variation of monovision.
One model of lens designed to change focus using the natural reflexes of the eye has two hinged struts on opposite edges, which displace the lens along the optical axis when an inward transverse force is applied to the haptic loops at the outer ends of the struts—the components transferring the movement of the contact points to the device—while recoiling when the same force is reduced. The lens is implanted in the eye's lens capsule, where the contractions of the ciliary body, which would focus the eye with the natural lens, are used to focus the implant, instead.
IOLs used in correcting astigmatism have different curvature on two orthogonal axes, as on the surface of a torus: for this reason, they are called toric lenses. Intraoperative aberrometry can be used to assist the surgeon in toric lens placement and minimize astigmatic errors.
The first aspheric IOLs were developed in 2004; they have a flatter periphery than the middle of the lens, improving contrast sensitivity. The effectiveness of aspheric IOLs depends on a range of conditions and they may not always provide significant benefit.
The development of light-adjustable intraocular lens (approved by the FDA in 2017), further expanded options for patients with cataracts.
Some IOLs are able to absorb ultraviolet and high-energy blue light, thus mimicking the functions of the natural crystalline lens of the eye, which usually filters potentially harmful frequencies. A 2018 Cochrane review found there is unlikely to be a significant difference in distance vision between blue-filtering and plain lenses, and was unable to identify a difference in contrast sensitivity or colour discrimination.
The light-adjustable IOL was approved by the U.S. Food and Drug Administration (FDA) in 2017. This type of IOL is implanted in the eye and then treated with ultraviolet light to alter the curvature of the lens before fixing it at the final strength.
In some cases, it may be necessary or desirable to insert an additional lens over the already implanted one, also in the posterior capsule. This type of IOL placement is called "piggyback" IOLs and is usually considered when the visual outcome of the first implant is not optimal. In such cases, implanting another IOL over the existing one is considered safer than replacing the initial lens. This approach may also be used in people who need high degrees of vision correction.
Cost is an important aspect of these lenses. Although Medicare covers the cost of monofocal IOLs in the United States, people will have to pay the price difference if they choose more expensive lenses.
== Operation procedures ==
=== Preparation ===
Preparation may begin three-to-seven days before surgery, with the pre-operative application of NSAIDs and antibiotic eyedrops. If the IOL is to be placed behind the iris, the pupil is dilated by using drops to help better visualise the cataract. Pupil-constricting drops are reserved for secondary implantation of the IOL in front of the iris, when the cataract has already been removed without primary IOL implantation.
The operation may occur on a stretcher or a reclining examination chair. The eyelids and surrounding skin are swabbed with a disinfectant, such as 10% povidone-iodine, and topical povidone-iodine is applied to the eye. The face is covered with a cloth or sheet with an opening for the operative eye. The eyelid is held open with a speculum to minimize blinking during surgery. Pain is usually minimal in properly anaesthetised eyes, though a pressure sensation and discomfort from the bright operating microscope light is common.
=== Anaesthesia ===
Most cataract operations are performed under local anaesthetic, allowing the patient to return home the same day. Lens and cataract procedures are commonly performed in an out-patient setting; in the United States, 99.9% of lens and cataract procedures were done in an out-patient setting by 2012.
Topical, sub-tenon, peribulbar, or retrobulbar local anaesthesia is generally used, usually causing little or no discomfort. Injections may be used to block regional nerves and prevent eye movement. Topical anaesthetics are most commonly used, placed on the globe of the eye as eyedrops (before surgery), or in the globe (during surgery). Oral or intravenous sedation to reduce anxiety may be combined with the local anaesthetic. General anaesthesia and retrobulbar blocks were historically used for intracapsular cataract surgery, and may be used for children and adults whose medical or psychiatric issues significantly affect their ability to remain still during the procedure.
=== Phacoemulsification ===
Phacoemulsification uses a machine with an ultrasonic handpiece with a titanium or surgical stainless steel tip, which vibrates at an ultrasonic frequency—commonly 40 kHz—to emulsify the lens tissue, which is aspirated by a coaxial annular suction tube. A second instrument, which is sometimes called a "cracker" or "chopper", may be used from a small side incision to break the hard cataract nucleus into smaller pieces, making emulsification and removal of the soft part of the lens around the nucleus easier. After phacoemulsification of the lens nucleus and cortical material is completed, an irrigation–aspiration (I-A) system is used to remove the remaining peripheral lens material. The procedure is done under a surgical microscope.
Femtosecond laser-assisted phacoemulsification surgery is a more recent development which may have fewer adverse effects on the cornea and macula than manual phacoemulsification. The laser is used to make the corneal incision and the capsulotomy, which provides access to the lens, and initiate lens fragmentation, which reduces energy requirements for phacoemulsification. It provides high-precision, effective lens fragmentation at lower power levels and consequent good optical quality. However, as of 2022, the technique has not been shown to have significant visual, refractive, or safety benefits over manual phacoemulsification, and it has a higher cost.
Entry into the eye is made through a minimal tunnel incision near the edge of the cornea. The incision for cataract surgery has evolved along with the techniques for cataract removal and IOL placement. In phacoemulsification, the width depends on the requirements for IOL insertion. With foldable IOLs, it is often possible to use incisions smaller than 3.5 mm (0.14 in). The shape, position, and size of the incision affect the capacity for self sealing, the tendency to induce astigmatism, and the surgeon's ability to maneuvre instruments through the opening. A more-posterior incision simplifies wound closure and decreases induced astigmatism, but it is more likely to damage blood vessels nearby. One or two smaller side-port incisions at 60-to-90 degrees from the main incision may be needed to access the anterior chamber with additional instruments.
Ophthalmic viscosurgical devices (OVDs), a class of clear, gel-like materials, are injected into the anterior chamber at the start of the procedure, to support, stabilize, and protect the eyeball, to help maintain eye shape and volume, and to distend the lens capsule during IOL implantation. Their consistency allows surgical instruments to move through them, although they do not flow and retain their shape under low shear stress. The OVD will also constrain lens fragments from drifting around in the chamber. OVDs are available in several formulations, which may be combined or used individually as best suits the procedure.
The lens is inside a capsule supported by the ciliary body, between the aqueous and vitreous, behind the opening in the iris. Capsulorhexis is the process of tearing a circular opening in the front membrane of the lens capsule to access the lens within. In phacoemulsification, an anterior continuous curvilinear capsulorhexis is usually used to create a round, smooth-edged opening through which the surgeon can emulsify the lens nucleus, and then implant the intraocular lens.
The cataract's outer (cortical) layer is then separated from the capsule by a gentle, continuous flow or pulsed dose of liquid from a cannula, which is injected under the anterior capsular flap, along the edge of the capsulorhexis opening, in a step called hydrodissection. In hydrodelineation, fluid is injected into the body of the lens through the cortex against the nucleus of the cataract, which separates the hardened nucleus from the softer cortex shell by flowing along the interface between them. As a result, the smaller hard nucleus can be more-easily emulsified. The posterior cortex serves as a buffer at this stage, protecting the posterior capsule membrane. The smaller size of the separated nucleus allows it to be broken up using shallower and less-peripheral grooving by the phaco tip, and produces smaller fragments after cracking or chopping. The posterior cortex also maintains the shape of the capsule through this stage, which reduces the risk of posterior capsule rupture.
After nuclear cracking or chopping (if needed), the cataract is reduced to small fragments using ultrasound which are simultaneously aspirated. The remaining lens cortex (outer layer of lens) material from the capsular bag is carefully aspirated, and if necessary, the remaining epithelial cells from the capsule are removed by capsular polishing. The folded intraocular replacement lens is implanted, usually into the remaining posterior capsule, and checked to see that it has unfolded and seated correctly. A toric IOL must also be aligned in the correct axis to counteract astigmatism.
=== Manual small incision cataract surgery (MSICS) ===
Many of the steps followed during MSICS are similar, if not identical, to those for phacoemulsification; the main differences are related to the alternative method of incision and cataract extraction from the capsule and eye.
Manual small incision cataract surgery (MSICS) is an evolution of extracapsular cataract extraction (ECCE); the lens is removed from the eye through a self-sealing tunnel wound through the sclera. A well-constructed scleral tunnel is held closed by internal pressure, is watertight, and does not require suturing. The wound is relatively smaller than the one in ECCE, but is still markedly larger than a phaco wound.
The small incision into the anterior chamber of the eye is made at or near the corneal limbus, where the cornea and sclera meet, either superior or temporal. Advantages of the smaller incision include use of few-to-no stitches and shortened recovery time. The MSICS incision is small in comparison with the earlier ECCE incision, but considerably larger than the one used in phacoemulsification. The precise geometry of the incision is important, as it affects the self-sealing of the wound and the amount of astigmatism induced by distortion of the cornea during healing. A sclerocorneal or scleral tunnel incision is commonly used, since it reduces the risk of induced astigmatism if suitably formed. A sclerocorneal tunnel, a three-phase incision, starts with a shallow incision perpendicular to the sclera, followed by an incision through the sclera and cornea approximately parallel to the outer surface, and then a beveled incision into the anterior chamber. This structure provides the self-sealing characteristic, because internal pressure presses together the faces of the incision. Bridle sutures may be used to help stabilize the eyeball during sclerocorneal tunnel incision, and during extraction of the nucleus and epinucleus through the tunnel.
The depth of the anterior chamber and position of the posterior capsule may be maintained during surgery by OVDs or an anterior chamber maintainer, which is an auxiliary cannula providing a sufficient flow of buffered saline solution (BSS) to maintain stability of the shape of the chamber and internal pressure. An anterior capsulotomy, is then done to open the front surface of the lens capsule for access to the lens. The continuous curvilinear capsulorhexis technique is often used, or can-opener capsulotomy or envelope capsulotomy.
The lens may be divided into two or more pieces of similar size using a constricting loop, blades or other devices. The cataract lens or fragments are then removed from the capsule and anterior chamber using hydroexpression, viscoexpression, or more direct mechanical methods. Following cataract removal, an IOL is usually inserted into the posterior capsule. When the posterior membrane of the capsule is damaged, the IOL may be inserted into the ciliary sulcus, or a glued intraocular lens technique may be applied.
=== Extracapsular cataract extraction ===
Extracapsular cataract extraction (ECCE), also known as manual extracapsular cataract extraction, is the removal of almost the entire natural lens in one piece, while most of the elastic lens capsule (posterior capsule) is left intact to allow implantation of an intraocular lens. The lens is manually removed through a 10–12 mm (0.39–0.47 in) incision in the cornea or sclera. Although it requires a larger incision and the use of stitches, this method may be preferable for very hard cataracts, which would require a relatively large ultrasonic energy input, which causes more heating, as well as in other situations in which phacoemulsification is problematic.
=== Converting to ECCE to manage a contingency ===
The most commonly used procedures are phacoemulsification and manual small incision cataract surgery (MSICS). In either of these procedures, it can sometimes be necessary to convert to ECCE to deal with a problem better managed through a larger incision. This may occur in the event of posterior capsule rupture, zonular dehiscence, a dropped nucleus with a nuclear fragment more than half the size of the cataract, problematic capsulorhexis with a hard cataract, or a very dense cataract where the heat developed by phacoemulsification is likely to cause permanent damage to the cornea. Similarly, a change from MSICS to ECCE is appropriate whenever the nucleus is too large for the MSICS incision, as well as in cases where the nucleus is found to be deformed during MSICS on a nanophthalmic eye.
=== Closing the wound ===
After the IOL is inserted, OVDs that were injected to stabilize the anterior chamber, protecting the cornea from damage and distending the cataract's capsule during IOL implantation, are removed from the eye to prevent post-operative viscoelastic glaucoma, a severe intra-ocular pressure increase. This is done via suction from the irrigation-aspiration instrument and replacement by buffered saline solution (BSS). Cohesive OVDs tend to adhere to themselves, a characteristic that makes their removal easier. Removal of OVDs from behind the implant reduces the risk and magnitude of post-operative pressure spikes or capsular distention. In the final step, the wound is sealed by increasing the pressure inside the globe with BSS, which presses the internal tissue against the external tissue of the incision, holding it closed. The surgeon will check whether the incision leaks fluid, because wound leakage increases the risk of penetration into the eye by microorganisms, thus predisposing it to endophthalmitis. If this does not achieve a satisfactory seal, a suture may be added. The wound is then hydrated, an antibiotic/steroid combination eyedrop is put in, and an eye-shield may be applied, sometimes supplemented with an eyepatch.
== Post-operative care ==
The use of an eye patch may be indicated, usually for some hours after surgery and for a few days while sleeping. A topical corticosteroid or nonsteroidal anti-inflammatory drug (NSAID) is used to control inflammation, in combination with topical antibiotics to prevent infection in the post-operative phase. These are generally self-administered as eyedrops for a few weeks.
== Complications ==
=== During surgery ===
Posterior capsular rupture, a tear in the posterior membrane of the natural lens capsule, is the most common complication during cataract surgery, with its rate ranging from 0.5% to 5.2%. In most cases the situation can be salvaged, though it may be necessary to modify the original plans for the placement, refractive strength, and type of IOL. Fragments of the nucleus can find their way through the tear into the vitreous chamber, and recovery of the fragments is not always desirable and is rarely successful. The rest of the fragments should generally be stabilised first, and vitreous should be prevented from entering the anterior chamber, and removed if it does. Removal of the fragments may be best referred to a vitreoretinal specialist. Surgical management of a rupture may involve the Intraocular lens scaffold procedure, anterior vitrectomy, and occasionally, alternative planning for implanting the IOL, either in the ciliary sulcus (the space between the iris and the ciliary body), in the anterior chamber in front of the iris, or less commonly, sutured to the sclera. Posterior capsule rupture can cause corneal oedema, cystoid macular oedema, and retention of lens fragments; it is also associated with a six-times increase in the risk of endophthalmitis and as much as a nineteen-times increase in the risk of retinal detachment. Risk factors for posterior capsule rupture include older age, male gender, glaucoma, diabetic retinopathy, white cataract, posterior polar cataract, inability to visualize the posterior segment preoperatively, pseudoexfoliation (exfoliation syndrome), small pupils, axial length greater than 26 mm, use of systemic alpha-1a antagonist medication (e.g., tamsulosin), previous trauma, inability of the patient to lie flat, history of intravitreal injections, patient movement, and resident-performed cataract surgery.
Suprachoroidal hemorrhage is a rare complication of intraocular surgery, which occurs when damaged ciliary arteries bleed into the space between the choroid and the sclera. It is a potentially vision-threatening pathology and must be treated immediately to preserve visual functions. Risk factors for suprachoroidal hemorrhage include anterior chamber intraocular lens (ACIOL), axial myopia, advanced age, atherosclerosis, glaucoma, systolic hypertension, tachycardia, uveitis and previous ocular surgery.
Intraoperative floppy iris syndrome has an incidence ranging from around 0.5% to 2.0%. Iris or ciliary body injury has an incidence of about 0.6–1.2%. Other complications include failure to aspirate all lens fragments, leaving some in the anterior chamber, and incisional burns, caused by overheating of the phacoemulsification tip when ultrasonic power continues while the irrigation or aspiration lines are blocked—the flow through these lines is used to keep the tip cool. Burns to the incision may make closure difficult and can cause corneal astigmatism.
=== After surgery ===
Complications after cataract surgery are relatively uncommon. Posterior vitreous detachment (PVD) does not directly threaten vision, but may increase the risk of future vitreoretinal conditions. It may be more problematic in younger eyes because many people older than 60 have already gone through PVD. PVD may be accompanied by peripheral light flashes and increasing numbers of floaters.
Some people develop posterior capsular opacification (PCO), also called an "after-cataract". After cataract surgery, posterior capsular cells usually undergo hyperplasia and cellular migration as part of a physiological change, showing up as a thickening, opacification, and clouding of the posterior lens capsule, which is left behind after the cataract is removed, for placement of the IOL. This may compromise visual acuity, and can usually be safely and painlessly corrected by using a Nd:YAG laser to clear the central portion of the opacified posterior pole of the capsule (posterior capsulotomy). This creates a clear central visual axis, which improves visual acuity. In very thick opacified posterior capsules, a manual surgical capsulectomy might be needed. In the event of IOL replacement, a posterior capsulotomy could allow vitreous to migrate into the anterior chamber through the opening previously occluded by the IOL, and this would have to be removed. Posterior capsule opacification reaches an incidence of about 28.4% by five years, and is influenced by many factors, including age, IOL lens material, lens design, quantity of residual lens cortex, history of ocular inflammation, and size of capsulorhexis.
Retinal detachment normally occurs at a prevalence of 1 in 1,000 (0.1%); however, people who have had cataract surgery are at an increased risk (0.5–0.6%) of developing rhegmatogenous retinal detachment (RRD)—the most common form of the condition. Cataract surgery increases the rate of vitreous humour liquefaction, which leads to increased rates of RRD. When a retinal tear occurs, vitreous liquid enters the space between the retina and retinal pigment epithelium (RPE), and presents as flashes of light (photopsia), dark floaters, and loss of peripheral vision. Toxic anterior segment syndrome (TASS), a non-infectious inflammatory condition, may also occur following cataract surgery: it is usually treated with topical corticosteroids in high dosage and frequency.
