First introduced in 1962 by Professor  Henry Buchwald  of the University of Minnesota, [ 2 ]  the procedure is used to treat a number of  hyperlipidemias  including  familial hypercholesterolemia . [ 3 ] [ 4 ]  The only  randomized controlled trial  comparing bypass surgery with standard management was the POSCH trial, which was conducted by Buchwald and his team. The trial ran between 1975 and 1983 and included 838 men who had survived a  heart attack . This trial initially failed to show any benefit on mortality, but in 1998 follow-up results indicated that in addition to its known benefit on cholesterol levels and disease events it had also decreased mortality in the treatment group. [ 5 ]


Ileal bypass surgery was mainly performed prior to the introduction of effective oral medication for the most common hypercholesterolemias. [ 6 ]  It is occasionally used in the surgical treatment of  obesity . [ 7 ]


As with any ileal resection, a possible complication is mild  steatorrhea  due to a reduced uptake of bile acids by the ileum.


Percutaneous endoscopic gastrostomy  ( PEG ) is an  endoscopic   medical procedure  in which a tube ( PEG tube ) is passed into a patient's stomach through the  abdominal wall , most commonly to provide a means of feeding when  oral  intake is not adequate (for example, because of  dysphagia  or  sedation ). This provides  enteral  nutrition (making use of the natural  digestion  process of the  gastrointestinal tract ) despite bypassing the mouth; enteral nutrition is generally preferable to  parenteral nutrition  (which is only used when the GI tract must be avoided). The PEG procedure is an alternative to open surgical  gastrostomy  insertion, and does not require a  general anesthetic ;  mild sedation  is typically used. PEG tubes may also be extended into the  small intestine  by passing a jejunal extension tube ( PEG-J tube ) through the PEG tube and into the  jejunum  via the  pylorus . [ 1 ]


PEG administration of enteral feeds is the most commonly used method of nutritional support for patients in the community. Many  stroke  patients, for example, are at risk of  aspiration pneumonia  due to poor control over the swallowing muscles; some will benefit from a PEG performed to maintain nutrition. PEGs may also be inserted to decompress the  stomach  in cases of  gastric volvulus . [ 2 ]


Gastrostomy may be indicated in numerous situations, usually those in which normal (or  nasogastric ) feeding is impossible. The causes for these situations may be neurological (e.g.  stroke ), anatomical (e.g.  cleft lip and palate  during the process of correction) or other (e.g.  radiation therapy  for tumors in head & neck region). [ citation needed ]


In certain situations where normal or nasogastric feeding is not possible, gastrostomy may be of no clinical benefit. In advanced  dementia , studies show that PEG placement does not in fact prolong life. [ 3 ]  Instead, oral  assisted feeding  is preferable. [ 4 ]  Quality improvement protocols have been developed with the aim of reducing the number of non-beneficial gastrostomies in patients with dementia. [ 5 ]


A gastrostomy can be placed to decompress the stomach contents in a patient with a malignant bowel obstruction. This is referred to as a "venting PEG" and is placed to prevent and manage nausea and vomiting.


A gastrostomy can also be used to treat  volvulus  of the stomach, where the stomach twists along one of its axes.  The tube (or multiple tubes) is used for gastropexy, or adhering the stomach to the abdominal wall, preventing twisting of the stomach. [ 2 ]


A PEG tube can be used in providing gastric or post-surgical drainage. [ 6 ]


Two major techniques for placing PEGs have been described in the literature.


The Gauderer-Ponsky technique involves performing a  gastroscopy  to evaluate the  anatomy  of the  stomach .  The anterior stomach wall is identified and techniques are used to ensure that there is no  organ  between the wall and the  skin :


An  angiocath  is used to puncture the abdominal wall through a small  incision , and a soft guidewire is inserted through this and pulled out of the  mouth .  The feeding tube is attached to the guidewire and pulled through the mouth, esophagus, stomach, and out of the incision. [ 2 ]


In the Russell introducer technique, the  Seldinger technique  is used to place a wire into the stomach, and a series of dilators are used to increase the size of the  gastrostomy .  The tube is then pushed in over the wire. [ 7 ]


There are several techniques such as moderate sedation with left transversus abdominis plane block, and moderate sedation with local anesthetic infiltration at feeding tube site. [ 8 ]


As with other types of feeding tubes, care must be made to place PEGs into an appropriate population.  The following are contraindications to PEG use: [ 9 ]


The  American Medical Directors Association , the  American Geriatrics Society  and the  American Academy of Hospice and Palliative Medicine  recommend against inserting percutaneous feeding tubes in individuals with advanced dementia and, instead, recommend oral assisted feedings. Artificial nutrition neither prolongs life nor improves its quality in patients with advanced dementia. It may increase the risk of the patient inhaling food, it does not reduce suffering, it may cause fluid overload, diarrhea, abdominal pain and local complications, and it can reduce the amount of human interaction the patient experiences. [ 10 ]


PEG tubes with rigid, fixed "bumpers" are removed endoscopically. The PEG tube is pushed into the stomach so that part of the tube is visible behind the bumper. An endoscopy snare is then passed through the endoscope, and passed over the bumper so that the tube adjacent to the bumper is grasped. The external part of the tube is then cut, and the tube is withdrawn into the stomach, and then pulled up into the esophagus and removed through the mouth. The PEG site heals without intervention. [ citation needed ]


PEG tubes with a collapsible or deflatable bumper can be removed using traction (simply by pulling the PEG tube out through the abdominal wall).


The first percutaneous endoscopic gastrostomy performed on a child was on June 12, 1979, at the  Rainbow Babies & Children's Hospital ,  University Hospitals of Cleveland . Michael W.L. Gauderer, pediatric surgeon, Jeffrey Ponsky, endoscopist, and James Bekeny, surgical resident, performed the procedure on a  4 + 1 ⁄ 2 -month-old child with inadequate oral intake. [ 15 ]  The authors of the technique, Michael W.L. Gauderer and Jeffrey Ponsky, first published the technique in 1980. [ 15 ]  In 2001, the details of the development of the procedure were published, the first author being the originator of the technique itself. [ 2 ]


Proctocolectomy  is the  surgical  removal of the entire  colon  and  rectum  from the human body, leaving the patients  small intestine  disconnected from their  anus . [ 1 ]  It is a major surgery that is performed by  colorectal surgeons , however some portions of the surgery, specifically the  colectomy  (removal of the colon) may be performed by  general surgeons . [ 2 ]  It was first performed in 1978 and since that time, medical advancements have led to the surgery being less invasive with great improvements in patient outcomes. [ 3 ]  The procedure is most commonly indicated for severe forms of  inflammatory bowel disease  such as  ulcerative colitis  and  Crohn's disease . It is also the treatment of choice for patients with  familial adenomatous polyposis . [ 4 ]


According to the guidelines published by the American Society of Colon and rectal surgery, a proctocolectomy can be considered in patients who are suffering from severe ulcerative colitis (UC), a form of inflammatory bowel disease. [ 5 ]  This procedure is considered curative for this condition because UC only affects the large colon and rectum. [ 6 ]  Proctocolectomy may also be performed for severe Crohn’s disease, another form of inflammatory bowel disease, however this intervention is not considered curative. Surgical intervention for Crohn's disease is only pursued when medications are no longer effective or when extensive damage to the large colon and rectum has occurred. [ 7 ]  The final most common indication for proctocolectomy is for individuals who suffer from Familial Adenomatous Polyposis. [ 4 ]  This is a condition that is inherited from past generations and leads to dozens or even thousands of polyps inside the colon and rectum that can then become cancerous. [ 8 ]


The surgical removal of the entire colon and rectum is a major surgery with many complex steps involved. In brief, the surgeon will begin by making an incision in the patient’s belly and then expose the colon (large intestine). They will then remove the entire large intestine being careful not to damage any other nearby internal organs. [ 9 ]  Next the surgeon will remove the patient’s rectum. Lastly the surgeon will connect the patient’s small intestine to their anus so that they will be able continue having bowel movements from their bottom. This is known as an ileoanal anastomosis. [ 9 ]  It is important to note that the surgeon preserves the patient’s anus and sphincter muscles in order to prevent fecal incontinence when the small intestine is connected to the anus. [ 10 ]


