Bariatric Journal

Complications of Gastric Bypass (RNY) Surgery

The surgical complication is defined as the deviation from ordinary postoperative course whether symptomatic or asymptomatic. This differs from failure or sequela. A surgical sequel is expected aftermath of a surgical procedure, i.e., inability to breastfeed following the removal of both breasts due to malignancy.

Failure, on the other hand, is said to have occurred when the purpose of the surgery is not achieved.1

Gastric bypass surgery is one of the surgical procedures performed for the treatment of morbid obesity (BMI≥ 40). It is also done for those who are not morbidly obese but have failed to lose appreciable weight with non-operative management of obesity and those with obesity-associated conditions.

The commonest of this type of surgery is the laparoscopic Roux-en-Y gastric bypass. This surgery is both a restrictive (limits the quantity of food that the individual can take) and malabsorptive (reduces the number of nutrients that can be absorbed) surgery.

It involves reduction of the stomach’s capacity by compartmentalization into an upper pouch of about 30mls and a lower bigger non-functioning pouch. This is achieved with the use of staples. In a proximal Roux-en-Y gastric bypass, the small intestine is then divided at about 45cm from the lower stomach pouch, and the distal end of the divide is connected to the small upper (functional) stomach pouch. While the proximal end of the divide is connected to the small intestine at about 100cm distal to the site of division.2

Complications following surgery can be from the type of anesthesia used or the surgery itself. Anesthetic complications following gastric bypass surgery are as for other surgical procedures. Those that are related to the gastric bypass procedure are either major or minor. Minor complications are those that do not require any surgical intervention and vice versa. The complications can also be classified as early (occurring within 2weeks) and late (occurring after 2weeks).3

The early difficulties include staple line leak, postoperative bleeding, and intestinal obstruction. Late complications are an anastomotic stricture, marginal ulcer formation, fistula formation, and nutritional deficiencies.3

The compartmentalization and connections (anastomosis) explained above are done using staples. Leakage from these sites remained the most feared complication of the gastric bypass surgery.4Most of these leakages occur at the site of anastomosis between the small stomach pouch and the intestine, i.e., gastro-jejunal anastomotic site (67.8%).4the presence of multiple obesity-associated disease conditions, older age, extremely obese, and male gender are all risk factors for staple line leak.5

A high index of suspicion is required to promptly make this diagnosis. The onset of abdominal pain, fever, increased heart rate, and drainage of pus from the abdominal drain are all pointers to the possibility of staple line leakage. This complication may require laparoscopic or open surgery with a subsequent increase in the duration of stay in the hospital with an overall increase in the cost of care.

Bleeding from the staple sites is an early complication of the Roux-en-Y gastric bypass. This can either be in the abdominal cavity or the stomach with a different mode of presentation. Incidence varies between 1.9%-4.4%.3For those with bleeding into the pointers include: vomiting of blood (hematemesis), the passage of dark shining stool (melena), or frank blood in stool (hematochezia). Intra-abdominal; bleeding may present with drainage of raw effluent from the drain site. This is however not the true sign.

Increase in heart rate, thread, and small volume pulse, abdominal pain, or unexplained drop in the hemoglobin level should warrant suspicion of post-operative bleeding. Abdominal re-exploration may be required to stop this bleeding.

Obstruction of the small intestine is another complication of laparoscopic gastric bypass surgery. They are mostly due to internal hernias. The defects created in the mesentery and transverse mesocolon while anastomosing the intestine with each other and with the stomach serve as potential sites for herniation of the small intestine. An incidence of 3.1% was reported in a study of over 2000 patients who had Laparoscopic Roux-en-Y gastric bypass.6

Patients may present with intermittent colicky abdominal pain, nausea, vomiting, and abdominal distension. Some patients may present in shock while others may have strangulation, gangrenous bowel and subsequent intestinal perforation if they present late. An open or laparoscopic surgery may be required to repair the hernia.

One of the late complications of Laparoscopic Roux-en-Y gastric bypass is anastomotic stricture. This is an abnormal narrowing of the site of anastomosis between the stomach and the intestine (gastro-jejunostomy anastomotic stricture). Studies have revealed a wide variation in the incidence of this complication.3Symptoms include difficulty in swallowing, vomiting, with or without abdominal pain. This condition may be managed by pneumatic dilatation of the stricture via endoscopy or by open surgery.

Exposure of the intestinal lining (at the site of an anastomosis of the stomach to the intestine) to the acidic content of the stomach in association with inadequate blood supply to this area and presence of Helicobacter pylori may lead to a peptic ulcer (marginal ulcer). Patient often presents with epigastric pain. Endoscopy may be required to confirm the diagnosis and treatment is similar to that of peptic ulcers.

Another long term complication is the development of an abnormal connection between the smaller and functional stomach pouch and the larger pouch. This may lead to inadequate weight loss after gastric bypass.

Complications after Laparoscopic Roux-en-Y gastric bypass may add to the overall mortality of this procedure. However, in safe hands these can be minimized or diagnosed early and promptly managed.

  1. Costs of Gastric Sleeve Surgery
  2. Life and Recovery of Gastric Sleeve Surgery


  1. Dindo D, Demartines N, Clavien P-A. Classification of Surgical Complications: A New Proposal With Evaluation in a Cohort of 6336 Patients and Results of a Survey. Annals of Surgery. 2004;240(2):205-213. doi:10.1097/
  2. Pories WJ. Bariatric Surgery: Risks and Rewards. The Journal of Clinical Endocrinology and Metabolism. 2008;93(11 Suppl 1):S89-S96. doi:10.1210/jc.2008-1641.
  3. Griffith PS, Birch DW, Sharma AM, Karmali S. Managing complications associated with laparoscopic Roux-en-Y gastric bypass for morbid obesity. Canadian Journal of Surgery. 2012;55(5):329-336. doi:10.1503/cjs.002011.
  4. Ballesta C, Berindoague R, Cabrera M, Palau M, Gonzales M. Management of Anastomotic Leaks After Laparoscopic Roux-en-Y Gastric Bypass. Obesity Surgery. 2008;18(6):623-630. doi:10.1007/s11695-007-9297-6.
  5. Fernandez Jr A, DeMaria E, Tichansky D et al. Experience with over 3,000 open and laparoscopic bariatric procedures: Multivariate analysis of factors related to leak and resultant mortality. Surgical Endoscopy. 2004;18(2):193-197. doi:10.1007/s00464-003-8926-y.
  6. Higa K, Ho T, Boone K. Internal Hernias after Laparoscopic Roux-en-Y Gastric Bypass: Incidence, Treatment and Prevention. Obesity Surgery. 2003;13(3):350-354. doi:10.1381/096089203765887642.

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