Endophthalmitis is a serious infection of intraocular tissues, usually following intraocular surgery complications or penetrating trauma, and one of the most severe. It rarely occurs as a complication of cataract surgery, due to the use of prophylactic antibiotics, but there is some concern that the clear cornea incision might predispose to the increase of endophthalmitis, although no conclusive study has corroborated this suspicion. An intracameral injection of antibiotics may be used as a preventive measure. A meta-analysis showed the incidence of endophthalmitis after phacoemulsification to be 0.092%. The risk gets higher in association with factors such as diabetes, advanced age, larger incision procedures, and vitreous communication with the anterior chamber caused by posterior capsule rupture. The risk of vitreous infection is at least six times higher than for the aqueous. Endophthalmitis typically presents within two weeks after the procedure, with manifestations such as decreased visual acuity, red-eye and pain. Hypopyon occurs about 80% of the time. About 80% of infections are caused by coagulase-negative staphylococci and Staphylococcus aureus. Management includes vitreous humour tap and injection of broad-spectrum antibiotics. Outcomes can be severe even with treatment, and may range from permanently decreased visual acuity to the complete loss of light perception, depending on the microbiological etiology.
Glaucoma may occur and may be very difficult to control. It is usually associated with inflammation, especially when fragments of the nucleus enter the vitreous cavity. Some experts recommend early intervention by posterior pars plana vitrectomy when this condition occurs. In most cases, raised post-operative intraocular pressure is transient and benign, usually returning to baseline within 24 hours without intervention. Glaucoma patients may experience further visual field loss or a loss of fixation, and are more likely to experience intraocular pressure spikes. On the other hand, secondary glaucoma is an important complication of surgery for congenital cataracts: patients can develop this condition even several years after undergoing cataract surgery, so they need lifelong surveillance.
Mechanical pupillary block manifests when the anterior chamber gets shallower as a result of the obstruction of the aqueous humour flow through the pupil by the vitreous face or IOL. This is caused by contact between the edge of the pupil and an adjacent structure, which blocks the flow of aqueous through the pupil itself. The iris then bulges forward and closes the angle between the iris and cornea, blocking drainage through the trabecular meshwork and causing an increase in intraocular pressure. Mechanical pupillary block has mainly been identified as a complication of anterior chamber intraocular lens implantation, but has been known to occur occasionally after posterior IOL implantation.
Occasionally, a peripheral iridectomy may be made to minimize the risk of pupillary block glaucoma. Surgical iridectomy can be done manually or with a Nd:YAG laser. Laser peripheral iridotomy may be done either before or following cataract surgery.
Swelling of the macula, the central part of the retina, results in macular oedema and can occur a few days or weeks after surgery. Most such cases can be successfully treated. Preventative use of nonsteroidal anti-inflammatory drugs has been reported to reduce the risk of macular oedema to some extent.
Uveitis–glaucoma–hyphema syndrome is a complication caused by the mechanical irritation of a mis-positioned IOL over the iris, ciliary body or iridocorneal angle.
Other possible complications include elevated intraocular pressure; swelling or oedema of the cornea, which is sometimes associated with transient or permanent cloudy vision (pseudophakic bullous keratopathy); displacement or dislocation of the IOL implant; unplanned high refractive error—either myopic or hypermetropic—due to errors in the ultrasonic biometry (measurement of the eye length and calculation of the required intraocular lens power); cyanopsia, which often occurs for a few days, weeks or months after removal of a cataract; and floaters, which commonly appear after surgery.
It may be necessary to exchange, remove or reposition an IOL after surgery, for any of the following reasons:
Capsular block syndrome, the hyper-distention of the lens capsular bag, due to the IOL blocking fluid from draining through the anterior capsulotomy. This may cause a myopic refractive error;
Chronic anterior uveitis, which is a persistent inflammation of the anterior segment;
Chronic loss of endothelial cells faster than the rate due to normal aging;
Iris pigment epithelium loss;
Physical pain;
Progressive elongation of the pupil in direction of the IOL's long axis;
Progressive closing of the anterior chamber angle, due to propagation of anterior synechiae without apparent anterior uveitis;
Incorrect IOL refractive power;
Incorrect positioning of the IOL (including decentring, tilt, or rotation), which partially prevents its correct function;
Damage or deformation of the IOL;
Unexpected optical results due to defects of the IOL;
Undesirable optical phenomena reported by the patient due to any other cause.
=== Risk ===
Cataract surgery and IOL implantation have the safest and highest success rates of any eye care-related procedures. As with any type of surgery, however, some level of risk remains.
Most complications of cataract surgery do not result in long-term visual impairment, but some severe complications can lead to irreversible blindness. A survey of adverse results affecting Medicare patients recorded between 2004 and 2006 showed an average rate of 0.5% for one or more severe post-operative complications, with the rate decreasing by about 20% over the study period. The most important risk factors identified were diabetic retinopathy and a combination of cataract surgery with another intraocular procedure on the same day. In the study, 97% of the surgeries were not combined with other intraocular procedures; the remaining 3% were combined with retinal, corneal or glaucoma surgery on the same day.
== Recovery and rehabilitation ==
Following cataract surgery, side-effects such as grittiness, watering, blurred vision, double vision, and a red or bloodshot eye may occur, although they usually clear after a few days. Full recovery from the operation can take four-to-six weeks. Patients are usually advised to avoid getting water in the eye during the first week after surgery, and to avoid swimming for two-to-three weeks as a conservative approach, to minimise risk of bacterial infection. Most people can return to normal activities the day after phacoemulsification surgery. Depending on the procedure, they should avoid driving for at least 24 hours after the surgery, largely due to effects from the anaesthesia, possible swelling affecting focus, and pupil dilation causing excessive glare. At the first post-operative check, the surgeon will usually assess whether the patient's vision is suitable for driving.
With small-incision self-sealing wounds used with phacoemulsification, some of the post-operative restrictions common with intracapsular and extracapsular procedures are not relevant. Restrictions against lifting and bending were intended to reduce the risk of the wound opening, because straining increases intraocular pressure. With a self-sealing tunnel incision, however, higher pressure closes the wound more tightly. Routine use of a shield is not usually required, because inadvertent finger pressure on the eye should not open a correctly structured incision, which should only open to point pressure. After surgery, patients need to prevent contamination by avoiding rubbing their eyes, as well as not using eye makeup, face cream or lotions. Any kind of contact with excessive dust, wind, pollen or dirt should also be avoided. Moreover, people are advised to wear sunglasses on bright days, since the eyes become more sensitive to bright light for a prolonged period after surgery.
Topical anti-inflammatory drugs and antibiotics are commonly used in the form of eyedrops to reduce the risk of inflammation and infection. A shield or eye-patch may be prescribed to protect the eye while sleeping. The eye will be checked to ensure the IOL remains in place, and once it has fully stabilized (after about six weeks), vision tests will be used to check whether prescription lenses are needed. In cases where the focal length of the IOL is optimised for distance vision, reading glasses are generally needed for near focus.
In some cases, people are dissatisfied with the optical correction provided by the initial implants, making removal and replacement necessary; this can occur with more complex IOL designs, as the patient's expectations might not match with the compromises inherent in these designs, or they might not be able to accommodate the difference in distance and near-focusing of monovision lenses. The patient should not participate in contact or extreme sports, or similar activities, until cleared to do so by the eye surgeon.
== Outcomes ==
After full recovery, visual acuity depends on the underlying condition of the eye, the choice of IOL, and any long-term complications associated with the surgery. More than 90% of operations are successful in restoring useful vision, with a low complication rate. The World Health Organization (WHO) recommends at least 80% of eyes should have a presenting visual acuity of 6/6 to 6/18 (20/20 to 20/60) after surgery, which is considered a good enough visual outcome; the percentage is expected to reach at least 90% with best correction. Acuity of between 6/18 and 6/60 (20/60 to 20/200) is regarded as borderline, whereas a value worse than 6/60 (20/200) is considered poor. Borderline or poor visual outcomes are usually influenced by pre-surgery conditions such as glaucoma, macular disease, and diabetic retinopathy.
Refractive results using power calculation formulae based on pre-operative biometrics leave people within 0.5 dioptres of target (correlates to visual acuity of 6/7.5 (20/25) when targeted for distance) in 55% of cases and within one dioptre (correlates to 6/12 (20/40) when targeted for distance) in 85% of cases. Developments in intra-operative wavefront technology have demonstrated power calculations that provide improved outcomes, yielding 80% of patients within 0.5 dioptres (6/7.5 (20/25) or better).
A ten-year prospective survey on refractive outcomes from a UK National Health Service (NHS) cataract surgery service from 2006 to 2016 showed a mean absolute error between the targeted and outcome refraction of 0.50 dioptres, with a standard deviation of 0.67 dioptres. 88.76% were within one diopter of target refraction and 62.36% within 0.50 dioptres.
According to a 2009 study conducted in Sweden, factors that affected predicted refraction error included sex, pre-operative visual acuity and glaucoma, together with other eye conditions. Second-eye surgery, macular degeneration, age and diabetes did not affect the predicted outcome. Prediction error decreased with time, which is likely due to the use of improved equipment and techniques, including more-accurate biometry. A 2013 American survey involving nearly two million bilateral cataract surgery patients found immediate sequential bilateral cataract surgery was statistically associated with worse visual outcomes than for delayed sequential bilateral cataract surgery; however, the difference was small and might not be clinically relevant.
There is a tendency for post-operative refraction to vary slightly over several years. A small overall myopic shift has been recorded in 33.6% and a small hypermetropic shift in 45.2% of eyes with the remaining 21.2% in the study having no reported change. Most of the change occurred during the first year after surgery.
Phacoemulsification via a coaxial incision may be associated with less astigmatism than the average for bimanual incisions, but the difference was found to be small and the evidence statistically uncertain.
== History ==
Cataract surgery has a long history in Europe, Asia, and Africa, with Chrysippus of Soli, a stoic Greek philosopher providing the earliest account. Couching was the original form of cataract surgery, and was used from antiquity. It is still occasionally found in traditional medicine in parts of Africa and Asia. In 1753, Samuel Sharp performed the first-recorded surgical removal of the entire lens and lens capsule, equivalent to intracapsular cataract extraction. The lens was removed from the eye through a limbal incision.
In 1884, Karl Koller became the first surgeon to apply a cocaine solution to the cornea as a local anaesthetic. By the beginning of the 20th century, the standard surgical procedure was intracapsular cataract extraction (ICCE). In 1949, Harold Ridley introduced the concept of implantation of the intraocular lens (IOL) after treating a Spitfire pilot who had fragments of acrylic plastic in his eye and realising that, unlike most other foreign material, the eye did not reject acrylic. This made visual rehabilitation after cataract surgery a more efficient, effective, and comfortable process.
Intracapsular cryoextraction was the favoured form of cataract extraction from the late 1960s to the early 1980s using a liquid-nitrogen-cooled probe tip to freeze the encapsulated lens to the probe. In 1967, Charles Kelman introduced phacoemulsification, which uses ultrasonic energy to emulsify the nucleus of the crystalline lens and remove cataracts by aspiration without a large incision. This method of surgery reduced the need for an extended hospital stay and made out-patient surgery the standard. Ophthalmic viscosurgical devices (OVDs), which were introduced in 1972, facilitate the procedure and improve overall safety, particularly of phacoemulsification, by maintaining the shape of the eye at reduced pressure, and protecting the internal tissues of the eye without interfering with the operation.
In the early 1980s, Danièle Aron-Rosa and colleagues introduced the neodymium-doped yttrium aluminum garnet laser (Nd:YAG laser) for posterior capsulotomy. In 1985, Thomas Mazzocco developed and implanted the first foldable IOL, and Graham Barrett and associates pioneered the use of silicone, acrylic, and hydrogel foldable lenses. In 1987, M. Blumenthal and J. Moisseiev described the use of a reduced incision size for ECCE. They used a 6.5 to 7 mm (0.26 to 0.28 in) straight scleral tunnel incision 2 mm (0.079 in) behind the limbus with two side ports, and an anterior chamber maintainer. In 1989, M. McFarland introduced a self-sealing incision architecture, and in 1990, S.L.Pallin described a chevron-shaped incision that minimized the risk of induced astigmatism.
In 1983 G.T. Keener Jr. introduced a constricting wire loop, L.L. Fry reported the phaco-sandwich technique, and Peter Kansas suggested the phacosection method for reducing the incision required. The sclerocorneal pocket tunnel incision introduced by Kratz allowed manual small incision cataract surgery without phacoemulsification. The introduction of the anterior chamber maintainer (ACM) by Blumenthal in 1987 facilitated a high-pressure and -flow system, for a stable intraocular environment during surgery.
Vision 2020: The Right to Sight, a global initiative of the International Agency for the Prevention of Blindness (IAPB), was intended to reduce or eliminate the main causes of avoidable blindness worldwide by 2020. Programs instituted under Vision 2020 facilitated the planning, development, and implementation of sustainable national eye-care programs, including technical support and advocacy. The IAPB and WHO launched the program on 18 February 1999.
The Vision 2020 initiative succeeded in bringing avoidable blindness to the global health agenda. The causes have not been eliminated, but there have been significant changes to their distribution, which have been attributed to global demographic shifts. Remaining challenges to management of avoidable blindness include population size, gender disparities in access to eye-care, and the availability of a professional workforce.
Recent developments as of 2022 include continuing research into the possibility of lens regeneration and pharmacological approaches to slowing the development of cataracts. Lens implants that help compensate for age-related macular degeneration by magnification have been developed, but require relatively large incisions. Improved management of inflammatory response, use of ray-tracing models, artificial intelligence and a range of new formulae for refraction prediction.
== Accessibility ==
Access to cataract surgery is very variable by country and region. Even in developed countries availability may vary significantly between rural and more densely populated areas.
The global health situation of cataracts is improving but this progress has not reduced the need for cataract surgery, which is still inadequate in large parts of the world. Older people, women, and lower socioeconomic status are associated with higher untreated cataract numbers.
Cataracts have the most uneven global distribution of non-communicable eye diseases, with the burden of cataracts more concentrated in countries with lower socioeconomic status. Blindness is also correlated with a lack of ophthalmologists, and density of ophthalmologists correlates with a higher national income. High-income countries had an average of 76.2
ophthalmologists, and low income countries an average of 3.7 ophthalmologists per million inhabitants. The countries with highest socioeconomic levels tend to have the best cataract surgery outcomes. Low income countries also tend to lack adequate training facilities for surgeons.
=== Europe ===
About 4.5 million cataract surgeries were done in the EU Member States in 2016. The rate of surgeries generally varied between 12000 and 4000 per million inhabitants. The highest rate was in Portugal, at 14000 per million and the lowest were Ireland and Slovakia at 2000 per million. The figures are not altogether comparable, as in some countries only surgeries at hospitals are included in the counts. The proportion of out-patient surgeries increased in almost all EU states between 2011 and 2016.
=== Asia ===
The estimated distribution of ophthalmologists in Asia ranges from more than 114 per million of population in Japan, to none in Micronesia.
South Asia has the highest global age-standardized prevalence of moderate-to-severe visual impairment (17.5%) and mild visual impairment (12.2%). Cataract has traditionally been a major cause of blindness in less-developed countries in the region, and in spite of improvements to the volume and quality of cataract surgeries, the rate of surgery remains low for some of these nations.
Cataracts are common in China; as of 2022, their estimated overall prevalence in Chinese people over 50 years old was 27.45%. The overall cataract-surgery coverage rate was 9.19%. The prevalence of cataract and cataract surgical coverage also significantly varies by region.
India's cataract-surgical rate rose from just over 700 operations per million people per year in 1981, to 6,000 per million per year in 2011, thus getting closer to the estimated requirement of 8,000–8,700 operations per million per year needed to eliminate cataract blindness in the country. The rate's rise was partly linked to factors such as increased efficiency due to improved surgical techniques, application of day-case surgery, improvements in operating theatre design, and efficient teamwork with sufficient staff.
=== Africa ===
Cataracts are the main cause of blindness in Africa, and affect approximately half of the estimated seven million blind people on the continent, a number that is expected to increase with population growth by about 600,000 people per year. As of 2005, the estimated cataract-surgery rate was about 500 operations per million people per year. Progress on gathering information on epidemiology, distribution and impact of cataracts within the African continent has been made, but significant problems and barriers limiting further access to reliable data remain.
These barriers relate to awareness, acceptance, and cost; some studies also reported community and family dynamics as discouraging factors. Most of the studies held locally reported that cataract-surgical rate was lower in females. The higher cataract-surgery coverage found in some settings in South Africa, Libya, and Kenya suggest many barriers to surgery can be overcome.
According to the International Agency for the Prevention of Blindness, some sub-Saharan African countries have about one ophthalmologist per million people, while the National Center for Biotechnology Information stated the percentage of adults above the age of 50 in western sub-Saharan Africa who have developed cataract-induced blindness is about 6%—the highest rate in the world.
A mathematical model using survey data from sub-Saharan Africa showed the incidence of cataracts varies significantly across the continent, with the required rate of surgery to maintain a visual acuity level of 6/18 (20/60) ranging from about 1,200 to about 4,500 surgeries per year per million people, depending on the area. Such variations may relate to genetic or cultural differences, as well as life expectancy.
=== Latin America ===
A four-year longitudinal study of 19 Latin American countries published in 2010 showed most of the countries had increased their surgery rates over that period, with increases of up to 186%, but still failed to provide adequate surgical coverage. The study also showed a significant correlation between gross national income per capita and cataract-surgery rate in the countries involved.
In a study published in 2014, the weighted-mean regional surgery rate was found to have increased by 70% from 2005 to 2012, rising from 1,562 to 2,672 cataract surgeries per million inhabitants. The weighted mean number of ophthalmologists per million inhabitants in the region was approximately 62. Cataract-surgery coverage widely varied across Latin America, ranging from 15% in El Salvador, to 77% in Uruguay. Barriers cited included cost of surgery and lack of awareness about available surgical treatment. The number of available ophthalmologists appeared to be adequate, but the number of those who practised eye surgery was unknown.