As previously stated, a proctocolectomy is a major surgery and with that comes the risk of complications. The major risks of the surgery include damage to nearby organs and nerves within the body, infection, scar tissue within the belly that can lead to small intestine blockage, poor absorption of nutrients and incisional hernias. [ 4 ]


A  pull-through procedure  is the definitive operation for  Hirschsprung disease , involving the removal of the abnormal segment of  bowel  that has no nerves, pulling through the normal bowel and  connecting  it to the  anus . Several types of pull-through procedures exist including the Soave,  Swenson  and Duhamel. It can be performed using an open or  minimally invasive approach . [ 1 ]


A pull-through procedure is the definitive treatment for Hirschsprung's disease, with the aim of removing the abnormal part of the bowel and joining the normal part of the intestine with the anus. [ 2 ]


The original pull-through procedure was designed by  Orvar Swenson  and his colleague Alexander Bill. The abnormal aganglionic part of the bowel is resected down to the  sigmoid colon  and  rectum , and the normal colon and the low rectum are subsequently  joined . [ 1 ] [ 3 ]


The Duhamel pull-through is a modified Swenson's pull-through, first described in 1956. [ 1 ]


The Soave procedure involves resecting the mucosa and submucosa of the rectum and pulling through the normal ganglionic bowel through the aganglionic muscular cuff of the rectum. It was introduced in the 1960s and initially did not include a formal join. It depended on scar tissue formation between the pull-through segment and the surrounding aganglionic bowel. The procedure was later modified by Boley. [ 1 ]


If the segment of Hirschsprung's is short, anorectal myomectomy maybe an alternative surgical option. [ 1 ]


Georgeson  first described laparoscopic surgical treatment of Hirschsprung's in 1999. [ 1 ]  Transanal pull-through procedures do not require an intra-abdominal dissection. [ 1 ] [ 4 ]


Complications include anaesthetic risks, infection,  bleeding  and  perforation of the bowel . [ 5 ]  Frequent loose stools may cause nappy rash. Toilet training may also pose problems. Occasionally a temporary  stoma  is required. [ 6 ]  A pull-through may sometimes fail if some of the abnormal bowel is left behind. [ 7 ]


Pyloromyotomy  is a surgical procedure in which a portion of the muscle fibers of the  pyloric muscle  are cut. This is typically done in cases where the contents from the stomach are inappropriately stopped by the pyloric muscle, causing the stomach contents to build up in the stomach and unable to be appropriately digested. The procedure is typically performed in cases of " hypertrophic pyloric stenosis " in young children. [ 1 ]  In most cases, the procedure can be performed with either an open approach or a laparoscopic approach [ 2 ]  and the patients typically have good outcomes with minimal complications. [ 3 ]


The development of the procedure has attributed to Dr.  Conrad Ramstedt  in 1911, who originally named the procedure Ramstedt's Operation. However, the procedure was truly performed about 17 months earlier by Sir  Harold Stiles   in 1910 at the  Royal Hospital for sick children . [ 4 ]  In 1991, the first laparoscopic pyloromyotomy was performed by Dr. Alain and Dr. Grousseau. [ 4 ]


After pyloric stenosis is identified in a patient, and any electrolyte and fluid imbalances are stabilized, the surgeon will perform the procedure. [ 4 ] [ 1 ]  During which, the surgeon must access the pylorus through the  abdominal wall . This can either be done  laparoscopically  or with an "open" procedure. In either case, the once the pylorus is accessed, the surgeon will visualize the  hypertrophied  pyloric muscle. Then, the surgeon will carefully cut through the outer layers of tissue and through the pyloric muscle to the  mucosa , which is the layer of tissue facing the inside of the gastrointestinal tract. From there, the two portions of the pyloric muscle are tested for mobility and the mucosal layer is inspected for any unintentional damage. Depending on the approach, the pylorus, stomach, and  gastrointestinal tract  are returned to their appropriate place in the  abdominal cavity  and the medical equipment is removed. Finally, each of the surgical incisions are stitched closed and the patient is taken back to post-operative area for monitoring. [ 5 ] [ 4 ]


Laparoscopic approach:  In the laparoscopic approach, the appropriate area of the gastrointestinal tract is accessed in a minimally invasive manner. [ 5 ]  This approach may be chosen due to the reduced hospital stay, quicker recovery time, and higher satisfaction with the appearance of the surgical site after the patient has healed when compared to the older open approach. [ 2 ]  Typically, two to three  trocars , a medical device used to penetrate the abdominal wall in laparoscopic medical procedures, are placed in their appropriate positions. This is typically done by making a small cut for each trocar in the abdominal wall before placing the trocar into the cut. The abdomen is then filled with a gas, such as carbon dioxide to increase visibility with the laparoscopic camera and increase working space. [ 1 ]  Once the laparoscopic instruments and camera are place through the trocars, the hypertrophied pylorus is visualized. Then, the pyloric muscle is cut down to the mucosa and the muscle fibers are spread apart using the laparoscopic instruments. From there, the two pyloric sections are tested independently for appropriate movement. After that, the mucosa is inspected for any unintentional damaged. This is done by inflating the patient's stomach and looking for the formation of bubbles along the mucosa. [ 4 ]  If a leak is identified it is typically repaired with  sutures  if determined to be appropriate. Finally, all instruments and trocars are removed before the surgical wound sites are repaired with stitches. [ 5 ]


Open approach:  In the older open pyloromyotomy, the appropriate area of the gastrointestinal tract is accessed by creating a single cut on the abdomen of the patient and the pylorus and stomach are gently pulled through the opening for the procedure. [ 5 ]  This approach may be chosen due to patient/parent preference or if determined by the surgeon to be more appropriate. [ 6 ]  Once the initial cut on the abdomen is made, a layer of  connective tissue  between the abdomen and stomach is cut through. Then, the stomach and pylorus are carefully pulled through the opening created by the initial cut and the hypertrophied pylorus is identified by the surgeon. After that, the pyloric muscle is cut down to the mucosa and the muscle fibers are spread apart using a pyloric spreader. The newly separated pyloric sections are tested for adequate movement and the mucosa is tested for holes or other damage, which are repaired using suture as appropriate. Finally, the stomach and pylorus are carefully placed back into the abdominal cavity and the various tissue layers are repaired with stitches. [ 5 ]


The pyloromyotomy is primarily indicated by the presence of hypertrophic pyloric stenosis. [ 5 ] [ 1 ]  Hypertrophic Pyloric stenosis is a gastrointestinal tract defect, most commonly seen in young children, typically in the first few months of life, caused by enlargement of the tissue in the pyloric muscle. [ 5 ] [ 4 ] [ 1 ]  This causes the contents of the stomach to be unable to empty leading to pain after eating, electrolyte abnormalities, and projectile vomiting among other clinical signs and symptoms. [ 7 ] [ 1 ]


While the procedure has been proven to be highly effective at treating pyloric stenosis, there are still several complications that may occur as a result of the procedure. [ 1 ] [ 3 ] [ 7 ]  The rate that any complications may occur as a result of the surgery are estimated to be 4.6–12% of cases. [ 3 ]  The most common complications include incomplete pyloromyotomy, perforation of the mucosa, and infection of the surgical site. [ 3 ]  Other complications reported to be related to the procedure, in addition to those stated above, are listed below:


The result of the surgery is typically successful at treating the patient's pyloric stenosis nearly 100% of the time with a quick recovery for most patients. [ 1 ] [ 7 ]  Typically, the patient will have a special liquid diet for a few feedings following the procedure. In most cases the patient can be expected to be able to resume feedings with breast milk within 1 day of the procedure. [ 1 ]


In  general surgery , a  Roux-en-Y anastomosis , or  Roux-en-Y , is an end-to-side  surgical anastomosis  of  bowel  used to reconstruct the  gastrointestinal tract .  Typically, it is between  stomach  and small bowel that is  distal  (or further down the  gastrointestinal tract ) from the cut end. [ 1 ]


