INTRODUCTION — The number of bariatric surgical operations performed in the United States has been steadily increasing for the last five years. It is estimated that 256,000 weight-loss surgeries were performed in 2019 [1]. Of those, 60 percent were sleeve gastrectomy, 18 percent were gastric bypass, 1 percent were gastric band, and 1 percent were biliopancreatic diversion with duodenal switch. The remaining 20 percent were revisional procedures.
Complications following surgical treatment of severe obesity vary based upon the procedure performed and can be as high as 40 percent [2,3]. Due to the high surgical volume, improving the safety of these operations has become a high priority, leading to the development of strict criteria for center accreditation, guidelines for safe and effective bariatric surgery, and careful monitoring of surgical outcomes [4-8].
This topic will review the major late complications of bariatric surgery, defined as occurring after 30 days. A description of bariatric procedures, indications and preoperative management, short-term medical outcomes, and long-term complications of laparoscopic operations are reviewed as separate topics.
●(See "Bariatric procedures for the management of severe obesity: Descriptions".)
●(See "Bariatric surgery for management of obesity: Indications and preoperative preparation".)
●(See "Outcomes of bariatric surgery".)
●(See "Bariatric operations: Early (fewer than 30 days) morbidity and mortality".)
●(See "Complications of laparoscopic surgery".)
●(See "Laparoscopic Roux-en-Y gastric bypass".)
●(See "Laparoscopic sleeve gastrectomy".)
ROUX-EN-Y GASTRIC BYPASS — Roux-en-Y gastric bypass (RYGB) involves the creation of a small gastric pouch and an anastomosis to a Roux limb of jejunum that bypasses 75 to 150 cm of small bowel, thereby restricting food and limiting absorption (figure 1) [9]. This procedure is one of the most common weight-loss procedures performed. Complications of RYGB are diverse and vary based upon the specific technique. Some complications are relatively specific to the surgical approach (open versus laparoscopic). Certain complications are seen during the early postoperative periods, while others may present weeks to months following the surgery.
Gastric remnant distension — Gastric remnant distension is a rare but potentially lethal complication following gastric bypass [10,11]. The gastric remnant is a blind pouch and may become distended if paralytic ileus or distal mechanical obstruction occurs postoperatively. Iatrogenic injury to vagal fibers along the lesser curvature may also contribute, possibly by leading to impaired emptying of the bypassed stomach. Progressive distension can ultimately lead to rupture, spillage of massive gastric contents, and subsequent severe peritonitis [12]. The combination of the large size of inoculum (liters) and the injurious contents (acid, bile, pancreatic enzymes, and bacteria) makes this complication much more serious than leakage occurring at the gastrojejunostomy.
Clinical features include pain, hiccups, left upper quadrant tympany, shoulder pain, abdominal distension, tachycardia, or shortness of breath. Radiographic assessment may demonstrate a large gastric air bubble.
Treatment consists of emergency operative decompression with a gastrostomy tube or percutaneous gastrostomy [13]. Immediate operative exploration and decompression are required if percutaneous drainage is not feasible or if perforation is suspected. Although gastrostomy is not performed routinely by most surgeons at the initial gastric bypass operation, drainage of the gastric remnant can prevent this rare but sometimes fatal complication. Routine gastrostomy should be considered in older patients with class III obesity, patients with diabetic gastropathy, and as part of revisional surgeries where gastric emptying may be delayed.
Stomal stenosis — Stomal (anastomotic) stenosis has been described in 6 to 20 percent of patients who have undergone RYGB [14]. The etiology is uncertain, although tissue ischemia, marginal ulcer, or increased tension on the gastrojejunal anastomosis is believed to have a role. The stomal stenosis rate is higher in LRYGB [15] and may be related to the use of the small-diameter (21 mm) circular staplers. (See "Laparoscopic Roux-en-Y gastric bypass", section on 'Other gastrojejunal anastomosis techniques'.)
A stomal stenosis manifests clinically when the anastomosis narrows to a diameter of <10 mm [16]. Patients typically present several weeks after surgery with nausea, vomiting, dysphagia, gastroesophageal reflux, and eventually an inability to tolerate oral intake, including liquids [16,17]. The diagnosis is usually established by endoscopy or with an upper gastrointestinal series.
Endoscopic balloon dilation is usually successful [18-20]. The stoma should be dilated to a diameter of approximately 15 mm; further dilation to 20 mm may reduce the restrictive effect of RYGB. The gastrojejunal (GJ) anastomosis should not be dilated by >3 to 4 mm at a time, and, as such, most patients will need two to three endoscopic procedures to reach a 15 mm anastomosis [16,21]. The complication rate for dilation is approximately 3 percent [21]. Careful communication between the endoscopist and the surgeon regarding the details of the original operation is important to minimize the risk of endoscopic complications.
Patients with a chronic stenosis that is refractory to multiple dilations require a surgical revision of the GJ anastomosis after a delay of a few months to allow the gastric pouch to dilate. Fortunately, <0.05 percent of patients require such a revision surgery.
Marginal ulcers — Marginal ulcers have been reported in 0.6 to 16 percent of patients [19,22-27]. Marginal ulcers occur near the gastrojejunostomy and result from acid injuring the jejunum, or they can be associated with a gastrogastric [26] or, rarely, gastrocolic fistula [28].
Causes of marginal ulcers include [23,24,29,30]:
●Poor tissue perfusion due to tension or ischemia at the anastomosis
●Presence of foreign material, such as staples or nonabsorbable suture
●Excess acid exposure in the gastric pouch due to gastrogastric fistulas
●Nonsteroidal anti-inflammatory drug use
●Helicobacter pylori infection
●Smoking
Patients with marginal ulcers can present with nausea, abdominal pain, gastrointestinal bleeding, stomal stenosis, or perforation. The diagnosis of a marginal ulcer is established by upper endoscopy. (See "Gastrointestinal endoscopy in patients who have undergone bariatric surgery", section on 'Gastrojejunal ulceration and bleeding'.)
