The obesity epidemic has grown in severity over the. Bariatric Surgery: A Review of Procedures and Outcomes

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1 GASTROENTEROLOGY 2007;132: Bariatric Surgery: A Review of Procedures and Outcomes KATHERINE A. ELDER and BRUCE M. WOLFE Department of Surgery, Oregon Health & Science University, Portland, Oregon Bruce M. Wolfe, MD The prevalence of obesity has increased in recent decades, and obesity is now one of the leading public health concerns on a worldwide scale. There is accumulating agreement that bariatric surgery is currently the most efficacious and enduring treatment for clinically severe obesity, and as a result, the number of bariatric surgery procedures performed has risen dramatically in recent years. This review will summarize historic and contemporary bariatric surgical techniques, including gastric bypass (open and laparoscopic), laparoscopic adjustable gastric banding, and biliopancreatic diversion (with or without duodenal switch). Data are presented on bariatric surgery outcomes, focusing on weight loss and obesity-related comorbidities. We also review possible complications from surgery. Bariatric surgery patients undergo many dramatic lifestyle changes, and comprehensive presurgical screening conducted by a multidisciplinary team is important to prepare patients for the numerous changes necessary for successful outcome. In addition, comprehensive presurgical screening can aid the treatment team in identifying patients who would benefit from additional services prior to or following surgery. Further research focused on presurgical variables that predict outcome especially the longer term outcome of bariatric surgery is needed. At present, approximately 1% of eligible individuals with morbid obesity receive bariatric surgery. In addition, there appears to be inequity in access to weight loss surgery. Given the accumulating evidence that bariatric surgery is efficacious in producing significant and durable weight loss, improving obesity-related comorbidities, and extending survival, the U.S. healthcare system should examine ways to improve access to this treatment for obesity. The obesity epidemic has grown in severity over the past several decades, and is now a world-wide public health priority. 1,2 There is growing consensus that bariatric surgery is the predominant treatment option for the majority of individuals who have clinically severe obesity and are at the highest risk for obesity-related mortality and comorbidity. 3 5 The number of bariatric surgery procedures has increased significantly over the past few decades. 6 9 Zhao (2007) 10 reported the number of bariatric surgical procedures in the United States increased from 13,386 in 1998 to 121,055 in 2004, an 800% increase. The rise in number of procedures is also apparent in data collected worldwide indicating an increase from 40,000 to 146,301 procedures between the years 1998 and The increase in bariatric surgery procedures is due to numerous factors. First, the escalating rate of obesity has led to more individuals seeking treatment. The prevalence of obesity in the adult population is approximately 30%, and has doubled since Although obesity is increasing in all subsets of the population, the prevalence of clinically severe obesity (Class III, ie, body mass index [BMI] 40) has increased at an even faster rate, quadrupling from , and is now 4.8% in adults. 12,14,15 The accumulating evidence identifying obesity-related mortality and comorbidities is a second factor that has led to increased numbers of patients seeking treatment through bariatric surgery. A large prospective study of the relation of BMI to mortality demonstrated that increased BMI was associated with increased risk of death for both men and women, in all ethnic and racial groups, and at all ages. 16 This association was found to be strongest among nonsmokers and in an analyses of midlife (age of 50 years) participants, where risk of death increased by 20% to 40% among overweight individuals and by 2 to 3 times among obese individuals. Similarly, Calle and colleagues (1999) 17 reported that the risk of mortality rose with increasing BMI in men and women of all age groups and when taking into account deaths of all Abbreviations used in this paper: BMI, body mass index; BPD, biliopancreatic bypass; BPD/DS, biliopancreatic bypass with duodenal switch; LAGB, laparoscopic adjustable gastric banding; SOS, Swedish Obese Subjects (study); VBG, vertical banded gastroplasty by the AGA Institute /07/$32.00 doi: /j.gastro

2 2254 ELDER AND WOLFE GASTROENTEROLOGY Vol. 132, No. 6 causes. Other reports have linked obesity with mortality. 18,19 Reviews have also detailed the associations between obesity and numerous medical problems including diabetes, nonalcoholic fatty liver disease, gallbladder disease, cardiovascular disease, hypertension, dyslipidemia, endocrine changes, musculoskeletal disorders, cancer, and pulmonary complications. 20,21 In addition, studies have demonstrated a relationship between obesity and poor health-related quality of life and psychosocial functioning, as well as increased rates of prejudice and stigmatization. 25,26 A third factor that has led to increased utilization of bariatric surgery for treatment of obesity is the lack of long-term effectiveness among nonsurgical treatments. Although behavioral and pharmacologic treatments of obesity can result in short-term weight loss of approximately 5% 10% body weight (with some of the most successful studies reporting weight loss as high as 18.8% at 12 months 27 ), they have not been able to produce more than a modest weight loss for most patients, nor have these treatments demonstrated longer-term success Although patients may be afforded a temporary respite from medical and psychologic complications of obesity, improvements in these areas often deteriorate with weight regain. 22,32 In contrast, bariatric surgery produces weight loss that ranges between 50% and 75% of excess body weight. 33,34 In addition, weight loss is maintained longer than that observed following nonsurgical treatment of obesity. 