Surgery Section - Surgery for Morbid Obesity

IMPORTANT REMINDER

This Medical Policy has been developed through consideration of medical necessity, generally accepted standards of medical practice, and review of medical literature and government approval status.

Benefit determinations should be based in all cases on the applicable contract language. To the extent there are any conflicts between these guidelines and the contract language, the contract language will control.

The purpose of medical policy is to provide a guide to coverage. Medical Policy is not intended to dictate to providers how to practice medicine. Providers are expected to exercise their medical judgment in providing the most appropriate care.

Description

Morbid obesity is defined as a body mass index (BMI) >40 kg/m2.  (Note: BMI may be calculated by using the BMI calculator.)

Individuals with morbid obesity are at high risk for developing weight-related complications such as diabetes, hypertension, obstructive sleep apnea, and various types of cancers (for men: colon, rectum, and prostate; for women: breast, uterus, and ovaries).  In addition, morbid obesity is associated with a shortened life span.

The first treatment of morbid obesity involves dietary and lifestyle changes. Although this strategy may be effective in some patients, frequently the weight loss is not durable, with only 5%-10% of patients able to comply with lifestyle modifications on a long-term basis.  When conservative measures fail, some patients may consider surgical approaches. 

Surgery for morbid obesity, termed bariatric surgery, falls into two general categories.

1. Gastric restrictive procedures, which decrease the size of the gastric pouch and limit food intake; and,
2. Malabsorptive procedures, which limits the absorption of calories and nutrients by altering the way food moves through the intestinal track.  Some bariatric procedures may include both a restrictive and a malabsorptive component.

The following summarizes the different restrictive and malabsorptive procedures:

Gastric Restrictive Procedures

1. Vertical Banded Gastroplasty - (also known as vertically banded gastric partition and gastric stapling) - CPT code 43842

   In this procedure the stomach is segmented along its vertical axis. To create a durable reinforced and rate-limiting stoma at the distal end of the pouch, a plug of stomach is removed and a propylene collar is placed through this hole and then stapled to itself. Because the normal flow of food is preserved, metabolic complications are rare. Complications include esophageal reflux, staple line disruption, and dilation or obstruction of the stoma, with the latter three requiring reoperation. Dilation of the stoma is a common reason for weight gain. Vertical banded gastroplasty may be performed using an open or laparoscopic approach. While this procedure was once the most common kind of gastric restrictive procedure performed in this country, it has fallen out of favor due to a high reoperation rate.

2. Adjustable Gastric Banding - CPT codes 43770-43774; 43886-43888

   Adjustable gastric banding involves placing a gastric band around the exterior of the stomach. The band is attached to a reservoir that is implanted subcutaneously in the rectus sheath. Injecting the reservoir with saline alters the diameter of the gastric band; therefore, the rate limiting stoma in the stomach can be progressively narrowed to induce greater weight loss, or expanded if complications develop. Because the stomach is not entered, the surgery and any revisions, if necessary, are relatively simple. Complications include slippage of the external band or band erosion through the gastric wall.

Currently, there are two devices approved by the U.S. Food and Drug Administration (FDA) for marketing in the United States, the Lap-Band® (BioEnterics, Carpentiera, CA) and the REALIZE™ (Ethicon Endo-Surgery, Inc.). The labeled indications for the devices are similar.

According to the FDA labeling the Lap-Band® system and REALIZE™ system are  indicated for use in weight reduction for severely obese patients with a BMI of at least 40 or a BMI of at least 35 with one or more severe comorbid conditions.  The adjustable gastric bands are indicated for use only in severely obese adult patients who have failed more conservative weight-reduction alternatives, such as supervised diet, exercise and behavior modification programs.

3. Gastric Bypass - CPT code 43846, 43644

   Gastric bypass with Roux-en-Y anastomosis (RYGB), involves both restrictive and malabsorptive components, with horizontal or vertical partition of the stomach in association with a Roux-en-Y procedure (i.e., a gastrojejunal anastomosis). Thus the flow of food bypasses the duodenum and proximal small bowel. The procedure may also be associated with an unpleasant "dumping syndrome," in which a large osmotic load delivered directly to the jejunum from the stomach produces abdominal pain and/or vomiting. The dumping syndrome may further reduce intake, particularly in "sweets eaters." Operative complications include leakage and marginal ulceration of the anastomotic site. Because the normal flow of food is disrupted, there are more metabolic complications compared to other gastric restrictive procedures, including iron deficiency anemia, vitamin B-12 deficiency, and impaired calcium absorption, all of which can be corrected by oral supplementation. Another concern is the ability to evaluate the "blind" bypassed portion of the stomach. Gastric bypass may be performed with either an open or laparoscopic technique.

