Obesity is defined as body mass index (BMI) >30 kg/m 2 . Obesity is increasing in prevalence in the United States and worldwide Centers for Disease Control and Prevention (CDC) data on obesity show a steady and appreciable increase in obesity in the United States from 1985 to 2008 More than 33 percent of adults in the United States (approximately 72 million people) are obese [ 4,5 ]. Furthermore, more than 64 percent of Americans are overweight (BMI ≥25 kg/m 2 ).
The economic costs of obesity are staggering The cost of treating obesity and its complications in the United States is approximately 100 billion dollars per year . Additionally, obesity and its complications lead to other significant costs, such as missed days of work and a decrease in life expectancy Similar trends have been reported in other parts of the world
There are several well-established health hazards associated with obesity, including type 2 diabetes, heart disease, stroke, certain cancers, osteoarthritis, liver disease, obstructive sleep apnea, and depression . The risk of development of complications rises with increasing adiposity, while weight loss can reduce the risk.
There are many behavioral, medical, and surgical options for achieving weight loss. Bariatric surgical procedures are increasingly common. Data from the Nationwide Inpatient Sample from 2003 through 2008 documented that the number of bariatric operations in the United States peaked in 2004 at 135,985 cases and plateaued at 124,838 cases in 2008
This topic review will focus on surgical procedures, which have been collectively referred to as “bariatric” surgery (from the Greek words “baros” meaning “weight” and “iatrikos” meaning “medicine”. Complications of bariatric procedures are discussed elsewhere.
The general approach to the management of obesity and clinical practice guidelines from the American College of Physicians for management of obesity in primary care are discussed elsewhere.
BODY MASS INDEX —
Body mass index (BMI) is considered to represent the most practical measure of a person’s adiposity. It is calculated by dividing the weight in kilograms by the height in meters squared (kg/m 2 ). In adults, a BMI of:
- 25 to 29.9 kg/m 2 is considered overweight
- 30 to 34.9 kg/m 2 is considered obese (class I obesity)
- 35 to 39.9 kg/m 2 is considered moderately obese (class II obesity)
- 40 to 49.9 kg/m 2 is considered severely or extremely obese (class III obesity)
- >50.0 kg/m 2 is considered super obese (class IV obesity)
MECHANISM OF WEIGHT LOSS
— Bariatric surgical procedures affect weight loss through two fundamental mechanisms: (1) malabsorption and (2) restriction Some procedures have both a restrictive and malabsorptive component. There is also growing recognition that bariatric surgical procedures contribute to neurohormonal effects on the regulation of energy balance
Restriction — Restrictive procedures limit caloric intake by reducing the stomach’s reservoir capacity via resection, bypass or creation of a proximal gastric outlet. Vertical banded gastroplasty (VBG) and laparoscopic adjustable gastric banding (LAGB) are purely restrictive procedures, and share similar anatomical configurations. Both limit solid food intake by restriction of stomach size as the only mechanism of action, leaving the absorptive function of the small intestine intact. Although these procedures are simpler in comparison to malabsorptive procedures, they tend to produce more gradual weight loss.
Malabsorption — Malabsorptive procedures decrease the effectiveness of nutrient absorption by shortening the length of the functional small intestine, either through bypass of the small bowel absorptive surface area or diversion of the biliopancreatic secretions that facilitate absorption. Jejunoileal bypass (JIB) and the duodenal switch operation (DS) are examples of malabsorptive procedures. Profound weight loss can be achieved by a malabsorptive operation, depending upon the effective length of the functional small bowel segment. However, the benefit of superior weight loss can be offset by significant metabolic complications, such as protein calorie malnutrition and various micronutrient deficiencies.
Combination of restriction and malabsorption — The Roux-en-Y gastric bypass (RYGB), the biliopancreatic diversion (BPD) and BPD with duodenal switch (BPD/DS) are both restrictive and malabsorptive. In the RYGB, a small gastric pouch limits oral intake. However, the small bowel reconfiguration provides additional mechanisms favoring weight loss including dumping physiology and mild malabsorption.
EFFECTIVENESS OF BARIATRIC SURGERY — The goal of surgery is to reduce the morbidity and mortality associated with obesity, and to improve metabolic and organ function. Several studies have demonstrated that bariatric surgery is effective in reducing obesity-related comorbidities, while having additional benefits such as reducing monthly medication costs and the number of sick days, and improving quality of life A significant reduction in overall and cause-specific mortality has also been clearly demonstrated ]. Although there have been dramatic improvements in the safety of bariatric procedures in the past decade, bariatric surgery is not without serious risks, including significant perioperative complications and mortality
Reduction of comorbidities — Meta-analyses have summarized data from numerous, mainly observational studies Findings are summarized here:
- Evidence supporting a benefit of bariatric surgery was strongest in patients with a BMI of >40, while the benefits in those with BMI of 35 to 39 were less clear
- The mean overall percentage of excess weight lost was 61 percent, varying according to the specific bariatric procedure performed Excess weight loss refers to the difference between the preoperative BMI and a BMI of 25 kg/m 2 (depending upon the study). Greater weight loss was observed with gastric bypass procedures compared with gastroplasty
- Overall mortality was less than 1 percent while adverse events occurred in approximately 20 percent of patients 30-day mortality was 0.1 percent for purely restrictive procedures (defined below), 0.5 percent for gastric bypass, and 1.1 percent for biliopancreatic diversion or duodenal switch
- Diabetes completely resolved in 77 percent and resolved or improved in 86 percent.