The mainstay of medical therapy for marginal ulcers is high-dose proton-pump inhibitors (PPIs). There is no consensus on the formulation or dose of therapy [31]. Some authors recommend the use of soluble PPIs, or opening capsules, to enhance absorption in bypass patients [32]. In addition to PPI twice a day, we recommend adding sucralfate 1 gram four times a day for a minimum of three months prior to considering revisional options.
Additionally, nonsteroidal anti-inflammatory drugs should be discontinued, and patients should be encouraged to stop smoking. An upper gastrointestinal series or a computed tomography (CT) scan with oral contrast should be performed to rule out a gastrogastric fistula.
The prevalence of H. pylori infection in patients undergoing weight loss surgery is high, and a significant proportion of them have postoperative foregut symptoms. Observational studies have shown that patients with H. pylori colonization have a higher incidence of marginal ulcer formation [30,33-36]. Furthermore, in one study, preoperative testing and treatment of H. pylori significantly reduced the incidence of postoperative marginal ulcers (2.4 versus 6.8 percent in unscreened patients) [33]. (See "Indications and diagnostic tests for Helicobacter pylori infection in adults" and "Treatment regimens for Helicobacter pylori in adults".)
Although medical management of marginal ulcers is successful in 85 to 95 percent of patients [19], surgery may be indicated if marginal ulcers perforate or if persistent pain or recurrent bleeding occurs despite maximal medical therapy. In stable patients, revision of the gastrojejunostomy with truncal vagotomy should be performed [19,37,38]. In unstable patients, a Graham patch can be used to seal any perforation, the local area washed out, and a feeding tube placed. If stenosis occurs, the GJ anastomosis can be revised at a later time when the patient is more stable.
Candy cane Roux syndrome — Candy cane Roux syndrome in patients who have undergone RYGB refers to an excessively long blind afferent Roux limb at the gastrojejunostomy causing postprandial pain often relieved by vomiting. It is believed that the blind afferent limb ("candy cane") acts as an obstructed loop when filled with food (often preferentially), and the distention of the loop causes pain until the food either spills into the Roux limb or is vomited back out (figure 2) [39].
Patients have been reported presenting as early as three months and as late as 11 years after their initial RYGB, typically with symptoms of postprandial epigastric pain, nausea, vomiting, and reflux or food regurgitation [40]. The diagnosis is confirmed by upper gastrointestinal contrast studies or endoscopy. On upper gastrointestinal series, the afferent limb fills before contrast spills into the Roux limb. On upper endoscopy, the afferent limb is usually the most direct outlet of the gastrojejunostomy [39].
The treatment is revision bariatric surgery, most commonly laparoscopic resection of the afferent limb [41], which ranged in length from 3 to 22 cm in one study (mean of 7.6 cm) [39]. Symptoms resolve after revision surgery in most patients. Surgeons should minimize the length of the blind afferent loop left at the time of initial RYGB to prevent candy cane Roux syndrome.
Cholelithiasis — Cholelithiasis develops in as many as 38 percent of patients within six months of surgery, and up to 41 percent of such patients become symptomatic [42]. Rapid weight loss can also contribute to the development of gallstones by increasing the lithogenicity of bile [43]. The high frequency of cholelithiasis can be reduced to as low as 2 percent with a six-month course of ursodeoxycholic acid (UDCA; ursodiol, a synthetic bile salt) given prophylactically after weight-loss surgery [44]. (See "Gallstones: Epidemiology, risk factors and prevention".)
The decision to perform a cholecystectomy at the time of bypass is controversial. Some surgeons recommend performing cholecystectomy at the time of bypass if a patient has symptomatic gallstones preoperatively. The surgical opinion about asymptomatic gallstones is more divided, and studies have failed to demonstrate a benefit for simultaneous cholecystectomy for incidental gallstones at the time of RYGB [45,46].
Patients can also develop choledocholithiasis (stones in the common bile duct), which can be difficult to treat in the postoperative RYGB patient. Diagnosis of choledocholithiasis can be confirmed by ultrasound or magnetic resonance cholangiopancreatography (MRCP); however, endoscopic intervention and management can be difficult because of the relative inaccessibility to the duodenum due to the altered anatomy of the Roux-en-Y configuration. As a result, successful endoscopic retrograde cholangiopancreatography (ERCP) with cannulation of the papilla is very difficult to perform [47,48]. Thus, treatment of choledocholithiasis may require surgery or transhepatic percutaneous access. Alternatively, placement of a gastrostomy tube into bypassed stomach at the time of gastric bypass, with the addition of a radiopaque marker to facilitate future percutaneous access to the gastric remnant, has also been described [49]. Surgical gastrostomy for pancreatobiliary and duodenal access following RYGB has been done with good results and may be an option when traditional endoscopic approaches are impossible [50].
Ventral incisional hernia — Ventral incisional hernias occur with a frequency of 0 to 1.8 percent in laparoscopic series and as high as 24 percent in open series, underscoring a clear advantage of the laparoscopic approach in this regard [15,22,51-53].
Incisional hernias present with an enlarging bulge, pain, or obstructive symptoms. Severe obesity is associated with increased intra-abdominal pressure and thus a high risk of hernia development after a laparotomy. Many surgeons postpone a formal repair until significant weight loss occurs (>1 year). Indications for early surgical repair include significant pain, bowel obstruction, and rapid enlargement of the hernia. (See "Overview of abdominal wall hernias in adults".)