4. Mini-Gastric Bypass (no specific CPT code)

   The "mini-gastric bypass" is a variant of the gastric bypass. Using a laparoscopic approach, the stomach is segmented, similar to a traditional gastric bypass, but instead of creating a Roux-en-Y anastomosis, the jejunum is anastomosed directly to the stomach, similar to a Billroth II procedure.  The unique aspect of this procedure is not based on its laparoscopic approach, but rather the type of anastomosis used. It should be noted that CPT code 43846 does not accurately describe the mini-gastric bypass, since the CPT code explicitly describes a Roux-en-Y gastroenterostomy, which is not used in the mini-gastric bypass.

5. Sleeve-Gastrectomy (no specific CPT code)

   A sleeve gastrectomy is an alternative to gastrectomy that can be performed on its own, or in combination with malabsorptive procedures (most commonly biliopancreatic diversion with duodenal switch).  In this procedure, the greater curvature of the stomach is resected from the angle of His to the distal antrum, resulting in a stomach remnant shaped like a tube or sleeve.  The pyloric sphincter is preserved, resulting in a more physiologic transit of food from the stomach to the duodenum, and avoiding the dumping syndrome (overly rapid transport of food through stomach into intestines) that is seen with distal gastrectomy.  This procedure is relatively simple to perform, and can be done by the open or laparoscopic technique.  Some surgeons have proposed this as the first stage in a two-stage procedure for very high-risk patients to improve a patient’s overall medical status, and thus reduce the risk of a subsequent more extensive malabsorptive procedure, such as biliopancreatic diversion.

Malabsorptive Procedures

There are multiple variants of malabsorptive procedures, which differ in the lengths of the alimentary limb, the biliopancreatic limb, and the common limb, where the alimentary and biliopancreatic limb are anastomosed. These procedures also may include an element of a restrictive surgery based on the size of the stomach pouch. The degree of malabsorption is related to the length of the alimentary and common limbs. For example, a shorter alimentary limb (i.e. the greater the amount of intestine that is excluded from the nutrient flow) will be associated with malabsorption of a variety of nutrients, while a short common limb (i.e. the biliopancreatic juices are allowed to mix with nutrients for only a short segment) will primarily limit the absorption of fat.

1. Biliopancreatic Bypass Procedure (also known as the Scopinaro procedure) - CPT code 43847

   The biliopancreatic bypass (BPB) procedure, developed and used extensively in Italy, was designed to address some of the drawbacks of the original intestinal bypass procedures that have been abandoned due to unacceptable metabolic complications. Many of the complications were thought to be related to bacterial overgrowth and toxin production in the blind, bypassed segment. In contrast, BPB consists of a subtotal gastrectomy and diversion of the biliopancreatic juices into the distal ileum by a long Roux-en-Y procedure. The procedure consists of the following components:

   1. A distal gastrectomy functions to induce a temporary early satiety and/or the dumping syndrome in the early postoperative period, both of which limit food intake.
   2. A 200-cm long "alimentary tract" consists of 200 cm of ileum connecting the stomach to a common distal segment.
   3. A 300- to 400-cm "biliary tract," which connects the duodenum, jejunum, and remaining ileum to the common distal segment.
   4. A 50- to 100-cm "common tract," where food from the alimentary tract mixes with biliopancreatic juices from the biliary tract. Food digestion and absorption, particularly of fats and starches, are therefore limited to this small segment of bowel, creating a selective malabsorption. The length of the common segment influences the degree of malabsorption.
   5. Because of the high incidence of cholelithiasis associated with the procedure, patients typically undergo an associated cholecystectomy.

   Many potential metabolic complications are related to biliopancreatic bypass, including most prominently, iron deficiency anemia, protein malnutrition, hypocalcemia, and bone demineralization. Protein malnutrition may require treatment with total parenteral nutrition. In addition, there have been several case reports of liver failure resulting in death or liver transplant.

2. Biliopancreatic Bypass with Duodenal Switch - CPT code 43845

   The duodenal switch procedure is essentially a variant of the biliopancreatic bypass described above. However, instead of performing a distal gastrectomy, a "sleeve" gastrectomy is performed along the vertical axis of the stomach, preserving the pylorus and initial segment of the duodenum, which is then anastomosed to a segment of the ileum, similar to the above procedure, to create the alimentary limb. Preservation of the pyloric sphincter is intended to ameliorate the dumping syndrome and decrease the incidence of ulcers at the duodenoileal anastomosis by providing a more physiologic transfer of stomach contents to the duodenum. The sleeve gastrectomy decreases the volume of the stomach and also decreases the parietal cell mass. However, the basic principle of the procedure is similar to that of the biliopancreatic bypass; i.e., producing selective malabsorption by limiting the food digestion and absorption to a short common ileal segment.