The name is derived from the  surgeon  who first described it ( César Roux ) [ 1 ]  and the  stick-figure  representation.  Diagrammatically , the Roux-en-Y anastomosis looks a little like the  letter   Y . [ citation needed ]


Typically, the two upper limbs of the Y represent (1) the  proximal  segment of stomach and the distal small bowel it joins with and (2) the blind end that is surgically divided off, and the lower part of the Y is formed by the  distal  small bowel beyond the anastomosis. [ citation needed ]


Roux-en-Ys are used in several operations and collectively called  Roux operations . [ 1 ]


When describing the surgery, the  Roux limb  is the  efferent  or antegrade limb that serves as the primary recipient of food after the surgery, while the  hepatobiliary  or  afferent  limb that anastomoses with the biliary system serves as the recipient for biliary secretions, which then travel through the excluded small bowel to the distal anastomosis at the mid jejunum to aid digestion. The altered anatomy can contribute to indigestion following surgery. [ 2 ]  The procedure has also been associated with an increased incidence of  iron-deficiency anemia . Iron-deficiency anemia develops in up to 45% of people who have had a Roux-en-Y anastomosis. [ 3 ]


Rubber band ligation  (RBL) [ 1 ]  is an outpatient treatment procedure for internal  hemorrhoids  of any grade. [ 2 ]  There are several different devices a physician may use to perform the procedure, including the traditional metal devices, endoscopic banding, and the CRH O'Regan System.


With rubber band ligation, a small band is applied to the base of the hemorrhoid, stopping the blood supply to the hemorrhoidal mass. The hemorrhoid will shrink and fibrose within a few days with shriveled hemorrhoidal tissue and band falling off during normal  bowel movements  - likely without the patient noticing. [ 3 ]


Rubber band ligation is a popular  procedure for the treatment of hemorrhoids, as it involves a much lower risk of pain than surgical treatments of hemorrhoids, as well as a shorter recovery period (if any at all). It is a very effective procedure and there are multiple methods available. When done with the CRH O’Regan System, it is also associated with a recurrence rate of 5% at 2 years. [ 4 ]  The procedure is typically performed by gastroenterologists, colorectal surgeons, and general surgeons.


Ligation  of hemorrhoids was first recorded by  Hippocrates  in 460 BC, who wrote about using thread to tie off hemorrhoids. [ 5 ]


In modern history, ligation using rubber band was introduced in 1958 by  Blaisdell  and refined in 1963 by  Barron , who introduced a mechanical, metal device called the  Barron ligator  (similar to the McGivney).


Dr. Patrick J. O’Regan, a laparoscopic surgeon, invented the disposable CRH O’Regan System. In 1997, the ligator was approved by the FDA for the treatment of hemorrhoids. [ 6 ]


Rubber band ligation procedure is as follows:


Possible complications from rubber band ligation include:


Serial transverse enteroplasty (STEP)  is a surgical procedure used primarily in the treatment of  short bowel syndrome  (SBS). In STEP, by making cuts in the intestine and creating a zigzag pattern, surgeons lengthen the amount of bowel available to absorb nutrients. The procedure was first performed in 2003 and more than 100 patients had undergone the surgery by 2013.


Short bowel syndrome (SBS) is the condition in which a patient cannot absorb adequate nutrients because a portion of the small intestine is damaged or absent. SBS commonly affects pediatric patients who have undergone surgery, such as premature infants with  necrotizing enterocolitis  and infants with gastrointestinal defects such as  gastroschisis . In adults,  Crohn's disease  is a possible cause of SBS. If they are unable to absorb nutrients in the gut, patients must be given  parenteral nutrition  (PN) intravenously, but long-term PN can be associated with liver failure. [ 1 ]


The procedure was studied by researchers in Boston utilizing a group of ten young pigs. Five of the pigs underwent removal of 90 percent of the bowel followed by STEP. The other pigs underwent the bowel resection without the STEP procedure, serving as control subjects. STEP was shown to lengthen the bowel from 105.2 ± 7.7 cm to 152.2 ± 8.3 cm. [ 2 ]


STEP was first performed on a human patient, a two-year-old who had been born with gastroschisis, in 2003. [ 3 ]   By 2010, it had been utilized by more than 20 hospitals, mostly in the United States. [ 4 ]  In addition to its use in treating SBS, STEP has been utilized to treat bacterial overgrowth in a dilated bowel loop and to prevent SBS upon the initial repair of certain types of intestinal atresia. [ 4 ]


In 2004, the International Serial Transverse Enteroplasty (STEP) Data Registry was created to serve as an online database to study outcomes following STEP. By 2013, 111 patients had been entered into the database, though 14 had been lost to follow-up. At that time, 11 patients had died and five had received intestinal transplants. 47% had attained enteral autonomy (sufficient bowel function). Pre-STEP bowel length was found to be inversely proportional to the likelihood of transplant or death. Pre-STEP  direct bilirubin  levels were found to be proportional to the likelihood of transplant or death. [ 5 ]


In STEP, the bowel is dilated and then partially transected (cut) at certain points, creating a zigzag pattern to the bowel that results in lengthening of the surface area available for digestion. [ 3 ]


Longitudinal intestinal lengthening and tapering (LILT), also known as the Bianchi procedure, is a surgical alternative to STEP. LILT and STEP have similar outcomes. With each procedure, more than half of patients gain the ability to absorb sufficient nutrients in the intestine. A single-center study compared STEP and LILT, reporting fewer complications with LILT. [ 6 ]


Strictureplasty  (also spelled  Stricturoplasty ) is a surgical procedure performed to alleviate bowel narrowing due to scar tissue that has built up in the intestinal wall from inflammatory bowel conditions such as Crohn's disease. The scar tissue accumulates as a result of repeated damage and healing, with the scarring causing a stricture (a narrowing of the lumen of the bowel). The narrowing can force bowel contents into fissures and ulcers at the site, causing additional damage and narrowing. The surgery restores free flow through the bowel without the need for removing bowel segments (i.e., without bowel resection).


The first strictureplasty for Crohn's disease was performed by Emanoel Lee in 1976 and was reported in 1982. [ 1 ]  The course of the following two decades several papers demonstrated that strictureplasties were safe and effective. [ 2 ]


Strictureplasties are categorized into three groups: Conventional, intermediate, and complex procedures.  The  Heineke-Mikulicz Strictureplasty  is the most common among the conventional stricutreplasties. Best-suited for short (up to 7 centimeters) strictures, the H-M Strictureplasty is performed by making a cut lengthwise along one side of the bowel, pushing the two ends of the cut together and then suturing the bowel widthwise  (picture) , thus, having the effect of widening the segment of narrowed bowel, therefore resolving the stricture.


The  Finney Strictureplasty  is the most common intermediate strictureplasty. Indicated for strictures up to 15 centimeters, the Finney Strictureplasty is performed by folding the diseased bowel on itself and creating a large opening between the two loops.


For multiple strictures or for longer strictures neither the conventional nor the intermediate strictureplasties are suitable. In these cases surgeons need to use complex procedures. The most common complex strictureplasty is the  Michelassi Strictureplasty . [ 3 ]  In this strictureplasty the long loop of the bowel affected by Crohn's is first divided at its midpoint. The two halves are then moved side to side. A very long opening is created between the two loops, which are then sutured together  (Figure 1) ,  (Figure 2) ,  (Figure 3) ,  (Figure 4) .