4,35 Some studies indicate weight loss can be sustained for up to 16 years after surgery, 36 whereas weight regain often occurs between 6 and 24 months following behavioral and psychopharmacologic treatments. 29,31,37,38 As a result, bariatric surgery is currently considered the most efficacious and enduring treatment for clinically severe obesity. Other factors that have led to the rising number of bariatric surgery procedures include technologic advances (eg, the introduction of laparoscopic approaches) that have improved safety, as well as facilitated shorter hospital stays The January 2007 Agency for Healthcare and Research Quality report indicated that the inhospital mortality decreased from 0.89% in 1998 to 0.19% in 2004, a 79% decrease. 10 In addition to technologic advances, increased awareness of the procedure among patients and physicians, 42,43 media attention (including celebrity patients stories), 9 and greater access through increased coverage by health insurance companies and third-party payers 44 have influenced the continued rise in bariatric surgical procedures conducted since the first operations were introduced in the 1950s. Specific Bariatric Surgical Procedures Historic Bariatric Surgical Procedures Jaw wiring. Jaw wiring enjoyed limited application in the past due to its simplicity, perceived safety, and Figure 1. Jejunoileal bypass. A surgical short bowel syndrome was created by bypassing 90% of the functioning small intestine, creating a long blind loop. potential effectiveness. This procedure proved to be ineffective, however, due to the unimpaired capacity to consume calorie-laden liquid nutrients and the finite time interval that the jaw wiring could be maintained. An important lesson learned from this experience was the necessity for operative intervention to be permanent, as the temporary weight loss achieved through jaw wiring was almost uniformly followed by weight regain after removal of the mandibular wires. Jejunoileal (intestinal) bypass. Variations of the jejunoileal bypass were first described in the 1960s and became popular in the late 1960s and early 1970s despite the substantial morbidity and mortality that was associated with these procedures (Figure 1). 45 The popularity was likely due to the remarkable success in achieving and maintaining weight loss. Variable lengths of intestine were excluded from the nutrient stream (generally 90% 95% of the total small intestine) utilizing either an endto-end or end-to-side connection. It was presumed that patients undergoing this procedure would experience continued hyperphasia but would accomplish weight loss due to malabsorption. Unfortunately, short- and long-term complications forced abandonment of these procedures. In addition to the perioperative complications expected with any major

3 May 2007 BARIATRIC SURGERY 2255 of the opening between the upper and lower partitioned gastric compartments. Vertical banded gastroplasty (VBG). In response to the gastric partitioning failures described above, VBG was developed, in which a stapling device placed 4 parallel rows of staples with the goal of diminishing the rate of staple disruption (Figure 2). The configuration of the partitioning was altered to facilitate placement of a band to the external gastric surface at the site of the stoma, or opening between the upper gastric pouch and the body of the stomach. This was to prevent dilation of the stoma over time. 47 A 1-cm width band of prosthetic mesh or a suture reinforced with silicon rubber tubing was generally used as the banding material. VBG became the predominant bariatric surgical procedure during the 1980s, but has largely fallen into disfavor due to unsatisfactory long-term maintenance of weight loss. In addition to failure to achieve or maintain weight loss, long-term complications of VBG include progressive intolerance of the gastric constriction manifested by persistent vomiting and/or gastroesophageal reflux disease. In some patients a chronic inflammatory response to the presence of the foreign body (ie, the band) leads to scarring and stricture formation. Balloon dilation of the stricture is ineffective, and is contraindicated due to the Figure 2. Vertical banded gastroplasty. The stomach was partitioned with staples. The stoma between the gastric pouch and body of the stomach was reinforced with prosthetic material to prevent dilation of this opening. procedure in a moderate to high-risk patient population, long-term metabolic problems including electrolyte disturbances secondary to fecal loss (hypokalemia, hypocalcemia, hypomagnesemia), hepatic failure, nephrolithiasis, and autoimmune complications (eg, arthritis and cutaneous lesions) continued to occur even many years following surgery. The number of patients who currently retain a jejunoileal bypass is small, as most patients who underwent intestinal bypass have died or undergone reversal of their operation or conversion to a different bariatric surgical procedure. Gastric partitioning. The unsatisfactory complication rate associated with intestinal bypass led to development of a variety of gastric partitioning procedures. The theory was that by partitioning the stomach, the reservoir for initial ingestion of a meal would be greatly reduced, thereby reducing energy intake. 46 These procedures were generally done by applying a single application of a double-row stapling device across the upper stomach, with a portion excluded from the staple lines to allow passage of nutrients into the body of the stomach. These procedures were soon identified as failures due to either frequent disruption of the staple rows or dilation Figure 3. Gastric bypass partitioned. In this version of gastric bypass, the stomach is partitioned rather than divided. A Roux-en-Y gastrojejunostomy is done with variable lengths. The alimentary limb refers to the jejunal Roux-en-Y limb anastomosed to the stomach. The biliopancreatic limb transmits bile and pancreatic secretions to the jejunojejunostomy where the ingested nutrients and digestive juices first mix. The common channel refers to the distance from the enteroenterostomy to the ileocecal valve.