A 2009 study showed that the prevalence of cataract blindness in people 50 years and older ranged from 0.5% in Buenos Aires, to 2.3% in parts of Guatemala. Poor vision due to cataracts ranged from 0.9% in Buenos Aires, to 10.7% in parts of Peru. Cataract-surgical coverage ranged from good in parts of Brazil to poor in Paraguay, Peru, and Guatemala. Visual outcome after cataract surgery was close to conformity with WHO guidelines in Buenos Aires, where more than 80% of post-surgery eyes had visual acuity of 6/18 (20/60) or better, but ranged between 60% and 79% in most of the other regions, and was less than 60% in Guatemala and Peru.
== Social, economic and environmental relevance ==
It has been estimated there were 43.3 million blind people in 2020, and 295 million with moderate and severe visual impairment (MSVI), 55% of whom were female. The age-standardised global prevalence in blindness decreased by 28.5% between 1990 and 2020, but the age-standardised prevalence of MSVI increased by 2.5%. Cataract remained the global leading cause of blindness in 2020.
Cataract impairs vision and lowers quality of life. Improvements in vision help with daily activities, including work productivity and education. Cataract surgery reduces risk of falling and of dementia. It can prevent disability and is very cost effective, so it has large socioeconomic benefits, but the demand is great and the cost remains a large financial burden to public health systems.
The cost of cataract surgery depends on the type of procedure, whether it is provided privately or by a government hospital, whether it is provided by out-patient (day care) or in-patient surgery, and on the economic status of people in the region. Because of the high cost of the equipment, phacoemulsification is generally more expensive than ECCE and MSICS.
A 2021 study found that perioperative procedures before and after surgery differ considerably between various surgeons and institutions, which suggests the possibility for large amounts of unnecessary expenditure worldwide. Standardised best practice perioperative procedures can improve patient safety and have the potential to reduce unnecessary costs and unnecessary diagnostic procedures.
The restoration of functional vision or improvement in vision possible in most cases has a large social and economic impact; patients may be able to return to paid work or continue their previous jobs, and may not become dependent on support from their family or the wider society. Studies show a sustained improvement to quality of life, financial situation, physical well-being, and mental health. Cataract surgery is one of the most cost-effective health interventions, since its economic benefits considerably exceed the cost of treatment.
The 1998 World Health Report estimated 19.34 million people were bilaterally blind due to age-related cataracts, and that cataracts were responsible for 43% of all cases of blindness. This number and proportion were expected to increase due to population growth, and increased life expectancy approximately doubling the number of people older than 60 years. The global increase in blindness from cataract is estimated to be at least five million per year; a figure of 1,000 new cases per million population per year is used for planning purposes. The average outcomes of cataract surgery are improving, and consequently, surgery is being indicated at an earlier stage in cataract progression, increasing the number of operable cases. To reduce the backlog of patients, it is necessary to operate on more people per year than the new cases alone.
As of 1998, the rate of surgeries in economically developed countries was about 4,000 to 6,000 per million population per year, which was sufficient to meet demand. India raised the cataract surgery rate (CSR) to over 3,000, but this was not considered to be sufficient to reduce the backlog. Middle-income countries of Latin America and Asia have CSRs of between 500 and 2,000 per million per year, whereas China, most of Africa, and poor countries of Asia had rates of less than 500. In India and South East Asia, the rate required to keep up with the increase is at least 3,000 per million population per year; in Africa and other parts of the world with smaller percentages of older people, a rate of 2,000 may be sufficient in the short term.
In addition to the direct costs, associated surgical complications may require further intervention. In high income countries the environmental costs also tend to be higher. A phacoemulsification surgery in a UK hospital was estimated to cost more than 20 times the greenhouse gas emission of an equivalent surgery in an Indian hospital. Some of the unnecessary costs may be due to regulatory requirements that are based on perceived safety rather than actual safety.
== Special populations ==
=== Congenital cataracts ===
In general, there is greater urgency to remove dense cataracts from very young children because of the risk of amblyopia. For optimal visual development in newborns and young infants, a visually significant unilateral congenital cataract should be detected and removed before the child is six weeks old, while visually significant bilateral congenital cataracts should be removed before 10 weeks. Congenital cataracts that are too small to affect vision will not be removed or treated, but may be monitored by an ophthalmologist throughout the patient's life. Commonly, a patient with small congenital cataracts that do not damage vision will be affected later in life, though this will take decades to occur.
As of 2015, the standard of care for pediatric cataract surgery for children older than two years is primary posterior intraocular lens (IOL) implantation. Primary IOL implantation before the age of seven months is considered to have no advantages over aphakia. According to a 2015 study, primary IOL implantation in the seven-months-to-two-years age groups should be considered in children who require cataract surgery. Research into the possibility of regeneration of infant lenses from lens epithelial cells showed interesting results in a small trial study reported in 2016.
=== Higher risk for operations on separate occasions ===
Most patients have bilateral cataracts; although surgery in one eye can restore functional vision, second-eye surgery has many advantages, so most patients undergo surgery in each eye on separate days. Operating on both eyes on the same day as separate procedures is known as immediately sequential bilateral cataract surgery; this can decrease the number of hospital visits, thus reducing risk of contagion in an epidemic. Immediately sequential bilateral cataract surgery also has significant cost savings, and faster visual rehabilitation and neuroadaptation. Another indication is significant cataracts in both eyes of patients for whom two rounds of anaesthesia and surgery would be unsuitable. The risk of simultaneous bilateral complications is low.
== Other animals ==
Cataract surgery in small animals such as dogs and cats is a routine ophthalmic procedure with a success rate of around 90%, and is usually better for eyes with relatively recent cataract development. The presence of other ocular problems may reduce the success rate. Procedures are similar to those for humans. General anesthesia is likely to be used, but sub-Tenon injection and a low-dose neuromuscular blockade protocol have also been used for canine cataract surgery.
== See also ==
Medicine portal
Media related to Cataract surgery at Wikimedia Commons
Africa Cataract Project
Eye surgery – Surgery performed on the eye or its adnexa
Himalayan Cataract Project – U.S. nonprofit organization
IOLVIP – Intraocular lens system to compensate for macular degeneration
Ophthalmology – Field of medicine treating eye disorders
Phakic intraocular lens implantation in series with the natural lens to correct vision in cases of high refractive errors.
Refractive lens exchange, or clear lens extraction – Effectively use of the same procedures as for cataract surgery to replace a natural lens with high refractive error when other methods are not effective.
== Notes ==
== References ==
== Further reading ==
== External links ==
YouTube video of phacoemulification technique | Wikipedia/Cataract_surgery |
The Alpins Method is a system to plan and analyze the results of refractive surgical procedures, such as laser in-situ keratomileus (LASIK). The Alpins Method is also used to plan cataract/toric intraocular lens (IOL) surgical procedures.
The Alpins Method uses vector mathematics to determine a goal for astigmatism correction and analyze factors involved if treatment fails to reach that goal. The method can also be used to refine surgical techniques or correct laser settings in future procedures.
== Background ==
In the early 1990s, astigmatism analysis and treatment applied to laser modalities was inconsistent and did not assess the success of the results or the extent to which surgical goals had been achieved. The advent of excimer laser technology (e.g., laser-assisted in situ keratomileusis, or LASIK) also introduced a conundrum between incisional and ablation techniques; specifically, should treatment be planned according to refractive cylinder values as introduced with laser refractive surgery, or corneal astigmatism parameters as had been customary with incisional surgery.
Developed by Australian ophthalmologist Noel Alpins and introduced in 1993, the Alpins Method provides a coherent basis for reporting astigmatism results, and on this basis became the standard in the major ophthalmology journals, and was accepted worldwide for studies that include refraction and corneal astigmatism measurements. The method provides a consistent, logical approach to quantifying and comparing the success of various refractive surgical procedures, and refining/planning surgery to achieve even better results, both in individuals and groups of individuals receiving refractive surgery.
The Alpins Method has been used in some research studies of LASIK. In 2006 the American National Standards Institute (ANSI) published guidelines based on the Alpins Method, designed to help manufacturers demonstrate the efficacy of refractive surgical lasers.
== Basics ==
The Alpins Method determines a treatment path and defined an astigmatic target that in many instances is not zero, although prior to the Alpins Method zero had been a nearly unanimous, but unachievable, preference.
=== Golf analogy ===
The Alpins Method of astigmatism analysis has many parallels to the game of golf. A golf putt is a vector, possessing magnitude (length) and axis (direction). The intended putt (the path from the ball to the hole) corresponds to Alpins' target-induced astigmatism vector (TIA), which is the astigmatic change (by magnitude and axis) the surgeon intends to induce to correct the patient's pre-existing astigmatism to the derived or calculated target. The actual putt (the path the ball follows when hit) corresponds to Alpins' surgical-induced astigmatism vector (SIA), which is the amount and axis of astigmatic change the surgeon induces. If the golfer misses the cup, the difference vector (DV) corresponds to the second putt—that is, a putt (by magnitude and axis) that would allow the golfer to hit the cup (the surgeon to completely correct it) on a second attempt.
=== Indices generated ===
The diagram superimposed on the golf putt image corresponds to a double-angle vector diagram (DAVD), which allows calculations using rectangular (Cartesian) coordinates. Vectors can only be calculated; they cannot be measured like astigmatism. Line 1 in the diagram represents a patient's preoperative astigmatism by magnitude (length of the line) and axis (which in a DAVD is twice the patient's measured axis of preoperative astigmatism). Line 2 represents the target astigmatism—that is, the magnitude and axis of the correction the surgeon would like to achieve. Line 3 represents the achieved astigmatism—that is, the magnitude and axis of postoperative astigmatism.
The TIA, SIA, and DV and their various relationships generate the following indices, which comprise the essence of the Alpins Method:
Correction index (CI)—The ratio of the SIA to the TIA—what the surgery-induced versus what the surgery was meant to induce. The CI is preferably 1; it is greater than 1 if an overcorrection occurs and less than 1 if there is an under-correction. The CI is calculated by dividing the SIA (actual effect) by the TIA (target effect).
Coefficient of adjustment (CA)—The inverse of the CI, the CA quantifies the modification needed to the initial surgery plan to have achieved a CI of 1, the ideal correction. If the surgeon achieves an overcorrection, for example, the CA might be 0.9, indicating that the surgeon should have selected a correction of 90% of what was selected. The CA can be used to refine nomograms for future procedures.
The magnitude of error (MofE)—The intended correction minus the actual correction in diopters.
Angle of error (AE)—The angle described by the vectors of the intended correction versus the achieved correction (SIA minus TIA). By convention, the AE is positive if the achieved correction is on an axis counterclockwise to where it was intended, and negative if the achieved correction is clockwise to its intended axis.
Index of success (IOS)—The IOS is calculated by dividing the DV (how far the target is missed) by the TIA (the original target effect). The IOS is a relative measure of success; that is, if golfer John attempts a long putt and golfer Bob a shorter one, and each ends up the same distance from the cup, John's putt can be considered more successful because he had the longer initial putt and a lower IOS (zero being perfect). The IOS is a valuable measure of the relative effectiveness of various surgical procedures.
=== Vector planning ===
Clinical studies support vector planning both in healthy astigmatic eyes and in eyes with keratoconus.
Additionally, Alpins and Stamatelatos showed that combining refraction (using wavefront measurements) with Vector Planning provided better visual outcomes than using wavefront planning alone.
In astigmatism treatments using Vector Planning, with the advance of tomography devices, various corneal astigmatism parameters can now be measured for different parts of the cornea (predominantly, one corneal parameter and one refractive parameter is used). By dividing the cornea into 2 halves, a total corneal astigmatism parameter can be measured for each half of the cornea with varying emphases on corneal and refractive parameters, maximally reducing the astigmatism for each half.
== References examination test radiation == | Wikipedia/Alpins_method |
Ocular surgery may be performed under topical, local or general anesthesia. Local anaesthesia is more preferred because it is economical, easy to perform and the risk involved is less. Local anaesthesia has a rapid onset of action and provides a dilated pupil with low intraocular pressure.
== History ==
Susruta Samhita has evidences of use of anaesthesia for ocular surgeries. Inhalational anaesthesia was used for this purpose. Egyptian surgeons used carotid compression to produce transient ischemia during eye surgery to reduce the perception of pain. In 1884, Karl Koller used cocaine for ocular surgery. The same year, Herman Knapp used cocaine for retrobulbar block. In 1914, van Lint achieved orbicularis akinesia by local injection.
== Topical (Surface) anaesthesia ==
Surface anaesthesia is given by instillation of 2.5 ml xylocaine. One drop of xylocaine instilled four times after every 4 minutes will produce conjunctival and corneal anaesthesia. Paracaine, tetracaine, bupivacaine, lidocaine etc. may also be used in place of xylocaine. Cataract surgery by phacoemulsification is frequently performed under surface anaesthesia. Facial nerve, which supplies the orbicularis oculi muscle, is blocked in addition for intraocular surgeries. Topical anaesthesia is known to cause endothelial and epithelial toxicity, allergy and surface keratopathy.
=== Facial block ===
There are four types of facial block : van Lint's block, Atkinson block, O' Brien block and Nadbath block.
van Lint's block : In van Lint's block, the peripheral branches of facial nerve are blocked. This technique causes akinesia of orbicularis oculi muscle without associated facial paralysis. Anaesthetic is injected just above the eyebrow and below the inferior orbital margin, through a point about 2 cm behind the lateral orbital margin in level with the outer canthus of the eye.
O' Brien's block : It is also known as facial nerve trunk block. The block is done at the level of the neck of the mandible near the condyloid process. The needle is inserted at this point and about 4 ml of local anaesthetic is injected while withdrawing the needle. Pain at the injection site may occur if O' Brien's block is applied.
Atkinson's block : The superior branch of the facial nerve is blocked by injecting the anaesthetic solution at the inferior margin of zygomatic bone.
Nadbath block : In Nadbath block, the facial nerve is blocked at the stylomastoid foramen. The patient is likely to experience pain.
=== Retrobulbar block ===
This technique was first practiced by Herman Knapp in 1884. Here, 2% xylocaine is introduced into the muscle cone behind the eyeball. The injection is usually given through the inferior fornix of the skin of the outer part of the lower lid when the eye is in primary gaze. The ciliary nerves, ciliary ganglion, oculomotor nerve and abducens nerve are anesthetized in retrobulbar block. As a result, global akinesia, anaesthesia and analgesia are produced. The superior oblique muscle, which is outside the muscle cone, is not usually paralyzed. The complications of retrobulbar block are globe perforation, optic nerve injury, retrobulbar haemorrhage and extraocular muscle palsy. Retrobulbar anaesthesia is contraindicated in posterior staphyloma, high axial myopia and enophthalmos.
=== Peribulbar block ===
This technique was first applied by Davis. In peribulbar block, local anaesthetic is injected to the peripheral spaces of the orbit. The anaesthetic diffuses into the muscle cone and eyelids, causing global and orbicularis akinesia and anaesthesia. After injection, orbital compression is applied for around 15 minutes.
== Regional (local) anaesthesia ==
Nearly all ocular surgeries viz keratoplasty, cataract extraction, glaucoma surgery, iridectomy, strabismus, retinal detachment surgery etc. can be done under regional anaesthesia. Conjunctiva, globe and orbicularis can be paralysed using a combination of surface anaesthesia, facial anaesthesia and retrobulbar block. The advantage is that it produces less post-operative restlessness. It has less post-operative lung complications and less bleeding.
== General anaesthesia ==
General anaesthesia is preferred for ocular surgeries in anxious adults, psychiatric patients, infants and children. It is also indicated in perforating ocular injuries and major surgeries like exenteration. During the surgery, it has to be ensured that no carbon dioxide retention occurs. If this occurs, the choroid swells up and ocular contents may prolapse as soon as the eye is opened. The advantages of general anaesthesia is that it produces complete akinesia, controlled intraocular pressure and safe operating environment. It is the safest option for bilateral surgery. The complications of general anaesthesia are laryngospasm, hypotension, hypercarbia, respiratory depression and cardiac arrhythmia.
== See also ==
Ocular surgery
== References ==
== External links ==
Anaesthesia for adults having ocular surgery
Ocular Local Anaesthetics in Doctor.co.uk | Wikipedia/Anesthesia_for_eye_surgery |
Photorefractive keratectomy (PRK) and laser-assisted sub-epithelial keratectomy (or laser epithelial keratomileusis) (LASEK) are laser eye surgery procedures intended to correct a person's vision, reducing dependency on glasses or contact lenses. LASEK and PRK permanently change the shape of the anterior central cornea using an excimer laser to ablate (remove by vaporization) a small amount of tissue from the corneal stroma at the front of the eye, just under the corneal epithelium. The outer layer of the cornea is removed prior to the ablation.
A computer system tracks the patient's eye position 60 to 4,000 times per second, depending on the specifications of the laser that is used. The computer system redirects laser pulses for precise laser placement. Most modern lasers will automatically center on the patient's visual axis and will pause if the eye moves out of range and then resume ablating at that point after the patient's eye is re-centered.
The outer layer of the cornea, or epithelium, is a soft, rapidly regrowing layer in contact with the tear film that can completely replace itself from limbal stem cells within a few days with no loss of clarity. The deeper layers of the cornea, as opposed to the outer epithelium, are laid down early in life and have very limited regenerative capacity. The deeper layers, if reshaped by a laser or cut by a microtome, will remain that way permanently with only limited healing or remodelling.