Multiple strictureplasty can be performed in the same patient.  All strictureplasty techniques spare the patient from bowel resections, an important consideration in a chronic recurrent intestinal condition or in patients with short gut. In addition, recent data suggests that strictureplasty has a protective effect on disease recurrence.  [ 4 ]   Because of the reconfiguration of the bowel, strictureplasty causes slight discontinuities in peristalsis, visible in some imaging tests.  [ 5 ]


Total mesorectal excision  ( TME ) is a standard surgical technique for treatment of  rectal cancer , first described in 1982 by Professor Bill Heald at the UK's  Basingstoke  District Hospital. [ 1 ] [ 2 ]  It is a precise dissection of the  mesorectal  envelope comprising rectum containing the tumour together with all the surrounding fatty tissue and the sheet of tissue that contains lymph nodes and blood vessels. Dissection is along the avascular alveolar plane between the  presacral  and mesorectal fascia, described as  holy plane  (Heald's " holy plane "). [ 3 ]  Dissection along this plane facilitates a straightforward dissection and preserves the sacral vessels and  hypogastric nerves  and is a  sphincter -sparing resection and decreases permanent  stoma  rates. [ 4 ]  It is possible to rejoin the two ends of the colon; however, most patients require a temporary  ileostomy  pouch to bypass the colon, allowing it to heal with less risk of infection, perforation or leakage. [ citation needed ]


TME has become the "gold standard" treatment for rectal cancer Worldwide. [ 5 ] [ 6 ]  The operation can be done by  open  surgery,  laparoscopic  or  Robot-assisted . [ 7 ]


For lower down tumours in the middle and lower third of the rectum a new procedure has been developed known as  Transanal-Total Mesorectal Excision (TaTME) . Instead of the dissection via the abdomen TaTME combines an abdominal and transanal endoscopic approach (endoscopic instruments are inserted into the anus) allowing easier dissection of the most difficult part of the surgery deep down in the pelvis (particularly in male patients or patients with visceral obesity or a narrow pelvis). The perceived benefits of this technique may include ease of procedure due to better views, decreased operative time and reduced complications. [ 8 ]


An occasional side effect of the operation is the formation and tangling of fibrous bands from near the site of the operation with other parts of the bowel.  These can lead to  bowel infarction  if not operated on. [ citation needed ]


TME results in a lower recurrence rate than traditional approaches and a lower rate of permanent  colostomy . Postoperative recuperation is somewhat increased over competing methods. When practiced with diligent attention to anatomy there is no evidence of increased risk of urinary incontinence or sexual dysfunction. [ 9 ]   However, there can be partial fecal incontinence and/or "clustering" – a series of urgent trips to the toilet separated by a few minutes, each trip producing only a very small yield. [ 10 ]  Other long-term bowel dysfunction symptoms may include fecal and gas incontinence, urgency, frequent bowel movements, and difficulty emptying. The symptoms collectively are referred to as low anterior resection syndrome (LARS) and adversely affect quality of life, sometimes so much so that some patients even prefer to have their stoma-reversal itself reversed, and to live with a permanent colonostomy or iliostomy. [ 11 ]


Depending on the  staging , size and location of the tumour,  neoadjuvant   radiotherapy  often combined with  chemotherapy  may be used to shrink the tumour prior to surgery and prevent further  spread .  Adjuvant  chemotherapy may also be used post-surgery to prevent further disease spread [ 12 ]


Transanal hemorrhoidal dearterialization (THD)  is a minimally invasive  surgical  procedure for the treatment of internal hemorrhoids.


In 1995, Morinaga et al. [ 1 ]  developed a non-excisional surgical technique for the treatment of internal  hemorrhoids .  Dal Monte et al. further refined this technique, introducing transanal hemorrhoidal dearterialization (THD). THD belongs to the category of minimally invasive surgery, since the procedure does not comprise incisions or removal of the hemorrhoidal tissue. [ citation needed ]


Hemorrhoids are normal vascular cushions found in the anal canal. 15% of a human's continence mechanism is attributed to the hemorrhoidal plexus. When a person coughs, for instance, the hemorrhoids will engorge with blood and increase one's ability to hold gas and stool. They are termed internal and external based on their positioning to an embryological line termed the  pectinate line . Hemorrhoids above the pectinate line are considered "internal" and those below it "external". [ 2 ] [ unreliable source? ]


Hemorrhoids are fed by arteries and drained by veins. The arterial blood supply is based on the superior rectal (hemorrhoidal) artery. Just as veins in the leg weaken and become prominent, hemorrhoidal veins also may become varicose, resulting in internal hemorrhoids or “piles”. Internal hemorrhoids are divided into four grades. Grade I hemorrhoids are composed of prominent vessels, without protrusion. Grade II hemorrhoids demonstrate prolapse upon straining, with spontaneous reduction. Grade III hemorrhoids demonstrate prolapse upon straining and require manual reduction. Grade IV hemorrhoids prolapse and cannot be manually reduced. [ 2 ]


THD [ 3 ]  uses a specially developed  anoscope  combined with a  Doppler transducer  to identify the hemorrhoidal arteries (originating from the  superior rectal artery ) 2–3 cm above the pectinate line. Once the superior rectal arteries are identified through the Doppler, a suture ligation is performed to effectively decrease the blood flow to the hemorrhoidal plexus.
In case of redundant prolapse, the prolapsed mucosal membrane is lifted and sutured (with the last suture minimum 5 mm above the pectinate line [ 4 ] ), repositioning hemorrhoidal cushions in situ.
This is different from a traditional hemorrhoidectomy, which focused on excising the hemorrhoidal bundle. In this procedure, there is no tissue excision. Because the suture line is above the pectinate line, post-operative pain is minimized for patients. THD can be performed with  conscious sedation ,  local [ 5 ]  or  general anesthesia .


After the operation, a  high-fiber diet  with plenty of liquids (approximately two litres per day) is recommended.
For most patients, the procedure can be performed in a day-surgery setting [ 6 ]  and normal activities can be resumed on average between two and three days post-operatively. [ 7 ]
The affected areas usually restore their normal anatomy after two to three months. [ citation needed ]


Reports on this procedure showed low complication rates and lower postoperative pain. Postoperative bleeding and constipation were included among some of the arising complications. [ 8 ]


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.


The most common abdominal surgeries are described below.


Complications of abdominal surgery include, but are not limited to:


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. [ 2 ]  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. [ 3 ]


Absorption of drugs administered orally was shown to be significantly affected following abdominal surgery. [ 4 ]


There is low-certainty evidence that there is no difference between using scalpel and  electrosurgery  in infection rates during major abdominal surgeries. [ 5 ]


Bariatric surgery  (also known as  metabolic surgery  or  weight loss surgery ) is a surgical procedure used to manage  obesity  and obesity-related conditions. [ 1 ] [ 2 ]  Long term weight loss with bariatric surgery may be achieved through alteration of gut hormones, physical reduction of stomach size ( stomach reduction surgery ), [ 3 ]  reduction of nutrient absorption, or a combination of these. [ 2 ] [ 4 ]   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 . [ 4 ]


In morbidly obese people, bariatric surgery is the most effective treatment for weight loss and reducing complications. [ 5 ] [ 6 ] [ 7 ] [ 8 ] [ 9 ]  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 . [ 10 ]  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. [ 10 ]  The risk of death in the period following surgery is less than 1 in 1,000. [ 11 ]  A 2016 review estimated bariatric surgery could reduce all-cause mortality by 30-50% in obese people. [ 1 ]  Bariatric surgery may also lower disease risk, including improvement in  cardiovascular disease   risk factors ,  fatty liver disease , and diabetes management. [ 12 ]


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. [ 3 ] [ 13 ]  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 . [ 3 ]  The efficacy of stomach reduction surgery varies depending on the specific type of procedure. [ 13 ]  There are two primary divisions of surgery, specifically  gastric sleeve  surgery and  gastric bypass  surgery. [ 3 ]


As of October 2022, [update]  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 . [ 12 ] [ 14 ]  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. [ 12 ]  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. [ 15 ]


As of October 2024, [update]  there has been a reported 30% drop in bariatric surgeries in the United States during the past year, and this can be attributed to GLP-1s such as  Novo Nordisk 's  Ozempic and Wegovy . [ 16 ]


Bariatric surgery has proven to be the most effective obesity treatment option for enduring weight loss. [ 17 ]  Along with this weight reduction, the procedure reduces risk of cardiovascular diseases, type 2 diabetes, fatty liver disease, depression syndromes, among others. [ 18 ]  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. [ 19 ]


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. [ 12 ]  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. [ 14 ]  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 . [ 14 ]  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. [ 12 ]


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. [ 20 ]


As of 2019, [update]  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. [ 21 ]  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. [ 21 ]


When counseling a patient on bariatric procedures, providers take an interdisciplinary approach. Psychiatric screening is also critical for determining postoperative success. [ 22 ] [ 23 ]  People with a BMI of 40 or greater have a 5-fold risk of depression, and half of bariatric surgery candidates are depressed. [ 22 ] [ 23 ]  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. [ 24 ]