3. Distal (Long Limb) Gastric Bypass (Roux or alimentary limb > 150 cm - CPT code 43847

   Recently variations of gastric bypass procedures have been described, consisting primarily of long limb Roux-en-Y procedures, which vary in the length of the alimentary and common limbs. For example, the stomach may be divided with a long segment of the jejunum (instead of ileum) anastomosed to the proximal gastric stump, creating the alimentary limb. The remaining pancreaticobiliary limb, consisting of stomach remnant, duodenum, and length of proximal jejunum is then anastomosed to the ileum, creating a common limb of variable length in which the ingested food mixes with the pancreaticobiliary juices. While the long alimentary limb permits absorption of most nutrients, the short common limb primarily limits absorption of fats. The stomach may be bypassed in a variety of ways, either by resection or stapling along the horizontal or vertical axis. Unlike the traditional gastric bypass, which is essentially a gastric restrictive procedure, these very long limb Roux-en-Y gastric bypasses combine gastric restriction with some element of malabsorptive procedure, depending on the location of the anastomoses. Note that CPT code for gastric bypass (43846) explicitly describes a short limb (<150 cm) Roux-en-Y gastroenterostomy, and thus would not apply to long limb gastric bypass.

Endoscopic Procedures for Patients who Gain Weight after Bariatric Surgery

There are a number of reasons why patients who are treated with accepted forms of bariatric surgery may not lose weight or may regain weight that is initially lost. These reasons include issues of adherence (compliance) as well as technical (structural) issues. Some patients who regain weight after bariatric surgery, e.g., after Roux-en-Y gastric bypass (RYGB), are found to have enlarged gastric stoma and/or enlarged gastric pouches. Correction of these abnormalities has been reported to again result in successful weight loss.

While these abnormalities can be revised using standard operative approaches, novel endoscopic procedures are being publicized as an option for these patients. Some of these procedures use devices that are also being evaluated for endoscopic treatment of gastroesophageal reflux.

The StomaphyX™ device, which is one device used in this approach, was cleared by the FDA through the 510(k) process. It was determined be equivalent to the EndoCinch™ system which has 510(k) marketing clearance for endoscopic suturing for gastrointestinal surgery.

Policy/Criteria

Scientific Background

Outcomes of bariatric surgeries are difficult to evaluate due in part to the constantly evolving nature of the surgery. Small modifications are commonly made to decrease the incidence of postoperative and long-term complications. In addition, with few exceptions (discussed below) there have been no controlled studies that have directly measured the weight loss and complications associated with the different surgical approaches, particularly comparing gastric restrictive procedures with malabsorptive procedures. Case series from individual institutions or individual surgeons with varying lengths of follow-up dominate the literature. The outcomes for specific surgeries may widely differ among institutions or surgeons, perhaps due to small variations in surgical technique, intensity of follow-up, or patient selection criteria. However, during the 1970s and 1980s both vertical banded gastroplasty (VBG) and gastric bypass became widely accepted types of bariatric surgery, although VBG is now performed infrequently. These two procedures were the focus of the 1991 NIH Consensus Development Conference on gastrointestinal surgery for severe obesity, which also noted that limited data were available regarding biliopancreatic bypass. (3) A 2003 BlueCross BlueShield Association Technology Evaluation Center (TEC) Assessment (4) summarized studies comparing open gastric bypass and vertical-banded gastroplasty. These comparisons demonstrated that open gastric bypass resulted in a greater amount of weight loss than vertical-banded gastroplasty, with no definite differences in complication rates. Therefore, gastric bypass is considered the gold standard for the purpose of this discussion, and the results of this procedure will be compared to the newer procedures not addressed by the 1991 conference; e.g., gastric banding and biliopancreatic bypass with or without duodenal switch.

Given the chronic nature of morbid obesity, ideally, long term outcomes (5 years or greater) are needed to determine the safety, efficacy and durability of results related to specific bariatric procedures. 

• Weight Loss
  
  The ultimate goal of bariatric surgery is to reduce weight into a range that minimizes obesity-related morbidity. An increasing degree of obesity will require a greater amount of weight loss to achieve these target goals. There are different definitions of successful outcomes, but a successful procedure is often considered one in which at least 50% of excess body weight (EBW) is lost, or the patient returns to a weight within 30% of ideal body weight. The results may also be expressed as the percentage of patients losing at least 50% of EBW.  However, it is noted by bariatric surgeons that significant health improvements can occur in patients with weight loss less than 50% EBW.