With PRK, the corneal epithelium is removed and discarded, allowing the cells to regenerate after the surgery. The procedure is distinct from LASIK (laser-assisted in-situ keratomileusis), a form of laser eye surgery where a permanent flap is created in the deeper layers of the cornea. However, PRK takes longer to heal and can, initially, cause more discomfort.
== LASEK ==
LASEK and PRK are two different procedures. While both procedures interact with the epithelium atop the cornea, the PRK procedure removes this entirely, while LASEK brushes the material away for the procedure, before being placed back for healing after laser surgery. The procedure can be used to treat astigmatism, nearsightedness, and farsightedness. During the procedure, the epithelium is displaced using a diluted alcohol solution.
PRK has advantages over LASIK in that it avoids added complications associated with the flap created during surgery. The procedure may also reduce the chances of dry eye symptoms after surgery. Due to the PRK procedure not requiring a surgical flap, athletes or individuals concerned with trauma introduced by the flap may see benefits to LASEK. Patients that wear contact lenses will typically need to stop wearing these for a specified time before the procedure.
PRK disadvantages include a longer recovery time for vision in contrast to LASIK which may be between five days and two weeks for blurred vision to properly clear. Another disadvantage is that patient may be required to apply steroid eye drops for a few weeks longer than that of a LASIK procedure.
When LASEK is compared to LASIK, LASIK can have better outcomes with corneal haze while LASEK has a lower rate of flap complications than LASIK.
== Eligibility ==
There are a number of basic criteria which a person should satisfy:
Normal ocular health
Age 18 years or older
Stable refraction error (no noticeable change in the last year) correctable to 20/40 or better
Between −1.00 to −12.00 diopters of myopia
Not pregnant at the time of surgery
Realistic expectations of the final results (with a complete understanding of the benefits, as well as the possible risks)
Pupil size 6 mm or less in a dark room is ideal (but some newer lasers may be acceptable for larger pupils)
Assessment of allergies, (e.g., pollen) where allergy may complicate the eyelid margins following surgery leading to dry eye.
There are also some pre-existing conditions that may complicate or preclude the treatment.
Collagen vascular disease (e.g., corneal ulceration or melting)
Ocular disease (e.g., dry eye, keratoconus, glaucoma)
Systemic disorders (e.g., diabetes, rheumatoid arthritis)
History of side effects from steroids
Granular corneal dystrophy type II
== Possible complications ==
Some complications that can be temporary or permanent include:
Dry eyes
Recurrent erosions during sleep
Long healing period
Pain
Glare, halos, or starburst aberrations
Increased ocular straylight
Under- or overcorrection
Recurrence of myopia
Corneal haze
Scarring
Reduced best corrected visual acuity
Reduced acuity in low light
Increased sensitivity
Neuropathic pain
=== Dry eyes ===
As with other forms of refractive surgery, keratoconjunctivitis sicca, colloquially referred to as 'dry eye,' is the most common complication of PRK, and can be permanent. In more advanced cases, recurrent erosions occur during sleeping from adherence of the corneal epithelium to the upper eyelid with rapid eye movement. Adjuvant polyunsaturated fatty acids (PUFAs) with high Omega-3 content before and after surgery improves sicca, possibly due to their anti-inflammatory effects. Foods containing PUFAs include flax and fish oil. Brush PRK to denude the epithelium, instead of alcohol based techniques, also result in quantitatively lower ocular dryness after surgery. The amount of corneal hazing after surgery is also decreased with brush technique. The platelet activating factor blocker LAU-0901 has shown effect in mitigating dry eye in mouse models. Rabbit models have also shown improvement with topical nerve growth factor (NGF) in combination with docosahexaenoic acid (DHA). Mitomycin C worsens post-surgical dry eye.
PRK may be performed on one eye at a time to assess the results of the procedure and ensure adequate vision during the healing process. Activities requiring good binocular vision may have to be suspended between surgeries and during the sometimes extended healing periods.
=== Halos, starbursts and refractive errors ===
PRK can be associated with glare, halos, and starburst aberrations, which can occur with postoperative corneal haze during the healing process. Night halos are seen more often in revisions with small ablation zone size. With more recent developments in laser technology, this is less common after 6 months though symptoms can persist beyond a year in some cases. A dilute concentration of the chemotherapeutic agent, Mitomycin-C, can be applied briefly at the completion of surgery to reduce risk of hazing, although with increased risk of sicca.
Predictability of the resulting refractive correction after healing is not totally exact, particularly for those with more severe myopia. This can lead to under/overcorrection of the refractive error. In the case of the overcorrection, premature consequences of presbyopia is a possibility. Experienced surgeons employ a custom-profile algorithm to further enhance predictability in their results.
In 1 to 3% of cases, loss of best corrected visual acuity (BCVA) can result, due to decentered ablative zones or other surgical complications. PRK results in improved BCVA about twice as often as it causes loss. Decentration is becoming less and less of a problem with more modern lasers using sophisticated eye centering and tracking methods.
== Comparison to LASIK ==
A systematic review that compared PRK and LASIK concluded that LASIK has shorter recovery time and less pain. The two techniques after a period of one year have similar results.
A 2016 systematic review found that it was unclear whether there were any differences in efficacy, accuracy, and adverse effects when comparing PRK and LASEK procedures among people with low to moderate myopia. The review stated that no trials have been conducted comparing the two procedures on people with high myopia.
A 2017 systematic review found uncertainty in visual acuity, but found that in one study, those receiving PRK were less likely to achieve a refractive error, and were less likely to have an over-correction than compared to LASIK.
== Types ==
LASIK
Alcohol assisted PRK
Transepithelial PRK (TransPRK)
ASA (Advanced Surface Ablation) LASEK, which uses Amoils Brush and gas cooling to reduce the pain
M-LASEK, which Uses mitomycin in an attempt to reduce post-operative haze but is of dubious effectiveness. Possible long-term side effects are unknown.
== US Military ==
In the U.S.A. candidates who have had PRK can get a blanket waiver for the Special Forces Qualification, Combat Diving Qualification and Military Free Fall courses. PRK and LASIK are both waived for Airborne, Air Assault and Ranger schools. However, those who have had LASIK must enroll in an observational study, if a slot is available, to undergo training in Special Forces qualification. LASIK is disqualifying/non-waiverable for several United States Army Special Operations Command (USASOC) schools (HALO, SCUBA, SERE) per Army Regulation 40-501.
The U.S. Federal Aviation Administration will consider applicants with PRK once they are fully healed and stabilized, provided there are no complications and all other visual standards are met. Pilots should be aware, however, that potential employers, such as commercial airlines and private companies, may have policies that consider refractive surgery a disqualifying condition. Also, civilians who wish to fly military aircraft should know that there are restrictions on those who have had corrective surgery. The Army now permits flight applicants who have undergone PRK or LASIK. Uncomplicated, successful corneal refractive surgery does not require a waiver and is noted as information only.
The Navy and Marines will routinely grant a waiver for pilots or student naval aviators, as well as naval flight officers, UAS operators and aircrew, to fly after PRK and LASIK, assuming preoperative refractive standards are met, no complications in the healing process were encountered, asymptomatic with regard to significant halos, glare or dry eye, off all medications, and passing their standard vision tests. In one study, 967 of 968 naval aviators having PRK returned to duty involving flying after the procedure. In fact, the U.S. Navy now offers free PRK and LASIK surgery at the National Naval Medical Center to Naval Academy Midshipmen who intend to pursue career paths requiring good uncorrected vision, including flight school and special operations training.
The U.S. Air Force approves the use of PRK and LASIK. Since 2000 the USAF has conducted PRK for aviators at the Wilford Hall Medical Center. More airmen were allowed over the years and in 2004 the USAF approved LASIK for aviators, with limits on the type of aircraft they could fly. Then in 2007 those limits were lifted. Most recently in 2011 the USAF expanded the program, making it easier for more airmen to qualify for the surgery. Current airmen (Active Duty and Air Reserve Components who are eligible) are authorized surgery at any DOD Refractive Surgery Center. Those airmen not eligible, are still able to get the surgery done at their own expense by a civilian surgeon, but must first be approved (approval is based on the same USAF-RS program). Others that do not fall into those categories (i.e. applicants who are seeking a pilot slot) can still elect to have the surgery done, but must follow the criteria in accordance with the USAF Waiver Guide. Those applicants will be evaluated at the ACS during their Medical Flight Screening appointment to determine if they meet waiver criteria.
In the majority of patients, PRK has proven to be a safe and effective procedure for the correction of myopia. PRK is still evolving with other countries currently using refined techniques and alternative procedures. Many of these procedures are under investigation in the U.S. Given that PRK is not reversible, a patient considering PRK is recommended to contact an eye-care practitioner for assistance in making an informed decision concerning the potential benefits and liabilities that may be specific to them.
== History ==
The first PRK procedure was performed in 1987 by Dr. Theo Seiler, then at the Free University Medical Center in Berlin, Germany. The first procedure similar to LASEK was performed at Massachusetts Eye and Ear Infirmary in 1996 by ophthalmologist and refractive surgeon Dimitri Azar. Dr. Massimo Camellin, an Italian surgeon, was the first to write a scientific publication about the new surgical technique in 1998, coining the term LASEK for laser epithelial keratomileusis.
== References == | Wikipedia/Photorefractive_keratectomy |
Micro-invasive glaucoma surgery (MIGS) is the latest advance in surgical treatment for glaucoma, which aims to reduce intraocular pressure by either increasing outflow of aqueous humor or reducing its production. MIGS comprises a group of surgical procedures which share common features. MIGS procedures involve a minimally invasive approach, often with small cuts or micro-incisions through the cornea that causes the least amount of trauma to surrounding scleral and conjunctival tissues. The techniques minimize tissue scarring, allowing for the possibility of traditional glaucoma procedures such as trabeculectomy or glaucoma valve implantation (also known as glaucoma drainage device) to be performed in the future if needed.
Traditional glaucoma surgery generally involves an external (ab externo) approach through the conjunctiva and sclera; however, MIGS procedures reach their surgical target from an internal (ab interno) route, typically through a self-sealing corneal incision. By performing the procedure from an internal approach, MIGS procedures often reduce discomfort and lead to more rapid recovery periods. While MIGS procedures offer fewer side effects, the procedures tend to result in less intraocular pressure (IOP) lowering than with trabeculectomy or glaucoma tube shunt implantation.
== Medical uses ==
Glaucoma is a group of eye disorders in which there is a chronic and progressive damage of the optic nerve. Increased intraocular pressure (IOP) is the main and only modifiable risk factor, attributed to the progression of the disease. During the last 25 years, glaucoma management has been based in the use of pharmaceutical therapies and incisional surgery. MIGS procedures can provide the patient sustained IOP reduction while minimizing the risk and complications associated with glaucoma interventions and decrease the dependence of glaucoma medications.
== Adverse events ==
MIGS procedures offer an excellent safety profile, with minimal incidence of complications, especially when compared with other forms of glaucoma surgery.
== Procedures ==
MIGS objective, like all glaucoma surgeries, is to achieve lowering of IOP by either increasing aqueous humour outflow, the fluid that is produced by the eye and fills the space between the cornea and the lens, or decreasing the production of aqueous humour. MIGS encompasses numerous devices and techniques, including trabecular outflow and Schlemm's canal targeted interventions, suprachoroidal outflow, gonioscopy-assisted procedures, and subconjunctival shunts.
=== Micro-stent/shunt devices ===
==== iStent ====
The iStent Trabecular Micro-Bypass Stent, or simply iStent, is the smallest implantable medical device, designed to lower intraocular pressure by facilitating trabecular outflow of aqueous fluid. The trabecular outflow is one of the major outflow pathways for aqueous humor in the eye and has been the target of both pharmaceutical and surgical therapeutic approaches in glaucoma.
The 1-millimeter long iStent is a titanium device inserted via an internal approach through the trabecular meshwork into Schlemm’s Canal, bypassing the trabecular meshwork and facilitating flow of aqueous from the eye. Studies have shown that the iStent is an effective procedure, typically lowering intraocular pressure to the mid-teens.
The iStent is the first MIGS device to get FDA approval for implantation in combination with cataract surgery. The device has also been shown to offer better IOP control than cataract surgery alone up to one year of follow-up in a large randomized controlled FDA study, although the effectiveness was significantly reduced by 2 years. Safety of the iStent was comparable to cataract surgery alone which is much better than conventional trabeculectomy. Common complications include failure to implant the device, touching the iris with the device, and touching the undersurface of the cornea (endothelium) with the device. Multiple studies have since confirmed the MIGS-type efficacy and safety profile of the iStent.
To address the reduced effectiveness at 2 years, some studies have been performed with multiple iStents.
A 2019 Cochrane Review found that individuals who receive iStents in combination with cataract surgery may be less likely than those who only receive cataract surgery to need glaucoma eye drops at medium-term follow-up; however, the evidence for this finding was of low quality.
The trabecular micro-bypass stents have been approved for use in the UK by the National Institute for Health and Care Excellence (NICE).
==== CyPass micro-stent ====
The CyPass Micro-Stent is the first MIGS device developed for lowering of IOP through the suprachoroidal space (virtual space between the choroid and sclera created by implantation of the device), a part of the uveoscleral outflow pathway for aqueous humor. The uveoscleral pathway is an important pathway for aqueous outflow and drainage which can account for up to 57% of total outflow. Cyclodialysis cleft procedures were initially used to access this pathway with significant IOP lowering, but the cleft was prone to high anatomic variability as well as early postoperative closure due to the lack of a permanent drainage implant with a standardized and uniform conduit.
It has a microlumen of 300 micrometres (0.012 in) and is designed to augment outflow to the suprachoroidal space in order to control intraocular pressure; it is indicated for the treatment of primary open-angle glaucoma. The stent is implanted through an ab interno approach and inserted into the supraciliary space (between the ciliary body and sclera), effectively creating a controlled cyclodialysis cleft, which is kept open by the device.
The first clinical data on the device was presented in 2010 showed sustained IOP lowering and MIGS-like safety profile. This has been substantiated in subsequent studies in the combined setting with cataract surgery and as a stand-alone treatment for patients failing glaucoma topical therapy. Data from a large randomized controlled study has reported positive efficacy after 2 years of follow-up and will be submitted to FDA for approval. The CyPass device has been CE-marked since 2009.
The CyPass micro-stent was voluntarily withdrawn from the market by manufacturers Alcon in August 2018.
==== Hydrus ====
The Hydrus Microstent is an implantable MIGS device for the treatment of primary open angle glaucoma; implantation of this device can be performed in conjunction with cataract surgery. The Hydrus Microstent is the longest of the MIGS devices (8-millimeter long implant), and similar to the iStent it is designed to increase trabecular outflow.
The implant is inserted through the trabecular meshwork, thus bypassing resistance of aqueous flow through the tissue. However, other glaucoma surgeries, such as canaloplasty, have shown that mechanical dilation of Schlemm's canal is also associated with a reduction in intraocular pressure. The Hydrus Microstent takes advantage of this property by mechanically dilating and holding open Schlemm’s Canal. The length of the Hydrus Microstent is thought to open approximately one quarter of Schlemm’s Canal, routing aqueous into open downstream collector channels.
Clinical data from a randomized controlled study demonstrates efficacy of the device at 1 and 2 years. The Hydrus Microstent is currently being investigated in an FDA approved study for mild-to-moderate glaucoma.
==== XEN gel stent ====
The XEN Gel Stent is an implantable transscleral microsurgical device that allows the aqueous fluid to drain from the anterior chamber into the subconjunctival space, a pathway utilized by traditional trabeculectomy and glaucoma drainage device surgeries. Unlike the latter two procedures, the XEN Gel Stent is performed through an internal approach and avoids directly incising and disrupting the conjunctiva itself.
The 6-millimeter stent is placed through the trabecular meshwork, with one end of the stent sitting directly underneath the conjunctiva, past the outer wall of the sclera. The inner tip of the stent sits in the anterior chamber, allowing a direct connection for aqueous to flow into the subconjunctival space. The stent is made of a non-bioreactive material, which does not promote scarring of the conjunctiva. The XEN Gel Stent was FDA approved on Nov 22, 2016.
==== InnFocus Microshunt ====
The InnFocus Microshunt is a small tube, 8 mm in length, that is inserted in to the eye to help lower intraocular pressure and reduce the need for medications. A Cochrane Review published in December 2019 did not find any published clinical trials to assess whether the InnFocus Microshunt is safer and more comfortable for patients than standard glaucoma surgery (trabeculectomy).
The InnFocus Microshunt has now been renamed the Preserflo.
=== Minimally invasive procedures ===
==== Endocyclophotocoagulation ====
Aqueous humor is produced in the portion of the eye known as the ciliary body. The ciliary body contains 72 protrusions known as ciliary processes, from which the aqueous is produced. The destruction of these ciliary processes with a diode laser, known as cyclophotocoagulation, can be used to decrease the amount of aqueous humor produced, thereby reducing the intraocular pressure.
Cyclophotocoagulation traditionally has been performed using an external laser through the sclera, known as transscleral cyclophotocoagulation. However, side effects of the transscleral approach can include significant inflammation, chronically low intraocular pressure, intraocular bleeding, and permanent shutdown of the eye, known as phthisis. Recent advances have now allowed a diode laser to be combined with a camera (endoscope) allowing for direct visualization of the ciliary processes during the ablation (Endo Optiks, Beaver Visitec, Waltham, MA).