Internal hernias — Mesenteric defects that are created during a Roux-en-Y gastric bypass include (figure 3):
●A mesenteric defect at the jejunojejunostomy
●A space between the transverse mesocolon and Roux-limb mesentery (ie, Petersen's defect)
●A defect in the transverse mesocolon in patients with a retrocolic Roux-limb (see "Laparoscopic Roux-en-Y gastric bypass", section on 'Antecolic versus retrocolic passage of the Roux limb')
Internal hernias have been described in 0 to 5 percent of patients after laparoscopic gastric bypass [15,22]. To reduce the incidence of internal hernias, all mesenteric defects should be closed with nonabsorbable sutures [22]. In a multicenter trial, 2507 patients were randomly assigned to undergo laparoscopic Roux-en-Y gastric bypass with or without mesenteric defect closure [54]. Compared with nonclosure, mesenteric closure significantly decreased the incidence of reoperation due to small bowel obstruction (6 versus 10 percent at three years) but increased early postoperative complications due to kinking of the jejunojejunostomy (4.3 versus 2.8 percent). In another study, the small bowel obstruction rate was reduced from 6 to 3 percent when all such defects were routinely closed [55].
The majority of internal hernias after laparoscopic gastric bypass occurred through the transverse mesocolon defect (44 of 66 in one study) [56]. The use of an antecolic Roux limb can, in theory, reduce the risk of internal hernia formation by eliminating the transverse mesocolic defect. A 2016 meta-analysis found that the use of an antecolic Roux limb, as opposed to a retrocolic Roux limb, was associated with lower rates of postoperative internal hernia (1.3 versus 2.3 percent) and small bowel obstruction (1.4 versus 5.2 percent) [57]. However, the two techniques have not been directly compared with each other in randomized trials.
Internal hernias can be difficult to detect radiographically because they are intermittent. Several studies have shown that the "mesenteric swirl" sign on CT scan is the best indicator of an internal hernia following gastric bypass [58-60]. The mesenteric swirl sign shows a swirled appearance of mesenteric vessels or fat at the root of the mesentery (image 1). The mesenteric swirl sign has high sensitivity (78 to 100 percent) and specificity (80 to 90 percent) and can be easily recognized by experienced radiologists with high interobserver agreement [58]. (See "Imaging studies after bariatric surgery", section on 'Internal hernia'.)
Small bowel obstruction — Small bowel obstruction (SBO) can occur at any time after an RYGB, with a lifetime incidence of 3 to 5 percent [57,61]. Post-RYGB SBO is most commonly caused by herniation of small intestine through one of the mesenteric defects (ie, internal hernias), which are discussed separately [62] (see 'Internal hernias' above). Alternatively, SBO can also be caused by adhesive disease, an incisional hernia, or intussusception (typically at the jejunojejunal [JJ] anastomosis).
Patients with SBO can present acutely or subacutely with vague, intermittent, crampy, and sharp abdominal pain usually unrelated to eating. Symptomatic patients should undergo CT scan, and those who are diagnosed with SBO due to internal hernia by CT scan should undergo urgent surgical exploration to reduce the hernia. SBO due to internal hernia is likely be a closed loop obstruction, which has a higher perforation risk. An uncorrected SBO due to internal hernia could lead to bowel strangulation, which may necessitate extensive bowel resection and could result in short bowel syndrome. (See 'Short bowel syndrome' below.)
If the CT scan is normal but patients continue to have symptoms suggestive of SBO, they should be explored laparoscopically to exclude an internal hernia or other cause of an SBO.
Intussusception — Jejunojejunal intussusception after RYGB is a rare but potentially catastrophic complication. Most patients present acutely with abdominal pain ranging from 25 to 52 months after RYGB [63]. Most intussusceptions after RYGB occur at the jejunojejunostomy site and are retrograde. Jejunojejunostomy length greater than 60 mm may be associated with the occurrence of intussusception [64].
Most patients require surgical intervention. Resection and revision of the jejunojejunostomy is mandatory in the presence of ischemic or nonreducible small bowel [63]. Less acute patients can be managed with laparoscopic reduction and enteropexy after reduction [64]. Imbrication of the jejunojejunal anastomosis has also been proposed as a method to reduce recurrences [65].
Short bowel syndrome — RYGB and other bariatric procedures can be complicated by short bowel syndrome (SBS) that results from small bowel resections for internal hernias or bowel obstruction from adhesions. In a retrospective review of 265 patients, 11 developed SBS following bariatric surgery [66]. In some cases, this complication may require intestinal transplantation [67]. (See "Pathophysiology of short bowel syndrome".)
Dumping syndrome — Dumping syndrome can occur in up to 50 percent of post-gastric bypass patients when high levels of simple carbohydrates are ingested [68]. In a Danish survey of 1429 patients who underwent RYGB, 9.4 and 6.6 percent reported experiencing moderate-to-severe symptoms indicative of early dumping and hypoglycemia, respectively [69]. In that cohort, the total prevalence of one or both types of symptoms was 12.6 percent (95% CI 10.9 to 14.4 percent). Patients who were younger than 35 years of age or had a body mass index (BMI) <25 kg/m2 were more likely to be symptomatic than those who were older or had a higher BMI. Dumping may contribute to weight loss in part by causing patients to modify their eating habits. (See "Postgastrectomy complications", section on 'Dumping syndrome'.)
There are two types of dumping syndrome, early and late. Early dumping syndrome has a rapid onset, usually within 15 minutes. It is the result of rapid emptying of food into the small bowel. Due to the hyperosmolality of the food, rapid fluid shifts from the plasma into the bowel occur, resulting in hypotension and a sympathetic nervous system response. Patients often present with colicky abdominal pain, diarrhea, nausea, and tachycardia [70].
Patients should avoid foods that are high in simple sugar content and replace them with a diet consisting of high-fiber, complex carbohydrate, and protein-rich foods. Behavioral modification, such as small, frequent meals and separating solids from liquid intake by 30 minutes, is also advocated. Usually, early dumping is self-limiting and resolves within 7 to 12 weeks [68].