• Durability of weight loss
  
  Weight change (gain or loss) at yearly intervals is often reported. Weight loss at 1 year is considered the minimum length of time for evaluating these procedures; weight loss at 3–5 years is considered to be an intermediate time period for evaluating weight loss; and weight loss at 5–10 years or more is considered to represent long-term weight loss following bariatric surgery.

• Short-term complications
  
  Operative and perioperative complications that occur within 30 days are considered in this category. There is an increased incidence of operative and perioperative complications in obese patients in general, particularly the incidence of thromboembolism and impaired wound healing. Other perioperative complications include anastomotic leaks, bleeding, bowel obstruction, and cardiopulmonary complications such as pneumonia or myocardial infarction.

• Reoperation Rate
  
  Reoperation may be required to either "take down" or revise the original procedure. Reoperation may be particularly common in vertical banded gastroplasty due to pouch dilation or in adjustable gastric banding due to band slippage or erosion.

• Long-term complications
  
  Metabolic side effects and nutritional deficiencies are included in this category. Metabolic side effects, including iron deficiency anemia, vitamin B-12 deficiency and hypocalcemia are of particular concern in malabsorptive procedures. Other long-term complications include anastomotic ulcers, esophagitis, and procedure-specific complications such as band erosion or migration for gastric banding operations.

• Improved health outcomes in terms of weight-related comorbidities
  
  Aside from psychosocial concerns, which may be considerable, one of the motivations for bariatric surgery is to decrease the incidence of complications of obesity, such as diabetes, cardiovascular risk factors (e.g., increased cholesterol, hypertension), obstructive sleep apnea, or arthritis. Except for type 2 diabetes mellitus, these final health outcomes are not consistently reported in the published literature.

There is strong evidence that bariatric surgery significantly resolves or improves Type 2 diabetes for adult patients with BMI ≥35.  In a meta-analysis published in 2004, Buchwald and colleagues found that after surgery diabetes was completely ameliorated in 76.8% (95% CI 70.7%-82.9%) of patients. (44)  In a study by Pories and colleagues resolution or marked improvement in type 2  diabetes was noted to begin within days of surgery even before weight loss. (45)  The correction of plasma insulin and glucose levels is due to changes in gastrointestinal hormones after surgery.  Sjostrom and colleagues found that at a 2 year follow-up, patients in the surgical groups had a 60% decrease in the plasma glucose level. (46) The patients in the non-surgical arm of this study at 2 years had a 3.7 times higher plasma glucose level.  Christou and colleagues found that mortality risk from diabetes over a 10 year follow-up after Roux-en-Y was less than in a non-surgical group matched for age, weight, and BMI (1.0% vs. 4.5% for every year of follow-up). (47)

The following discussion provides a representative summary of the literature on bariatric surgery, focusing on improvements in the co-morbidities associated with obesity.

Vertical Banded Gastroplasty (VBG)

While initial reported results for VBG were good in terms of weight loss, complications and improvement in comorbid conditions (6-9), the procedure has largely been abandoned as results were noted to deteriorate over time and longer term, less favorable outcomes were reported in the literature.  Staple-line perforations requiring reoperation and poor sustained weight loss were cited as reasons for long-term failure of VBG.  (5,12,13)

In addition, a smaller body of literature comparing outcomes between vertical banded gastroplasty and open gastric bypass consistently reported better weight loss with gastric bypass. (10,11, 17,18)  This outcome was also confirmed in a 2003 BlueCross BlueShield Association Technology Evaluation Center (TEC) Assessment which evaluated eight nonrandomized comparative studies and two randomized, controlled trials of open gastric bypass versus VBG. (4)

Gastric Bypass with Short Limb (150 cm or less)

While vertical banded gastroplasty was perhaps the dominant bariatric surgery in the 1980's, it has been surpassed in this country by the gastric bypass procedure, based on a variety of studies that report improved weight loss with a gastric bypass procedure. This body of literature has been instrumental in establishing that gastric bypass should be the reference procedure to which other procedures are compared. Practice patterns in the U.S. have adopted this approach, with gastric bypass now comprising the vast majority of all bariatric procedures performed.