- Hyperlipidemia improved in 70 percent or more of patients.
- Hypertension resolved in 62 percent and resolved or improved in 79 percent.
- Obstructive sleep apnea resolved in 86 percent and resolved or improved in 84 percent.
- Gastroesophageal reflux symptoms improved and complete or partial regression of Barrett’s esophagus has been demonstrated.
- Urinary stress incontinence episodes decreased by 47 percent in women who achieved 8 percent weight loss
Reduction in mortality
— The reduction in comorbidities appears to translate into a 29 percent reduction in mortality . These findings were confirmed in a large cohort study, in which nearly 8000 patients who had undergone RYGB were matched to a similar sized obese cohort Deaths from all causes were reduced by 40 percent, from diabetes by 92 percent, from coronary disease by 56 percent, and from cancers by 60 percent.
Although the majority of mortality data for bariatric surgery comes from patients under age 65, retrospective studies suggest that survival is improved, even in patients over age 65 However, most studies have included a primarily female population. In a retrospective study of 850 patients who were predominantly male (74 percent), bariatric surgery was not associated with improved survival in older severely obese patients after almost seven years of follow-up
Surgery compared to medical treatment
— The striking benefits on important obesity-related morbidity contrast with relatively disappointing results in the management of severe obesity with medical and behavioral therapy. The Swedish Obese Subjects Trial (SOS) is the largest trial comparing surgical versus medical treatment of severe obesity. A total of 6328 obese (BMI >34 kg/m 2 for men and >38 kg/m 2 for women) subjects were recruited of whom 2010 underwent surgery for obesity (gastric banding, gastroplasty or gastric bypass) while 2037 chose conventional treatment. Although the study was not randomized, there was an attempt to match patients by relevant covariates. Begun in 1987, the SOS has spawned multiple publications; the following summarizes the major observations
- Weight decreased by 23 percent after two years in the surgery group while it increased in the control group by 0.1 percent After 10 years, weight had decreased by 16 percent in the surgery group and increased in the control group by 1.6 percent. Energy intake was lower and the proportion of physically active subjects was higher in the surgery group.
- The surgery group had better 2- and 10-year incidence rates of diabetes, hypertriglyceridemia, lowered HDL levels, improved hypertension and hyperuricemia rates.
- Surgically treated patients were significantly less likely to require medications for cardiovascular disease or diabetes at two and six years Among those not already requiring such medications, surgery reduced the proportion of those who required initiation of treatment. Costs of medications were reduced significantly in the surgically treated group
- Surgically treated patients had dramatic improvement in scores on validated measures of quality of life and psychiatric dysfunction compared with only minor and sporadic improvement in medically treated patients at two years The magnitude of benefit was related mostly to the degree of weight loss, which was greater in the surgical group. After 10 years of follow-up, the improvements in quality of life diminished somewhat in the surgery group due to weight regain, but overall outcome was still significantly better in the surgical than the medically treated group
The longer-term weight loss benefits of RYGB were confirmed by another population-based study. In a prospective study of 418 severely obese patients undergoing RYGB, 96 percent had maintained at six years more than 10 percent weight loss from baseline and 76 percent maintained more than a 20 percent weight loss . The mean weight loss at six years was 27.7 percent (95% CI 26.6-28.9 percent). In comparison, there was no significant decrease from baseline weight at six years for 417 severely obese patients who sought surgical advice but did not undergo the operation, or for 321 randomly selected severely obese individuals from the general population. In addition, diabetes remission rates at six years were significantly higher for patients undergoing a RYGB compared with the patients seeking advice/not undergoing surgery and the population-based patients (62 versus 8 versus 6 percent, respectively). Patients undergoing RYGB also had better remission rates of hypertension (42 versus 18 versus 9 percent, respectively).
