Bariatric Surgery Treatment & Management

Updated: Mar 16, 2023
  • Author: Alan A Saber, MD, MS, FACS, FASMBS; Chief Editor: John Geibel, MD, MSc, DSc, AGAF  more...
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Approach Considerations

Surgery for obesity should be considered as a treatment of last resort after dieting, exercise, psychotherapy, and drug treatments have failed.

Since the 1991 National Institutes of Health (NIH) Consensus Development Conference Panel, the generally accepted criteria for surgical treatment have included a body mass index (BMI) higher than 40 kg/m2 or a BMI higher than 35 kg/m2 in combination with high-risk comorbid conditions, such as sleep apnea, pickwickian syndrome, diabetes mellitus, or degenerative joint disease.

In 2022, however, the American Society of Metabolic and Bariatric Surgery (ASMBS) and the International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO) issued updated indications for metabolic and bariatric surgery that included all individuals with BMIs of 35 kg/m2 or greater, as well as selected individuals with lower BMIs (see Guidelines). [10]

Guidelines have also been developed for the use of bariatric surgery in pediatric patients and patients with type 2 diabetes mellitus (see Guidelines). [11, 12]

Contraindications for bariatric surgery include illnesses that greatly reduce life expectancy and are unlikely to be improved with weight reduction, including advanced cancer and end-stage renal, hepatic, and cardiopulmonary disease. Conditions that may render patients unable to understand the nature of bariatric surgery or the behavioral changes required afterward, including untreated schizophrenia, active substance abuse, and noncompliance with previous medical care, are also considered contraindications for bariatric surgery.

Favorable outcomes of bariatric surgery can lead to socioeconomic advancement, which may require patient guidance. Postoperative care may also include planning for reconstructive operations after weight stabilization for certain patients.


Medical Therapy

A preoperative trial of weight loss is beneficial to ensure patient compliance with the postoperative diet protocol. Also, a preoperative liquid diet can shrink the liver, thus facilitating the surgical procedure.


Surgical Therapy

Surgical options

Types of bariatric surgery include the following:

  • Restrictive procedures (eg, adjustable gastric banding, sleeve gastrectomy)
  • Restrictive procedures with some malabsorption (eg, Roux-en-Y gastric bypass)
  • Malabsorptive procedures with some restriction (eg, biliopancreatic diversion with duodenal switch)

Bariatric surgery can be performed either via an open approach or via a laparoscopic approach. The laparoscopic approach has become the more popular one.

Preoperative considerations

The diversity of clinical and occult obesity-related comorbidities necessitates a multidisciplinary team approach in the preoperative evaluation of the patient who is morbidly obese. This evaluation will enhance the postoperative outcome. Preoperative cardiac, pulmonary, psychiatric, and endocrine evaluations may be necessary. These evaluations help to exclude patients who may not benefit from surgery; at the same time, they optimize those considered being potential good candidates for surgery. Preoperative nutritional consultation helps in obtaining a detailed diet history and in explaining preoperative and postoperative diet protocol.

Gastric bypass

Gastric bypass is currently the most popular procedure performed in the United States. (See the image below.) This procedure has earned the reputation of being the gold standard, against which other procedures are compared. The procedure has a restrictive and a malabsorptive component.

Laparoscopic Roux-en-Y gastric bypass. Laparoscopic Roux-en-Y gastric bypass.

The gastric bypass provides a substantial amount of dietary restriction. The restriction is created by the small stomach pouch, which gives the patient a feeling of satiety after eating a small meal. The restrictive element of the operation consists of the creation of a small gastric pouch (approximately 20 mL in volume) and probably a small outlet that, on distention by food, causes the sensation of satiety.

In addition, the gastric bypass provides a small-to-moderate degree of intentional malabsorption due to the separation of food, which passes through the alimentary limb of the Y, from the biliopancreatic secretions, which pass through the biliopancreatic limb of the Y. The degree of malabsorption can be adjusted by modifying the length of the alimentary and biliopancreatic limbs.