Postprandial hyperinsulinemic hypoglycemia — Previously referred to as late dumping syndrome, postprandial hyperinsulinemic hypoglycemia (PHH) is a rare complication of bariatric surgery. It occurs in 0.1 to 0.3 percent of patients, most commonly after RYGB. Symptoms of PHH, including dizziness, fatigue, diaphoresis, and weakness, usually occur one to three hours after ingestion of a carbohydrate-rich meal, typically months to years after surgery, and are associated with documented hypoglycemia [71]. The pathophysiology of PHH is not fully understood but likely includes alterations in multiple hormonal and glycemic patterns (eg, increase in incretin levels). Most patients with PHH can be managed with the same dietary modification suggested above for early dumping syndrome. Patients refractory to dietary modification can be treated with medications (eg, nifedipine, acarbose, diazoxide, or octreotide), gastrostomy tube feeding into the remnant stomach, or revisional bariatric surgery. Pancreatic resection has unproven benefit and should not be performed for PHH.
Metabolic and nutritional derangements — Metabolic and nutritional derangements are common in patients with severe obesity and can be exacerbated following after bariatric surgery, making postoperative life-long compliance with appropriate dietary choices and vitamin supplementation imperative. Decreased oral intake as well as altered absorption of food from the stomach and small bowel reduces absorption of various micronutrients, particularly iron, calcium, vitamin B12, thiamine, and folate. (See "Bariatric surgery: Postoperative nutritional management", section on 'Micronutrient management'.)
Hyperoxaluria and nephrolithiasis have been reported following Roux-en-Y gastric bypass surgery. (See "Kidney stones in adults: Epidemiology and risk factors".)
Hyperammonemic encephalopathy — Hyperammonemic encephalopathy has been reported in patients who are failing to thrive after complicated gastrointestinal surgeries that can include RYGB. The underlying etiologies are incompletely understood but include both genetic (eg, proximal urea cycle disorders) and nongenetic causes (eg, splenorenal shunt). The typical clinical features include hypoalbuminemia, hypoglycemia, low plasma zinc level, and other nutritional deficiencies [72].
The key to diagnosis is the early assessment of plasma ammonia levels in such patients with normal hepatic function but characteristic symptoms of encephalopathy [73]. Once hyperammonemic encephalopathy is diagnosed, it can be treated with supportive and medical care to reduce ammonia levels. (See "Hepatic encephalopathy in adults: Treatment".)
Nephrolithiasis and renal failure — RYGB has been linked to metabolic changes that could alter urine chemistry profiles, resulting in both higher calcium oxalate supersaturation and urine oxalate, lower citrate, and lower volume. Consequently, patients have a higher risk of developing nephrolithiasis after RYGB (pooled relative risk 1.79, 95% CI 1.54-2.10) [74].
While uncommon, increased absorption of calcium oxalate could also lead to deposition in the renal parenchyma, resulting in oxalate nephropathy and renal failure [75]. A retrospective review of 11 patients with oxalate nephropathy found that all were hypertensive and nine were diabetic before the procedure [76]. Renal biopsies revealed diffuse tubular degenerative changes, abundant tubular calcium oxalate deposits, and varying degrees of tubulointerstitial scarring.
Change in bowel habits — Loose stool and diarrhea are more common after BPD and RYGB. Constipation is more common after restrictive procedures, like sleeve gastrectomy and gastric banding [77]. In a study of 290 patients undergoing bariatric surgery, 126 underwent RYGB, BPD was performed in 103 patients, and 61 patients had gastric banding [77]. After RYGB, the proportion of patients with loose stools, diarrhea, or frequent flatus increased significantly (46 versus 8 percent preoperatively). After BPD, 55 percent of the patients reported an increase in loose stools or diarrhea or frequent flatus versus 8 percent preoperatively. Conversely, after gastric banding, 39 percent of patients complained of constipation.
Steatorrhea and more frequent stools can occur with excessive fat intake. In addition, these symptoms can be due to subclinical lactose intolerance, which is only recognized when dairy products are used in an effort to achieve adequate protein intake after bariatric surgery.
Gastrogastric (GG) fistula — A gastrogastric fistula is a channel that develops between the gastric pouch and the excluded stomach remnant, allowing ingested food to enter the bypassed foregut (stomach and duodenum). GG fistulas occur in approximately 1 to 2 percent of patients after RYGB and most commonly cause marginal ulcers or weight regain [78].
In the early days of gastric bypass, surgeons stapled the stomach without completely dividing the gastric remnant from the pouch. The gastric pouch and gastric remnant stapled in continuity was associated with a 49 percent rate of gastrogastric fistula [79]. The introduction of complete transection of these two segments has decreased the rate of GG fistula to 0 to 3 percent (figure 4) [78-80].
When persistent marginal ulcers or significant weight regain are seen in a post-RYGB patient, particularly in the setting of recurrent or new-onset gastroesophageal reflux symptoms, an upper gastrointestinal series or a CT scan with oral contrast should be performed to exclude a GG fistula as a cause. Patients diagnosed with a GG fistula who also have either significant weight regain or persistent symptoms from marginal ulcers (eg, abdominal pain, stomal stenosis, or gastrointestinal bleeding) are candidates for revision or repair [81].
Endoscopic techniques, including clipping, suturing, and stenting, have been used to treat GG fistula causing weight regain, but results are varied at best and recurrence rates are high [82]. Surgical revision is probably the best option for patients with persistent pain, bleeding, or stenosis from a GG fistula. Although revisional bariatric surgery is generally riskier than primary procedures, acceptable complication rates as low as 22 percent have been achieved in experienced hands [13].
In preparation for dividing the GG fistula, the gastric pouch should be fully mobilized, and the path of the Roux limb should be outlined with an orogastric tube or endoscope. The GG fistula can be resected by stapling, in which case one must staple inside the previous staple line to avoid creating a blind pouch. Alternatively, the gastric remnant can be opened to allow the fistula to be accessed from the distal side. Once the anatomy is defined, a revision of the GJ anastomosis is performed. Following revisional bariatric surgery, drains and a feeding tube should be placed.