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. [ 20 ]


Stomach reduction surgery is not suitable for people with the following conditions:


In adults, malabsorptive procedures lead to more weight loss than restrictive procedures, but they have a higher risk profile. [ 27 ]  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. [ 27 ]  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. [ 28 ]  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. [ 29 ] [ 30 ]


Concerning  metabolic syndrome , bariatric surgery patients were able to achieve remission 2.4 times as often as those who underwent nonsurgical treatment. [ 31 ] [ 29 ]  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. [ 31 ] [ 29 ]


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. [ 32 ]  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. [ 33 ] [ 34 ]  In this context, studies have reported an 85.3–90% 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. [ 33 ] [ 34 ]  Furthermore, there is a difference in effectiveness between bariatric surgery and traditional interventions. The Swedish Obese Subjects (SOS) study demonstrated the difference in T2DM remission rates between conventional medical therapy and bariatric surgery: while conventional methods achieved a 21% remission at two years and 12% at 10 years, bariatric surgery exhibited a 72% remission at two years and 37% at 10 years. [ 34 ]


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. [ 30 ]  Predictors for post-operative diabetes resolution include the current method of diabetes control, adequate blood sugar control, age, duration of diabetes, and waist circumference. [ 32 ]


Bariatric surgery likewise plays a role in the reduction of medication use. [ 33 ] [ 30 ]  During postoperative follow-up, 76% of people discontinued the use of insulin, while 62% no longer required T2DM medications at all. [ 33 ] [ 30 ]


Bariatric surgery is also considered for individuals with new-onset T2DM and obesity, although the level of improvement may be slightly less. [ 34 ] [ 30 ] [ 33 ]  The International Diabetes Federation Task recommends bariatric surgery under certain circumstances, including failure of conventional weight and T2DM therapy in individuals with a BMI of 30–35. [ 34 ]  The Centers for Medicare and Medicaid Services, however, maintain their recommendation of bariatric surgery for only those of BMI above 35. [ 34 ]


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. [ 10 ]  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. [ 10 ]  The overall cancer risk in bariatric surgery patients was decreased by 44%, especially in colorectal, endometrial, breast, and ovarian cancer. [ 35 ]  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. [ 35 ] [ 30 ]


Bariatric surgery in older patients is a safety concern; the relative benefits and risks in this population are not known. [ 36 ]


The position of the  American Society for Metabolic and Bariatric Surgery as of 2017 [update]  was that it was not clearly understood whether medical weight-loss treatments or bariatric surgery had an effect responsiveness to subsequent treatments for infertility in both men and women. [ 37 ]  Bariatric surgery reduces the risk of  gestational diabetes  and  hypertensive disorders of pregnancy  in women who later become pregnant, but increases the risk of  preterm birth , and maternal anemia. [ 35 ] [ 38 ]  For women with  PCOS , post-operatively there tends to be a reduction in menstrual irregularity,  hirsutism , infertility, and the overall prevalence of PCOS is reduced at 12 and 23 months. [ 35 ]


Among people seeking bariatric surgery, pre-operative mental health disorders are commonly reported. [ 39 ] [ 24 ]  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). [ 40 ]  Bariatric surgery has consistently been associated with postoperative decreases in depression symptoms and reduced severity. [ 40 ]


Weight loss surgery in adults is associated with an elevated risk of complications compared to nonsurgical treatments for obesity. [ 41 ] [ 42 ]  can be separated into 2 stages, early complication (within 30 days after surgeries) and late complications (after 30 days). [ 43 ]


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%. [ 27 ] [ 31 ] [ 35 ]  In fact, several studies have reported a reduced overall long-term all-cause mortality compared to controls. [ 27 ] [ 31 ] [ 35 ]  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. [ 27 ] [ 31 ] [ 35 ]


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. [ 29 ]  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. [ 44 ]


Laparoscopic  bariatric surgery requires an average hospital stay of 2–5 days, barring potential complications. [ 45 ]  Minimally invasive procedures (i.e.  adjustable gastric band ) tend to have less complications than open procedures (i.e.  Roux-en-Y ). [ 27 ] [ 35 ]  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. [ 27 ] [ 35 ]


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. [ 27 ]  Gastric band malpositioning can be devastating, leading to gastric prolapse, overdistention, and resultingly, gastric ischemia and necrosis. [ 27 ]  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. [ 27 ]


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. [ 27 ]  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 . [ 27 ]


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). [ 18 ] [ 27 ]


Deficiencies of  micronutrients  like iron (15%), vitamin D, vitamin B12, fat-soluble vitamins, thiamine, and folate are common after bariatric procedures. [ 27 ] [ 29 ]  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. [ 27 ] [ 35 ]  Sleeve gastrectomy leads to fewer long-term vitamin deficiencies compared to gastric banding.


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. [ 43 ]


Late complications: They include gastric  stenosis ,  nutrient deficiencies , and  Gastroesophageal  reflux disease. For gastric stenosis, the symptoms are  food intolerance  and vomiting. [ 43 ]  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 . [ 46 ]


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. [ 47 ]  The symptoms included vomiting, abdominal pain and  peritonitis . Common complications such as internal  gastrointestinal hemorrhage  (bleeding) and staple line  leakage  occur in both surgeries. [ 47 ]


Late complication: For the anastomotic stricture, [ 48 ]  there is a 2.9%-23% chance for patients to experience  gastrojejunal   anastomosis . [ 47 ]  This complication more often occurs in the  laparoscopic  era than open RYGB surgery. Symptoms such as difficulty  swallowing  and  vomiting . [ 47 ]


The most common complication, especially after sleeve gastrectomy, is GERD, which may occur in up to 25% of cases. [ 49 ]  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. [ 49 ]  Dumping syndrome in some cases may be associated with more efficient weight loss, however, it can be uncomfortable. [ 49 ]  Symptoms of dumping syndrome include nausea, diarrhea, painful abdominal cramps, bloating, and autonomic symptoms such as tachycardia, palpitations, flushing, and sweating. [ 49 ]  Early dumping syndrome (emptying within 1 hour of eating) is also associated with a rapid drop in blood pressure, which may cause fainting. [ 49 ]  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. [ 49 ]  Dumping syndrome is best mitigated by consuming small meals and avoiding high carb or high-fat foods. [ 49 ]


Rapid weight loss after obesity surgery can contribute to the development of  gallstones , especially at 6 and 18 months. [ 27 ] [ 29 ]  Estimates for prevalence of symptomatic gallstones after Roux-En-Y gastric bypass range from 3–13%. [ 18 ]  The risk of gallstones following bariatric surgery has shown to be higher among those of the female sex. [ 50 ]


Kidney stones  are common after Roux-En-Y gastric bypass, with estimates of prevalence ranging from 7-11%. [ 18 ]  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. [ 51 ]


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. [ 52 ]  There are guidelines for multivitamin supplementation, but adherence rates are reported to be less than 20%. [ 53 ]


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. [ 54 ]  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. [ 54 ]


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. [ 2 ] [ 55 ]  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. [ 2 ] [ 4 ]  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. [ 18 ]  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. [ 18 ]


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. [ 2 ] [ 18 ] [ 56 ]  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 . [ 56 ]  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. [ 4 ]


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. [ 2 ] [ 4 ] [ 57 ]


Procedures may reduce the amount of intestine that food passes through to decrease the absorption of nutrients from food. [ 2 ] [ 4 ]  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. [ 4 ]


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. [ 2 ]  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. [ 18 ]


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 . [ 18 ]  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. [ 18 ]


This was the most commonly performed bariatric surgery as of 2021 [update]  in the United States, and is one of the two most commonly performed bariatric surgeries in the world. [ 2 ] [ 4 ]  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. [ 2 ] [ 57 ]


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 . [ 58 ] [ 59 ]


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. [ 58 ]


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. [ 59 ]  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. [ 58 ] [ 60 ]


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. [ 58 ]


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. [ 58 ]


The key mechanism is  gastrointestinal   motility  adjustment of SG surgery, which impacts the speed and efficiency of food processing. [ 58 ]  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. [ 58 ]