Many clinical series reporting results of open gastric bypass have been published.  Griffen summarized the experience of over 10,000 gastric bypass operations from a number of bariatric surgeons. (14)  It was estimated that 85% of patients reduced their weight to at least 50% above the ideal weight. In approximately 5,000 patients who were followed for 10 years, 80% were able to maintain this result. Pories and colleagues reported on 608 patients who underwent a gastric bypass procedure and were followed for 1-14 years. (15)  One of the unique features of this report is that only 3% of patients were lost to follow-up. The average weight loss was 75% of excess weight at one year, declining to 50% by the eighth year. The authors observed an immediate drop in both blood glucose and exogenous insulin requirements after surgery. Long-term observation of 298 patients with preoperative diabetes or impaired glucose tolerance revealed that 91% had normal values for blood glucose and hemoglobin A1-C after surgery. The incidence of hypertension declined from 58% before surgery to 14% after gastric bypass. Flickinger and colleagues reported on the incidence of diabetes and hypertension in a case series of 397 patients. (16)  Prior to surgery, 22% had diabetes mellitus and 13% had impaired glucose tolerance. After surgery, all but one of the patients remained euglycemic. A total of 57% of patients were hypertensive before surgery compared to only 18% after surgery. Similarly, Pories and colleagues reported that of 163 obese patients with diabetes or impaired glucose tolerances, only 5% remained with inadequate control after gastric bypass surgery and associated weight loss. Other studies have reported that gastric bypass surgery and weight loss are associated with improvements in the lipid profile. (15)

As discussed previously, comparative trials summarized in the 2003 TEC Assessment (4) consistently reported favorable outcomes for open gastric bypass when compared with vertical banded gastroplasty, including two randomized, controlled trials. Some nonrandomized trials that compared open gastric bypass with procedures other than vertical banded gastroplasty were also summarized in the TEC Assessment.  While there were fewer trials for these other procedures, comparisons of open gastric bypass to gastric banding, horizontal gastroplasty, and silastic ring gastroplasty all reported that weight loss was superior with open gastric bypass.

Metabolic abnormalities were seen more frequently in gastric bypass patients compared to those receiving a vertical banded gastroplasty. Anemia, iron deficiency, vitamin B-12 deficiency, and red blood cell folate deficiency are commonly seen. Marginal ulcerations are also seen in gastric bypasses, particularly in those whose gastric pouches are too large and include acid-secreting parietal cells.

Mini-gastric Bypass

The mini-gastric bypass has been primarily advocated by one surgeon who published his experience with 1,274 patients. (19)  The mean operating time was 36 minutes, and the mean hospital stay was 1.5 days.  Mean excess weight loss was 51% at 6 months, 68% at 12 months and 77% at 2 years.  The overall complication rate reported was 5.2%.  While this surgical approach may result in decreased surgical time, the anastomosis creates the risk of biliary reflux gastritis, one of the reasons that this anastomosis has been abandoned, in general, in favor of a Roux-en-Y anastomosis that diverts the biliary juices away from the stomach.  One other large case series was published in 2005; however, only short-term results were reported, so conclusions concerning long-term effects on weight loss and adverse effects cannot be reached. (20)

Adjustable Gastric Banding

A 2006 TEC Assessment (21) reviewed the evidence on laparoscopic adjustable gastric banding (LAGB), and compared outcomes to those of gastric bypass.  This Assessment concluded that for patients considering bariatric surgery, there was sufficient evidence to allow an informed choice to be made between gastric bypass and LAGB.  An informed patient may reasonably choose either GBY or LAGB as the preferred procedure.  Preoperative counseling should include education on the comparative risks and benefits (such as extent of weight loss and frequency and timing of potential complications) of the two procedures in order to allow the optimal choice to be made based on preferences and shared decision making.

Weight loss outcomes from the studies reviewed in the Assessment confirm the conclusions of previous TEC Assessments that weight loss at one year is less for LAGB compared with GBY.  The percent excess weight loss (%EWL) at one year is in the range of approximately 40%, compared to 60% or higher for GBY.  At time points longer than one year, some of the comparative studies report that the difference in weight loss between LAGB and GBY lessens, but others do not.  Weight loss outcomes from the nine single-arm series with the most complete follow-up do not support the hypothesis that weight loss continues to increase after one to two years of follow-up.  It appears more likely from the current data that attrition bias may account for the diminution of the difference in weight loss over time, particularly when patients who have their band removed or deflated are excluded from analysis.  These studies also confirm that short-term (perioperative) complications are very low with LAGB, and lower than either open or laparoscopic GBY.  Death is extremely rare, and serious perioperative complications probably occur at rates of less than 1%.