Endocyclophotocoagulation is indicated for the treatment of both open and closed angle glaucoma and is performed in eyes which have already undergone cataract surgery or performed concomitantly with cataract removal. The largest investigation of endocyclophotocoaguation has shown a significant decrease in intraocular pressure of up to 10 mmHg, as well as a significant reduction in number of glaucoma medications needed. Reported adverse reactions include intraocular inflammation, bleeding, and cystoid macular edema (swelling of the retina). A Cochrane Review published in 2019 found no relevant published studies on endoscopic cyclophotocoagulation to assess its effectiveness compared to other surgical treatments (including other MIGS), laser treatment or medical treatment.
==== Trabectome ====
The Trabectome, or trabeculectomy ab interno, is a microsurgical device cleared by the U.S. Food and Drug Administration since 2006, used in patients with open angle glaucoma to excise a strip of trabecular meshwork, the tissue primarily responsible for the increased resistance of aqueous outflow in glaucoma. The Trabectome uses electrocautery via an internal approach to vaporize the trabecular meshwork, creating a large pathway for aqueous to flow, with minimal trauma to surrounding tissues. The procedure can be performed alone or in conjunction with cataract surgery.
Trabectome is unique among the MIGS procedures, as there is no physical device implanted inside the eye; the pressure lowering is a direct result from the destruction and removal of the trabecular meshwork. Studies have found a decrease in intraocular pressure to the mid-teens following the procedure, which has a favorable safety profile. The most common complication from Trabectome surgery is bleeding, which can blur vision and take extra time to recover. The surgery site can scar over time and the pressure can go back up.
In early 2014, the NeoMedix received a warning letter from the FDA regarding marketing practices.
==== Excimer laser trabeculostomy ====
Excimer laser trabeculostomy is a procedure which creates holes in the trabecular meshwork to reduce intraocular pressure by using a excimer laser. First developed in 1987, a 2020 review of 8 studies found the procedure reduced intraocular pressure by 20-40% and had generally positive outcomes.
== References == | Wikipedia/Minimally_invasive_glaucoma_surgery |
Indocyanine green angiography (ICGA) is a diagnostic procedure used to examine choroidal blood flow and associated pathology. Indocyanine green (ICG) is a water soluble cyanine dye which shows fluorescence in near-infrared (790–805 nm) range, with peak spectral absorption of 800-810 nm in blood. The near infrared light used in ICGA penetrates ocular pigments such as melanin and xanthophyll, as well as exudates and thin layers of sub-retinal vessels. Age-related macular degeneration is the third main cause of blindness worldwide, and it is the leading cause of blindness in industrialized countries. Indocyanine green angiography is widely used to study choroidal neovascularization in patients with exudative age-related macular degeneration. In nonexudative AMD, ICGA is used in classification of drusen and associated subretinal deposits.
== Indications ==
Indications for indocyanine green angiography include:
Choroidal neovascularisation (CNV): Indocyanine green angiography is widely used to study choroidal neovascularization in patients with exudative age-related macular degeneration. In ICGA, CNV is seen as hyperflourescent spot or plaque. It is also useful in diagnosing and classifying CNV associated to serous pigment epithelial detachments in Nonexudative macular degeneration.
Idiopathic polypoidal choroidal vasculopathy (IPCV)
Pigmented choroidal melanomas
Choroidal haemangioma: ICGA can be used to differentiate choroidal haemangioma from other intraocular tumors.
Choroiditis: In multifocal choroiditis, lesions are visualized as hypoflourescent spots.
Chorioretinopathy: In Central serous chorioretinopathy, using ICGA multifocal areas of choroidal hyperpermiability can be visualized. In birdshoot chorioretinopathy, lesions appear as symmetrical round or oval hypoflourescent spots. ICGA allows better visualization of lesions in serpiginous chorioretinopathy, punctate inner chorioretinopathy, acute zonal occult outer retinopathy etc. In multiple evanescent white dot syndrome, numerous hypoflourescent spots can be visualized using ICGA.
Pigmented epithelial detachment
Retinal angiomatous proliferation (RAP)
Chorioretinal atrophy: ICGA help evaluating different stages of chorioretinal atrophy.
Anterior uveitis: ICGA is rarely indicated in anterior uveitis, but it might be used to find out associated choroidal pathology.
Stargardt disease: Numerous hypoflourescent spots are seen in ICGA.
Angioid streaks: ICGA can be used for diagnosing angioid streaks and their associated ocular pathologies.
Vogt–Koyanagi–Harada disease (VKH): ICGA is useful in diagnosing VKH. In VKH, delay in filling of the choriocapillaris along with larger choroidal vessel perfusion and multiple hypofluorescent spots are visible with ICGA.
Sympathetic ophthalmia: Sympathetic ophthalmia is a bilateral, granulomatous form of uveitis. In sympathetic ophthalmia, numerous dark spots may be visible during the intermediate phase of ICGA.
Acute idiopathic blind spot enlargement syndrome, to detect hypofluorescent spots around the optic disc and arcades.
== Procedure ==
Fundus camera-based indocyanine green angiography techniques and scanning laser ophthalmoscope-based indocyanine green angiography techniques are there. The concentration of indocyanine green dye may vary according to instrument used. For fundus cameras, 25 ml ICG dissolved in 5 ml solvent is used, it may be increased to 50 ml in patients with poorly dilated pupil and high pigmentation. In case of iodine allergy, instead of ICG, iodine-free dye Infracyanine green should be used.
To perform test, pupil should be dilated. The dye is injected through the antecubital vein as bolus. Images are taken in several second intervals until the retinal and choroidal circulations are maximally hyperfluorescent. Then for first few minutes, take photos at approximately 30 to 60 second intervals. Pictures taken are classified under three phases:
Early phase at 60 seconds: large choroidal arteries and veins are highlighted in this phase.
Mid phase at 5–15 minutes: in this phase choroidal vasculature become less distinct and more diffuse, and hyperfluorescent lesions appear bright against the fading background.
Late phase at 15–30 minutes: in this phase hyperfluorescent lesions appear bright against the dark background. The choroidal neovascularization are best detected in this phase.
== Advantages over fluorescein angiography ==
Indocyanine green angiography has many advantages over commonly used fundus fluorescein angiography (FFA). Because of its protein-binding properties, its leakage from choriocapillaries is less and thus it will remain longer in choroidal vessels compared to fluorescein dye. Choroidal neovascularization is better visualized by ICGA, than fluorescein angiography. The patient toleration is also better compared to FFA.
== History ==
Physical and physiological properties of indocyanine green dye were first described by Fox and Wood, in 1960. Indocyanine green angiography was developed by Kodak Research Laboratories for determining cardiac output. In 1968, Kogure et al. performed intra-arterial choroidal absorption angiography using indocyanine green dye in monkeys. In the year 1969, using ICGA, Kogure and Choromokos studied cerebral circulation in a dog. In 1971, Hochhimer replaced color film with black and white infrared film. First human ICG angiogram was of carotid artery. First intravenous ICGA in human eye was performed by Flower and Hochheimer in 1972. In 1986 Hayashi et al. used infrared-sensitive video camera to perform ICGA. In the year 1992, Guyer et al. introduced the use of high resolution (1024 × 1024) digital imaging system coupled with infrared video cameras to produce better high resolution images.
== See also ==
Fundus photography
Fundus fluorescein angiography
Eye examination
== References == | Wikipedia/Indocyanine_green_angiography |
Electrodiagnosis (EDX) is a method of medical diagnosis that obtains information about diseases by passively recording the electrical activity of body parts (that is, their natural electrophysiology) or by measuring their response to external electrical stimuli (evoked potentials). The most widely used methods of recording spontaneous electrical activity are various forms of electrodiagnostic testing (electrography) such as electrocardiography (ECG), electroencephalography (EEG), and electromyography (EMG). Electrodiagnostic medicine (also EDX) is a medical subspecialty of neurology, clinical neurophysiology, cardiology, and physical medicine and rehabilitation. Electrodiagnostic physicians apply electrophysiologic techniques, including needle electromyography and nerve conduction studies to diagnose, evaluate, and treat people with impairments of the neurologic, neuromuscular, and/or muscular systems. The provision of a quality electrodiagnostic medical evaluation requires extensive scientific knowledge that includes anatomy and physiology of the peripheral nerves and muscles, the physics and biology of the electrical signals generated by muscle and nerve, the instrumentation used to process these signals, and techniques for clinical evaluation of diseases of the peripheral nerves and sensory pathways.
== Training ==
In the United States, neurologists receive training in performing needle electromyography and nerve conduction studies during a fellowship in clinical neurophysiology or neuromuscular medicine. Physical medicine and rehabilitation physicians receive this training during their residency. and can get further training in a neuromuscular fellowship. The American Board of Electrodiagnostic Medicine certifies US physicians in electrodiagnostic medicine. In Europe, nerve conduction studies and electromyography training may be part of neurology, physical medicine and rehabilitation, or clinical neurophysiology training. In the United States, there is also a certification in neuromuscular medicine. This certification is open only to neurologists and physical medicine and rehabilitation specialists that have completed a fellowship in neuromuscular medicine. The neuromuscular medicine examination includes electrodiagnostic testing as part of the certification examination but also includes broader topics such as genetics, biopsy, and rehabilitation. Technologists sometimes assist in the performance of the NCSs but not the interpretation. In the United States, the Current Procedural Terminology code of the American Medical Association, states ""Waveforms must be reviewed on site in real time..." In addition, it states that the "Reports must be prepared on site by the examiner, and consists of the work product of the interpretation of numerous test results...along with summarization of clinical and electrodiagnostic data, and physician or other qualified health care professional interpretation.
Patients will typically be referred to a specialist in electrodiagnostic medicine if they have numbness, tingling, pain, weakness or spasms. Common muscle and nerve disorders seen by these types of specialists include pinched nerves in the neck or back (radiculopathy), carpal tunnel syndrome, and neuropathies. More uncommon diseases include ALS, myasthenia gravis, and chronic inflammatory demyelinating polyneuropathy. Using their broader training, physicians in electrodiagnostic medicine, often perform more detailed evaluations which may include laboratory tests, CT or MRI scans, genetic evaluation, biopsy of nerve, skin, or muscle, or perform neuromuscular ultrasound. A more complete listing of disorders and testing can be found under neuromuscular medicine.
== Relationship to neurophysiology ==
Clinical neurophysiology, is a broader field that includes EEG, intraoperative monitoring, nerve conduction studies, EMG and evoked potentials. The American Board of Psychiatry and Neurology provides certification examination in clinical neurophysiology. The American Board of Electrodiagnostic Medicine provides certification in EDX medicines. The American Board of Clinical Neurophysiology certifies in electroencephalography (EEG), Evoked Potentials (EP), Polysomnography (PSG), Epilepsy Monitoring, and Neurologic Intraoperative Monitoring (NIOM). In the US physicians typically specialize in EEG or EDX medicine but not both.
== History ==
Electrodiagnostic medicine traces its origin back to a 1791 experiment by Luigi Galvani. Galvani depolarized frog leg muscles by using metal rods to make contact with the leg muscles. The development of the oscilloscope in 1897 significantly enhanced the ability of scientists to record signals from nerve and muscle. However, it was the needs of those with severe injuries during World War II that created the field of modern electrodiagnostic medicine. In the early 1950s, the first society dedicated to the development of this field, the AAEE, was founded in Chicago by a group of interested specialists in neurology and physical medicine and rehabilitation. James Golseth was instrumental in creating this organization. Over time, newer techniques, such as somatosensory evoked potentials, single fiber electromyography, autonomic testing, and neuromuscular ultrasound have evolved as useful complementary techniques to nerve conduction studies and elecytromyography, which remain the core of electrodiagnostic medicine.
== References ==
== Further reading ==
Electromyography and Neuromuscular Disorders: Clinical-Electrophysiologic Correlations (Expert Consult - Online and Print), 3e; December 5, 2012; David C. Preston, Barbara E. Shapiro OCLC 821857515.
McLean Course in Electrodiagnostic Medicine; August 4, 2010; Christopher J. Visco, Gary P. Chimes OCLC 726740636.
Electrodiagnosis in Diseases of Nerve and Muscle: Principles and Practice; September 9, 2013; Jun Kimura OCLC 793814205.
Essentials of Electrodiagnostic Medicine; September 17, 2013; William Campbell OCLC 858764627.
Electromyography in Clinical Practice: Clinical and Electrodiagnostic Aspects of Neuromuscular Disease, 3e: September 8, 1997; Michael J. Aminoff OCLC 472926408.
Neuromuscular Function and Disease: Basic, Clinical, and Electrodiagnostic Aspects, 2-Volume Set, 1st edition: April 30, 2002; William F. Brown, Charles F. Bolton OCLC 46873002.
== External links ==
American Association of Sensory Electrodiagnostic Medicine
American Association of Neuromuscular & Electrodiagnostic Medicine
Muscle & Nerve, ISSN 1097-4598 official journal of the AANEM | Wikipedia/Electrodiagnosis |
Glaucoma is a group of diseases affecting the optic nerve that results in vision loss and is frequently characterized by raised intraocular pressure (IOP). There are many glaucoma surgeries, and variations or combinations of those surgeries, that facilitate the escape of excess aqueous humor from the eye to lower intraocular pressure, and a few that lower IOP by decreasing the production of aqueous humor.
== Procedures that facilitate outflow of aqueous humor ==
=== Laser trabeculoplasty ===
A trabeculoplasty is a modification of the trabecular meshwork. Laser trabeculoplasty (LTP) is the application of a laser beam to burn areas of the trabecular meshwork, located near the base of the iris, to increase fluid outflow. LTP is used in the treatment of various open-angle glaucomas. The two types of laser trabeculoplasty are argon laser trabeculoplasty (ALT) and selective laser trabeculoplasty (SLT). As its name suggests, argon laser trabeculoplasty uses an argon laser to create tiny burns on the trabecular meshwork. Selective laser trabeculoplasty is newer technology that uses a Nd:YAG laser to target specific cells within the trabecular meshwork and create less thermal damage than ALT. SLT shows promise as a long-term treatment. In SLT a laser is used to selectively target the melanocytes in the trabecular meshwork. Though the mechanism by which SLT functions is not well understood, it has been shown in trials to be as effective as the older ALT. However, because SLT is performed using a laser with much lower power than ALT, it does not appear to affect the structure of the trabecular meshwork (based on electron microscopy) to the same extent, so retreatment may be possible if the effects from the original treatment should begin to wear off, although this has not been proven in clinical studies. ALT is repeatable to some extent with measurable results possible.
=== Iridotomy ===
An iridotomy involves making puncture-like openings through the iris without the removal of iris tissue. Performed either with standard surgical instruments or a laser, it is typically used to decrease intraocular pressure in patients with angle-closure glaucoma. A laser peripheral iridotomy (LPI) is the application of a laser beam to selectively burn a hole through the iris near its base. LPI may be performed with either an argon laser or Nd:YAG laser.
There is currently no sufficient evidence to show any benefit on the use of iridotomy versus no iridotomy to slow down visual field loss. This is based on analysing four studies with a sample of 3,086 eyes of 1,543 participants; iridotomy seems to improve gonioscopic findings, but does not show to be clinically significant.
=== Iridectomy ===
An iridectomy, also known as a corectomy or surgical iridectomy, involves the removal of a portion of iris tissue. A basal iridectomy is the removal of iris tissue from the far periphery, near the iris root; a peripheral iridectomy is the removal of iris tissue at the periphery; and a sector iridectomy is the removal of a wedge-shaped section of iris that extends from the pupil margin to the iris root, leaving a keyhole-shaped pupil.
=== Clear lens extraction ===
Clear lens extraction, a surgical procedure in which clear lens of the human eye is removed, may be used to reduce intraocular pressure in primary angle closure glaucoma. A study found that CLE is even more effective than laser peripheral iridotomy in patients with angle closure glaucoma.
=== Filtering procedures: penetrating vs. non-penetrating ===
Filtering surgeries are the mainstay of surgical treatment to control intraocular pressure. An anterior sclerotomy or sclerostomy is used to gain access to the inner layers of the eye in order to create a drainage channel from the anterior chamber to the external surface of the eye under the conjunctiva, allowing aqueous to seep into a bleb from which it is slowly absorbed. Filtering procedures are typically divided into either penetrating or non-penetrating types depending upon whether an intraoperative entry into the anterior chamber occurs.
==== Penetrating filtering surgeries ====
Penetrating filtering surgeries are further subdivided into guarded filtering procedures, also known as protected, subscleral, or partial thickness filtering procedures (in which the surgeon sutures a scleral flap over the sclerostomy site), and full thickness procedures. Trabeculectomy is a guarded filtering procedure that removes of part of the trabecular meshwork. Full thickness procedures include sclerectomy, posterior lip sclerectomy (in which the surgeon completely excises the sclera on the area of the sclerostomy), trephination, thermal sclerostomy (Scheie procedure), iridenclesis, and sclerostomy (including conventional sclerostomy and enzymatic sclerostomy).
Anterior chamber paracentesis is a penetrating surgical procedure done to reduce intraocular pressure of the eye.
==== Non-penetrating filtering surgeries ====
Non-penetrating filtering surgeries do not penetrate or enter the eye's anterior chamber. There are two types of non-penetrating surgeries: Bleb-forming and viscocanalostomy. Bleb forming procedures include ab externo trabeculectomy and deep sclerectomy. Ab externo trabeculectomy (AET) involves cutting from outside the eye inward to reach Schlemm's canal, the trabecular meshwork, and the anterior chamber. Also known as non-penetrating trabeculectomy (NPT), it is an ab externo (from the outside), major ocular procedure in which Schlemm's canal is surgically exposed by making a large and very deep scleral flap. The inner wall of Schlemm's canal is stripped off after surgically exposing the canal. Deep sclerectomy, also known as nonpenetrating deep sclerectomy (PDS) or nonpenetrating trabeculectomy, is a filtering surgery where the internal wall of Schlemm's canal is excised, allowing subconjunctival filtration without actually entering the anterior chamber. In order to prevent wound adhesion after deep scleral excision and maintain good filtering results, it is sometimes performed with a variety of biocompatible spacers or devices, such as the Aquaflow collagen wick, ologen Collagen Matrix, or Xenoplast glaucoma implant.