4 2256 ELDER AND WOLFE GASTROENTEROLOGY Vol. 132, No. 6 Figure 4. Gastric bypass loop. In this example, the stomach has been divided rather than partitioned. Rather than a Roux-en-Y limb, a loop gastrojejunostomy is done. Bile reflux gastritis and esophagitis are problematic with this procedure. presence of the fixed band. Erosion of the band usually occurs over a period of time such that free perforation of the stomach and associated diffuse peritoneal infection is uncommon. Rather, patients with band erosion may experience loss of effectiveness of the band or manifestations of local (contained) infection. Removal of the eroded band and gastric repair is generally indicated, although some patients may get along remarkably well despite such band erosion. Contemporary Bariatric Surgical Procedures Gastric bypass. The gastric bypass procedure was developed in the late 1970s and consisted of a horizontal partitioning of the upper stomach to create a small gastric pouch. Gastrointestinal (GI) continuity was reestablished with a gastrojejunostomy (Figure 3). Initially a loop of jejunum was utilized (Figure 4). A shift to Rouxen-Y reconstruction of continuity soon followed due to a high incidence of complications of bile reflux associated with the loop procedure. 48 Gastric bypass has evolved over the 30 years following its initial description to include multiple modifications. The size of the gastric pouch has gradually been reduced to the present mL capacity. The gastric pouch is most commonly constructed by dividing, rather than partitioning, the stomach to avoid potential creation of gastrogastric fistulae by partial or complete disruption of the staples (Figure 5). The development of devices that staple and divide the stomach simultaneously facilitated this advancement. Various lengths of small intestine have been used for construction of the Roux-en-Y limb. The following terminology has evolved regarding these limbs (Figure 5). Biliopancreatic limb: the limb of jejunum extending from the ligament of Treitz to the jejunojejunostomy, which is the point at which the nutrient stream, the bile, and pancreatic secretions come together. This limb is typically cm in length in gastric bypass procedures. Alimentary limb: the Roux limb that extends from the gastrojejunostomy to the jejunojejunostomy. This limb transmits the ingested nutrients in the absence of bile and pancreatic juice. The length of this limb is typically cm, although longer lengths may be used. A Roux or alimentary limb 150 cm is referred to as a long limb or distal gastric bypass (Figure 6). 49 Common channel: the remainder of the small intestine from the jejunojejunostomy distally to the ileocecal valve. The length of this segment of intestine is typically not measured and is highly variable depending on the total length of the small intestine. The common channel usually constitutes the majority of the small intestine. The gastrojejunostomy is generally constructed using 1 of 3 techniques. The first, hand suturing, creates an anastomosis that varies from 1 2 cm in diameter. With a second technique, circular stapling, the anastomosis may Figure 5. Retrocolic Roux-en-Y gastric bypass. This diagram depicts the anatomic details for the most common gastric bypass. The Rouxen-Y limb may be transmitted to the small gastric pouch either anterior or posterior to the colon and stomach.

5 May 2007 BARIATRIC SURGERY 2257 Figure 6. Long-limb Roux-en-Y gastric bypass. Variable lengths for the alimentary and biliopancreatic limbs and the common channel have been used in an effort to achieve maximum outcomes. If the Roux-en-Y or alimentary limb is 150 cm in length, the procedure is generally termed a long-limb Roux-en-Y gastric bypass. be reinforced with additional sutures or sealant. The diameter of the anastomosis varies from 1 2 cm based on the specific device utilized. Finally, a side-to-side stapled anastomosis can be used with suture closure of the defect for placement of the stapling device. The anastomosis produced by the side-to-side technique also varies between 1 2 cm in diameter. Banded gastric bypass. One approach to reduce the potential for weight regain following gastric bypass procedures is to add a prosthetic band to the gastric pouch (Figure 7). Such bands are typically similar to the band used in VBG. The same complications of the band that occur in VBG may be seen with this procedure. Laparoscopic vs. open approach. The popularity of the laparoscopic methodology for the performance of abdominal operations was extended to gastric bypass 50 and is now utilized in approximately 90% of gastric bypass procedures. The anatomic aspects of the gastric bypass itself are essentially the same as for open gastric bypass. The advantages to the laparoscopic method are numerous, and include reduced postoperative pain, decreased impairment due to pulmonary complications, quicker recovery, diminished parameters of systemic injury, and a dramatic reduction in the frequency of wound infection and delayed ventral hernias. 40,51 Laparoscopic adjustable gastric banding (LAGB). LAGB procedures are routinely done using a laparoscopic approach, although an open approach can be used if necessary (Figure 8). 52 In these procedures, a band or collar is placed around the upper stomach 1 2 cm below the gastroesophageal junction, thereby creating an approximate 30-mL upper gastric pouch. The degree of constriction of the stomach is variable and may be adjusted by modifying the amount of saline injected into a subcutaneous port, which is linked to a balloon within the confines of the band. The capacity to adjust the degree of constriction is believed to be responsible for the superior outcomes associated with this procedure compared to the largely abandoned VBG. Biliopancreatic diversion. Scopinaro developed the biliopancreatic diversion, creating malabsorption but avoiding the stasis associated with the intestinal bypass by maintaining a flow of bile and pancreatic juice through the biliopancreatic limb (Figure 9). 53 The extent of malabsorption is thought to be a function of the length of the common channel, varying from cm above the ileocecal valve. This procedure is combined with a subtotal gastrectomy as described by Scopinaro. A modification known as the biliopancreatic bypass with duodenal switch (BPD/DS; Figure 10) consists of a sleeve gastrectomy in which the greater curvature of the stomach is resected creating a tubular section along the lesser curvature of the stomach. 54 The pylorus is preserved, and an ileoduodenostomy is constructed distal to the pylorus. The alimentary and biliopancreatic limbs are generally of approximately equal length. Figure 7. Banded gastric bypass. In this operation, the features of constriction of the gastric pouch by prosthetic material applied in a similar manner to that done in vertical banded gastroplasty are combined with gastric bypass.