The reported rates of long-term adverse events vary considerably.  In the comparative trials, re-operations are reported in approximately 25% of patients, while in the single-arm studies the composite rate for re-operations is approximately half of this value (11.9%).  The rates of other long term complications are also highly variable, for example, the range of rates for band slippage is 1 to 36% and the range for port access problems is 2 to 20%.  These data on long-term complications remain suboptimal.  The reporting of long-term complications in these trials is not systematic or consistent.  It is not possible to determine the precise rates of long-term complications from these data; however, it is likely that complications are under-reported in many studies due to incomplete follow-up and a lack of systematic surveillance.  The rates of long-term complications reported in some studies raise concern for the impact of these events on the overall benefit/risk ratio for LAGB.

In comparing LAGB to GBY, there is a tradeoff in terms of risks and benefits.  LAGB offers a less-invasive procedure that is associated with fewer procedural complications, a decreased hospital stay and earlier return to usual activities.  However, the benefits, as defined by the amount of weight loss, will also be less for LAGB.  The patterns of long-term complications also differ between the two procedures.  For LAGB, longer-term adverse events related to the presence of a foreign body in the abdomen may occur, and may result in re-operations and removal of the band in a minority of patients.  Patients who have their bands removed can later be offered an alternative bariatric surgery procedure, such as gastric bypass.

Sleeve Gastrectomy

Sleeve gastrectomy may be performed as a stand-alone procedure, or in combination with a malabsorptive procedure, such as the biliopancreatic diversion with duodenal switch. It has also been proposed as the first step in a 2-stage procedure, with gastric bypass or biliopancreatic diversion as the second stage.

As a stand-alone procedure, there are limited data to evaluate outcomes and/or compare efficacy to other procedures. A small number of clinical series have been published that report on outcomes after sleeve gastrectomy alone:

• In a series of 60 patients who had undergone sleeve gastrectomy and who had at least 1-year follow-up, 83% EWL was reported at 12 months. (22) Diabetes resolved in 100% of patients and hypertension resolved in 93%.
• In a smaller series of 23 patients, 56% EWL was reported at one year. (23)

There are also a small number of clinical series that report on sleeve gastrectomy as the initial procedure of a 2-stage operation. This approach has been generally attempted in patients with “super” obesity (BMI >50), in whom a more complex initial operation may be associated with higher risk. Weight loss following sleeve gastrectomy may reduce the risk of these patients undergoing a more complex malabsorptive procedure in the future. The available series to date report only on very small numbers of patients. (24,25) The published data on outcomes following completion of both stages of a 2-stage operation are limited to case reports and case series with very small numbers of patients.

Biliopancreatic Bypass (BPB)

There have been numerous clinical series of BPB published, but as with other procedures, there is a lack of high-quality trials that directly compare outcomes of this procedure with gastric bypass.  The bulk of experience with BPB appears to be in Europe, particularly Italy. There are no case series reported in this country. According to Murr and colleagues, BPB has not been widely accepted in this country due to unacceptable serious long-term morbidities. (26)  For example, BPB has largely been abandoned at the Mayo clinic due to the occurrence of steatorrhea, diarrhea, foul-smelling stools, severe bone pain, and the need for a life-long commitment to supplemental vitamins and minerals. In addition, there have been scattered case reports of liver damage, resulting either in death or liver transplant. (27,28)  Murr hypothesizes that the incidence of protein malnutrition may be higher in this country compared to Scopinaro's Italian series, since the North American diet has a higher percentage of fat and lesser amounts of carbohydrates. (26)

In a 2005 TEC Assessment, the outcomes of BPB, with or without duodenal switch, were compared with those of gastric bypass. (29) One comparative trial and seven single arm series suggested that weight loss outcomes at one year were in the same range as for gastric bypass.  While this data is not sufficient to distinguish small differences in weight loss between the two procedures, it does not support the hypothesis that  BPB results in greater weight loss than open gastric bypass.

Complication rates were poorly reported in these trials. The data suggested that mortality was low (approximately 1%) and in the same range as for open gastric bypass. However, rates of other complications, especially long-term complications, could not be determined.  Limited data suggested that long-term nutritional and vitamin deficiencies occur at a high rate following BPB. For example:

• Slater and colleagues focused specifically on vitamin and calcium deficiencies following BPB. (30)  These authors reported high rates of vitamin and calcium abnormalities in their population over a 4-year period. By year 4, approximately half (48%) of the patients were found to have low calcium and 63% had low levels of vitamin D. Other fat-soluble vitamins showed similar patterns of abnormalities. Low vitamin A was found in 69% of patients at 4 years; low vitamin K in 68%; and low zinc in 50%.
• Dolan and colleagues reported similar data in a study that compared several technical variations ofBPB. (31)  These authors reported low calcium levels in 12–34% of patients; low vitamin D in 22.2–70.6%; low vitamin A in 53–67%; and low vitamin K in 44–59%.  In addition, this study reported high rates of iron deficiency (11–47%) and anemia (11–40%).