Treatment for type 2 diabetes
— The predominantly observational studies described above have generated much interest in the role of weight loss surgery in the treatment algorithm of diabetes, with some suggesting that bariatric surgery is one of the best treatments for type 2 diabetes. Data from randomized trials comparing surgical versus medical therapy, specifically in obese patients with diabetes, have reported a significant rate of remission of diabetes, and the cost-effectiveness of surgery In one trial, for example, 60 obese subjects (BMI between 30 and 40 kg/m 2 ), with type 2 diabetes diagnosed within the previous two years, were randomly assigned to conventional therapy (lifestyle modification and medical therapy) or laparoscopic adjustable banding and conventional therapy Remission of diabetes occurred more often in the surgical group (73 versus 13 percent). Remission was related to lower baseline A1C values and to weight loss.
All commonly performed procedures for weight loss seem to improve glucose metabolism. The optimal surgical approach for improvement and remission of diabetes has yet to be fully elucidated.
The mechanism for diabetes improvement depends upon the type of surgery performed In a meta-analysis of predominantly observational studies, diabetes resolution was highest after biliopancreatic diversion/duodenal switch (95 percent) and lowest after laparoscopic adjustable gastric banding (57 percent) One study suggested that insulin sensitivity improved in proportion to weight loss with the use of predominantly restrictive procedures, but was reversed completely by predominantly malabsorptive approaches long before normalization of body weight
The rapid normalization of insulin sensitivity after bypass types of bariatric procedures may be related to duodenal isolation following the bypass surgery and subsequent changes in gastrointestinal hormones (the incretins, glucagon-like peptide and glucose-dependent insulinotropic polypeptide) following surgery. In a study of eight obese women with type 2 diabetes, the release of incretins after oral glucose and their effect on insulin secretion improved within one month of Roux-en-Y gastric bypass surgery ]. The role of gastrointestinal peptides in glucose homeostasis is reviewed in detail elsewhere .)
— Obese patients are at risk for fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) which may progress to cirrhosis and hepatocellular carcinoma. NALFD can be considered part of the metabolic syndrome (insulin resistance) Insulin resistance improves after significant prolonged weight loss and may also improve immediately after bypass of the duodenum as with the RYGB Accordingly, some studies note improvement of NAFLD and metabolic syndrome with bariatric surgery In addition, the measurement of adipokines used to measure fatty liver disease and insulin resistance improve after weight loss surgery .
While the cornerstone of therapy for NALFD and NASH is weight loss, no randomized trials of bariatric surgery for these diagnoses have been performed and the surgical approach remains controversial A review of 21 retrospective cohort studies showed improvement in steatosis and inflammation, with surgery ]. However, four studies reviewed showed deterioration in the degree of fibrosis. In addition, none of the studies provided adequate follow up to document whether surgery had any effect on progression to cirrhosis and hepatocellular carcinoma.
Preoperative assessment may also need to be altered to help determine the best course of action in bariatric patients with liver disease as the presence of fatty liver disease does not predict poor outcome after bariatric surgery
Cirrhosis is found incidentally during weight loss surgery in 1.4 to 3.2 percent of patients because preoperative liver function tests do not predict the extent of cirrhosis ]. The diagnosis of cirrhosis can be confirmed with an intraoperative biopsy. In a retrospective study of 30 patients with cirrhosis who underwent laparoscopic RYGB, there were no perioperative deaths, conversions to laparotomy, or liver-related complications However, data from the Nationwide Inpatient Sample on patients who underwent bariatric surgery demonstrated lower mortality rates in patients without cirrhosis as compared with patients with compensated and decompensated cirrhosis (0.3, 0.9 and 16 percent, respectively). In addition, the average length of stay was longer for patients with decompensated and compensated cirrhosis, compared with patients without liver disease (7, 4, and 3 days, respectively) However, portal hypertension with large esophageal or gastric varices makes all bariatric procedures very risky. The safest approach when portal hypertension is detected intraoperatively is to perform a liver biopsy and conclude the procedure. The patient should then be evaluated by a hepatologist to help control the portal hypertension. Patients with mild portal hypertension may be candidates for restrictive procedures. Bariatric surgery is not recommended for patients with severe portal pressure
The model for end-stage liver disease (MELD) score can be used to predict mortality in patients with cirrhosis or fatty liver disease being considered for bariatric surgery Those with high MELD scores should be referred to a hepatologist for evaluation. If possible, bariatric surgery for these risk patients should be performed in a high-volume tertiary referral center ]. The MELD score is discussed in detail elsewhere.
— Elevated BMI is associated with poor outcomes after transplantation, thus the need for preoperative weight loss, surgical or nonsurgical, has been questioned.