6 2258 ELDER AND WOLFE GASTROENTEROLOGY Vol. 132, No. 6 Figure 8. Adjustable gastric band. In this procedure a collar constricting the cardia of the stomach is placed and imbricated to prevent slippage of stomach in a retrograde manner through the band. These bands are generally placed by a laparoscopic technique (laparoscopic adjustable gastric band, LAGB). because obesity severely impairs their quality of life. In addition, the 1991 document stated that surgery could be considered for individuals with a BMI between 35 and 40 who suffer from high-risk comorbidities (eg, cardiovascular disease, diabetes mellitus, hyperlipidemia, obstructive sleep apnea). Further, the recommendations suggested that nonsurgical treatments should be attempted prior to considering bariatric surgery and that the patients be well-informed and motivated. The Agency for Healthcare Research and Quality Evidence-Based Practice Center report and the guidelines published by the American College of Physicians corroborated the NIH Consensus Statement stating that appropriate candidates for surgery were patients with BMI 40 who had implemented, but failed at, previous nonsurgical treatments for weight loss. 4,58,59 In addition, these reports stated that candidates for surgery should be motivated to avoid unhealthy presurgical eating habits. Buchwald (2005) 60 summarized the findings of the American Society for Bariatric Surgery Consensus Conference that was convened to update the NIH 1991 report. The American Society for Bariatric Surgery Statement maintained the earlier NIH guidelines and added several recommendations including: candidates should have a comprehensive Gastric sleeve resection. For patients at increased risk for a variety of reasons including general debility, markedly severe obesity, or other high operative risk, the first phase of the duodenal switch procedure may be accomplished in which the sleeve gastrectomy alone is performed. This procedure can then constitute the definitive bariatric surgical procedure or, at a later stage, be combined with the duodenoileostomy to construct the intestinal bypass component of the biliopancreatic bypass procedure. 55 Investigational Procedures Numerous efforts are in progress to develop transluminal endoscopic methods to create some of the above procedures including gastric partitioning and gastric bypass. These procedures are at preliminary stages of development. Application of a gastric stimulator to the stomach (Figure 11), designed to reduce energy intake, is another method that is under active investigation. 56 Qualifications for Patient Selection The National Institutes of Health (NIH) defined patient selection guidelines and indications in their 1991 Consensus Statement on Gastrointestinal Surgery for Severe Obesity. 57 The statement indicated that surgical treatment should be considered for individuals whose BMI exceeds 40 and who strongly desire weight loss Figure 9. Biliopancreatic diversion. In this original description, an approximate 50% 80% gastrectomy is done. Limb lengths vary from a gastric bypass in that the enteroenterostomy is very distal, creating a common channel from cm in length. The forward flow of bile and pancreatic juice in the biliopancreatic limb is believed to reduce complications of bacterial statis that were associated with the long blind loop of intestinal bypass.

7 May 2007 BARIATRIC SURGERY 2259 Figure 10. Biliopancreatic diversion with duodenal switch. In this procedure a gastric sleeve is created by vertical resection of the greater curvature of the stomach creating a long tubular stomach along the lesser curvature. A duodenoileostomy is done either end-to-end or end-to-side fashion, thereby preserving the pylorus. The intestinal lengths are similar to those described for biliopancreatic diversion. of participants who would be willing to receive either surgical or nonsurgical treatment. 61 Nevertheless, the multiple publications reporting outcomes have been of sufficient magnitude and consistency to justify conclusions regarding the appropriate role of bariatric surgery for severe obesity and its complications. 4,58,59 Weight Loss The efficacy of bariatric surgery as a weight-loss treatment has been established, 4,33,62 although replication is warranted to further assess the procedures as surgical techniques continue to evolve and improve. Approximately 80% of gastric bypass patients (the most common type of obesity surgery) experience a 60% 80% excess weight loss in the first year, with longer term stabilization at 50% 60% loss of excess body weight (defined as body weight that is in excess of the ideal, that is, generally BMI 25). 33,34,62 In their meta-analysis, Buchwald and colleagues (2004) 33 reported that the mean percentage excess weight loss 2 years following surgery was 61.2% (58.1% 64.4%, 95% confidence interval) for all bariatric surgery procedures, and ranged from 47.5% (40.7% 54.2%) for gastric banding to 70.1% (66.3% 73.9%) for biliopancreatic diversion or duodenal switch. In studies that reported decrease in absolute weight, mean weight loss was 39.7 kg ( ) among the medical evaluation before the operation, the surgical team should be receptive to change in selecting procedures as techniques evolved, laparoscopic and open techniques are standards of care, and there is a need for consideration and further investigation of the benefits of bariatric surgery for adolescents and individuals with Class I obesity. In addition, the American Society for Bariatric Surgery recommendations stated that although candidates should have attempted to lose weight through nonsurgical means, participating in a formal nonoperative obesity treatment should not be a prerequisite for weight loss surgery. Outcomes Several studies have demonstrated the efficacy of bariatric surgery for the treatment of obesity and its medical comorbidities. Most studies to date have reported data from case series. Prospective, controlled studies, including randomized controlled trials, are desirable to compare the outcomes of surgical vs. nonsurgical treatments. Unfortunately, the conduct of such prospective trials has not been feasible due to practical considerations including challenges regarding obtaining informed consent, lack of research resources to fund the clinical care of such trials, and the need for large numbers Figure 11. Gastric stimulation. A gastric pacemaker of similar design to cardiac pacemakers is connected to the stomach by leads that are sutured in place. The gastric stimulation can be controlled externally.