Viscocanalostomy is also an ab externo, major ocular procedure in which Schlemm's canal is surgically exposed by making a large and very deep scleral flap. In the VC procedure, Schlemm's canal is cannulated and viscoelastic substance injected (which dilates Schlemm's canal and the aqueous collector channels).
Surgical adjuvants
Where wound modulation is needed to prevent closure of surgically created drainage channels, adjuvants such as the ologen collagen matrix implants may be used to facilitate healthy tissue regeneration. Scar formation at the site of excision or operation may block aqueous humor circulation, while healthy tissue regeneration will keep newly created drainage channels functional.
=== Other surgical procedures ===
Goniotomy and trabeculotomy are similar simple and directed techniques of microsurgical dissection with mechanical disruption of the trabecular meshwork. Goniotomy procedures include surgical goniotomy and laser goniotomy. A surgical goniotomy involves cutting the fibers of the trabecular meshwork to allow aqueous fluid to flow more freely from the eye. Laser goniotomy is also known as goniophotoablation and laser trabecular ablation . In many patients with congenital glaucoma, the cornea is not clear enough to visualize the anterior chamber angle. Although an endoscopic goniotomy, which employs an endoscope to view the anterior chamber angle, may be performed, a trabeculotomy which accesses the angle from the exterior surface of the eye, thereby eliminating the need for a clear cornea, is usually preferred in these instances. A specially designed probe is used to tear through the trabecular meshwork to open it and allow fluid flow.
Tube-shunt surgery or drainage implant surgery involves the placement of a tube or glaucoma valves to facilitate aqueous outflow from the anterior chamber. Trabeculopuncture uses a Q switched Nd:YAG laser to punch small holes in the trabecular meshwork. Goniocurretage is an "ab interno" (from the inside) procedure that used an instrument "to scrape pathologically altered trabecular meshwork off the scleral sulcus". A surgical cyclodialysis is a rarely used procedure that aims to separate the ciliary body from the sclera to form a communication between the suprachoroidal space and the anterior chamber. A cyclogoniotomy is a surgical procedure for producing a cyclodialysis, in which the ciliary body is cut from its attachment at the scleral spur under gonioscopic control.
A ciliarotomy is a surgical division of the ciliary zone in the treatment of glaucoma.
=== Canaloplasty ===
Canaloplasty is a nonpenetrating procedure utilizing microcatheter technology. To perform a canaloplasty, an incision is made into the eye to gain access to Schlemm's canal in a similar fashion to a viscocanalostomy. A microcatheter will circumnavigate the canal around the iris, enlarging the main drainage channel and its smaller collector channels through the injection of a sterile, gel-like material called viscoelastic. The catheter is then removed and a suture is placed within the canal and tightened. By opening the canal, the pressure inside the eye can then be relieved. Canaloplasty has two main advantages of over more traditional glaucoma surgeries. The first of these advantages is an improved safety profile over trabeculectomy. As canaloplasty does not require the creation of a bleb, significant long-term risks such as infection and hypotony (extremely low eye pressure) are avoided. The second main advantage is that when combined with cataract surgery, the IOP is reduced even further than when done alone.
Long term (three year) results have been published both in the US and Europe demonstrating a significant and sustained reduction in both eye pressure and the number of glaucoma medications required for glaucoma control.
== Procedures that decrease production of aqueous humor ==
Certain cells within the eye's ciliary body produce aqueous humor. A ciliary destructive or cyclodestructive procedure is one that aims to destroy those cells in order to reduce intraocular pressure.
Cyclocryotherapy, or cyclocryopexy, uses a freezing probe. Cyclophotocoagulation, also known as transscleral cyclophotocoagulation, ciliary body ablation, cyclophotoablation, and cyclophototherapy, uses a laser.[1] Cyclodiathermy uses heat generated from a high frequency alternating electric current passed through the tissue, while cycloelectrolysis uses the chemical action caused by a direct current.
A systematic review seeking to assess the safety and effectiveness of diode transscleral cyclophotocoagulation found one study in Ghana comparing patients who received low-energy versus high-energy variations of the procedure to treat glaucoma. Overall, the review found that 47% of eyes treated with transscleral cytophotocoagulation saw an IOP decrease of at least 20%. There were no differences between the low-energy and high-energy variations of the procedure in all reported outcomes, such as IOP control, and number of medications used after treatment. Another Cochrane Systematic Review explored whether cyclodestructive procedures are better than other glaucoma treatments for the treatment of refractory glaucoma; however, the evidence was inconclusive.
== See also ==
Minimally invasive glaucoma surgery
== References == | Wikipedia/Glaucoma_surgery |
Manual small incision cataract surgery (MSICS) is an evolution of extracapsular cataract extraction (ECCE); the lens is removed from the eye through a self-sealing scleral tunnel wound. A well-constructed scleral tunnel is held closed by internal pressure, is watertight, and does not require suturing. The wound is relatively smaller than that in ECCE but is still markedly larger than a phacoemulsification wound. Comparative trials of MSICS against phaco in dense cataracts have found no statistically significant difference in outcomes but MSICS had shorter operating times and significantly lower costs. MSICS has become the method of choice in the developing world because it provides high-quality outcomes with less surgically induced astigmatism than ECCE, no suture-related problems, quick rehabilitation, and fewer post-operative visits. MSICS is easy and fast to learn for the surgeon, cost effective, simple, and applicable to almost all types of cataract.
== Description ==
MSICS is a procedure that was developed to reduce costs in comparison with phacoemulsification, which requires expensive high-tech equipment that needs skilled maintenance, and is relatively unsuited to less developed regions, and to eliminate the need for suturing the incision, by using a self-sealing incision. This reduces operating time, and for some geometries of incision, considerably reduces surgery induced astigmatism, or induces a reduction in pre-surgery astigmatism. The procedure is fast, economical, effective, and produces results statistically similar to phaco surgery. It is extensively used in less developed countries and regions, with good outcomes.
== Contraindications ==
The same general contraindications for cataract surgery apply. Specific contraindications for MSICS include hard or dense cataracts where the nucleus is too large for the MSICS incision; and in cases where the nucleus is found to be deformed on a nanophthalmic (very small) eye.
== Preparation and precautions ==
Preparation may begin three-to-seven days before surgery with the preoperative application of NSAIDs and antibiotic eye drops. The pupil is dilated using drops if the IOL is to be placed behind the iris to help better visualise the cataract and for easier access.
=== Anaesthesia ===
Anaesthesia may be placed topically as eyedrops or injected next to (peribulbar) or behind (retrobulbar) the eye or sub-tenons. Local anaesthetic nerve blocking has been recommended to facilitate surgery. Topical anaesthetics may be used at the same time as an intracameral lidocaine injection to reduce pain during the operation. Oral or intravenous sedation may also be used to reduce anxiety. General anaesthesia is rarely necessary but may be used for children and adults with medical or psychiatric issues affecting their ability to remain still during the procedure.
=== Site preparation ===
The operation may occur on a stretcher or a reclining examination chair. The eyelids and surrounding skin are swabbed with a disinfectant, such as 10% povidone-iodine, and topical povidone-iodine is put in the eye. The face is covered with a cloth or sheet with an opening for the operative eye. The eyelid is held open with a speculum to minimize blinking during surgery. Pain is usually minimal in properly anaesthetised eyes, though a pressure sensation and discomfort from the bright operating microscope light is common. Bridle sutures may be used to help to stabilize the eyeball during sclerocorneal tunnel incision, and during extraction of the nucleus and epinucleus through the tunnel.
== Surgical technique ==
A defining characteristic of this technique is in the incision made for access to the cataract, which is smaller than for ECCE, and larger than for phacoemulsification, but like phaco, the wound is self sealing due to its geometry.
=== Incision ===
The small incision into the anterior chamber of the eye is made at or near the corneal limbus, where the cornea and sclera meet, either superior or temporal. Advantages of the smaller incision include use of few-or-no stitches and shortened recovery time. The "small" incision is small in comparison with the earlier ECCE incision but considerably larger than the phaco incision. The precise geometry of the incision is important as it affects the self-sealing of the wound and the amount of astigmatism caused by distortion of the cornea during healing. A sclerocorneal or scleral tunnel incision is commonly used, which reduces induced astigmatism if suitably formed. A sclerocorneal tunnel, a three-phase incision, starts with a shallow incision perpendicular to the sclera, followed by an incision through the sclera and cornea approximately parallel to the outer surface, and then a beveled incision into the anterior chamber. This structure provides the self-sealing characteristic because internal pressure presses together the faces of the incision.
==== Incision geometries and their characteristics ====
The incision provides access to the interior of the anterior chanber for access to the lens, a passage for removal of the lens, and a passage for insertion of the IOL. The primary characteristic of scleral tunnel incisions is self sealing, which is a consequence of the location relative to the limbus, and the shape of the wound, which also influences the post operative astigmatism.
The characteristics of an incision that is reliably self-sealing include:
Approximately square incisional geometry – the length and width of the incision surfaces are roughly equal,
The external incision opening is narrower than the internal opening with a tunnel that flares between them,
An external incision shape that allows some stretch,
The incision must extent at least a millimetre into the cornea, and follow the curve of the edge of the cornea.
The size of the incision, i.e. the straight line distance between the ends of the external opening, is determined primarily by the expected size of the nucleus, and secondarily by the size of the IOL, and is usually between 5 and 8 mm. The distance between the outer opening of the tunnel and the inner opening should be at least 4 mm for a good seal. The shape of the outer opening may be straight or curved, and will affect astigmatism and the tendency for wound edge separation. A small flap of the conjunctiva is folded back before making the initial incision perpendicular to the sclera.
The "frown" form is a curve with the ends further from the limbus than the middle, and has a lesser tendency to induce astigmatism or separate on the outside edge.
A straight incision follows a great circle route across the sclera, with the ends equidistant from the edge of the cornea. This induces moderate astigmatism.
Blumenthal side cuts are short cuts at the ends of a straight incision which angle obliquely away from the cornea. This induces minimal astigmatism and is used for a wide tunnel.
A "smile" incision is parallel to the edge of the cornea. It is an easy incision but induces more astigmatism and is more prone to separation.
The "chevron" incision is much like the frown but comprises two straight lines of equal length. This shape induces minimal astigmatism.
The tunnel extends from the scleral incision approximately parallel to the outer surface, and slightly deeper than half the thickness of the sclera, and should extend at least a millimetre into the cornea. The inner edge should follow the curve of the corneal edge.
As the incision heals, the meridian along which the wound is centered tends to progressively flatten, which may continue for up to 3 weeks until healing is complete. The geometry of the incision may be chosen to permanently reduce pre-operative refractive error, or maintain original cornea shape.
=== Maintaining the eye shape ===
The depth of the anterior chamber and position of the posterior capsule may be maintained during surgery by OVDs or an anterior chamber maintainer, which is an auxiliary cannula providing a sufficient flow of BSS to maintain the stability of the shape of the chamber and internal pressure.
=== Capsulorhexis ===
Using an instrument called a cystotome, an anterior capsulotomy, also known as a cystotomy, is made to open the front surface of the lens capsule , giving access to the lens. The continuous curvilinear capsulorhexis technique is in common use, and is preferred as it produces a tougher edge without stress raisers and is less likely to tear further during the procedure. A posterior capsulotomy is an opening of the back portion of the lens capsule, which is not usually necessary or desirable unless it has opacified. The types of capsular openings commonly used in MSICS are the continuous curvilinear capsulorhexis, the can-opener capsulotomy, and the envelope capsulotomy.
=== Extraction of the lens ===
The cataract is removed from the capsule and anterior chamber using hydroexpression viscoexpression, or more-direct mechanical methods.
The extraction of the cataract must be done with due care so as not to compromise the integrity of the tunnel; the endothelium and capsule are also vulnerable to injury. Bisection, trisection and fragmentation into more pieces is possible, but all must be removed. The pressure in the eye can be maintained at the desired level by using an anterior chamber maintainer, or may be allowed to drop to ambient atmospheric pressure. Larger well-structured tunnels and larger capsulorhexis are acceptable to allow better control of the surgery.
Various methods may be used:
Management with irrigating vectis:
Hydrodissection is performed until a part of the nucleus prolapses into the anterior chamber, or the surgeon hooks and lifts the nucleus edge, and rotates it until it prolapses into the anterior chamber. The nucleus is then removed through the tunnel using an irrigating vectis. Viscoelastic is injected above and below the nucleus to protect the endothelium. A bridle suture is used to steady the globe. The irrigating vectis is inserted under the nucleus, then withdrawn towards the tunnel until the nucleus starts to enter the tunnel. At this point BSS is injected into the chamber through the vectis to provide pressure to expel the nucleus while the vectis is withdrawn with it. An iris spatula may be used in the sandwich technique, where the spatula is used to hold the nucleus against the vectis.
Alternatively, the nucleus may be guided out of the eye through the tunnel with the help of a Sheet's glide, and pushed out by internal pressure induced by adding saline from the anterior chamber maintainer or injecting viscoelastic into the chamber.
The nucleus may be broken into a few pieces to aid removal, or removed in one piece.
Phacosection is the division of the nucleus into two or three narrower parts. This avoids stretching the tunnel and thereby reduces surgically induced astigmatism and possible damage to the endothelium. The epinucleus and most of the cortex are divided and removed along with the nucleus.
Preparation for phacosection is by hydrodissection to separate the cortex from the capsule, but hydrodelineation is not done and the entire lens is carefully released from the capsule and removed into the anterior chamber through the capsulorhexis opening, avoiding stress on the zonules. The lens is then divided into narrower sections by any one of several possible methods, and the sections are then extracted individually. The epinucleus and most of the cortex remain attached to the nucleus, and get removed with it during these maneuvers.
=== Prosthetic lens insertion ===
Following cataract removal, an IOL is usually inserted into the posterior capsule. When the posterior capsule is damaged, the IOL may be inserted into the ciliary sulcus, or a glued intraocular lens technique may be applied. It is economical to use a rigid IOL if the incision size is already over 6 mm wide, but foldable IOLs can also be used if cost is not a limiting factor or incision size is <5 mm.
=== Removal of OVDs ===
After the IOL is inserted, ophthalmic viscosurgical devices are aspirated or flushed out and replaced with BSS. Residues of OVDs can cause raised intraocular pressure (IOP) by blocking the trabecular meshwork until they dissipate. IOP spikes can cause damage to the optic nerve and visual disturbances in patients with glaucoma. Postoperative endophthalmitis is also associated with OVD residue.
=== Wound sealing ===
The surgeon checks the incision does not leak fluid because wound leakage increases the risk of microorganisms gaining access into the eye and predisposing it to endophthalmitis. An antibiotic/steroid combination eye drop is put in, and an eye shield may be applied, sometimes supplemented with an eye patch. A well constructed scleral tunnel should be self-sealing, but if it does not seal sufficiently, one or more sutures will be added.
=== Contingency procedures ===
A change from MSICS to ECCE is appropriate when the nucleus is too large for the MSICS incision; and in cases where the nucleus is found to be deformed during MSICS on a nanophthalmic (very small) eye.
== Complications ==
Complications can develop during and after surgery.
=== During surgery ===
Posterior capsular rupture, a tear in the posterior capsule of the natural lens, is the most-common complication during cataract surgery. Posterior capsule rupture can cause lens fragments to be retained, corneal oedema, and cystoid macular oedema; it is also associated with increased risk of endophthalmitis and retinal detachment. It may make it necessary to place the IOL outside the capsular bag.
Suprachoroidal hemorrhage is a rare complication.
Intraoperative floppy iris syndrome has an incidence of around 0.5% to 2.0%. Iris or ciliary body injury has an incidence of about 0.6%-1.2%. In the event of a posterior capsule rupture, fragments of the nucleus can find their way through the tear into the vitreous chamber; this is called posterior dislocation of nuclear fragments.
=== After surgery ===
Complications after cataract surgery are relatively uncommon. Posterior vitreous detachment (PVD) may occur but does not directly threaten vision.
Some people develop a posterior capsular opacification (PCO), also called an after-cataract. This may compromise visual acuity, and can usually be safely and painlessly corrected using a laser. to create a clear central visual axis.
Patients who have had cataract surgery are at an increased risk of developing rhegmatogenous retinal detachment (RRD)—the most-common form of retinal detachment. Toxic anterior segment syndrome (TASS), a non-infectious inflammatory condition, may occur following cataract surgery.
Endophthalmitis is a serious infection of the intraocular tissues, usually following intraocular surgery complications or penetrating trauma, and one of the most-severe. It is rare in cataract surgery due to the use of prophylactic antibiotics. Hypopyon occurs about 80% of the time.
Glaucoma may occur and may be very difficult to control. It is usually associated with inflammation, especially when small fragments or chunks of the nucleus access the vitreous cavity.
Mechanical pupillary block can occur when contact between the edge of the pupil and an adjacent structure blocks the flow of aqueous through the pupil. This is more frequent as a complication of anterior chamber intraocular lens implantation, but has been known to occasionally occur with posterior IOL implantation.