Failure to lose weight and weight regain — Failure to lose weight following Roux-en-Y gastric bypass is rare and is often due to maladaptive eating patterns during the early postoperative period. By contrast, significant late weight regain occurs in up to 20 percent of patients, especially those with super-obesity (BMI >50 kg/m2) at the time of the initial operation. It is often due to progressive noncompliant eating and other behavioral habits [83], development of a functional GG fistula, gradual enlargement of the gastric pouch, or dilatation of the gastrojejunal anastomosis.
A GG fistula can cause weight regain by allowing food passage into the remnant stomach, thereby decreasing the restrictive effect of RYGB. The diagnosis and treatment of GG fistulas has been discussed above. (See 'Gastrogastric (GG) fistula' above.)
Dilatation of the gastric pouch or the gastrojejunal anastomosis may be responsible for weight gain in other patients. The stretched pouch and/or the outlet are thought to arise from repeated overdistension due to excessive food intake. These patients usually do not benefit from the high-risk revisional surgery. However, less invasive endoscopic procedures aimed at suture reduction of the pouch size or tightening of the stoma have been successful, at least with short-term follow-up [84,85]. The long-term efficacy of these therapies is not known and is being formally assessed as part of a clinical trial.
GASTRIC BANDING — Gastric banding (GB) is a purely restrictive procedure that involves placement of an adjustable silicone device at the gastric cardia near the gastroesophageal junction, limiting the amount of food consumed. Restriction can be adjusted by injecting saline into a subcutaneous port connected to the band (figure 5). (See "Bariatric surgery for management of obesity: Indications and preoperative preparation".)
GB is the third most common weight-loss surgery performed in the United States. GB has the lowest mortality rate among all bariatric procedures. The Australian Safety and Efficacy Register of New Interventional Procedures reported three deaths out of 5827 gastric banding procedures (0.05 percent) [86].
However, GB has been associated with several complications. An initial trial of GB in the United States showed disappointing weight loss outcomes and high complication rates, associated with relatively high revisional surgery rate (40 percent) [87]. Following changes in the surgical technique, subsequent trials in Europe, Australia, and the United States have shown fewer complications [87-91]. Long-term results from a series of 78 GB patients showed that nearly 40 percent of patients experienced major complications, 22 percent had minor complications, and almost half of the patients required reoperation [92]. Major complications included pouch dilation (11 percent), band erosion (28 percent), and band infection (1 percent). Minor complications included incisional hernias (5 percent), port-tubing disconnections (20 percent), and port infections (2 percent).
Late complications of GB include band erosion, band slippage or prolapse, port or tubing malfunction, leakage at the port site tubing or band, pouch or esophageal dilatation, and esophagitis [87,88,93-95]. Almost 50 percent of patients will need surgical revision or removal of the band. Failed bands (due either to complications or inadequate weight loss) can generally be converted to other bariatric procedures such as RYGB, sleeve gastrectomy, or a duodenal switch [13,96,97].
In addition, the rate of long-term complications and rates of reoperation are higher with laparoscopic adjustable gastric banding (LAGB) compared with RYGB. In a prospective study of 442 patients matched for age, gender, and BMI, patients undergoing LAGB had a significantly higher rate of long-term complications compared with patients undergoing RYGB (41.6 versus 19.0 percent) [98]. Patients undergoing LAGB also had a higher rate of reoperation at six years of follow-up (26.7 versus 12.7 percent).
Stomal obstruction — Acute stomal obstruction is an early complication that can occur in up to 14 percent of GB patients [99,100]. Obstruction is usually caused by inclusion of excess perigastric fat, use of a band of insufficient diameter for the thickness of the tissue, or significant tissue edema. Patients usually present with persistent nausea, vomiting, and inability to tolerate secretions or oral intake. The diagnosis is confirmed with an upper gastrointestinal series demonstrating no passage of contrast beyond the band.
Acute stomal obstruction due to edema can initially be treated conservatively with nasogastric tube decompression until the edema subsides, although a potential for aspiration pneumonia and stomach ischemia exists [13]. Persistent obstruction requires surgical revision or removal of the band. Meticulous removal of excess perigastric fat at the time of initial band placement may help prevent this complication [101]. The use of larger-diameter bands may also help to reduce the incidence of acute postoperative obstruction.
Port infection — Port infection has been reported in 0.3 to 9 percent of GB patients [90,102,103]. Because the port is a foreign body, port infection is treated with surgical removal, especially in association with band erosion. Overall, the incidence of port site infection ranges from 0.3 to 9 percent [90,103]. If an isolated port infection is found, the infected port is removed and a new port is reimplanted once the infection clears.
Band erosion — Band erosion through the wall of the stomach has been reported in up to 7 percent of GB patients, and it is thought to occur as a result of either gastric wall ischemia from an excessively tight band, mechanical trauma related to the band buckle, or thermal trauma from electrosurgical energy sources used during band placement [104-106]. Band erosion is a late complication and occurs at a mean of 22 months after surgery [104]. Introduction of new band technology and placement technique is likely to result in a reduction of band erosions (figure 6) [99].
Clinical signs of band erosion include infection, failure of weight loss, or nausea and vomiting. Epigastric pain and hematemesis can also signal erosion of the lap band into the left gastric artery [95]. This can happen when the lap band erodes into the posterior part of the stomach near the cardioesophageal junction. This complication can be avoided by careful placement during the initial surgery, making sure not to include the ascending branch of the left gastric artery during band placement.
Band erosion can be diagnosed by endoscopy, and treatment involves removal of the band, which can be done laparoscopically. Successful endoscopic removal has also been reported when the buckle of the band is visible endoscopically [107-109]. It is generally recommended that revision to another bariatric procedure be delayed for at least two to three months after an episode of band erosion, as the complication rate with immediate revision is increased. (See "Gastrointestinal endoscopy in patients who have undergone bariatric surgery", section on 'Band erosion'.)