8 2260 ELDER AND WOLFE GASTROENTEROLOGY Vol. 132, No patients studied. These results are similar to those from another meta-anlaysis 4 that included weight-loss data from 89 studies and reported that pooled weight loss across various surgeries (ie, Roux-en-Y gastric bypass, open and laparoscopic; vertical banded gastroplasty; adjustable gastric banding, and biliopancreatic diversion) ranged from kg ( , 95% confidence interval) for adjustable gastric banding to kg ( ) for biliopancreatic diversion at 12 months followup. At 36 months follow-up, pooled weight loss ranged from kg ( ) for vertical banded gastroplasty to kg ( ) for biliopancreatic diversion. Overall, the results of this study indicate that surgical patients experienced a kg weight loss that was maintained up to 10 years following surgery. This stands in contrast to studies of behavioral or pharmacologic obesity treatments that have reported a 3 10 kg weight loss at 1 to 2 years. 29,38 Two studies are notable as well-designed prospective, observational studies of bariatric surgery patients and matched morbidly obese controls with long-term follow-up ( 10 years). These are the Swedish Obese Subjects (SOS) Study 35 and a 2-cohort study conducted at the McGill University Health Center. 36 The SOS authors report that at the 10-year follow-up, weight loss was 25% 11% of total body weight for gastric bypass patients, 16.5% 11% for vertical banded gastroplasty, and 13.2% 13% in the fixed gastric banding subgroup, while the matched controls experienced a 1% 6% weight gain. 35 In the Christou et al (2004) 36 study of 1035 surgical patients and 5746 matched controls, the mean initial excess weight loss for surgery patients was 67.1% (SD 23.7%) and follow-up results indicated that patients were able to maintain that weight loss for up to 16 years following surgery. However, although initial follow-up rates were impressive (ie, over 80% up to 11 years), follow-up rates from years dropped below 40%. MacLean and colleagues (2000) 63 tracked 274 gastric bypass patients for a mean of 5.5 years and reported a follow-up rate of 88.6%. Results indicated that 93% of obese (BMI 36 39) or morbidly obese (BMI 40 49) patients obtained a good or excellent result using modified Reinhold classification (ie, good or excellent BMI 35, or loss of excess weight 50%). However, the failure rate (ie, BMI 35, or loss of excess weight 50%) was 43% among the superobese (BMI 50) patients, suggesting that initial BMI may be a predictor of weight loss outcome. Despite the favorable outcomes of bariatric surgery, approximately 10% 40% of patients do not achieve successful long-term weight loss (using a rating system similar to Reinhold classification described above). 34,36,63,64 In a study of patients undergoing biliopancreatic diversion (BPD), the failure-rate doubled every 5 years, 64 highlighting the importance of long-term follow-up in clinical outcome research. Given that bariatric surgery is an invasive treatment for obesity and is often viewed as the last chance for patients, research focused on improving outcome for patients who fail to achieve or maintain weight loss following surgery is a priority. Weight loss following LAGB is not as rapid as weight loss after gastric bypass, especially during the first year. There is conflicting data regarding longer term (beyond 5 years) weight loss of LAGB vs. gastric bypass. 65,66 A review reported that weight loss among LAGB patients is 56% of excess weight at 5 years, in comparison to 59% of excess weight loss for Roux-en-Y gastric bypass patients. 67 Another study comparing laparoscopic Roux-en-Y gastric bypass and LAGB indicated that although weight loss was higher for laparoscopic Roux-en-Y patients for the first 4 years following surgery, the data regarding longer term weight loss are inconclusive, and further research is warranted to examine this issue. 66 Medical Comorbidities In an observational 2-cohort study of bariatric surgery patients and matched severely obese controls, surgical patients experienced a significant relative risk reduction of cancer (76%), cardiovascular disease (82%), endocrinologic disease (65%), infectious diseases (77%), musculoskeletal problems (59%), nervous system disease (39%), respiratory conditions (76%), and psychiatric and mental health problems (47%) compared with controls. 36 Importantly, this study also included an analysis of healthcare costs, and demonstrated that in comparison with controls, surgically treated patients had significantly lower rates of health care use (measured by hospitalization rates, hospital stays, and physician visits) and significantly lower total direct health care costs (mean of $8813 for surgical patients vs. $11,854 for controls) over the 5 years following surgery. The authors of the prospective, controlled SOS study, reported results for bariatric surgery patients at 2- and 10-year follow-up for hypertriglyceridemia, low high-density lipoprotein cholesterol, hypercholesterolemia, diabetes, hypertension, and hyperuricemia. 35 Results indicated that the rate of recovery from all of these conditions, with the exception of hypercholesterolemia, was significantly more frequent among surgically treated patients compared with conventionally treated matched controls. However, the advantage for the surgery group over the control group diminished between the 2-year and 10-year follow-ups, 68 reinforcing a need for more longer term, controlled studies of bariatric surgery outcomes. A limitation of the SOS study is the predominant use of VBG, which resulted in disappointing long-term weight loss. Buchwald and colleagues (2004) 33 reported resolution of diabetes in 76.8% of patients following bariatric surgery, a finding consistent with the 82.9% diabetes resolution 10 years following bariatric surgery reported in an earlier study. 62 The rapid improvement, if not resolution, of diabetes following gastric bypass (often before major