Swelling of the macula, the central part of the retina, results in macular oedema and can occur a few days or weeks after surgery. Most such cases can be successfully treated. Uveitis–glaucoma–hyphema syndrome is a complication caused by the mechanical irritation of a mis-positioned IOL over the iris, ciliary body or iridocorneal angle.
Other possible complications include Elevated intraocular pressure; swelling or oedema of the cornea; displacement or dislocation of the IOL implant (rare); unplanned high refractive error—either myopic or hypermetropic—due to error in the ultrasonic biometry (measurement of the eye length and calculation of the required intraocular lens power); cyanopsia, in which the patient's vision is tinted blue and often occurs for a few days, weeks or months after removal of a cataract; and floaters, which commonly appear after surgery.
== Recovery and rehabilitation ==
Following cataract surgery, side-effects such as grittiness, watering, blurred vision, double vision or a red or bloodshot eye may occur, and will usually clear after a few days. Full recovery can take four-to-six weeks. Patients are usually advised to avoid getting water in the eye during the first week after surgery, and to avoid swimming for two-to-three weeks as a conservative approach, to minimise risk of bacterial infection. Patients should avoid driving for at least 24 hours after the surgery, largely due to effects from the anaesthesia, possible swelling affecting focus, and pupil dilation causing excessive glare. At the first post-operative check, the surgeon will usually assess whether vision is suitable for driving.
After surgery, to prevent contamination, the eyes should not be rubbed and the use of eye makeup, face cream or lotions should be avoided. Excessive dust, wind, pollen or dirt should also be avoided. Sunglasses should be worn on bright days because the eyes will be more sensitive to bright light for a while.
Topical anti-inflammatory drugs and antibiotics are commonly used in the form of eye-drops to reduce the risk of inflammation and infection. A shield or eye-patch may be prescribed to protect the eye while sleeping. The eye will be checked to ensure the IOL remains in place, and once it has fully stabilised, after about six weeks, vision tests will be used to check whether prescription lenses are needed. Where the focal length of the IOL is optimised for distance vision, reading glasses will generally be needed for near focus. The patient should not participate in contact or extreme sports or similar activities until cleared to do so by the eye surgeon.
== Outcomes ==
After full recovery, visual acuity depends on the underlying condition of the eye, the choice of IOL, and any long-term complications associated with the surgery. More than 90% of operations are successful in restoring useful vision, with a low complication rate.
== History ==
MSICS was a later development in cataract surgery after phacoemulsification was already established. It is a technique which does not rely on high tech and expensive equipment, and is not much used in Western countries. In developing countries where cost is a more significant factor in limiting access to medical support, and the necessary maintenance for phaco equimpment may not be available or convenient, MSICS is a cost-effective alternative with comparable outcomes.
Self-sealing cataract incisions were mentioned by R. P. Kratz et al. in 1980 and by L. J. Girard in 1984. Kratz described the tunnel as an astigmatically neutral way of accessing the anterior chamber. In 1984, B. H. Thrasher et al. showed that incision position relative to the limbus has a strong effect on surgically induced astigmatism, as a 9 mm posterior incision induces less astigmatism than a 6 mm limbal incision.
In 1987, M. Blumenthal and J. Moissiev described the use of the anterior chamber maintainer (ACM) in ECCE, which combined with a reduction in incision size can keep the eye at a normal internal pressure during surgery.
In 1990, Michael McFarland developed a sutureless incision geometry, and S. L. Pallin described a chevron shaped incision for sutureless closure. In 1991, J. A. Singer described the "frown" incision as a way to minimise asigmatism when using a rigid IOL.
In 1999, S. Ruit et al. described a technique using a 6.5–7 mm temporal scleral tunnel with a straight incision 2 mm from the limbus. A V-shaped capsulorhexis was followed by hydrodissection, and the nucleus was delivered by viscoexpression. The cortical residue was aspirated and an IOL was implanted in the capsular bag.
Around 2009 P. Kosakarn developed a technique of manual phacofragmentation called double-nylon loop, by which the lens is divided into three pieces so that the incision can be smaller and sutureless, and which allows implantation of foldable IOL to be implanted.
K.P. Malik et al. modified the MSICS technique c2016 by a continuous infusion of 2% hydroxymethyl cellulose through the AC maintainer during nuclear delivery to prevent corneal endothelial cell loss.
== See also ==
Medicine portal
Africa Cataract Project
Eye surgery – Surgery performed on the eye or its adnexa
Himalayan Cataract Project – U.S. nonprofit organization
IOLVIP – Intraocular lens system to compensate for macular degeneration
Ophthalmology – Field of medicine treating eye disorders
Phacoemulsification – Method of cataract surgery
== Notes ==
== References == | Wikipedia/Manual_small_incision_cataract_surgery |
The Heidelberg Retinal Tomography is a diagnostic procedure used in ophthalmology. The Heidelberg Retina Tomograph (HRT) is an ophthalmological confocal point scanning laser ophthalmoscope for examining the cornea and certain areas of the retina using different diagnostic modules (HRT retina, HRT cornea, HRT glaucoma). However, the most widely used area of application for HRT is the inspection of the optic nerve head (papilla) for early detection and follow-up of glaucoma. The procedure has established itself as an integral part of routine glaucoma diagnostics alongside the visual field examination (perimetry), the chamber angle examination (gonioscopy) and the measurement of intraocular pressure (tonometry). The HRT is the most widely used application of confocal scanning laser ophthalmoscopy.
== Principle ==
It is based on the principle of spot illumination and spot detection. The optic nerve and retina are illuminated through a single pinhole, and the light returning from the area of interest results in a 2D image. from a series of 2D images, a 3D image is made.
== Advantages and disadvantages ==
Its advantages include rapid image acquisition without the need for pupillary dilation, three-dimensional topographic representation of the optic nerve head, advanced data analysis capabilities built into the machine, and the ability to provide accurate data analysis over time. Also, the technology of HRT is very accurate and test-retest variability is very low. Another important advantage is that it is more comfortable for the patient as the laser only illuminates the area of interest with a low light intensity and short duration (1.6 seconds).
It is necessary to use a reference plane, drawing the contour line depends on the examiner (this is difficult in many eyes where the edge of the disc is not clearly visible), the sensitivity and accuracy decreases in large eyes with myopic changes, and the pulsation of blood vessels may cause deviations in measurements. Changes in intraocular pressure may also affect HRT measurements. These are main disadvantages of HRT.
== Glaucoma Diagnosis ==
During the examination, a laser beam passes through the pupil opening onto the back of the eye and scans the optic nerve head and the retina. A three-dimensional image is generated from several tens of thousands of measuring points, which allows a quantitative assessment of all relevant anatomical structures:
disc cup (shape, asymmetry),
neuroretinal rim (area and volume) and
peripapillary retinal nerve fiber layer (retinal surface height variation, thickness, asymmetry).
These stereometric parameters are compared with extensive databases and thus enable the eye to be classified taking into account the individual papillae size and the patient's age. Two independent classification methods based on different approaches are available.
== See also ==
Fundus photography
Fundus fluorescein angiography
Eye examination
== Bibliography ==
Friedrich E. Kruse, Reinhard O. Burk, Hans E. Völcker, Gerhard Zinser, Ulrich Harbarth (1989). "Reproducibility of topographic measurements of the optic nerve head with laser tomographic scanning". Ophthalmology. 96 (9): 1320–1324. doi:10.1016/S0161-6420(89)32719-9. PMID 2780001.{{cite journal}}: CS1 maint: multiple names: authors list (link)
Reinhard O. W. Burk, Klaus Rohrschneider, Friedrich E. Kruse, Hans E. Völcker (1990). "Glaucoma. Diagnostics and Therapy". laser scanning tomography of the papilla. Stuttgart: Enke. pp. 113–119. ISBN 3-432-98691-2.{{cite book}}: CS1 maint: multiple names: authors list (link)
P. Janknecht, J. Funk (1994). "Optic nerve head analyzer and Heidelberg retina tomograph: accuracy and reproducibility of topographic measurements in a model eye and in volunteers". British Journal of Ophthalmology. 78 (10): 760–768. doi:10.1136/bjo.78.10.760. PMC 504930. PMID 7803352.
Ville Saarela, P. Juhani Airaksinen (2008). "Heidelberg retina tomograph parameters of the optic disc in eyes with progressive retinal nerve fiber layer defects". Acta Ophthalmologica. 86 (6): 603–608. doi:10.1111/j.1600-0420.2007.01119.x. PMID 18752515. S2CID 7590532.
M. Durmus, R Karadag, M Erdurmus, Y Totan, I Feyzi Hepsen (2009). "Assessment of cup-to-disc ratio with slit-lamp funduscopy, Heidelberg Retina Tomography II, and stereoscopic photos". European Journal of Ophthalmology. 19 (1): 55–60. doi:10.1177/112067210901900108. PMID 19123149. S2CID 23439646.{{cite journal}}: CS1 maint: multiple names: authors list (link)
Albert J. Augustin: Augenheilkunde (Ophthalmology). 3rd, completely revised and expanded edition. Springer, Berlin 2007, ISBN 978-3-540-30454-8, p. 961.
== References == | Wikipedia/Heidelberg_Retinal_Tomography |
Botulinum toxin therapy of strabismus is a medical technique used sometimes in the management of strabismus, in which botulinum toxin is injected into selected extraocular muscles in order to reduce the misalignment of the eyes. The injection of the toxin to treat strabismus, reported upon in 1981, is considered to be the first ever use of botulinum toxin for therapeutic purposes. Today, the injection of botulinum toxin into the muscles that surround the eyes is one of the available options in the management of strabismus. Other options for strabismus management are vision therapy and occlusion therapy, corrective glasses (or contact lenses) and prism glasses, and strabismus surgery.
The effects that are due only to the toxin itself (including the side effects) generally wear off within 3 to 4 months. In contrast, improvements in alignment may be long-lasting, particularly in two circumstances. First, if the "antagonist" muscle (the muscle pulling in the opposite direction) is active, the injected muscle will be stretched, and may permanently lengthen by adding tissue during the period of toxin paresis.https://beautybyzizi.com/understanding-botulinum-toxin/ Second, if binocular vision has been achieved and stabilized, alignment may "lock in". There are indications that botulinum toxin therapy is as successful as strabismus surgery for patients with binocular vision and that it is less successful than surgery for those who have no binocular vision.
== Principle ==
Botulinum toxin is the most acutely lethal toxin that is known. It is produced by the bacterium clostridium botulinum. It acts inside nerve terminals by decreasing the release of acetylcholine, blocking neuromuscular transmission and thereby causing flaccid muscular paralysis. As a result, the muscle is weakened for about 3 to 4 months.
For treating strabismus, the toxin is used in much diluted form, and the injection is targeted to reach specific muscles that move the eye, thereby temporarily weakening the selected muscles.
== Technique ==
=== Injection ===
After local or general anaesthesia has been applied, the botulinum toxin is injected directly into the selected eye muscles using a specially designed needle electrode that is connected to an electromyography (EMG) apparatus as well as to a syringe containing the botulinum toxin solution.
When under local anaesthesia, the patient is asked to move the eyes just before the toxin is injected. This results in an EMG signal which provides instant feedback on the correct placement of the needle. If the patient is a young child, general anaesthesia is always used.
The duration of the intervention is one to two minutes if the person performing the procedure has sufficient experience.
=== Dosage ===
The dosage to be used cannot be determined with precision, as no reliable relation between dose and effect could be established so far. The toxicity of botulinum toxin varies from one lot to the next; furthermore, the body may show an immunoreaction by which the efficacy of subsequent treatments is reduced.
== Clinical use ==
Botulinum toxin is considered as an alternative to surgery in certain clinical situations. A study performed in the 1980s found outcomes of surgery to be "more predictable and longer lasting" than those of botulinum toxin therapy. As stated in a review article of 2007, its use for strabismus "varies enormously in different cities and countries for no apparent reason."
In a small-scale study, adults whose reading difficulties due to convergence insufficiency had been unsuccessfully addressed by convergence exercises, base-in prism glasses or strabismus surgery showed improved reading after botulinum toxin therapy, maintaining improved reading remaining also after six months.
=== Use as primary therapy ===
Botulinum toxin is considered a useful alternative to surgery in particular cases, for example for persons unfit for general anaesthesia, in evolving or unstable clinical conditions, after unsuccessful surgery, or to provide short-term relief from diplopia.
For patients who have had healthy vision heretofore until a small, horizontal deviation set in suddenly, the injection of botulinum toxin may allow them to maintain the binocular vision skills that had been acquired earlier.
Some consider botulinum injections to be a treatment option for children with small- to moderate-angle infantile esotropia. Studies have provided indications that performing injections into both medial rectus muscles may be more effective than an injection into one medial rectus muscle alone.
Botulinum toxin therapy has been reported to be similarly successful as strabismus surgery for patients with binocular vision and less successful than surgery for those who have no binocular vision. One study found that botulinum toxin therapy had similar long-term success rates for treating infantile esotropia with botulinum toxin A before the age of 12 months as would have been expected from strabismus surgery. Another study reported similar long-term success rates for infantile esotropia treated before 24 months of age by either strabismus surgery or botulinum toxin treatment.
=== Intra- and postoperational use ===
Botulinum toxin has also been used postoperatively for improving the alignment in patients with over- or undercorrection after strabismus surgery, leading to rapid elimination of postoperative diplopia but possibly requiring repeated injections or reoperation later on. It is considered particularly useful for patients who have the potential for binocular vision; success rates are higher for treating postoperative esotropia than for treating postoperative exotropia.
It has also been employed in combination with strabismus surgery in cases in which there is a large horizontal eye deviation and eye muscle surgery on both eyes (binocular surgery) is not an option for other reasons.
== Side effects ==
The most common side effects are droopy eyelids (ptosis) and over- or undercorrections; further common side effects are diplopia and inadvertent vertical deviation (hypo- or hypertropia). The side effects typically resolve in 3–4 months.
Vision-threatening complications are rare, and the intervention is generally considered safe, also when performed repeatedly.
== Bupivacaine ==
It is also under investigation whether the injection of bupivacaine into extraocular muscles is of possible therapeutic use for treating some forms of strabismus, be it alone or in combination with botulinum toxin.
Bupivacaine is a local anaesthetic known to cause considerable myotoxicity and neurotoxicity. Its injection into muscle tissue leads to a dramatic degeneration of muscle fibres accompanied by a moderate inflammatory response. It subsequently leads to a thickening and strengthening of the muscle. The thickening of bupivacaine-injected extraocular muscle has been demonstrated by means of magnetic resonance imaging and by means of ultrasonography.
Bupivacaine injection is therefore being investigated as a further possibility in the treatment of strabismus. In some interventions bupivacaine has been used alone. In others, a botulinum toxin injection into an extraocular muscle is accompanied by a bupivacaine injection into the antagonist muscle.
== History ==
Alan B. Scott first injected botulinum toxin into extraocular muscles in the early 1970s and published his results in 1981, giving rise to a wide scope of clinical research on the use of the toxin.
The effect of bupivaine injection on extraocular muscles was first known as causing postsurgical strabismus as a complication of cataract surgery due to the myotoxicity of the local anaesthetic drug bupivaine when inadvertently injected into an extraocular muscle.
== References ==
== Further reading ==
Reassessing Botulinum Toxin for Childhood Strabismus (Gabrielle Weiner interviewing Alejandra de Alba Campomanes, David G. Hunter, and Gregg T. Lueder), Clinical Update: Pediatrics, EyeNet Magazine, August 2012 (American Academy of Ophthalmology) | Wikipedia/Botulinum_toxin_therapy_of_strabismus |
The lens, or crystalline lens, is a transparent biconvex structure in most land vertebrate eyes. Relatively long, thin fiber cells make up the majority of the lens. These cells vary in architecture and are arranged in concentric layers. New layers of cells are recruited from a thin epithelium at the front of the lens, just below the basement membrane surrounding the lens. As a result the vertebrate lens grows throughout life. The surrounding lens membrane referred to as the lens capsule also grows in a systematic way, ensuring the lens maintains an optically suitable shape in concert with the underlying fiber cells. Thousands of suspensory ligaments are embedded into the capsule at its largest diameter which suspend the lens within the eye. Most of these lens structures are derived from the epithelium of the embryo before birth.
Along with the cornea, aqueous, and vitreous humours, the lens refracts light, focusing it onto the retina. In many land animals the shape of the lens can be altered, effectively changing the focal length of the eye, enabling them to focus on objects at various distances. This adjustment of the lens is known as accommodation (see also below). In many fully aquatic vertebrates, such as fish, other methods of accommodation are used, such as changing the lens's position relative to the retina rather than changing the shape of the lens. Accommodation is analogous to the focusing of a photographic camera via changing its lenses. In land vertebrates the lens is flatter on its anterior side than on its posterior side, while in fish the lens is often close to spherical.
Accommodation in humans is well studied and allows artificial means of supplementing our focus, such as glasses, for correction of sight as we age. The refractive power of a younger human lens in its natural environment is approximately 18 dioptres, roughly one-third of the eye's total power of about 60 dioptres. By 25 years of age the ability of the lens to alter the light path has reduced to 10 dioptres and accommodation continues to decline with age.
== Structure ==
=== Position in the eye ===
The lens is located towards the front part of the vertebrate eye, called the anterior segment, which includes the cornea and iris positioned in front of the lens. The lens is held in place by the suspensory ligaments (Zonule of Zinn), attaching the lens at its equator to the rest of the eye through the ciliary body. Behind the lens is the jelly-like vitreous body which helps hold the lens in place. At the front of the lens is the liquid aqueous humor which bathes the lens with nutrients and other things. Land vertebrate lenses usually have an ellipsoid, biconvex shape. The front surface is less curved than the back. In a human adult, the lens is typically about 10mm in diameter and 4mm thick, though its shape changes with accommodation and its size grows throughout a person's lifetime.