The malabsorptive element is a result of bypassing the distal stomach, the entire duodenum, and varying the length of the jejunum. The extent of the bypass of the intestine determines the degree of macronutrient malabsorption. The standard Roux limb is about 75 cm. More extensive malabsorptive variations consist of gastric bypasses with a 150-cm Roux limb (long-limb) or with a very long-limb (distal gastric bypass). In addition to restricting food intake, causing some degree of malabsorption, it also causes dumping syndrome in response to a high-sugar liquid meal.

Weight loss after a standard 75-cm Roux gastric bypass usually exceeds 100 lb or about 65-70% of excess body weight and about 35% of BMI. The longer-limb bypasses are used to obtain comparable weight reductions in patients who are super obese (BMI >50 kg/m2). Weight loss generally levels off in 1-2 years, and a regain of up to 20 lb from the weight loss nadir to a long-term plateau is common.


For all bariatric procedures, pure reversal without conversion to another bariatric procedure is almost certainly followed by a return to morbid obesity. Gastric bypass can be reversed, though this is rarely required.


A standard Roux gastric bypass with failed weight loss can be revised to a very-long-limb Roux-en-Y procedure (see the image below), or the dilated gastric pouch can be revised.

Long Roux-en-Y gastric bypass. Long Roux-en-Y gastric bypass.


After gastric bypass surgery, some patients may experience dumping syndrome upon ingestion of sweets. This is caused by the rapid passage of gastric pouch contents directly into the small bowel, unimpeded by a pyloric valve. The presence of concentrated simple sugars in the Roux limb presents a substantial osmotic load that may result in cramping and abdominal discomfort; additionally, the ensuing rapid release of insulin by the pancreas may cause symptomatic hypoglycemia. This unpleasant reaction to sugar is considered to be a desired effect of gastric bypass surgery, and it has been referred to by patients as the postoperative police officer.

Weight loss after gastric bypass has been shown to be greater than that obtained by dietary, medical, behavioral, or combined approaches to weight loss.

A long-term follow-up study performed by MacLean et al defined postoperative success as a reduction in weight to a BMI of less than 35 kg/m2. [13] By this criterion, a successful outcome was achieved in 93% of patients with an initial BMI of less than 50 kg/m2 and in 57% of patients with an initial BMI of greater than 50 kg/m2.

Since its initial description in 1994 by Wittgrove et al, laparoscopic gastric bypass has been shown to combine the efficacy of the open approach with the decreased pain, lower wound morbidity, and shorter convalescence of a minimally invasive procedure. [14] Results of several laparoscopic gastric bypass series have paralleled or improved upon those of open surgery.

In Higa's series of 400 laparoscopic procedures, patients lost an average of 69% of their initial excess weight by 12 months after the procedure. [15] Schauer's group reported even better weight loss; a group of 275 patients undergoing laparoscopic gastric bypass lost an average of 83% of excess weight at 24 months after surgery.

A prospective, randomized trial was completed that compared the results of laparoscopic gastric bypass to the results of open gastric bypass. Patients who had undergone laparoscopic gastric bypass were found to have substantially less impairment of pulmonary function after surgery and decreased postoperative pain.

In the author's experience, convalescence after laparoscopic gastric bypass is substantially reduced relative to open procedures, with some patients returning to work in 2 weeks or less.

Laparoscopic adjustable gastric banding

Laparoscopic adjustable gastric banding is the most common bariatric procedure and is performed in Europe, Australia, and South America. (See the image below.) Currently, two devices are approved by the US Food and Drug Administration (FDA) for this use in the United States: the Lap-Band (Apollo Endosurgery, Austin, TX) and the Realize Band (Ethicon Endo-Surgery, Somerville, NJ).

Adjustable gastric banding. Adjustable gastric banding.