A retrospective study of 51,927 primary, adult renal transplants registered in the United States Renal Data System (USRDS) showed that elevated BMI was significantly associated with worse graft survival and mortality ]. The impact of BMI on outcomes is likely due to associated comorbid conditions and altered pharmacokinetics
The USRDS data included 188 patients who underwent bariatric surgery, 72 before being listed for transplant, 29 on the transplant waitlist, and 87 post-transplant Thirty-day mortality after bariatric surgery performed on the waitlist and post-transplant was 3.5 percent. Some centers now limit transplant to patients with a BMI <35, deferring transplant evaluation until appropriate weight loss has been achieved
ACCREDITATION OF BARIATRIC PROGRAMS
— The ultimate goal of The American Society of Metabolic and Bariatric Surgeons (ASMBS) and the American College of Surgeons (ACS) is to improve patient safety and outcomes by reducing medical errors, and hence in 2012, these two organizations have combined their criteria for Bariatric Centers of Excellence into the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Project (MBS-AQIP) [ 69 ]. The recommendations of the MBS-AQIP should be the standard under which hospital programs providing bariatric services should function.
The goals of MBS-AQIP include:
- Accredit Metabolic and Bariatric Surgery Programs according to outcomes based standards
- Establish national/regional and state collaboratives to improve care
- Decrease morbidity by 50 percent throughout five years
- Decrease readmissions, reoperations
- Improve the value of metabolic surgery by increasing safety, improving efficacy and decreasing cost of care
- Share best practices
The benefits of these guidelines include the improved ability to compare short-term and long-term results across institutions providing medical and surgical bariatric services. For those hospitals that do provide bariatric care, the recommendations of the MBS-AQIP should be the standard under which they operate.
INDICATIONS — Indications for the surgical management of severe obesity were first outlined by the National Institutes of Health (NIH) Consensus Development Panel in 1991 Potentially eligible patients should:
- Be well-informed and motivated
- Have a BMI >40
- Have acceptable risk for surgery
- Have failed previous nonsurgical weight loss
- Adults with a BMI >35 who have serious comorbidities such as diabetes, sleep apnea, obesity-related cardiomyopathy, or severe joint disease may also be candidates
Bariatric surgery should be performed in conjunction with a comprehensive follow-up plan consisting of nutritional, behavioral, and medical programs. Clinical practice guidelines from the American College of Physicians for management of obesity in primary care are discussed elsewhere.
CONTRAINDICATIONS — Contraindications to bariatric surgery include patients with untreated major depression or psychosis, binge-eating disorders, current drug and alcohol abuse, severe cardiac disease with prohibitive anesthetic risks, severe coagulopathy, or inability to comply with nutritional requirements including life-long vitamin replacement. Bariatric surgery in advanced (above 65) or very young age (under 18) is controversial, but is considered when comorbidity is severe
CHOOSING A PROCEDURE — The most commonly performed bariatric surgery procedures are laparoscopic adjustable gastric banding (LAGB) and Roux-en-Y gastric bypass (RYGB). There are benefits and risks associated with each procedure.
The comparative efficacy and safety of the procedures were evaluated in a five-year trial of 50 obese patients (mean BMI 43 kg/m 2 ) randomly assigned to LAGB versus laparoscopic RYGB (LRYGB) After five years, patients in the LRYGB group lost a greater percentage of excess body weight (67 versus 47 percent) and had a lower failure rate (4 versus 35 percent). A similar study of 250 patients randomly assigned to gastric bypass or gastric banding showed that LRYGB resulted in better weight loss, but was associated with more complications and a higher 30-day readmission rate
A meta-analysis of 14 studies (13 observational and one randomized trial evaluating clinical outcomes after LAGB and RYGB showed the following advantages and disadvantages of RYGB
- Weight loss at one year was superior (median difference 26 percent, 95% CI 19-34 percent)
- Resolution of comorbidities, such as diabetes and dyslipidemia, was better
- Operative times and length of hospitalization were longer (median differences of 68 minutes and two days, respectively)
- Perioperative complications (9 versus 5 percent) were greater, but reoperation rates (16 versus 24 percent) lower
- Mortality was higher, although it was low in both groups (0.06 and 0.17 percent for LAGB and RYGB, respectively)
Thus, in this meta-analysis of predominantly observational studies, RYGB was associated with greater long-term success but higher short-term morbidity.
In addition to laparoscopic Roux-en-Y gastric bypass and adjustable gastric band, biliopancreatic diversion with duodenal switch, and primary laparoscopic sleeve gastrectomy are also effective means of treating severe obesity ]. In the United States, two national databases, Bariatric Outcomes Longitudinal Database™ (BOLD) and National Surgical Quality Improvement Program (NSQIP) are being implemented to track weight loss surgery outcomes. Results from these prospective, risk-adjusted and benchmarked data collection systems will hopefully provide useful data for further comparison of procedures
The choice of procedure depends upon patient preference, the institution, and expertise of the surgeons. The surgeons, and all members of the multidisciplinary bariatric team, should educate patients fully regarding the risks, benefits and alternatives to weight loss surgery Data from the National Inpatient Sample database on 304,515 patients showed that male gender (odds ratio 1.7), age >50 years (odds ratio 3.8), congestive heart failure (odds ratio 9.5), peripheral vascular disease (odds ratio 7.4), chronic renal failure (odds ratio 2.7), and open surgery (odds ratio 5.5), were associated with greater mortality ]. Ethnicity, hypertension, diabetes, liver disease, chronic lung disease, sleep apnea, and alcohol abuse, had no significant association with mortality. These factors should be considered when counseling patients preoperatively.