9 May 2007 BARIATRIC SURGERY 2261 weight loss has occurred) has led to intense investigation of the role of altered gut hormone secretion in modulating carbohydrate metabolism. 69,70 Glucagon like peptide-1 (GLP-1), which is released from the distal small intestine in response to feeding, is of particular interest. 71 In addition to resolution of diabetes, Buchwald et al (2004) 33 also found excellent resolution of other obesityrelated comorbidities: obstructive sleep apnea (85.7%), hypertension (61.7%), and improvement of dyslipidemia (70%). The prevalence of nonalcoholic fatty liver disease is increasing parallel to the increasing rates of obesity. 72 Nonalcoholic fatty liver disease, which begins with steatosis, can progress to nonalcoholic hepatosteatitis, and ultimately to cirrhosis and hepatic failure. 73 Nonalcoholic fatty liver disease and nonalcoholic hepatosteatitis significantly improve post bariatric surgery; some aspects of cirrhosis may also improve. 72 Mechanisms of Action of Bariatric Surgical Procedures Bariatric surgery procedures can be categorized into operations utilizing 3 methods to produce weight loss: gastric restriction, malabsorption, or a combination of the 2. Gastric restriction is accomplished by creating a very small gastric pouch and a degree of outlet obstruction to delay gastric emptying from the pouch into the body of the stomach or intestine. The goal of creating the small pouch is to produce early satiety and a consequent reduction in food intake. Furthermore, satiety will be prolonged by delayed gastric emptying as the result of the relative outlet obstruction, secondary to the intentionally small size of the gastric outlet. Malabsorption has been conceptually attractive as a mechanism in that it allows patients to consume greater amounts of energy than would otherwise be allowable to accomplish and maintain weight loss. The malabsorption is achieved by creating a short gut syndrome and/or by accomplishing distal mixing of bile and pancreatic juice with ingested nutrients thereby reducing absorption. The gastric partitioning and banding procedures have been repeatedly described as purely restrictive, whereas the weight loss associated with intestinal bypass was attributed to malabsorption. Procedures such as gastric bypass and BPD/DS are presumed to contain elements of both restriction and malabsorption as their mechanism of action. It is now clear that this categorization represents a substantial oversimplification of the mechanisms of action of bariatric surgical procedures. The efficacy of these procedures results from a complex interaction of gastric restriction, malabsorption, learned behavior change, and neural and endocrine signals that affect appetite and satiety. Some degree of learned behavior change is a necessary component of a patient s adjustment to the operative procedure. For example, a patient who consumes a meal that exceeds the capacity of the gastric pouch may experience abdominal discomfort, nausea, vomiting, or gastroesophageal regurgitation. For most patients, these unpleasant sensations lead to change of eating behavior to avoid recurrence of these symptoms. For patients who experience severe short bowel syndrome (as in the historic intestinal bypass procedures or as the result of resection for intestinal pathology) marked restriction of fat intake, as well as restriction of overall intake, is a necessary adaptation to avoid excessive diarrhea, associated fluid and electrolyte disturbances, and unmanageable social impairment. Energy balance studies conducted in patients with intestinal bypass showed that approximately 80% of the weight loss achieved was attributable to diminished energy intake. 74 Malabsorption occurred, but the energy content of the malabsorbed nutrients was diminished compared to presurgical amounts. Recent physiologic studies of the control of food intake has shed light on the existence of neural and endocrine phenomena affecting appetite and satiety, in addition to the learned behavior changes which occur. 75 Dixon, for example, has demonstrated that the degree of constriction by the LAGB has a direct impact on appetite and satiety independent of the extent of food intake. 76 This phenomenon was demonstrated in patients who had undergone LAGB and were blinded to the extent of gastric restriction. In the fasting state, appetite was demonstrated to vary in proportion to the degree of constriction. The mediation of this phenomenon has not been determined. There is increasing evidence of neural impulses mediated through vagal pathways that may impact eating behavior. 77,78 Multiple hormones are secreted from various components of the GI tract and likely play a role in regulating food intake. The orexigenic gastric hormone ghrelin is released during fasting and stimulates increased food intake. 79 Consumption suppresses ghrelin secretion, thereby reducing appetite and continued consumption of nutrients. Gastric bypass has been reported to markedly obliterate the ghrelin response to fasting, thereby possibly contributing to the anorectic effect commonly observed following gastric bypass. 79 Other investigators have not consistently demonstrated this phenomenon; therefore, the role of alterations of ghrelin secretion following gastric bypass in accomplishing weight loss is controversial. 80 Multiple hormones arising from the small intestine have been demonstrated to suppress appetite and presumably play a role in modulating food intake as well. Cholecystokinin, released from the proximal intestine, as well as peptide YY and GLP-1, released from the distal intestine, are known appetite suppressants There is increasing evidence that delivering luminal nutrients to the distal GI tract for digestion and absorption leads to increased release of peptide YY and GLP-1. These hormones, in turn, signal central nervous system receptors

10 2262 ELDER AND WOLFE GASTROENTEROLOGY Vol. 132, No. 6 that have the effect of diminishing food intake. Both vagal stimulation and interruption have been shown to impact feeding behavior. 77,78 The magnitude of this effect remains to be determined. The diminished food intake associated with the so-called malabsorptive procedures may be a function, at least in part, of secretion of these and possibly yet to be identified hormones and neural signals. Active research to further define this physiologic regulation of food intake is continuing with the intent of identifying the mechanisms by which the bariatric surgery procedures achieve superior weight loss compared to present nonsurgical means. As these mechanisms are identified, pharmacologic interventions can be developed that will mimic the physiologic effects of the current bariatric surgical procedures. The mechanism(s) by which gastric stimulation reduces appetite and food intake and accomplishes weight loss has not been established. 56 Possible mechanisms include delayed gastric emptying secondary to disordered antral motility, pyloric stimulation, 84 and antral distention. 85 Direct vagal stimulation has also been associated with weight loss. 86 Complications There are numerous complications that may arise following any of the bariatric surgical procedures that require understanding and delineation of the specific anatomy of the operation performed. These complications may include nutrient deficiencies or GI pathology. Nutrient Deficiencies Any operative procedure that dramatically alters or reduces the anatomic pathways of nutrient intake will necessarily affect the intake of specific nutrients. Gastric restrictive procedures may lead to nutrient deficiencies due to inadequate intake or nutrient loss as a result of frequent vomiting, but malabsorption is not an issue. Thus, avoidance of excessive vomiting and attention to replacement of vitamin and mineral requirements will avoid micronutrient deficiencies in these patients. Careful attention must be paid to a possible history of frequent vomiting, as examples of acute encephalopathy induced by thiamin deficiency have been reported. 