In this procedure, an adjustable inflatable band is placed around the proximal part of the stomach. This creates a small gastric pouch (~15 mL in volume) and a small stoma. Band restriction is adjustable by adding or removing saline from the inflatable band by a reservoir system of saline attached to the band and accessible through a port, which is attached by a catheter to the band. The port is placed subcutaneously in the anterior abdominal wall after the band is secured around the stomach.

Adjustment of the band through the access port is an essential part of laparoscopic adjustable gastric banding therapy. Appropriate adjustments, performed as often as six times annually, are critical for successful outcomes. Patients must chew food thoroughly to allow food to pass through the band. Adjusting the inflation of the cuff changes the size of the opening through which food passes but does not change the size of the gastric pouch; deflation of the cuff is useful when the outlet is obstructed.

Weight loss after laparoscopic adjustable gastric banding is about 50-60% of excess body weight in approximately 2 years.

Laparoscopic adjustable gastric banding can be completely reversed with removal of the band, tubing, and port.

Combining laparoscopic adjustable gastric banding with gastric plication may improve weight-loss outcomes, at least in the short term. [16]

Biliopancreatic diversion with duodenal switch

Biliopancreatic diversion with duodenal switch (see the image below) includes the following:

  • Lateral 75% gastrectomy, resulting in a tubular stomach
  • Duodenum divided past the pyloric valve
  • Ileum divided
  • Distal end anastomosed to proximal duodenum
  • Common channel created distally with Y-anastomosis
  • Optional appendectomy and cholecystectomy
Biliopancreatic diversion with duodenal switch. Biliopancreatic diversion with duodenal switch.

Malabsorption is achieved by separating food from biliopancreatic digestive fluids. More weight loss results from fat malabsorption. Protein absorption is also reduced. This has the best weight loss with the least regain. There is less disruption of eating patterns. Early weight loss is from restriction and malabsorption, and, later, it is mostly from malabsorption; 75-85% of excess body weight loss is at 18 months. Pyloric preservation protects against marginal ulceration and dumping syndrome.

The procedure is technically challenging and difficult to reverse. Insurance companies may not cover this procedure, because it is still considered investigational.

Laparoscopic sleeve gastrectomy

Laparoscopic sleeve gastrectomy (LSG), a type of unbanded gastroplasty, employs subtotal gastric resection to create a long lesser curvature–based gastric conduit. (See the image below.)

Sleeve gastrectomy. Sleeve gastrectomy.

In this procedure, the stomach is reduced to about 15-20% of its original size by the surgical removal of a large portion of the stomach, following the greater curve. The mechanism of weight loss and resultant comorbidity improvement that follows sleeve gastrectomy may be related to gastric restriction or to neurohumoral changes observed following the procedure (due to the gastric resection).

Sleeve gastrectomy has been used as the first stage of a two-stage procedure for high-risk patients, [17] but owing to its simplicity and favorable outcomes, [18] it is currently being offered as a standalone primary procedure. In the first decade of the 21st century, many hundreds of sleeve gastrectomies were performed in the United States. On the basis of follow-up periods of 6 months to 3 years, patients were found to have lost 33-83% of their excess weight. [19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32]

Compared with other bariatric procedures, sleeve gastrectomy is the more physiologic treatment because it does not involve malabsorption, abnormal tracts, blind tracts, or the placement of a foreign body. This procedure is widely performed laparoscopically. [31]

Hutter et all conducted the first large, prospective, multi-institutional study comparing 1-year outcomes of LSG to other procedures. Results show LSG has morbidity and effectiveness between laparoscopic adjustable gastric banding and standard Roux bypass. [33]

As with other bariatric procedures that involve stomach transection, the main drawback of sleeve gastrectomy is the severity of postoperative complications. The use of staple-line reinforcement was shown to be associated with improved perioperative outcomes and can be considered as an effective method for preventing leaks. [34]