A thorough discussion of the pros and cons of the various surgical approaches as part of the informed consent is very important. Patients need to understand the need to make major dietary and lifestyle changes postoperatively, and must have realistic expectations. The medical management of patients after bariatric surgery is discussed elsewhere.
Many accredited multidisciplinary programs hold information sessions to discuss different weight loss surgery options and provide extensive nutritional education. Patients planning surgery are usually tested on their understanding
BARIATRIC SURGICAL PROCEDURES
Roux-en-Y gastric bypass — The Roux-en-Y gastric bypass (RYGB) was developed in the 1960s based on the observation that patients who underwent partial gastrectomy experienced significant long-term weight loss . Many subsequent modifications have been made to improve the weight loss outcome and limit operative complications. It is the most common bariatric procedure performed in the United States and is considered the gold standard among bariatric procedures.
Surgical procedure — The Roux-en-Y gastric bypass configuration is characterized by a small (less than 30 mL) proximal gastric pouch divided and separated from the stomach remnant, with drainage of food to the rest of the gastrointestinal tract via a small gastrojejunal anastomosis and a Roux-en-Y small bowel arrangement The small pouch and the small outlet act to restrict caloric intake, as seen in VBG and LAGB. A much larger gastric remnant becomes disconnected from the food stream while secretion of gastric acid, pepsin, and intrinsic factor continues.
The small intestine is then divided at a distance of 30 to 50 cm distal to the Ligament of Treitz. By dividing the bowel, the surgeon creates a proximal biliopancreatic limb that transports the secretions from the gastric remnant, liver, and pancreas. The Roux limb (or alimentary limb) is anastomosed to the new gastric pouch, and functions to drain consumed food. The cut ends of the biliopancreatic limb and the Roux limb are then connected 75 to 150 cm distally from the gastrojejunostomy. Major digestion and absorption of nutrients then occurs in the common channel where pancreatic enzymes and bile mix with ingested food.
Minimally invasive technique
— Most bariatric procedures are now performed laparoscopically. Data from the Nationwide Inpatient Sample from 2003 through 2008 documented that the proportion of laparoscopic bariatric operations increased from 20 percent in 2003 to 90 percent in 2008 . Minimally invasive techniques were first applied in bariatric surgery in the 1990s. The first laparoscopic RYGB series was reported in 1994 in the United States Although technically challenging with a steep learning curve, laparoscopic RYGB can be performed safely by experienced surgeons . The laparoscopic approach offers several advantages, such as reduced blood loss, lower incidence of incisional hernia, wound infection, faster recovery, and a shorter hospital stay than with open surgery ]. Although the procedure can be limited by patient size, instrument and trocar length, even the extremely large patients have been successfully completed laparoscopically
Weight loss mechanism — While the RYGB, with its small pouch, is primarily a restrictive operation, a malabsorptive component also contributes to weight loss. RYGB has been shown repeatedly to be better than purely restrictive procedures, such as the vertical banded gastroplasty (VBG), in long-term weight reduction [ 89 ]. Other mechanisms, such as dumping syndrome, Roux limb length, and gut hormones, may have a role in the weight loss seen following gastric bypass:
- Gastrojejunostomy anatomy (connection between the stomach pouch and jejunum) is associated with dumping physiology, and causes unpleasant symptoms of lightheadedness, nausea, diaphoresis and/or abdominal pain, and diarrhea when a high sugar meal is ingested [ 90 ]. This response may serve as a negative conditioning response against consumption of a high sugar diet postoperatively.