87 Malabsorptive procedures represent a substantially greater risk for micronutrient deficiency, as malabsorption of micronutrients may occur and be clinically problematic even though malabsorption of the consumed energy occurs to a minimal extent, if at all. The stomach, duodenum, and proximal jejunum are known to have important roles in the digestion and absorption of vitamin B 12, iron, and calcium. Vitamin B 12 deficiency has not emerged as a common long-term clinical problem in patients who have undergone gastric bypass. This is likely the result of persistence of intrinsic factor (as the body of the stomach is rarely resected), the routine recommendation to supplement vitamin B 12 intake, and the presence of a normally functioning terminal ileum where vitamin B 12 is absorbed. Similarly, there are no reports at this time of an increased incidence of pathologic fractures among patients who have undergone gastric bypass despite demonstration of a degree of calcium malabsorption following the procedure. 88 Presumed factors involved in this observation include the relative young age of patients who have undergone gastric bypass (such that they have not yet reached the most frequent age in which pathologic fractures occur), the stimulation of enhanced bone mass that results from obesity, increased estrogen production by adipocytes, and the routine recommendation to supplement calcium and vitamin D intake. Procedures that induce a greater degree of malabsorption such as BPD/DS raise greater concern regarding possible longterm demineralization of bone. Increased circulating parathormone concentration has been reported following BPD/DS, 89 although a rigorous replacement protocol appears to avoid serious bone pathology, at least in the short term. 90 Dietary deficiency of protein intake may occur in the early months following bariatric surgery. This deficiency is more difficult to prevent than are micronutrient deficiencies as supplementation requires ingestion of actual protein to meet nutritional requirements, and overall consumption following procedures such as gastric bypass may be so limited that protein intake falls well below the recommended daily allowance of 0.8 g per kilo (estimated based on ideal body weight). Alopecia is a relatively common early finding of deficient protein intake. Thus, careful attention to the dietary intake of protein during the early months following bariatric surgery is recommended. Iron deficiency is the most commonly recognized micronutrient deficiency following gastric bypass. A degree of iron deficiency may be present preoperatively and exacerbated by operative blood loss, postoperative GI pathology (see below), deficient intake of iron, and a degree of iron malabsorption due to bypass of the stomach and duodenum. For all of these reasons, routine supplementation of iron intake and monitoring of iron concentration, as well as possible anemia, is advised. Gastrointestinal Pathology Following Bariatric Surgery There are several specific complications involving the GI tract that may occur following bariatric surgical procedures. Banded restrictive procedures. The most frequently reported complication of LAGB placement is gastric slippage or prolapse of stomach superiorly through the band 91 producing obstruction at the band. The obstruction is associated with vomiting and gastroesophageal regurgitation. Radiographs may show an air fluid level in the gastric pouch, malposition, or angula-

11 May 2007 BARIATRIC SURGERY 2263 tion of the band, and gastric obstruction. This complication has been reduced by alteration of the technique for operative placement of the band. 92 Any of the procedures that involve application of a foreign body to the serosal surface of the stomach may result in erosion of the foreign body through the gastric wall into the lumen of the stomach. 93 Perforation of the stomach by such erosion with secondary diffuse peritonitis is rare due to the gradual erosion, secondary inflammation, and walling off of the site of the foreign body that occurs. Patients with such erosion may experience upper abdominal pain, fever, or other manifestations of localized infection, although symptoms may be remarkably minimal. Some patients may experience a reduced efficacy of their operative procedure due to the loss of the constrictive aspect of their band. Endoscopy is generally required to establish the diagnosis. Some patients may elect to decline surgical removal of the foreign body and repair of the stomach, although such a procedure is usually required to restore health. Some patients with restrictive procedures may not limit their consumption of food to an amount appropriate to the size of their gastric pouch and its delayed gastric emptying. In this situation, progressive dilation of the gastric pouch may occur. Failure to achieve or maintain weight loss is often attributed to stretching of the gastric pouch. This explanation would appear to be a substantial oversimplification because repeated surgery to reduce the size of the pouch does not consistently result in restoration of weight loss. If the process of excess food intake in relation to gastric pouch size extends to use of the distal esophagus as a reservoir, esophageal dilation with associated regurgitation and possible nocturnal aspiration may occur. 94 The clinical importance of a distal esophagus giving the appearance of an achalasia-like process remains to be determined. Gastrointestinal complications of gastric bypass. Anastomotic leak most commonly occurs at the site of the gastrojejunostomy, but leaks involving the jejunojejunostomy, closure of the gastric staple lines, secondary to other GI injury, may also occur. 40,95,96 Most leaks occur in the early postoperative interval and require prompt intervention for resolution. Drainage to control local (as well as possible widespread) peritoneal infection is crucial to successful outcome. The anatomic location of the leaks from the gastrojejunostomy may preclude satisfactory positioning of percutaneous radiographically directed catheters at the site of the leak such that operative drainage may be required. Nutrition support is necessary in such patients. Subclinical, small, contained leaks of the gastrojejunostomy may be demonstrated if routine postoperative upper GI radiographs are made. The clinical importance of identification of these leaks by routine radiographs, as well as their management, is uncertain. 