The TEC Assessment did not find that the evidence was sufficient to conclude that weight loss following biliopancreatic bypass was greater than for gastric bypass. In addition, the TEC Assessment found that rates of nutritional and metabolic complications appear to be very high following BPB.

Biliopancreatic Bypass with Duodenal Switch (DS)

There is a lack of high-quality trials that directly compare outcomes of DS with gastric bypass.

• The largest case series reported on 465 patients who underwent the duodenal switch procedure compared to 252 patients who underwent the biliopancreatic bypass. (32)  It should be noted that in addition to the preservation of the duodenum, the common segment was elongated to 100 cm. The authors noted similar weight loss in the two groups. In the DS group, a lower incidence of metabolic abnormalities such as protein malnutrition was noted, which prompted reversal of the procedure in 1.7% of those undergoing BPB vs. only 0.1% after the duodenal switch procedure. However, it is not known whether this outcome was attributed to the lengthening of the common segment versus retention of the pylorus.
• Hess reported on a case series of 440 patients with variable lengths of the common channel. (33)  The percentage excess weight loss varied between 60% and 90%, depending on the length of the common segment and alimentary limb. There were 2 late deaths, 1 due to septic shock secondary to an infected panniculus and 1 related to liver failure. A total of 10 patients underwent revision to lengthen the common segment secondary to low protein or excessive diarrhea. Seven patients underwent shortening of the common segment due to inadequate weight loss.
• In 2005, Hess and colleagues reported 10-year outcomes for 167 of 1,404 patients (12%). (34)  Of the 167 patients, 94% achieved 50% or greater excess weight loss.  Specific complication rates for this cohort of patients were not reported; however, the authors did report overall that  8 reversals and 37 revisions were needed for excessive weight loss, protein malnutrition, uncontrolled diarrhea, or inadequate weight loss.
• Baltasar and colleagues reported on a case series of 60 patients undergoing DS with a common segment length of 75 cm. (35)  One patient succumbed to liver failure and another to malnutrition. The authors questioned the safety of the procedure.

Gastric Bypass with Long Limb (greater than 150 cm)

As discussed in the Description section, the degree of malabsorption associated with long limb gastric bypass will vary with the length of the alimentary and biliary limbs. These modifications have been developed in an effort to decrease the metabolic side effects associated with biliopancreatic bypass. However, there is limited published evidence on outcomes of this procedure, with a large amount of variability in the technical aspects of the procedure reported.

A 2005 TEC Assessment reviewed studies that compared outcomes of standard or “short” limb gastric bypass with outcomes of “long” limb gastric bypass. (29)  There were six comparative studies in which two or more different lengths of the Roux limb were compared. However, although the categorization of patients into “standard” versus “long-limb” is based on the length of the Roux (alimentary) limb, there is not a definite cutoff for “long” versus “standard” limbs. In these studies, there was variability in the lengths of the Roux limbs for both the “standard” gastric bypass and for the “long-limb” groups.

The majority of comparisons of weight loss do not reveal significant differences between “short” and “long” limb gastric bypass. The strongest evidence in this category is from two randomized, controlled trials (36,37)  In both of these trials, there were no significant differences in weight loss between groups. Brolin and colleagues compared three limb lengths, with the longest limb (distal gastric bypass) group having a significantly larger decrease in BMI at one year, while the other two groups had similar decrease in BMI. (38)  MacLean and colleagues examined morbidly obese and superobese patients separately, and reported a significant difference in favor of the long-limb gastric bypass group. (39)  However, this analysis compared the final BMI of the two groups, and did not report the actual change in BMI or the initial BMI for each group.

Adverse events were poorly reported by these studies, with only three of the studies reporting data on adverse events. Mason and colleagues reported the percent of patients with “major post-op complications,” which was 2.3% for standard gastric bypass and 1.2% for long-limb gastric bypass. (40)  There was no further breakdown of the types of major complications recorded, and no statistical testing for this outcome. In the remaining two studies, the rates of short-term adverse events reported by Inabnet and colleagues (36)  were higher for standard gastric bypass, while the rates reported by Brolin and colleagues (38) were higher for the long-limb gastric bypass. Data on long-term complications were scant, and did not reveal any apparent differences between “short” and “long” limb procedures.