Techniques:


After 1-3 postoperative days, patients begin oral intake, contingent on a successful  gastrografin  leak test, and receive continuous metabolic monitoring. [ 61 ]  To reduce early respiratory risk,  prophylactic  measures such as oxygen support and  ultrasound  evaluations are employed. [ 61 ]


Late postoperative care involves careful observation for  anastomotic  leaks, patient change to a clear liquid diet, and managing potential  nausea  and  vomiting . [ 61 ]  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. [ 61 ]


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 . [ 4 ]


The surgery is a permanent procedure that aims to decrease the absorption of nutrients due to the new, limited connection created. [ 4 ]  The surgery also works by affecting gut hormones, resetting hunger and satiety levels. [ 4 ]   The physically smaller stomach and increase in baseline satiety hormones help people to feel full with less food after the surgery. [ 4 ]


This is the most commonly performed operation for weight loss in the United States, with approximately 140,000 gastric bypass procedures performed in 2005. [ 18 ]  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. [ 62 ]  Though, since 2013, sleeve gastrectomy has overtaken RYGB as the most common bariatric procedure. [ 18 ]  RYGB remains one of the two most commonly performed bariatric surgeries in the world. [ 2 ] [ 4 ]


Gastric bypass  is the most frequently employed technique for weight reduction, the abnormal absorption in the  intestines  and the physical restriction of the stomach. [ 3 ] [ 13 ]  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. [ 13 ]  The  jejunoileal bypass  (JIB) is the most traditional technique for gastric bypass. [ 63 ]  This procedure has no limitations in the flow and processing of food; [ 63 ]  it only allows the transport of nutrients from the small intestine to the surrounding areas of the intestine. [ 63 ]  The impact of weight loss is apparent and remarkable. [ 13 ]  Individuals who undergo  ROUX-en-Y gastric bypass  (RYGB) consume fewer snacks and meals compared to those who undergo JIB. [ 13 ]  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. [ 13 ]


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. [ 13 ]  The laparoscopic approach is a safe procedure that is associated with fewer problems resulting from wound  inflammation . [ 13 ]


There are three main areas of techniques for performing laparoscopic RYGB: (1) Anastomotic technique [ 64 ]  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. [ 13 ]


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. [ 13 ]


Jejuno-jejunal first: This technique is prevalent within gastric bypass surgery.


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. [ 13 ]


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 . [ 43 ]


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. [ 65 ]


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. [ 65 ]  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. [ 65 ]  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. [ 65 ]


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. [ 66 ]  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. [ 66 ]


Vertical banded gastroplasty  was more commonly used in the 1980s, and is not typically performed in the 21st century. [ 68 ]


In the vertical banded gastroplasty, a part of the stomach is permanently stapled to create a smaller, new stomach. [ 68 ]  This new stomach is physically restricted, allowing people to feel full with smaller meals. [ 69 ]  Short-term weight loss is similar to other bariatric procedures, but long-term complications may be higher. [ 69 ]


This procedure is similar to the sleeve gastrectomy surgery, but a sleeve is created by  suturing , rather than physically removing stomach tissue. [ 70 ]  This allows for the natural ability of the stomach to absorb nutrients to remain intact. [ 70 ]  This procedure is reversible, is a less invasive procedure, and does not use hardware or staples. [ 71 ]


Gastric plication significantly reduces the volume of the patient's stomach, so smaller amounts of food provide a feeling of satiety. [ 71 ]  In a 2020 review and meta-analysis, long-term weight loss was not as durable as other, more common bariatric techniques. [ 71 ]  Gastric plication has not performed as well as the sleeve gastrectomy, with the sleeve gastrectomy associated with greater weight loss and fewer complications. [ 70 ]


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. [ 36 ]   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. [ 36 ]  It is considered somewhat of a safe surgical procedure, with a mortality rate of 0.05%. [ 36 ]


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. [ 72 ] [ 73 ]   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. [ 72 ] [ 73 ]  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. [ 73 ]


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. [ 74 ]  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. [ 74 ]


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. [ 36 ]  Follow-up after surgery is typically focused on helping avoid complications and tracking the progress toward body weight goals. [ 36 ]  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. [ 24 ]


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. [ 75 ]  This diet is continued until the gastrointestinal tract begins to recover approximately 2–3 weeks after surgery. [ 75 ]  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. [ 36 ] [ 75 ]  People in recovery are encouraged to compose their diet mainly of  plant-based foods  and soft proteins (1.0–1.5g/kg/day). [ 36 ] [ 75 ]  During recovery, people must adapt to eating more slowly and avoid eating past fullness; overeating may lead to nausea and vomiting. [ 36 ] [ 75 ]  Alcohol is avoided completely in the first 6 months to 1 year after surgery. [ 75 ]  Some people may take a daily  multivitamin  to compensate for reduced absorption of essential nutrients. [ 36 ]


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. [ 35 ] [ 38 ] [ 75 ]


After a person successfully loses weight following bariatric surgery, excess skin may occur. [ 76 ]  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. [ 77 ]   Targeted areas include the arms, buttocks and thighs, abdomen, and breasts, with changes occurring slowly over years. [ 78 ]


The rising  prevalence  of  lawsuits  related to gastric bypass surgery is a legal concern in different countries. [ 79 ]  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. [ 79 ]


In the 21st century, obesity rates increased globally, and with this, a proportional rise in related diseases and complication. [ 18 ] [ 80 ]  In the United States during 2017-20, an estimated 40% of adults were obese, up from 30% in 1999-2000. [ 18 ]  The costs of treating obesity and related conditions has a large economic impact globally. [ 81 ] [ 82 ]  This  economic impact  results from direct treatment of obesity, treatment of obesity-related conditions, as well as other economic losses from decreased workforce productivity. [ 18 ] [ 82 ]


Bariatric surgery is cost-effective when compared to savings estimated from treatment or prevention of obesity-related conditions. [ 82 ]  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. [ 83 ] [ 82 ]


During the early 21st century, obesity among children and adolescents increased globally, as did treatment options including lifestyle changes, drug treatments, and surgical procedures. [ 84 ] [ 85 ]  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 . [ 85 ] [ 86 ]  Childhood obesity may affect mental health and impact eating practices. [ 85 ]


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. [ 84 ] [ 87 ]  Among high-quality randomized control trial data for surgical treatment of obesity, many studies are not specific to children and adolescents. [ 88 ]  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. [ 85 ]


Bariatric surgical procedures available to adolescents include: Roux-en-Y gastric bypass, vertical sleeve gastrectomy, and adjustable gastric banding. [ 89 ]  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. [ 90 ] [ 12 ] [ 91 ]


Reviews have shown similar weight loss in adolescents following bariatric surgery as in adults. [ 92 ]  Reduction of eating disorders for several years after bariatric surgery has also been shown in adolescents after bariatric surgery. [ 92 ]  Long-term reduction in or resolution of weight-related conditions, such as diabetes and  high blood pressure , occurred in adolescents after bariatric surgery. [ 93 ]  Long-term effects of bariatric surgery in adolescents remains under research, as of 2023. [ 92 ] [ 93 ]


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. [ 94 ] [ 95 ]  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 . [ 95 ]  A modified version of this procedure showed long-term improvement of lipid levels in people with known  high levels of cholesterol  following the procedure. [ 95 ]


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. [ 94 ]  During the late 1960s, the initiation of bariatric surgery followed the development of a procedure to bypass portions of the stomach – the  gastric bypass . [ 94 ] [ 95 ] [ 96 ]


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. [ 96 ]


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 . [ 96 ] The SG laparoscopic version was first performed in 1999. [ 13 ]


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. [ 13 ]  Nowadays, SG has a lower risk of complication, and the  mortality  rate has become the more favorable option for the patients. [ 97 ]


Eye surgery , also known as  ophthalmic surgery  or  ocular surgery , is  surgery  performed on the  eye  or its  adnexa . [ 1 ]  Eye surgery is part of  ophthalmology  and is performed by an ophthalmologist or eye surgeon. The eye is a fragile organ, and requires due care before, during, and after a surgical procedure to minimize or prevent further damage. An eye surgeon is responsible for selecting the appropriate surgical procedure for the patient, and for taking the necessary safety precautions. Mentions of eye surgery can be found in several ancient texts dating back as early as 1800 BC, with cataract treatment starting in the fifth century BC. [ 2 ]  It continues to be a widely practiced class of surgery, with various techniques having been developed for treating eye problems.