A larger prospective comparative study involving 187 patients undergoing laparoscopic sleeve gastrectomy found that reinforcement of the staple line with bovine pericardium strips was associated with a significant reduction in bleeding from the staple line and intra-abdominal collections, whereas the leak rate was not significantly reduced. It is unclear, though, whether controlling for high BMI, previous bariatric surgery, and diabetes was taken into account. [35]

In a randomized study that involved 120 patients who had undergone laparoscopic sleeve gastrectomy, using either polyglycolide acid with tri-methylene carbonate or gelatin fibrinmatrix for SLR was found to be faster as compared with oversewing, whereas no significant differences in postoperative complications were observed between the three methods. [36]

According to two studies presented at Obesity Week 2017, LSG is safer than laparoscopic gastric bypass at 30 days (though both procedures are very safe); however, in the longer term (7 years and beyond), one quarter to one third of LSG patients may require a revision or regain lost weight. [37]

Incision reduction strategies

There has been a growing trend in bariatric surgery toward reduction of abdominal incisions, a change offering much-improved cosmetic outcomes and, potentially, shorter patient hospital stays. (See the image below.)

Progression of surgical techniques, with open surg Progression of surgical techniques, with open surgery in first image and single-incision transumbilical laparoscopic surgery in third illustration.

Such minimally invasive surgery also provides, as a result of decreased abdominal trauma, reductions in pain, scarring, and tissue injury. Saber et al developed a single-incision transumbilical laparoscopic approach for sleeve gastrectomies, in which the procedure is performed mainly through the umbilicus; the sleeve is extracted through the umbilicus without extending the incision. [31, 38]

In addition, Saber et al developed a single-incision transumbilical laparoscopic technique for the placement of an adjustable gastric band; in addition to offering the aforementioned benefits of such an approach, this technique facilitates later outpatient adjustment of the band. [39, 40]


Postoperative Care

After surgery, patients must remain on a high-protein, low-fat diet, and they must supplement their diet with multivitamins, iron, and calcium, usually on a twice-daily basis. Ursodiol may be given to minimize the risk of developing gallstones during the period of acute weight loss. Patients must modify their eating habits by avoiding chewy meats and other foods that may inhibit normal emptying of their stomach pouch.

Nutritional and metabolic blood tests must be performed on a frequent basis; in the author's practice, these tests are performed at 6 months after surgery, 12 months after surgery, and then annually thereafter.

Postoperative body contouring

Massive weight loss is associated with negative consequences for the body, such as flabby skin, abdominal skin overhang, and pendulous breasts. The excess skin does not regain the tightness it had before the weight gain. Redundant rolls of tissue may also be associated with intertrigo and significant hygiene problems. Surgical correction of these body deformities can significantly enhance physical and physiologic changes. The usual time lapse between gastric bypass and plastic surgery procedures is 12-18 months.

Treatment alternatives for body contouring procedures are as follows:

  • Lipoplasty
  • Conventional surgery
  • Combination of the two procedures

Conventional contouring procedures include abdominoplasty, buttock lift, lower body lift, thigh lift, upper arm lift, facelift, breast reduction, mastopexy, and augmentation. Multiple procedures are usually required, and a staged approach to body contouring surgery following bariatric surgery seems to improve safety and outcomes.

Complications of body contouring procedures include hematomas and seromas, as well as fat necrosis, skin slough, infection, and deep vein thrombosis (DVT). In addition, the patient should be involved with a team that assesses nutritional and psychological issues as needed. [41]



Gastric bypass

Early complications of Roux-en-Y gastric bypass are as follows:

  • Anastomotic leak (1-3%)
  • Pulmonary embolism, DVT (< 1%)
  • Wound infection (more common with open approach)
  • Gastrointestinal hemorrhage, bleeding (0.5-2%)
  • Respiratory insufficiency, pneumonia
  • Acute distention of the distal stomach

Late complications (less frequent and less dramatic than with gastric banding) of the Roux-en-Y procedure are as follows:

  • Stomal stenosis, most common (20%)
  • Bowel obstruction, small bowel obstruction (1%)
  • Internal hernia
  • Cholelithiasis
  • Micronutrient deficiencies
  • Marginal ulcer
  • Staple line disruption
  • Ventral hernia formation (more prevalent after open approach)

Although there is a statistical increase in the number of patients needing cholecystectomy after obesity surgery, the number is small enough to prevent suggesting a prophylactic procedure at the time of their bariatric surgery. [42]

In a large study (N = 42,345) that included a substantial population of older adults, Yu et al found that Roux-en-Y gastric bypass (n = 29,624) was associated with a 73% increased risk of nonvertebral (eg, hip, wrist, and pelvis) fracture after the procedure as compared with adjustable gastric banding (n = 12,721). [43] The difference in postoperative fracture risk between the two procedures was consistent across different subgroups and occurred to a similar degree among older and younger adults.

Risk factors associated with an increased risk of postoperative morbidity include the following [44] :

  • Recent myocardial infarction/angina
  • Stroke
  • Bleeding disorder
  • Hypertension
  • Higher BMI

Operative (30-day) mortality for gastric bypass when performed by skilled surgeons is about 0.5%. The risk of dying in the first month after a Roux-en-Y gastric bypass from complications of the operation is about 0.2-0.5% in expert centers. Studies have demonstrated that the mortality reported by hospitals with less experience with the procedure is far higher than that reported by expert centers. Compared with open procedures, laparoscopic gastric bypass has a higher rate of intra-abdominal complications, whereas the duration of hospitalization is shorter, wound complications are lower, and the postoperative patient comfort is higher. [45]

Lifelong oral or intramuscular vitamin B12 supplementation and iron, vitamin B, folate, and calcium supplementation are recommended to avoid specific nutrient deficiency conditions, such as anemia.

Adjustable gastric banding

Early complications of the adjustable gastric band procedure are as follows:

  • Injury of the stomach or esophagus
  • Bleeding
  • Food intolerance (most common immediate postoperative complication)
  • Wound infection
  • Pneumonia

Late complications are as follows:

  • Food intolerance or noncompliance to band (13%)
  • Band slippage (stomach prolapse) (2.2-8%)
  • Pouch dilatation
  • Band erosion into the stomach
  • Port complications
  • Reoperation rate (2-41%)
  • Esophageal dilatation
  • Failure to lose weight
  • Port infection, band infection
  • Leakage of the balloon or tubing
  • Mortality (0.5%; 0% in some series)

Biliopancreatic diversion with duodenal switch

Because the biliopancreatic diversion with duodenal switch procedure is less well known, the complications are potentially more problematic if the surgeon is unfamiliar with the procedure.

Fat malabsorption results in diarrhea and foul-smelling gas in approximately 30% of patients.

The potential nutritional deficiencies mandate frequent follow-up visits, with close monitoring and supplementation of multivitamins and minerals.

  • Malabsorption of fat soluble vitamins (vitamins A, D, E, and K)
  • Vitamin A deficiency, which causes night blindness
  • Vitamin D deficiency, which causes osteoporosis
  • Iron deficiency (similar incidence to Roux-en-Y gastric bypass procedure)
  • Protein-energy malnutrition (may require a second operation to lengthen the common channel)

In a case series and national database study, Ungaro et al found bariatric surgery to be associated with an increased risk of new-onset inflammatory bowel disease. [46]


Long-Term Monitoring

Care of the postoperative bariatric surgery patient is recommended for the lifetime of the patient, with at least three follow-up visits with the bariatric surgery team within the first year. Laparoscopic adjustable gastric banding requires more frequent visits for band adjustment. Postoperative dietary changes (including vitamin, mineral, and possibly liquid protein supplementation), exercise, and lifestyle changes should be reinforced by counseling, support groups, and the patient's family physician.