Patient Selection Criteria

Clinical practice guidelines published by the National Institutes of Health (NIH) and the National Heart, Lung and Blood Institute (NHLBI) specifically define surgical candidates as those patients with a BMI of >40 kg/m2 or >35 kg/m2 with comorbid conditions when less invasive methods of weight loss have failed and there is high risk for obesity-related morbidity or mortality. (2)

In order to achieve optimal outcomes following bariatric surgery,  the guidelines further stress the importance of careful patient selection as all bariatric surgeries require a high degree of patient compliance. (2)  For gastric restrictive procedures, the weight loss is primarily due to reduced caloric intake, and thus the patient must be committed to eating small meals. For example, gastric restrictive surgery will not be successful in patients who consume high volumes of calorie rich liquids. In patients undergoing procedures with a malabsorptive component, reduced intake may not be as much of an issue, but patients must adhere to a balanced diet to avoid metabolic complications.

The guidelines specify that less invasive methods of weight loss must have failed.  Diet, exercise and behavior modification are considered first-line treatments for weight loss (and maintenance of weight loss).  The guidelines found strong evidence that better results were achieved with dietary therapy when the duration of the intervention was at least six months. (2)  In morbidly obese patients, while nonsurgical treatment may not result in sustained, significant weight loss, participation in a medically supervised weight loss program for six months prior to surgery is expected to achieve the following:

• Weight loss (or failure to gain further weight)
  This provides an objective measure of the patient’s commitment and ability to comply with diet and physical activity requirements that are necessary for long-term success following bariatric surgery.
• Health benefits
  Improvement or control of risk factors for cardiovascular disease and diabetes are associated with even modest weight loss.  Control of co-morbid conditions prior to surgery may lower surgical risks.

Bariatric Surgery Centers of Excellence

The NIH/NHLBI clinical practice guidelines discuss the importance of a multidisciplinary approach to the clinical management of bariatric surgery patients. (2)  Comprehensive programs should address nursing, nutrition, exercise, behavior modification, and psychological support, and they should  provide lifelong follow-up for treated patients.

The published data indicate that high volume bariatric programs are likely to be more successful in achieving optimal outcomes. Accumulating evidence supports a correlation between increasing volume and positive outcomes for bariatric surgery:

• Nguyen and colleagues compared outcomes of low- and high-volume academic medical centers. (41)  The authors reported that higher volume hospitals (>100 cases/year) had lower rates of mortality (0.3% vs. 1.2%, p<0.01) and overall complications (10.2% vs. 14.5%, p<0.01) when compared with lower volume hospitals.
• Liu and colleagues examined complication rates from bariatric surgery in California, classifying programs as very low (<50 cases/year), low (50–99 cases/year), or high (>200 cases/year) volume. (42)  After adjusting for differences in case-mix, patients at very low-volume hospitals were 2.72 times more likely to experience perioperative complications, and patients at low-volume hospitals were 2.7 times more likely to experience complications, compared with high-volume hospitals.
• Courcoulas and colleagues examined mortality and complications in Pennsylvania bariatric surgery programs by individual surgeon and hospital volume. (43) This study reported that low-volume surgeons had higher rates of adverse events (28% vs. 5%, p<0.05), and a trend toward higher mortality (5% vs. 0.3%, p= 0.06), when compared to high-volume surgeons.

This data has lead to national efforts to establish bariatric surgery centers of excellence by the American Society for Metabolic and Bariatric Surgery and the American College of Surgeons.

Bariatric Surgical Procedures as a Treatment of Gastroesophageal Reflux Disease

While there have been reports of improvement in GERD symptoms after gastric bypass or laparoscopic adjustable gastric banding, the suggestion that bariatric surgery should be considered in obese patients to treat GERD is based on the added health benefit of weight loss and its effect on comorbid conditions.  In order to determine the safety and efficacy of bariatric surgical procedures as treatments for GERD, they need to be compared to standard medical or surgical treatments of this condition in well-designed randomized trials.  There are no published studies of this nature.  In addition, there are no published evidence-based clinical practice guidelines that recommend any bariatric surgical procedure as a treatment of GERD.

Endoscopic Procedures for Patients who Gain Weight after Bariatric Surgery

Enlarged gastric stoma and/or enlarged gastric pouches may be associated with weight regain after bariatric surgery.  It is not known if endoscopic procedures (e.g., insertion of the StomaphyX™ or other devices, sclerotherapy, Restorative Obesity Surgery, Endoscopic ™) are effective in the treatment of these abnormalities.

Results are reported for a number of different devices and procedures (including sclerosing injections) as treatments for regained weight following bariatric surgery; however, the published data concerning use of these devices is limited to small published case series. (48,49)  No comparative trials were identified.  Comparative trials are needed to reach conclusions about the effectiveness of these treatments because of the known association between an intervention and short-term weight loss.

References

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Cross References

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Surgery Section Table of Contents