- The optimal length of the Roux limb in achieving the best balance between weight reduction and complications of malabsorption is controversial. Increasing Roux limb length can lead to increased malabsorption, since lengthening the Roux limb effectively shortens the common limb where major digestion and absorption of the ingested nutrients occur. At present, most surgeons do not make the Roux length longer than 150 cm. Distal gastric bypass with a short common limb has been used to treat patients with inadequate weight loss following standard RYGB, but the risk for metabolic complications increases similar to other malabsorptive operations
- Ghrelin is a peptide hormone secreted in the foregut (stomach and duodenum) that stimulates the early phase of meal consumption. The normal pulsatile release of this orexigenic (appetite-producing) hormone appears to be inhibited in gastric bypass patients due to its unique foregut bypass configuration [ Such inhibition of ghrelin has also been observed in laparoscopic sleeve gastrectomy The reduced ghrelin levels may contribute to the characteristic loss of appetite seen in post RYGB patients. An exaggerated response of peptide YY (PYY) may also contribute to the loss of appetite
— Excess weight loss (EWL) after Roux-en-Y gastric bypass (RYGB) is durable and reliable. On average, 62 to 68 percent EWL is reported after the first year. Early weight loss following gastric bypass is typically rapid, but usually reaches a plateau after one to two years to an average EWL percent between 50 to 75 percent [ Sustained weight loss is seen up to 16 years , which makes this procedure an excellent tool for a permanent surgical weight loss. Improvement and/or resolution of comorbid conditions (including diabetes, sleep apnea, hypertension, and dyslipidemia) following gastric bypass has also been well established
Some patients may experience a precipitous drop in blood glucose due to altered insulin metabolism after RYGB ]. Clinical approaches to severe hypoglycemia after gastric bypass are addressed in detail elsewhere
Laparoscopic adjustable gastric banding
— Laparoscopic gastric banding (LAGB) is a purely restrictive procedure that compartmentalizes the upper stomach by placing a tight, adjustable prosthetic band around the entrance to the stomach
Although LAGB was performed extensively in Europe and Australia for almost a decade, it was not until June 2001 that the first adjustable band (LapBand, Allergan) was approved for use in the United States. Another adjustable gastric band also received FDA approval (Realize band, Ethicon) It works on similar principle, and has similar short-term outcomes to LapBand. In 2011, the FDA approved the laparoscopic adjustable gastric band for use in patients with BMI greater than 30 with one or more weight related comorbid conditions Use of the gastric band for this population has not been universally embraced by the bariatric surgery community or the third party insurance payers because of the high complication rate.
The gastric band consists of a soft, locking silicone ring connected to an infusion port placed in the subcutaneous tissue. The port may be accessed with relative ease by a syringe and needle. Injection of saline into the port leads to reduction in the band diameter, resulting in an increased degree of restriction. The band is adjustable and is placed laparoscopically Postoperatively, the patient must be followed with frequent office visits to the nutritionist for diet counseling and surgical staff for band adjustments . The goal of band adjustments is to give the patient restriction of about a cup of dried food and satiety for at least 1.5 to 2 hrs after a meal.
Indications for the use of LAGB are similar to the indications for gastric bypass, and patients must meet full NIH criteria LAGB is generally contraindicated in patients with portal hypertension, connective tissue disorders with severe esophageal dysmotility, or chronic steroid use (relative contraindication).
LAGB has gained significant attention among bariatric surgeons and patients primarily because of its perceived simplicity and lower perioperative complication rates when compared with more involved procedures such as RYGB Because of its many advantages, it has largely replaced the conventional VBG as the main restrictive procedure for treatment of severe obesity:
- LAGB does not require division of the stomach or intestinal resection. As a result, it has the lowest mortality rate (0 to 0.5 percent) among all bariatric procedures
- The band eliminates the need for staple lines used in VBG that may break down and cause weight regain.
- Avoidance of a fixed prosthetic mesh at the stoma reduces the incidence of stomal stenosis seen in VBG.
- The adjustability of the outlet by the new band design offers a theoretical advantage of addressing various nutritional issues after surgery. As an example, a patient who becomes pregnant following this procedure may have her stoma widened to allow for greater caloric and fluid intake, if necessary. In addition, restoration of the original anatomy by the removal of the band is possible. A significant scar capsule remains after band removal, however, which may contribute to the increased rate of complications seen with revisional bariatric procedures following failed banding procedures
The effectiveness of the LAGB for achieving excess weight loss has been variable. As a general rule, weight loss following LAGB is more gradual and less, compared with gastric bypass procedures, but some have reported comparable long-term outcomes Based on a few retrospective studies, there was a 15 to 20 percent EWL at three months, 40 to 53 percent EWL at one year, with eventual increases in up to 45 to 75 percent EWL at two years [ A retrospective review of 3227 obese patients undergoing LAGB identified a durable weight loss of 47 percent EWL at 15 years . In addition to weight loss, LAGB is associated with improvements in various comorbidities (diabetes, asthma, sleep apnea, hypertension) and quality of life [
Complications of LAGB are discussed elsewhere