=== Anatomy ===
The lens has three main parts: the lens capsule, the lens epithelium, and the lens fibers. The lens capsule is a relatively thick basement membrane forming the outermost layer of the lens. Inside the capsule, much thinner lens fibers form the bulk of the lens. The cells of the lens epithelium form a thin layer between the lens capsule and the outermost layer of lens fibers at the front of the lens but not the back. The lens itself lacks nerves, blood vessels, or connective tissue. Anatomists will often refer to positions of structures in the lens by describing it like a globe of the world. The front and back of the lens are referred to as the anterior and posterior "poles", like the North and South poles. The "equator" is the outer edge of the lens often hidden by the iris and is the area of most cell differentiation. As the equator is not generally in the light path of the eye, the structures involved with metabolic activity avoid scattering light that would otherwise affect vision.
==== Lens capsule ====
The lens capsule is a smooth, transparent basement membrane that completely surrounds the lens. The capsule is elastic and its main structural component is collagen. It is presumed to be synthesized by the lens epithelium and its main components in order of abundance are heparan sulfate proteoglycan (sulfated glycosaminoglycans (GAGs)), entactin, type IV collagen and laminin. The capsule is very elastic and so allows the lens to assume a more spherical shape when the tension of the suspensory ligaments is reduced. The human capsule varies from 2 to 28 micrometres in thickness, being thickest near the equator (peri-equatorial region) and generally thinner near the posterior pole.
The photos from electron and light microscopes show an area of the capsule lens equator where the capsule grows and adjacent to where thousands of suspensory ligaments attach. Attachment must be strong enough to stop the ligaments being detached from the lens capsule. Forces are generated from holding the lens in place and the forces added to during focusing. While the capsule is thinnest at the equator where its area is increasing, the anterior and posterior capsule is thinner than the area of ligament attachment.
==== Lens epithelium ====
The lens epithelium is a single layer of cells at the front of the lens between the lens capsule and the lens fibers. By providing the lens fibers with nutrients and removing waste, the cells of the epithelium maintain lens homeostasis. As ions, nutrients, and liquid enter the lens from the aqueous humor, Na+/K+-ATPase pumps in the lens epithelial cells pump ions out of the lens to maintain appropriate lens osmotic concentration and volume, with equatorially positioned lens epithelium cells contributing most to this current. The activity of the Na+/K+-ATPases keeps water and current flowing through the lens from the poles and exiting through the equatorial regions.
The cells of the lens epithelium also divide into new lens fibers at the lens equator. The lens lays down fibers from when it first forms in embryo until death.
==== Lens fibers ====
The lens fibers form the bulk of the lens. They are long, thin, transparent cells, firmly packed, with diameters typically 4–7 micrometres and lengths of up to 12mm long in humans. The lens fibers stretch lengthwise from the posterior to the anterior poles and, when cut horizontally, are arranged in concentric layers rather like the layers of an onion. If cut along the equator, cells have a hexagonal cross section, appearing as a honeycomb. The approximate middle of each fiber lies around the equator. These tightly packed layers of lens fibers are referred to as laminae. The lens fiber cytoplasms are linked together via gap junctions, intercellular bridges and interdigitations of the cells that resemble "ball and socket" forms.
The lens is split into regions depending on the age of the lens fibers of a particular layer. Moving outwards from the central, oldest layer, the lens is split into an embryonic nucleus, the fetal nucleus, the adult nucleus, the inner and outer cortex. New lens fibers, generated from the lens epithelium, are added to the outer cortex. Mature lens fibers have no organelles or nuclei.
==== Cell fusion, voids and vacuoles ====
With the advent of other ways of looking at cellular structures of lenses while still in the living animal it became apparent that regions of fiber cells, at least at the lens anterior, contain large voids and vacuoles. These are speculated to be involved in lens transport systems linking the surface of the lens to deeper regions. Very similar looking structures also indicate cell fusion in the lens. The cell fusion is shown by micro-injection to form a stratified syncytium in whole lens cultures.
=== Development ===
Development of the vertebrate lens begins when the human embryo is about 4mm long. The accompanying picture shows the process in a more easily studied chicken embryo. Unlike the rest of the eye which is derived mostly from the inner embryo layers, the lens is derived from the skin around the embryo. The first stage of lens formation takes place when a sphere of cells formed by budding of the inner embryo layers comes close to the embyro's outer skin. The sphere of cells induces nearby outer skin to start changing into the lens placode. The lens placode is the first stage of transformation of a patch of skin into the lens. At this early stage, the lens placode is a single layer of cells.
As development progresses, the lens placode begins to deepen and bow inwards. As the placode continues to deepen, the opening to the surface ectoderm constricts and the lens cells bud off from the embryo's skin to form a sphere of cells known as the "lens vesicle". When the embryo is about 10mm long the lens vesicle has completely separated from the skin of the embryo.
The embryo then sends signals from the developing retina, inducing the cells closest to the posterior end of the lens vesicle to elongate toward the anterior end of the vesicle. These signals also induce the synthesis of proteins called crystallins. As the name suggests the crystallins can form a clear highly refractive jelly. These elongating cells eventually fill in the center of the vesicle with cells, that are long and thin like a strand of hair, called fibers. These primary fibers become the nucleus in the mature lens. The epithelial cells that do not form into fibers nearest the lens front give rise to the lens epithelium.
Additional fibers are derived from lens epithelial cells located at the lens equator. These cells lengthen towards the front and back wrapping around fibers already laid down. The new fibers need to be longer to cover earlier fibers but as the lens gets larger the ends of the newer fibers no longer reach as far towards the front and back of the lens. The lens fibers that do not reach the poles form tight, interdigitating seams with neighboring fibers. These seams being less crystalline than the bulk of the lens are more visible and are termed "sutures". The suture patterns become more complex as more layers of lens fibers are added to the outer portion of the lens.
The lens continues to grow after birth, with the new secondary fibers being added as outer layers. New lens fibers are generated from the equatorial cells of the lens epithelium, in a region referred to as the "germinative zone" and "bow region". The lens epithelial cells elongate, lose contact with the capsule and epithelium at the back and front of the lens, synthesize crystallin, and then finally lose their nuclei (enucleate) as they become mature lens fibers. In humans, as the lens grows by laying down more fibers through to early adulthood, the lens becomes more ellipsoid in shape. After about age 20 the lens grows rounder again and the iris is very important for this development.
Several proteins control the embryonic development of the lens though PAX6 is considered the master regulator gene of this organ. Other effectors of proper lens development include the Wnt signaling components BCL9 and Pygo2. The whole process of differentiation of the epithelial cells into crystallin filled fiber cells without organelles occurs within the confines of the lens capsule. Older cells cannot be shed and are instead internalized towards the center of the lens. This process results in a complete temporally layered record of the differentiation process from the start at the lens surface to the end at the lens center. The lens is therefore valuable to scientists studying the process of cell differentiation.
=== Variations in lens structure ===
In many aquatic vertebrates, the lens is considerably thicker, almost spherical resulting in increased light refraction. This difference helps compensate for the smaller angle of refraction between the eye's cornea and the watery environment, as they have more similar refractive indices than cornea and air. The fiber cells of fish are generally considerably thinner than those of land vertebrates and it appears crystallin proteins are transported to the organelle free cells at the lens exterior to the inner cells through many layers of cells. Some vertebrates need to see well both above and below water at times. One example is diving birds which have the ability to change focus by 50 to 80 dioptres. Compared with animals adapted for only one environment diving birds have a somewhat altered lens and cornea structure with focus mechanisms to allow for both environments. Even among terrestrial animals the lens of primates such as humans is unusually flat going some way to explain why our vision, unlike diving birds, is particularly blurry under water.
== Function ==
=== Focusing ===
In humans the widely quoted Helmholtz mechanism of focusing, also called accommodation, is often referred to as a "model". Direct experimental proof of any lens model is necessarily difficult as the vertebrate lens is transparent and only functions well in the living animals. When considering all vertebrates aspects of all models may play varying roles in lens focus.
==== The shape changing lens of many land based vertebrates ====
==== External forces ====
The model of a shape changing lens of humans was proposed by Young in a lecture on the 27th Nov 1800. Others such as Helmholtz and Huxley refined the model in the mid-1800s explaining how the ciliary muscle contracts rounding the lens to focus near and this model was popularized by Helmholtz in 1909. The model may be summarized like this. Normally the lens is held under tension by its suspending ligaments being pulled tight by the pressure of the eyeball. At short focal distance the ciliary muscle contracts relieving some of the tension on the ligaments, allowing the lens to elastically round up a bit, increasing refractive power. Changing focus to an object at a greater distance requires a thinner less curved lens. This is achieved by relaxing some of the sphincter like ciliary muscles. While not referenced this presumably allows the pressure in the eyeball to again expand it outwards, pulling harder on the lens making it less curved and thinner, so increasing the focal distance. There is a problem with the Helmholtz model in that despite mathematical models being tried none has come close enough to working using only the Helmholtz mechanisms.
Schachar has proposed a model for land based vertebrates that was not well received. The theory allows mathematical modeling to more accurately reflect the way the lens focuses while also taking into account the complexities in the suspensory ligaments and the presence of radial as well as circular muscles in the ciliary body. In this model the ligaments may pull to varying degrees on the lens at the equator using the radial muscles while the ligaments offset from the equator to the front and back are relaxed to varying degrees by contracting the circular muscles. These multiple actions operating on the elastic lens allows it to change lens shape at the front more subtly. Not only changing focus, but also correcting for lens aberrations that might otherwise result from the changing shape while better fitting mathematical modeling.
The "catenary" model of lens focus proposed by Coleman demands less tension on the ligaments suspending the lens. Rather than the lens as a whole being stretched thinner for distance vision and allowed to relax for near focus, contraction of the circular ciliary muscles results in the lens having less hydrostatic pressure against its front. The lens front can then reform its shape between the suspensory ligaments in a similar way to a slack chain hanging between two poles might change its curve when the poles are moved closer together. This model requires fluid movement of the lens front only rather than trying to change the shape of the lens as a whole.
==== Internal forces ====
When Thomas Young proposed the changing of the human lens's shape as the mechanism for focal accommodation in 1801 he thought the lens may be a muscle capable of contraction. This type of model is termed intracapsular accommodation as it relies on activity within the lens. In a 1911 Nobel lecture Allvar Gullstrand spoke on "How I found the intracapsular mechanism of accommodation" and this aspect of lens focusing continues to be investigated. Young spent time searching for the nerves that could stimulate the lens to contract without success. Since that time it has become clear the lens is not a simple muscle stimulated by a nerve so the 1909 Helmholtz model took precedence. Pre-twentieth century investigators did not have the benefit of many later discoveries and techniques. Membrane proteins such as aquaporins which allow water to flow into and out of cells are the most abundant membrane protein in the lens. Connexins which allow electrical coupling of cells are also prevalent. Electron microscopy and immunofluorescent microscopy show fiber cells to be highly variable in structure and composition. Magnetic resonance imaging confirms a layering in the lens that may allow for different refractive plans within it. The refractive index of human lens varies from approximately 1.406 in the central layers down to 1.386 in less dense layers of the lens. This index gradient enhances the optical power of the lens. As more is learned about mammalian lens structure from in situ Scheimpflug photography, MRI and physiological investigations it is becoming apparent the lens itself is not responding entirely passively to the surrounding ciliary muscle but may be able to change its overall refractive index through mechanisms involving water dynamics in the lens still to be clarified. The accompanying micrograph shows wrinkled fibers from a relaxed sheep lens after it is removed from the animal indicating shortening of the lens fibers during near focus accommodation. The age related changes in the human lens may also be related to changes in the water dynamics in the lens.
==== Lenses of birds, reptiles, amphibians, fish and others ====
In reptiles and birds, the ciliary body which supports the lens via suspensory ligaments also touches the lens with a number of pads on its inner surface. These pads compress and release the lens to modify its shape while focusing on objects at different distances; the suspensory ligaments usually perform this function in mammals. With vision in fish and amphibians, the lens is fixed in shape, and focusing is instead achieved by moving the lens forwards or backwards within the eye using a muscle called the retractor lentus.
In cartilaginous fish, the suspensory ligaments are replaced by a membrane, including a small muscle at the underside of the lens. This muscle pulls the lens forward from its relaxed position when focusing on nearby objects. In teleosts, by contrast, a muscle projects from a vascular structure in the floor of the eye, called the falciform process, and serves to pull the lens backwards from the relaxed position to focus on distant objects. While amphibians move the lens forward, as do cartilaginous fish, the muscles involved are not similar in either type of animal. In frogs, there are two muscles, one above and one below the lens, while other amphibians have only the lower muscle.
In the simplest vertebrates, the lampreys and hagfish, the lens is not attached to the outer surface of the eyeball at all. There is no aqueous humor in these fish, and the vitreous body simply presses the lens against the surface of the cornea. To focus its eyes, a lamprey flattens the cornea using muscles outside of the eye and pushes the lens backwards.
While not vertebrate, brief mention is made here of the convergent evolution of vertebrate and Molluscan eyes. The most complex Molluscan eye is the Cephalopod eye which is superficially similar structure and function to a vertebrate eye, including accommodation, while differing in basic ways such as having a two part lens and no cornea. The fundamental requirements of optics must be filled by all eyes with lenses using the tissues at their disposal so superficially eyes all tend to look similar. It is the way optical requirements are met using different cell types and structural mechanisms that varies among animals.
=== Crystallins and transparency ===
Crystallins are water-soluble proteins that compose over 90% of the protein within the lens. The three main crystallin types found in the human eye are α-, β-, and γ-crystallins. Crystallins tend to form soluble, high-molecular weight aggregates that pack tightly in lens fibers, thus increasing the index of refraction of the lens while maintaining its transparency. β and γ crystallins are found primarily in the lens, while subunits of α -crystallin have been isolated from other parts of the eye and the body. α-crystallin proteins belong to a larger superfamily of molecular chaperone proteins, and so it is believed that the crystallin proteins were evolutionarily recruited from chaperone proteins for optical purposes. The chaperone functions of α-crystallin may also help maintain the lens proteins, which must last a human for their entire lifetime.
Another important factor in maintaining the transparency of the lens is the absence of light-scattering organelles such as the nucleus, endoplasmic reticulum, and mitochondria within the mature lens fibers. Lens fibers also have a very extensive cytoskeleton that maintains the precise shape and packing of the lens fibers; disruptions/mutations in certain cytoskeletal elements can lead to the loss of transparency.
The lens blocks most ultraviolet light in the wavelength range of 300–400 nm; shorter wavelengths are blocked by the cornea. The pigment responsible for blocking the light is 3-hydroxykynurenine glucoside, a product of tryptophan catabolism in the lens epithelium. High intensity ultraviolet light can harm the retina, and artificial intraocular lenses are therefore manufactured to also block ultraviolet light. People lacking a lens (a condition known as aphakia) perceive ultraviolet light as whitish blue or whitish-violet.
=== Nourishment ===
The lens is metabolically active and requires nourishment in order to maintain its growth and transparency. Compared to other tissues in the eye, however, the lens has considerably lower energy demands.
By nine weeks into human development, the lens is surrounded and nourished by a net of vessels, the tunica vasculosa lentis, which is derived from the hyaloid artery. Beginning in the fourth month of development, the hyaloid artery and its related vasculature begin to atrophy and completely disappear by birth. In the postnatal eye, Cloquet's canal marks the former location of the hyaloid artery.
After regression of the hyaloid artery, the lens receives all its nourishment from the aqueous humor. Nutrients diffuse in and waste diffuses out through a constant flow of fluid from the anterior/posterior poles of the lens and out of the equatorial regions, a dynamic that is maintained by the Na+/K+-ATPase pumps located in the equatorially positioned cells of the lens epithelium. The interaction of these pumps with water channels into cells called aquaporins, molecules less than 100 daltons in size among cells via gap junctions, and calcium using transporters/regulators (TRPV channels) results in a flow of nutrients throughout the lens.
Glucose is the primary energy source for the lens. As mature lens fibers do not have mitochondria, approximately 80% of the glucose is metabolized via anaerobic metabolism. The remaining fraction of glucose is shunted primarily down the pentose phosphate pathway. The lack of aerobic respiration means that the lens consumes very little oxygen.
== Clinical significance ==
Cataracts are opacities of the lens. While some are small and do not require any treatment, others may be large enough to block light and obstruct vision. Cataracts usually develop as the aging lens becomes more and more opaque, but cataracts can also form congenitally or after injury to the lens. Nuclear sclerosis is a type of age-related cataract. Diabetes is another risk factor for cataract. Cataract surgery involves the removal of the lens and insertion of an artificial intraocular lens.
Presbyopia is the age-related loss of accommodation, which is marked by the inability of the eye to focus on nearby objects. The exact mechanism is still unknown, but age-related changes in the hardness, shape, and size of the lens have all been linked to the condition.
Ectopia lentis is the displacement of the lens from its normal position.
Aphakia is the absence of the lens from the eye. Aphakia can be the result of surgery or injury, or it can be congenital.
== Additional images ==
== See also ==
Accommodation reflex
Crystallin
Evolution of the eye, for how the lens evolved
Intraocular lenses
Iris
Lens capsule
Phacoemulsification
Visual perception
Zonules of Zinn
== References ==
== External links ==
Histology image: 08001loa – Histology Learning System at Boston University | Wikipedia/Lens_(vertebrate_anatomy) |
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