Since the eye is heavily supplied by nerves,  anesthesia  is essential.  Local anesthesia  is most commonly used.  Topical anesthesia  using  lidocaine  topical gel is often used for quick procedures. Since topical anesthesia requires cooperation from the patient,  general anesthesia  is often used for children, traumatic eye injuries, or major orbitotomies, and for apprehensive patients. The  physician administering anesthesia , or a  nurse anesthetist  or  anesthetist assistant  with expertise in anesthesia of the eye, monitors the patient's cardiovascular status. Sterile precautions are taken to prepare the area for surgery and lower the risk of infection. These precautions include the use of  antiseptics , such as  povidone-iodine , and sterile drapes, gowns, and gloves.


Although the terms laser eye surgery and  refractive surgery  are commonly used as if they were interchangeable, this is not the case. Lasers may be used to treat nonrefractive conditions (e.g. to seal a retinal tear). [ 3 ]  Laser eye surgery or laser corneal surgery is a medical procedure that uses a laser to reshape the surface of the eye to correct  myopia  (short-sightedness),  hypermetropia  (long-sightedness), and  astigmatism  (uneven curvature of the eye's surface). Importantly, refractive surgery is not compatible with everyone, and people may find on occasion that eyewear is still needed after surgery. [ 4 ]


Recent developments also include procedures that can change eye color from brown to blue. [ 5 ] [ 6 ]  Before proceeding with laser surgery, the eye specialist needs to certify that the patient is a suitable candidate for the surgery and there are several factors to be considered before doing laser surgery. [ 7 ]


A  cataract  is an opacification or cloudiness of the eye's  crystalline lens  due to aging, disease, or trauma that typically prevents light from forming a clear image on the  retina . If  visual loss  is significant, surgical removal of the lens may be warranted, with lost  optical power  usually replaced with a plastic  intraocular lens . Owing to the high prevalence of cataracts, cataract extraction is the most common eye surgery. Rest after surgery is recommended. [ 8 ]


Glaucoma  is a group of diseases affecting the  optic nerve  that results in  vision loss  and is frequently characterized by raised  intraocular pressure . Many types of glaucoma surgery exist, and variations or combinations of those types can facilitate the escape of excess  aqueous humor  from the eye to lower intraocular pressure, and a few that lower it by decreasing the production of aqueous humor.


Canaloplasty  is an advanced, nonpenetrating procedure designed to enhance drainage through the eye's natural drainage system to provide sustained reduction of intraocular pressure. Canaloplasty uses microcatheter technology in a simple and minimally invasive procedure.
To perform a canaloplasty, an ophthalmologist creates a tiny incision to gain access to a canal in the eye. A microcatheter circumnavigates 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. [ clarification needed ]  The catheter is then removed and a suture is placed within the canal and tightened. [ clarification needed ]  By opening up the canal, the pressure inside the eye can be reduced. [ clarification needed ] [ 9 ] [ 10 ] [ 11 ] [ 12 ]


Refractive surgery aims to correct errors of refraction in the eye, reducing or eliminating the need for corrective lenses.


Corneal surgery  includes most refractive surgery, as well as:


Vitreoretinal surgery includes:


With about 1.2 million procedures each year,  extraocular muscle  surgery is the third-most common eye surgery in the United States.
 [1]   Archived  2016-08-18 at the  Wayback Machine


Oculoplastic surgery, or oculoplastics, is the subspecialty of  ophthalmology  that deals with the reconstruction of the eye and associated structures. Oculoplastic surgeons perform procedures such as the repair of droopy eyelids ( blepharoplasty ), [ 30 ]  repair of tear duct obstructions, orbital fracture repairs, removal of tumors in and around the eyes, and facial rejuvenation procedures including laser skin resurfacing, eye lifts, brow lifts, and even facelifts. Common procedures are:


Many of these described procedures are historical and are not recommended due to a risk of complications. Particularly, these include operations done on ciliary body in an attempt to control glaucoma, since highly safer surgeries for glaucoma, including lasers, nonpenetrating surgery, guarded filtration surgery, and seton valve implants have been invented.


' General'  surgery  is a  surgical specialty  that focuses on  alimentary canal  and  abdominal  contents including the  esophagus ,  stomach ,  small intestine ,  large intestine ,  liver ,  pancreas ,  gallbladder ,  appendix  and  bile ducts , and often the  thyroid gland . General surgeons also deal with diseases involving the  skin ,  breast ,  soft tissue ,  trauma ,  peripheral artery disease  and  hernias  and perform  endoscopic  as such as  gastroscopy ,  colonoscopy  and laparoscopic procedures.


General surgeons may sub-specialise into one or more of the following disciplines: [ 1 ]


In many parts of the world including  North America ,  Australia  and the  United Kingdom , the overall responsibility for  trauma care  falls under the auspices of general surgery. Some general surgeons obtain advanced training in this field (most commonly surgical critical care) and specialty certification surgical critical care. General surgeons must be able to deal initially with almost any surgical emergency. Often, they are the first port of call to critically ill or gravely injured patients, and must perform a variety of procedures to stabilize such patients, such as thoracostomy,  cricothyroidotomy , compartment fasciotomies and emergency  laparotomy  or  thoracotomy  to  stanch  bleeding. They are also called upon to staff surgical intensive care units or trauma intensive care units. [ citation needed ]


All general surgeons are trained in emergency surgery. Bleeding, infections, bowel obstructions and organ perforations are the main problems they deal with.  Cholecystectomy , the surgical removal of the gallbladder, is one of the most common surgical procedures done worldwide. This is most often done electively, but the gallbladder can become acutely inflamed and require an emergency operation. Infections and rupture of the  appendix  and small bowel obstructions are other common emergencies.


This is a relatively new specialty dealing with  minimal access techniques  using cameras and small instruments inserted through 3- to 15-mm  incisions.  Robotic surgery  is now evolving from this concept (see below). Gallbladders, appendices, and colons can all be removed with this technique. Hernias are also able to be repaired laparoscopically.  Bariatric surgery  can be performed laparoscopically and there a benefits of doing so to reduce wound complications in  obese  patients. General surgeons that are trained today are expected to be proficient in laparoscopic procedures.


General surgeons treat a wide variety of major and minor colon and rectal diseases including inflammatory bowel diseases (such as  ulcerative colitis  or  Crohn's disease ),  diverticulitis , colon and rectal cancer, gastrointestinal bleeding and hemorrhoids.


General surgeons can specialise in Upper Gastro-intestinal (or  foregut ) surgery, which includes the surgical treatment of diseases of the  stomach  and  oesophagus ,  liver ,  pancreas  and  gallbladder . [ 2 ]  In the UK, Upper GI surgeons can subspecialise further as benign surgeons, dealing with  hiatus hernias  and gallbladder diseases, bariatric surgeons, providing surgical care for  weight management  and metabolic diseases, or oesophago-gastric surgeons, dealing with complex problems related to the upper gastrointestinal tract (the foregut), including cancer. Surgical care of complex liver and pancreatic problems (including  liver cancer  and  pancreatic cancer ) is undertaken by  Hepatobiliary and Pancreatic Surgery  sub-specialists.


General surgeons perform a majority of all non-cosmetic breast surgery from lumpectomy to  mastectomy , especially pertaining to the evaluation, diagnosis and treatment of  breast cancer .


General surgeons can perform vascular surgery if they receive special training and certification in vascular surgery. Otherwise, these procedures are typically performed by vascular surgery specialists. However, general surgeons are capable of treating minor vascular disorders.


General surgeons are trained to remove all or part of the thyroid and  parathyroid glands  in the neck and the  adrenal glands  just above each  kidney  in the abdomen. In many communities, they are the only surgeon trained to do this. In communities that have a number of subspecialists, other subspecialty surgeons may assume responsibility for these procedures.