— Sleeve gastrectomy (SG) is a partial gastrectomy, in which the majority of the greater curvature of the stomach is removed and a tubular stomach is created. SG was initially offered to patients with super severe obesity (BMI > 60kg/m 2 ) as the first stage in surgical management The tubular stomach is small in its capacity (restriction), resistant to stretching due to the absence of the fundus, and has few ghrelin-producing cells (a gut hormone involved in regulating food intake) . Although SG is a restrictive procedure, gastric motility changes also occur with surgery and may affect weight loss outcomes
SG is technically easier than RYGB, as it does not require multiple anastomoses. It is also safer, as it reduces the risks of internal herniation and protein and mineral malabsorption SG can be considered a restrictive option for the treatment of severe obesity as a single stage primary operation, rather than just a bridge procedure to a more technically challenging gastric bypass or biliopancreatic diversion in high-risk patients A randomized study of 80 patients showed that SG results in better weight loss and hunger control at three years after surgery than adjustable gastric banding (EWL of 66 versus 48 percent respectively The benefits of SG have been attributed in part to better suppression of ghrelin compared with gastric bypass
SG is an effective and relatively safe procedure that appears to combine the safety profile of the gastric band with the effectiveness of the more complicated procedures, such as the gastric bypass. Data from the American College of Surgeons-Bariatric Surgery accreditation program on 944 SG, 12,193 gastric banding, and 15,479 RYGB patients showed no difference in mortality between procedures SG had higher morbidity, readmission and reoperation rates than the gastric band, but less than the RYGB with one year follow up. Weight loss after SG also lies between that of the gastric band and the RYGB. Similar results were reported in other series ]. One retrospective review of 176 patients shows that persistent reflux occurred in 47 percent of patients ]. However, long term data are still lacking
Biliopancreatic diversion — The biliopancreatic diversion (BPD) was introduced as a solution to the high rates of liver failure resulting from bowel exclusion in the jejunoileal bypass
The procedure consists of a partial gastrectomy and gastroileostomy with a long segment of Roux limb and a short common channel (the part of the small bowel that receives both food and biliopancreatic secretions) resulting in fat and starch malabsorption. Up to 72 percent excess weight loss at 18 years after surgery has been reported. Laparoscopic BPD has also been performed with acceptable outcomes ]. Its use has been limited by the high rates of protein malnutrition, anemia, diarrhea, and stomal ulceration In the United States, the role of BPD has generally been limited to revisional bariatric surgery.
Duodenal switch — The duodenal switch (DS) procedure combines gastric restriction (sleeve gastrectomy or vertical gastrectomy) and malabsorption (DS with functional shortening of the small intestine) to attain weight loss . The DS with shortening of the small intestine is achieved with division of the duodenum 4 cm distal to the pylorus, anastomosis of the duodenum to the distal ileum, and anastomosis of the biliopancreatic limb to the distal ileum to create a 100 cm common channel and a 150 cm enteric limb. A randomized trial of 60 patients who underwent either gastric bypass or DS showed greater weight loss with the duodenal switch procedure than the gastric bypass (25 versus 17 kg respectively) However, patients who underwent the DS had a much higher rate of adverse events as compared with the gastric bypass (62 vs 32 percent of patients respectively). In the DS group, there were 3 cases of protein calorie malnutrition, 2 cases of night blindness and 1 case of severe iron deficiency. The DS patients also had lower levels of vitamin A and D. Thus, the DS procedure cannot be recommended for surgical management of obesity.
Biliopancreatic diversion with duodenal switch
— The biliopancreatic diversion with duodenal switch (BPD/DS) is a variant of the BPD and is primarily a malabsorptive operation
The BPD/DS procedure involves a partial sleeve gastrectomy with preservation of the pylorus, and creation of a Roux limb with a short common channel. The BPD/DS procedure differs from the BPD in the portion of the stomach that is removed, as well as preservation of the pylorus [ It is associated with a lower incidence of stomal ulceration and diarrhea than with BPD alone. Although complex, BPD/DS has been performed laparoscopically by several groups This procedure is performed at only a few centers in the United States.
This procedure has been advocated for patients with very severe obesity (BMI >50 kg/m 2 ), a group in which it has been associated with improved weight loss BPD/DS is not widely accepted as a first-line surgical treatment for less severe obesity because of concerns regarding the risks of long-term malabsorption.
Intragastric balloon — The intragastric balloon (Bioenterics Intragastric Balloon, Allergan) is a temporary alternative for weight loss in moderately obese individuals It consists of a soft, saline-filled balloon, placed endoscopically, which promotes a feeling of satiety and restriction
The intragastric balloon is not available for use in the United States, outside of clinical trials Mean excess weight loss is reported to be 38 percent and 48 percent for 500 and 600 mL balloons, respectively However, the results of a Brazilian multicenter study indicate weight loss is transient, with only 26 percent of patients maintaining over 90 percent of the excess weight loss out over one year It appears to reduce the risk of conversion to open surgery and the risk of intraoperative complications when it is used for preoperative weight loss in super-obese patients before a definitive bariatric procedure Side effects include nausea, vomiting, abdominal pain, ulceration, and balloon migration.