Band slippage and gastric prolapse — Band slippage involves prolapse of part of the stomach through the band, with varying degrees of gastric obstruction.
●Anterior prolapse involves migration of the band cephalad, which creates an acute angle with the stomach pouch and esophagus, resulting in obstruction.
●Posterior gastric prolapse occurs when the stomach migrates cephalad, displacing the band caudally and creating a new pouch (figure 7).
Slippage rates were as high as 24 percent in the initial FDA trial but were lower (2 to 14 percent) in subsequent studies [93,110]. An early technique (involving perigastric dissection with placement of an LAGB directly on the stomach wall) was associated with frequent gastric prolapse. The modern technique (via pars flaccida without exposure of the stomach wall) has decreased this complication significantly [111-113].
Anterior band fixation by gastro-gastric sutures is commonly performed to prevent band slippage. In a randomized trial of 706 patients who underwent LAGB in France, patients who had band fixation required fewer reinterventions (11 versus 19 percent) at three years in part because of a reduced band slippage rate (4 versus 10 percent) [114]. This trial also showed that patients with a baseline BMI <40 kg/m2 were more likely to experience band slippage compared with those with a higher BMI (odds ratio 2.8, 95% CI 1.4-5.6).
Gastric prolapse is characterized by food intolerance, epigastric pain, and acid reflux. Diagnosis is confirmed with an upper gastrointestinal series demonstrating either malposition of the band or dilatation and prolapse of the gastric pouch. (See "Imaging studies after bariatric surgery", section on 'Band slippage and gastric prolapse'.)
Surgery is required urgently, depending on the presentation [115,116]. Repair of the prolapse can sometimes be accomplished by repositioning the band, but often the band needs to be replaced or removed altogether, especially if significant inflammation is found.
Port malfunction — Port malfunction results if the tubing disconnects, subcutaneous port flips, or leakage within the system occurs. Such problems lead to inability to titrate the instilled volume of saline in the system. Reported incidence of port and tubing malfunction ranges from 0.4 to 7.0 percent [93,117]. These problems usually become evident as an inability to access the port and maintain band volume, or with the development of weight gain. These complications require surgical repair or exchange of the hardware to attain band adjustability. Port dislocation can be reduced by attaching the port to a broad surface mesh first before anchoring to the rectus fascia [118]. (See "Imaging studies after bariatric surgery", section on 'Tubing migration or disconnection'.)
Esophagitis — Esophagitis and reflux are infrequent complications following LAGB [110]. Deflation of the band and acid suppression therapy are the mainstays of treatment. However, if intractable to medical therapy, band removal or conversion to other procedure such as RYGB may be necessary.
Esophageal dilatation — Esophageal dilatation proximal to the band device has been observed in as many as 10 percent of patients [94]. This so-called "pseudoachalasia syndrome" may develop when the band is excessively inflated or in the setting of excessive amounts of food intake. Pouch dilatation has also been associated with a history of binge eating behavior [119]. Patients often present with food and saliva intolerance, reflux, and epigastric discomfort. The diagnosis can be confirmed with an upper gastrointestinal series. (See "Imaging studies after bariatric surgery", section on 'Esophageal dilation'.)
The initial treatment should be removal of all the fluid from the band and behavioral diet modifications. This is usually successful in reversing esophageal dilatation. However, persistent dilatation may require replacement of the band in a new location on the stomach or conversion to a different procedure.
Hiatus hernia — Hiatus hernia is often a preexisting but unrecognized condition in patients undergoing bariatric surgery [120]. This can lead to ongoing intractable reflux necessitating reoperation or band removal (image 2). Thus, a simple crural repair can be performed at the initial operation to avoid these complications [121]. A retrospective review of 1298 patients who underwent GB alone and 520 patients who underwent GB with concurrent hiatal hernia repair showed that the rate of reoperation was significantly reduced in patients who had hiatal repair at the time of GB as compared with those who had GB alone (1.7 versus 5.6 percent, respectively) [120]. (See "Imaging studies after bariatric surgery", section on 'Hiatus hernia' and "Hiatus hernia", section on 'Management'.)
SLEEVE GASTRECTOMY — Laparoscopic sleeve gastrectomy (SG) is a restrictive procedure initially developed as part of a staged approach for high-risk patients with class III obesity [122,123]. SG is typically performed as a standalone operation with good weight loss and resolution of obesity-related comorbidities [124-127]. A study of 14,776 sleeve gastrectomies confirmed that SG was intended as the sole operation in 86.3 percent of the procedures [128]. In 2013, sleeve gastrectomy surpassed gastric bypass as the most commonly performed weight loss surgery in the United States.
Sleeve gastrectomy involves creating a "sleeve" of stomach over a bougie and removes a large portion of the greater curvature of the stomach, leaving a small tube along the lesser curvature. SG also produces a decrease in ghrelin levels for up to a year, which may reduce the desire for food (figure 8) [129,130].
Significant advantages of SG include low complication (3 to 24 percent) and mortality (0.39 percent) rates, the ease of performing the procedure, preservation of the pylorus, maintenance of physiological food passage, and the avoidance of foreign material [4,128,131-138].
The most common complications of SG include bleeding, narrowing or stenosis of the stoma, and leaks:
Bleeding — Bleeding can occur from the gastric or short gastric vessels during dissection of the greater curve. Most of the bleeding problems associated with SG occur from the staple line after transection of the stomach [131,139,140]. The bleeding is most likely a result of the large staples used for the thick tissue in the distal stomach. Large staples are not adequate to seal small vessels [141]. This has led many surgeons to reinforce the staple line by over-sewing, buttressing, or both [128].