Responsible for all aspects of pre-operative, operative, and post-operative care of abdominal organ transplant patients.  Transplanted organs include liver, kidney, pancreas, and more rarely small bowel.


Surgical oncologist refers to a general surgical oncologist (a specialty of a general surgeon), but thoracic surgical oncologists, gynecologist and so forth can all be considered surgeons who specialize in treating cancer patients.  The importance of training surgeons who sub-specialize in cancer surgery lies in evidence, supported by a number of clinical trials, that outcomes in surgical cancer care are positively associated to surgeon volume (i.e., the more cancer cases a surgeon treats, the more proficient he or she becomes, and his or her patients experience improved survival rates as a result). This is another controversial point, but it is generally accepted, even as common sense, that a surgeon who performs a given operation more often, will achieve superior results when compared with a surgeon who rarely performs the same procedure. This is particularly true of complex cancer resections such as  pancreaticoduodenectomy  for pancreatic cancer, and  gastrectomy  with extended (D2) lymphadenectomy for gastric cancer. Surgical oncology is generally a 2-year fellowship following completion of a general surgery residency (5–7 years).


Most cardiothoracic surgeons in the U.S. (D.O. or M.D.) first complete a general surgery residency (typically 5–7 years), followed by a cardiothoracic surgery fellowship (typically 2–3 years). However, new programmes are currently offering cardiothoracic surgery as a residency (6–8 years).


Pediatric surgery is a subspecialty of general surgery. Pediatric surgeons do surgery on patients under age 18. Pediatric surgery is 5–7 years of residency and a 2-3 year fellowship.


In the 2000s,  minimally invasive surgery  became more prevalent. Considerable enthusiasm has been built around  robot-assisted surgery  (also known as  robotic surgery ), despite a lack of data suggesting it has significant benefits that justify its cost. [ 3 ]


In Canada, Australia, New Zealand, and the United States general surgery is a five to seven year  residency  and follows completion of  medical school , either  MD, MBBS, MBChB , or  DO  degrees. In Australia and New Zealand, a residency leads to eligibility for Fellowship of the  Royal Australasian College of Surgeons . In Canada, residency leads to eligibility for certification by and Fellowship of the  Royal College of Physicians and Surgeons of Canada , while in the United States, completion of a residency in general surgery leads to eligibility for board certification by the  American Board of Surgery  or the  American Osteopathic Board of Surgery  which is also required upon completion of training for a general surgeon to have operating privileges at most hospitals in the United States.


In the  United Kingdom , surgical trainees may apply to enter training after five years of medical school and two years of the  Foundation Programme . During the two year core surgical training programme ("phase 1"), doctors are required to sit the Membership of the  Royal College of Surgeons  (MRCS) examination. On award of the MRCS by one of the four surgical colleges, surgeons may hold the title ' Mister ' or ' Miss / Ms. / Mrs ' rather than doctor. This tradition dates back hundreds of years in the United Kingdom from when only physicians attended medical school and surgeons did not, but were rather associated with  barbers  in the  Barber Surgeon's  Guild. The tradition is also present in many  Commonwealth  countries including  New Zealand  and some states of  Australia . After completion of phase 1 training, trainees may apply for a nationally awarded Higher Surgical Training (HST) programme, which lasts six years and is now divided into two further phases (phases 2 and 3). Trainees are expected to declare a sub-specialty before the end of phase 2, and training during phase 3 focuses on that sub-specialty. Before the end of HST, the examination for  Fellowship of the Royal College of Surgeons  (FRCS) must be taken in general surgery plus the subspeciality. Upon completion of training, the surgeon will be eligible for entry on the  GMC  Specialist Register. They may then apply to work both in the  NHS  and independent sector as a consultant surgeon, although many trainees complete further fellowships. [ 4 ]  The implementation of the European Working Time Directive limited UK surgical residents to an average 48-hour working week. [ 5 ]


Oculoplasty , or oculoplastic surgery, involves medical and surgical treatment for deformities and abnormalities of the eyelids, lacrimal (tear) system, orbit (bony cavity around the eye), and the adjacent face. This specialized branch of ophthalmology requires adherence to strict medical guidelines and legal frameworks to ensure patient safety and professional accountability. [ 1 ]


Ophthalmology  ( / ˌ ɒ f θ æ l ˈ m ɒ l ə dʒ i / ,  OFF -thal- MOL -ə-jee ) [ 1 ]  is a  clinical  and  surgical  specialty within  medicine  that deals with the diagnosis and treatment of  eye  disorders. [ 2 ]  A former term is  oculism .


An  ophthalmologist  is a physician who undergoes subspecialty training in medical and surgical eye care. [ 3 ]  Following a  medical degree , a doctor specialising in ophthalmology must pursue additional postgraduate  residency training  specific to that field. This may include a one-year integrated internship that involves more general medical training in other fields such as internal medicine or general surgery. Following residency, additional specialty training (or fellowship) may be sought in a particular aspect of eye pathology. [ 4 ]


Ophthalmologists prescribe medications to treat ailments, such as eye diseases, implement laser therapy, and perform surgery when needed. [ 5 ]   Ophthalmologists provide both primary and specialty eye care—medical and surgical. [ 5 ]  Most ophthalmologists participate in academic research on eye diseases at some point in their training and many include research as part of their career. [ 6 ]
Ophthalmology has always been at the forefront of medical research with a long history of advancement and innovation in eye care. [ 7 ]


A brief list of some of the most common diseases treated by ophthalmologists: [ 8 ] [ 9 ]


The most valued pharmaceutical companies worldwide whose leading products are in Ophthalmology are  Regeneron  (United States) for  Macular degeneration (AMD)  treatment and  Bausch Health  (Canada) for Front of eye. [ 10 ]


Following are examples of examination methods performed during an  eye examination  that enables diagnosis [ citation needed ]


Optical coherence tomography  (OCT)  is a medical technological platform used to assess ocular structures. The information is then used by physicians to assess staging of pathological processes and confirm clinical diagnoses. Subsequent OCT scans are used to assess the efficacy of managing diabetic retinopathy, age-related macular degeneration, and glaucoma.


Optical coherence tomography angiography  (OCTA)  and  Fluorescein angiography  to visualize the vascular networks of the retina and choroid.


Electroretinography   (ERG)  measures the electrical responses of various cell types in the  retina , including the  photoreceptors  ( rods  and  cones ), inner retinal cells ( bipolar  and  amacrine  cells), and the  ganglion cells .


Electrooculography  ( EOG ) is a technique for measuring the corneo-retinal standing potential that exists between the front and the back of the human eye. The resulting signal is called the electrooculogram. Primary applications are in ophthalmological  diagnosis  and in recording  eye movements .


Visual field testing  to detect dysfunction in central and  peripheral vision  which may be caused by various medical conditions such as  glaucoma ,  stroke ,  pituitary disease ,  brain tumours  or other neurological deficits.


Corneal topography  is a  non-invasive   medical imaging  technique for mapping the anterior curvature of the  cornea , the outer structure of the  eye .


Ultrasonography  of the eyes may be performed by an ophthalmologist.


Eye surgery , also known as ocular surgery, is surgery performed on the eye or its adnexa by an ophthalmologist. The eye is a fragile organ, and requires extreme care before, during, and after a surgical procedure. An eye surgeon is responsible for selecting the appropriate surgical procedure for the patient and for taking the necessary safety precautions.


Ophthalmology includes subspecialities that deal either with certain diseases or diseases of certain parts of the eye. Some of them are: [ 11 ]


Medical retina and vitreo-retinal surgery sometimes are combined and together they are called  posterior segment  subspecialisation


The  Greek  roots of the word ophthalmology are ὀφθαλμός ( ophthalmos , "eye") and -λoγία (- logia , "study, discourse"), [ 14 ] [ 15 ]  i.e., "the study of eyes". The discipline applies to all animal eyes, whether human or not, since the practice and procedures are quite similar with respect to disease processes, although there are differences in the anatomy or disease prevalence.


In the  Ebers Papyrus  from ancient Egypt dating to 1550 BC, a section is devoted to eye diseases. [ 2 ]