Vertical banded gastroplasty — Vertical banded gastroplasty (VBG) is a purely restrictive procedure in which the upper part of the stomach is partitioned by a vertical staple line with a tight outlet wrapped by a prosthetic mesh or band
The small upper stomach pouch is filled quickly by solid food, and prevents consumption of a large meal. Weight loss occurs because of decreased caloric intake of solid food. Patients who have undergone VBG can be expected to have excess weight loss (EWL) of 58 percent The effectiveness of such a restrictive mechanism depends upon the durability of pouch and stoma (outlet) size.
Ingestion of high-calorie liquid meals and gradually increased pouch capacity due to overeating has been some of the major causes of its failure. Sweets eaters who rely on soft meals (ie, ice cream, milk shakes) do not benefit significantly from this procedure
VBG has been replaced largely by other procedures and is rarely performed due to lack of sustained/desired weight loss, as well as the high incidence of complications requiring revision (20 to 56 percent The majority of revisions are required for staple line disruption, stomal stenosis, band erosion, band disruption, pouch dilatation, vomiting, and gastroesophageal reflux disease.
Endoluminal vertical gastroplasty
— Endoscopic methods for suturing the stomach have been developed, which offer the potential to perform gastric-restrictive procedures endoluminally. Initial experience is promising, but longer-term studies are needed
Jejunoileal bypass — The jejunoileal bypass was one of the first bariatric operations, performed initially in 1969 ]. It has since been abandoned due to the high complication rate and frequent need for revisional surgery. Its importance lies in the care of surviving patients who have undergone this procedure.
The procedure was performed by dividing the jejunum close to the ligament of Treitz, and connecting it a short distance proximal to the ileocecal valve ), thereby diverting a long segment of small bowel, resulting in malabsorption. Although excess weight loss was excellent, jejunoileal bypass was associated with multiple complications, such as liver failure (up to 30 percent), death, diarrhea, electrolyte imbalances, oxalate renal stones, vitamin deficiencies, malnutrition, and arthritis ].
Patients who have undergone this procedure should be monitored closely for complications (particularly liver disease) and undergo reversal if such complications arise.
Liposuction — Although not generally considered to be a bariatric procedure, removal of fat by aspiration after injection of physiologic saline has been used to remove and contour subcutaneous fat. While this can result in reduction in fat mass and weight, the amount of weight loss is insignificant in comparison with bariatric procedures, and it does not appear to improve insulin sensitivity or risk factors for coronary heart disease
COMPLICATIONS — Bariatric surgery has serious risks Complications of these procedures are discussed separately. .)
INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, “The Basics” and “Beyond the Basics.” The Basics patient education pieces are written in plain language, at the 5th to 6th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10th to 12th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.
Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on “patient info” and the keyword(s) of interest.)
SUMMARY AND RECOMMENDATIONS
- Obesity is a major health problem, and its incidence is increasing rapidly in developed countries. Severe obesity leads to numerous medical problems and a shortened life expectancy.
- Body mass index (BMI) is the most practical measure of a person’s adiposity
- Bariatric surgical approaches are based primarily on two main mechanisms: restriction of caloric intake via a small stomach reservoir and malabsorption of nutrients via reduced functional small bowel length. Restrictive procedures are generally simpler in techniques, but seem to achieve less weight loss. Malabsorptive procedures are highly effective in weight loss, but can carry significant metabolic complications.
- Bariatric surgery is effective in reducing obesity-related comorbidities and mortality.
- Bariatric surgery needs to be performed in conjunction with a comprehensive follow-up plan consisting of nutritional, behavioral, and medical programs. These complex procedures must be performed in appropriately accredited facilities and follow the combined guidelines of the American College of Surgeons and the American Society of Metabolic and Bariatric Surgeons (MBS-AQIP).
- The Roux-en-Y gastric bypass has been the most commonly performed procedure in the United States due to its multiple mechanisms of action and durable long-term weight loss.
- Laparoscopic Roux-en-Y gastric bypass, compared to the open approach, can decrease surgical pain, infectious and hernia complications, as well as allow for quicker postoperative recovery.
- Laparoscopic adjustable gastric banding is becoming increasingly more popular in the United States due to its simplicity in technique, adjustability, reversibility, and relatively low perioperative mortality. Weight loss following gastric banding is more gradual and less, compared with gastric bypass procedures. Frequent band adjustments and revisional surgery may be required over time.
- Laparoscopic vertical sleeve gastrectomy is an effective procedure to treat severe obesity. This procedure combines the nutritional benefits of a purely restrictive procedure, such as the adjustable gastric band, and the weight loss benefits of the gastric bypass
- Laparoscopic biliopancreatic diversion with duodenal switch (BPD/DS) is an effective operation for very severe obesity (BMI >50.0 kg/m 2 ). BPD/DS is not widely accepted as a first-line surgical treatment in less severely obese patients because of concerns regarding the long-term risks of nutritional deficiencies.