Stenosis — Narrowing or stenosis can create gastric outlet obstruction [131]. The presentation varies depending on the severity of the obstruction and can include dysphagia, vomiting, dehydration, and the inability to tolerate an oral diet [142,143]. The gastroesophageal junction and the incisura angularis are the two most common areas where stenosis occurs, and this can be diagnosed by an upper gastrointestinal series [142]. (See "Imaging studies after bariatric surgery", section on 'Stricture or stenosis of the SG'.)
The most common reasons for the development of narrowing or stenosis are over-sewing the staple line and using a bougie that is too small. The preferable bougie size is currently debated in the literature and can range from 30 to 60 French. In most cases, surgeons use a 36 to 40 French bougie for the sleeve construction, and the larger sizes of bougies are reserved for when SG is being performed as part of a staged procedure.
Management of stenosis primarily consists of endoscopic dilation. If the area of stenosis is too long, surgical intervention may be necessary with conversion to an RYGB, gastric stricturoplasty, or resection with gastrogastrostomy.
Gastric leaks — Gastric leaks after SG are one of the most serious complications and can occur in up to 5.3 percent of patients [123,126,132,136,140,144-150]. (See "Imaging studies after bariatric surgery" and "Imaging studies after bariatric surgery", section on 'Leak after SG'.)
Most leaks are due to local factors at the site of the staple line, such as inadequate blood supply and oxygenation, which impede the healing process. Leaks can also be due to gastric-wall heat ischemia, a consequence of the heat generated by the surgical energy device used during dissection of the greater curve [146]. Although the blood supply to the stomach is robust, the gastroesophageal junction tends to be an area of decreased vascularity and thus more prone to leaks. Additionally, the stomach tends to be thinner at the angle of His, and some authors suggest that the large staple height used by many surgeons may not adequately seal this area of the stomach [139,151]. Some surgeons recommend leaving a small portion of stomach distal to the angle of His and then imbricating with a running silk suture [126]. However, clinical studies have not provided evidence that reinforcing the suture line decreases the rate of leak after sleeve gastrectomy [152].
Sleeve gastrectomy produces high intragastric pressure, which can affect the healing process and lengthen the amount of time for a leak to close [153].
Reoperation with primary repair during the early postoperative course is the best option for a leak following SG [146]. Clinically stable patients may be able to undergo percutaneous drainage, antibiotic therapy, and parenteral nutrition until the leak is healed. Endoscopic therapy with the use of stents has been increasingly employed for management of leaks, but migration of the stents remains a problem [154-158]. Early diagnosis, adequate drainage, and gastric decompression are the mainstay of treatment for leaks. (See "Bariatric operations: Early (fewer than 30 days) morbidity and mortality".)
Reflux — Gastroesophageal reflux after SG presents with classic symptoms such as burning pain, heartburn, and regurgitation (image 3). It can occur as an early and late complication. The first-line treatment is antireflux medical therapy [159]. GERD unresponsive to antireflux medical therapy with no clear anatomic abnormalities, such as stoma stenosis or a hiatal hernia, can be effectively treated by conversion to RYGB [160].
VERTICAL BANDED GASTROPLASTY — Vertical banded gastroplasty (VBG), also known as "stomach stapling," is a purely restrictive procedure involving creation of a small proximal gastric pouch lined by a vertical staple line and a tight prosthetic mesh (figure 9) [161].
The theoretical advantages of VBG include the relative simplicity of the procedure and avoidance of rerouting of the gastrointestinal tract and associated malabsorption. The VBG has been largely supplanted by the RYGB, but patients who underwent VBG still present to bariatric surgeons today with complications including staple line disruption, stomal stenosis, band erosion, GERD, nausea/vomiting, marginal ulcers, and weight regain [162,163].
Staple line disruption — Disruption of the staple line results in a fistula to the fundus, which can lead to decreased restriction in the VBG [164,165]. This complication can occur in 27 to 31 percent of the patients and can be as high as 48 percent if assessed on routine postoperative endoscopy [166]. Staple line disruption typically leads to weight regain due to increased food consumption since patients can eat around their restriction without feeling full. Surgical treatment of this complication is conversion to an RYGB or a BPD [167,168].
Obstruction — Stomal stenosis occurs in approximately 20 to 33 percent and can occur due to fibrosis in the stomach or by the band itself [169]. The resulting obstruction leads to food intolerance, reflux, and often weight regain due to dietary shifts to calorically dense liquids and softer foods. Staple line dehiscence, esophageal dilatation, and a fistula between the VBG pouch and occluded stomach have also been reported [3].
Stomal stenosis following VBG can initially be managed nonoperatively by endoscopic dilation, with surgery reserved for failures. However, dilation may be unsuccessful due to the rigid nature of the prosthetic band. A success rate of 68 percent for endoscopic dilation of stomal stenosis was described in one series [29]. Symptomatic relief following endoscopic dilation is often short lived, and surgical revision may be necessary when symptoms persist. Dense scarring also presents a significant operative risk when revision is required.
Erosion of mesh band — Band erosion is a frequent late complication of VBG occurring with an incidence of 1 to 7 percent and usually occurs one to three years after the surgery [166,170]. Patients generally present with abdominal pain and vomiting. Surgical removal is indicated if erosion is visualized by endoscopy.
Reflux — Gastroesophageal reflux after VBG presents with classic symptoms such as burning pain, heartburn, aspiration, and cough. It typically occurs as a late complication, as a result of stomal stenosis and pouch dilatation [171]. GERD unresponsive to antireflux medical therapy often requires reversal of the VBG or conversion to RYGB. In a review of 25 patients undergoing a revision of a VBG for symptomatic reflux, esophagitis was present in 58 percent of patients and Barrett's esophagus in 28 percent [171].
Vomiting — Recurrent vomiting occurs in approximately 8 to 21 percent of patients following VBG [172]. The etiology may be multifactorial, including maladaptive dietary patterns (such as eating too quickly or not chewing properly) as well as functional problems such as stomal stenosis, pouch dilatation, staple line disruption, or GERD. These patients will often become sweet eaters in an attempt to ingest calories in a form that does not cause vomiting.
