Bariatric Surgery Treatment & Management

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.

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 by an open technique and by a laparoscopic technique. The laparoscopic approach has currently become the more popular approach.

Gastric bypass

Gastric bypass is currently the most popular procedure performed in the United States. (See 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.

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.

Reversal

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.

Revision

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

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.^[1] 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 and others, the laparoscopic gastric bypass approach 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.^[2] 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 their operations.^[3] Schauer's group reported even better weight loss; in a group of 275 patients undergoing laparoscopic gastric bypass, there was an average loss of excess weight of 83% 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, the 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 image below.) In June 2001, the US Food and Drug Administration (FDA) approved it for use in the United States. Lap-Band (Inamed) is the only device approved for this use in the United States.

The device consists of an adjustable inflatable band placed around the proximal part of the stomach. This creates a small gastric pouch (approximately 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 up to 6 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.

Biliopancreatic diversion with duodenal switch

See the image below.

The procedure 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

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 curve–based gastric conduit. (See image below.)

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 of a 2-stage procedure for high-risk patients,^[4] but owing to its simplicity and favorable outcomes,^[5] it is currently being offered as a primary, stand-alone procedure. In the first decade of the 21st century, many hundreds of sleeve gastrectomies were performed in the United States.Based on follow-up periods of 6 months to 3 years, patients were found to have lost 33-83% of their excess weight.^{[6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20]}

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.^[18]

Hutter et all conducted the first large, prospective, multiinstitutional study comparing 1-yr outcomes of LSG to other procedures. Results show LSG has morbidity and effectiveness between laparoscopic adjustable gastric banding and standard Roux bypass.^[21]

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.^[22] A larger, prospective comparative study involving 187 patients undergoing the laparoscopic sleeve gastrectomy procedure found that reinforcement of the staple line with bovine pericardium strips was associated with a significant reduction in bleeding from the staple line and intraabdominal collections, whereas the leak rate was not significantly reduced. It is unclear, though, if controlling for high BMI, previous bariatric surgery, and diabetes was taken into account.^[23]

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 image below.)

Such minimally invasive surgery also provides, as a result of decreased abdominal trauma, reductions in pain, scarring, and tissue injury. Saber and colleagues 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.^[18]

In addition, Saber and colleagues 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.

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.

See Surgical Therapy.

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-a-day basis. Ursodiol (Actigall) 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 need to 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.

Postbariatric surgery 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 contract back to its preweight gain tightness. 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 physiological changes. The usual time lapse between gastric bypass and plastic surgery procedures is 12-18 months.

Treatment alternatives for body contouring procedures include lipoplasty, conventional surgery, or a combination of the 2 procedures. Conventional contouring procedures include abdominoplasty, buttock lift, lower body lift, thigh lift, upper arm lift, facelift, breast reduction, mastopexy, and/or 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. In addition, the patient should be involved with a team that assesses nutritional and psychological issues as needed.

For excellent patient education resources, visit eMedicine's Public Health Center. Also, see eMedicine's patient education articles Obesity and Surgery in the Treatment of Obesity.

Complications of Roux-en-Y gastric bypass are as follows:

• Early complications

  • Anastomotic leak (1-3%)
  • Pulmonary embolism, deep vein thrombosis (< 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)

  • 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)

Risk factors associated with an increased risk of postoperative morbidity include recent myocardial infarction/angina, stroke, bleeding disorder, hypertension, and higher BMI.^[24] 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 rate from 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.

Lifelong oral or intramuscular vitamin B-12 supplementation and iron, vitamin B, folate, and calcium supplementation are recommended to avoid specific nutrient deficiency conditions, such as anemia.

Complications of the adjustable gastric band procedure are as follows:

• Early complications

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

  • 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 rate (0.5%; 0% in some series)

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)

Care of the postoperative bariatric surgery patient is recommended for the lifetime of the patient, with at least 3 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.

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.

The Swedish Obese Subjects (SOS) study is an ongoing, prospective study of 2010 obese participants who underwent bariatric surgery and 2037 obese patients who received usual care in the primary health care system. Compared to the control group, obese adults who underwent surgery experienced a reduced number of cardiovascular deaths and a lower incidence of heart attack and stroke.^[25]

An Australian study by Keating et al compared the results of weight-loss treatments in patients who had been diagnosed with type 2 diabetes mellitus in class I/II obesity, estimating the lifetime costs and quality-adjusted life-years (QALYs) for individuals who had undergone surgically induced weight loss and for patients who had utilized conventional weight loss treatment.^[26]

The investigators found that the mean length of time for diabetes remission over a lifetime was 11.4 years for patients who had undergone surgical treatment and 2.1 years for patients who had utilized conventional therapy. Over the remainder of their lifetime, patients in the surgical therapy group lived 15.7 discounted QALYs, compared with 14.5 discounted QALYs for patients in the conventional therapy group. For surgical and conventional therapy patients, the mean discounted lifetime costs were, respectively, 98,900 and 101,400 Australian dollars per patient (1 Australian dollar = 0.74 US dollars). Compared with conventional therapy, surgically induced weight loss was associated with a mean health care saving of 2,400 Australian dollars and with 1.2 additional QALYs per patient.

In another study, Keating and coauthors looked at the within-trial cost efficacy, over 2 years, of surgical treatment relative to that of conventional therapy for achieving remission in patients recently diagnosed with type 2 diabetes mellitus with class I/II obesity.^[27] Trial intervention costs included gastric banding surgery, mitigation of complications, outpatient medical consultations, medical investigations, pathology, weight-loss therapies, and medication.

An incremental cost-effectiveness analysis demonstrated that the mean 2-year intervention costs per patient were 13,400 Australian dollars for surgical therapy and 3,400 Australian dollars for conventional therapy; laparoscopic adjustable gastric band (LAGB) surgery was responsible for 85% of the difference. For surgical patients, outpatient medical consultation costs were 3-fold greater than those for conventional patients, but medication costs were 1.5 times higher for patients who underwent conventional therapy. The cost differences occurred primarily in the trial's first 6 months. In relation to conventional treatment, the incremental cost-effectiveness ratio for surgical therapy was 16,600 Australian dollars per case of diabetes remitted.

Over the past 10 years, the field of bariatric surgery has been enriched by data from numerous clinical investigations and experience. The direction of future clinical investigations is manifold and includes the following:

• Controlled, prospective, intervention studies
• Establishment of a major prospective database to study bariatric surgery outcomes
• Establishment of a pediatric (adolescent) bariatric surgery registry
• Performance of randomized clinical trials to compare the safety and efficacy of different operative procedures
• Controlled studies of new operative modalities (eg, gastric pacing) and nonoperative modalities of treatment
• Study by meta-analysis of outcomes of comorbid conditions of morbid obesity
• Study of the socioeconomic outcomes of bariatric surgery
• Study by stratified risk assessment of the risk-to-benefit ratio of treating morbid obesity with bariatric surgery and without bariatric surgery