Not all patients with recurrent vomiting require an operative revision. Initial treatment should consist of dietary modification (ie, proper chewing, eating at slower pace, and avoidance of problem foods that give recurrent vomiting) and radiologic and/or endoscopic evaluations for structural problems. Operative revision is required if the vomiting persists and leads to malnutrition and/or dehydration [168].
BILIOPANCREATIC DIVERSION AND DUODENAL SWITCH — Biliopancreatic diversion (BPD) is a malabsorptive procedure that relies on limiting absorption of fats and starches to a relatively short segment of small intestine as well as decreasing the gastric reservoir size. BPD has not become widespread because of the technical complexity of the procedure with historically high surgical morbidity and mortality rates and concerns regarding the long-term nutritional outcomes, including significant protein calorie malnutrition, anemia, metabolic bone disease, and deficiencies of fat-soluble vitamins (figure 10) [173,174].
Biliopancreatic diversion differs from jejunoileal bypass in that no intestinal limb is excluded from flow, thus avoiding creation of a blind loop (see 'Jejunoileal bypass' below). Excellent weight loss results with morbidity and mortality rates comparable to RYGB have been described by the few centers that perform BPD along with its duodenal switch variant (figure 11) [175-177].
JEJUNOILEAL BYPASS — Jejunoileal bypass (JIB) is a purely malabsorptive procedure that was popular in the 1960s and 1970s. The procedure produces significant weight loss by creating a surgical short bowel syndrome (figure 12).
JIB is no longer used today because of a 50 percent morbidity rate and 10 percent mortality rate [178]. Patients who previously underwent JIB should be followed carefully for signs of complications, particularly a deterioration in liver function [173]. Studies have shown a high long-term complication rate, with a 21 percent rate of cirrhosis after 15 years [179].
Electrolyte imbalances — Over half of the patients who underwent JIB developed diarrhea and electrolyte imbalances, and these problems could persist more than five years after surgery [180,181]. Arthritis, protein malnutrition, vitamin deficiencies, cirrhosis, nephrolithiasis with oxalate stones, and renal failure have also been associated with JIB [180-188].
Renal failure — Increased absorption of calcium oxalate leads to deposition in the renal parenchyma. This can lead to a postobstruction nephropathy and renal failure, which has been described in up to 19 percent of patients [189]. Conversion to a gastric bypass or reversal should be considered in patients with metabolic complications [190].
Cirrhosis — Hepatic abnormalities that may lead to cirrhosis can occur in up to 40 percent of patients and may persist or progress despite reversal in more than one-third of patients [182,191]. Some patients have progressed to decompensated cirrhosis requiring transplantation [183]. If not already performed, reversal of the jejunoileal bypass at the time of transplant should be considered. Reversal prior to transplant may not be feasible, because of the risk of precipitating hepatic decompensation in patients with advanced liver disease. Patients who do not undergo reversal at the time of transplant should be monitored closely, with reversal performed in those who develop progressive liver injury [180,183,184]. Progressive liver injury appears histologically as increasing steatosis, lobular lymphocytic inflammation, pericellular fibrosis, Mallory bodies, and deranged architecture, all features resembling those seen in alcoholic liver disease [180,185].
REOPERATIONS — Evaluations of longer-term safety of bariatric operations most often center on rates of reoperation and reinterventions. In contemporary series, the rate of reoperation following bariatric surgery generally ranges from 5 to 22.1 percent [192,193]. RYGB has higher rates of reoperations compared with sleeve gastrectomy in cohort studies [194,195] but not randomized trials [196,197].
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Bariatric surgery".)
SUMMARY
●Roux-en-Y gastric bypass – Roux-en-Y gastric bypass complications are diverse and include gastric remnant distension, stomal stenosis, marginal ulcer formation, cholelithiasis, ventral hernias, internal hernias, small bowel obstructions, hypoglycemia, dumping, metabolic and nutritional derangements, gastrogastric fistulas, and weight regain. Some complications are seen during the early postoperative periods while others may present weeks to months following the surgery. (See 'Roux-en-Y gastric bypass' above.)
●Laparoscopic adjustable gastric banding – Laparoscopic adjustable gastric banding (LAGB) complications include acute stomal obstruction, band erosion, band slippage leading to gastric prolapse, port malfunction, esophageal dilatation, esophagitis, and infection. (See 'Gastric banding' above.)
●Laparoscopic sleeve gastrectomy – Laparoscopic sleeve gastrectomy complications include bleeding, narrowing or stenosis of the stoma, leaks, and reflux. (See 'Sleeve gastrectomy' above.)
●Vertical banded gastroplasty – Vertical banded gastroplasty complications include staple line disruption, stomal stenosis, band erosion, reflux, nausea/vomiting, marginal ulcers, and weight regain. (See 'Vertical banded gastroplasty' above.)
●Biliopancreatic diversion – Biliopancreatic diversion complications include significant protein calorie malnutrition, anemia, metabolic bone disease, and deficiencies of fat-soluble vitamins and vitamin B12. (See 'Biliopancreatic diversion and duodenal switch' above.)
●Jejunoileal bypass – Jejunoileal bypass is no longer performed because of a high morbidity and mortality rate. However, patients who underwent this procedure can present years later with significant complications, including arthritis, protein malnutrition, vitamin deficiencies, cirrhosis, nephrolithiasis with oxalate stones, and renal failure. (See 'Jejunoileal bypass' above.)
●Reoperations – In contemporary series, the rate of reoperation following bariatric surgery generally ranges from 5 to 22.1 percent. Roux-en-Y gastric bypass is associated with higher rates of reoperations compared with sleeve gastrectomy in cohort studies but not randomized trials. (See 'Reoperations' above.)