95 Prior to the advent of the gastric division in the performance of gastric bypass, partial disruption of the staple lines creating a gastrogastric fistula was relatively common and patients with these problems may still present for evaluation and treatment. The usual manifestation is weight regain, as the disruption typically does not involve leakage of GI contents outside of the gastric lumen. Any patient who experiences either early failure of weight loss or regain of weight following gastric bypass should be evaluated for possible gastrogastric fistula, particularly if the procedure has been done using the gastric partitioning rather than division technique. A second manifestation of a gastrogastric fistula may be a gastrojejunal marginal ulcer. Patients with marginal ulcers, particularly in the presence of a small gastric pouch, should be evaluated for a possible gastrogastric fistula because the smaller gastric pouches typically do not contain acid producing parietal cells. Radiographic upper GI examination with contrast is the most sensitive means of detecting gastrogastric fistulas. Transluminal endoscopic suturing of such defects has been attempted, although the efficacy of such intervention remains unknown. The surgical approach is generally to divide the communicating structures and close both sides of the fistula separately. Any GI anastomosis may be followed by development of a stricture. The incidence of stricture of the gastrojejunostomy appears to be higher following laparoscopic gastric bypass than following the open procedure. 40,95,96 Factors involved in the causation of such strictures may include technical errors during operation, anastomotic leaking (which may be subclinical and therefore clinically unrecognized), ischemia resulting from vascular compromise of the jejunal limb, tension on the anastomosis, or a delayed fibrosis following marginal ulceration. Upper GI radiographs may not accurately identify such strictures when the patient is able to tolerate liquid but not solid feeding. A definite diagnosis is made by endoscopy. The functional degree of obstruction may be increased by local inflammation and edema. In general, an anastomosis that is less than 10 mm in diameter requires dilation, although symptoms of obstruction may respond to dilation of anastomoses that will allow passage of a 10-mm endoscope. Balloon dilation to mm is commonly done, and a single dilation is often sufficient. Serial dilations may be necessary if the stricture is late and the fibrotic response well established. 97 GI perforation by such dilation, particularly when done less than 4 weeks postoperative, would appear to be a substantial risk; however, this complication has proved to be infrequent. Liberal use of early postoperative endoscopy for patients intolerant of oral feeding is therefore appropriate. The frequency of marginal ulceration following gastric bypass has varied widely in reports from 1% to 16%. 36,98 Factors involved in the etiology of these ulcers may include acid production by the gastric pouch, Helicobacter

12 2264 ELDER AND WOLFE GASTROENTEROLOGY Vol. 132, No. 6 pylori infection, 97 a contribution from the postoperative stress response, use of nonabsorbable suture, 99 and ischemia. Treatment with acid suppression usually resolves the problem. 98,100 Refractory ulcers may be clinically problematic and ultimately require resection and reanastomosis. Prophylaxis (by perioperative and postoperative acid suppression) is widely practiced, but the efficacy of this practice has not been demonstrated in a controlled trial. Early postoperative GI hemorrhage may occur from any of the gastric staple lines or anastomoses as is the case with all upper GI surgical procedures. 101 Supportive care, including blood transfusion, is generally sufficient in the great majority of cases. Identification of the source by endoscopy may be successful; however, if the bleeding is from the bypassed stomach, duodenum, or jejunojejunostomy, the esophagogastric endoscopy will not reveal the source. In such cases, acid suppression, supportive care, and patience are appropriate unless the magnitude of the hemorrhage mandates operative intervention. Partial GI obstruction may also occur due to the presence of luminal blood clot. 101 Operative intervention may be required to establish this diagnosis and correct the problem. GI hemorrhage may also occur several years following gastric bypass. GI ulceration in the body of the stomach and/or duodenum has been infrequent, but may lead to major hemorrhage requiring operative intervention. The identification of the bleeding site may be particularly difficult due to the inability of endoscopy to reach the location of the bleeding. In cases of recurrent upper GI hemorrhage, gastrectomy is indicated. 102 Complaints of abdominal pain following virtually any major abdominal procedure may occur. The incidence of intestinal obstruction as a cause of such pain appears to be more frequent after laparoscopic gastric bypass compared to open gastric bypass, particularly if occurring within the first few weeks or months following operation. 103,104 Internal hernias are more common following laparoscopic gastric bypass. Upper GI radiographs are notoriously insensitive in establishing this diagnosis. 105 Abdominal computerized tomography scan with GI contrast may establish the diagnosis; however, intermittent obstruction may be missed by radiographic evaluation. In these cases, diagnostic laparoscopy and reduction and closure of any internal hernias is required. Rapid weight loss is a known cause of development of gallstones. Rapid weight loss following bariatric surgery may occur in approximately 30% of gastric bypass patients who retain their gallbladder. 106,107 Routine oral bile salt administration has been demonstrated to substantially decrease the frequency of this complication. As a result, most bariatric surgery programs advise bile salt supplementation for the first 6 months following gastric bypass. 108 A diagnosis of cholelithiasis should be actively pursued in any postbariatric surgery patient with a clinical profile suggesting this diagnosis, even if the gallbladder was known to be free of gallstones before surgery. Postprandial severe hypoglycemia has been reported and attributed to pancreatic islet hyperplasia, possibly secondary to exaggerated GLP-1 secretion. 109 Patti and colleagues (2005) 110 attribute this reactive hypoglycemia to inappropriate insulin secretion but not islet cell hyperplasia; thus, partial pancreatectomy is not recommended. Complication outcomes. In a study utilizing a state-wide hospital administrative discharge database and state vital statistics for mortality, the in-house mortality rate for gastric bypass patients between 1987 and 2001 was 1.02%, and 30-day mortality was 1.9%. 111 The almost 2% mortality rate in this population-based study was about 4 times higher than mortality rates identified in published case series. 33 A more recent study using a state database in California showed the 30-day mortality rate to be 0.33%. 112 This improved mortality figure may be due to improved surgical technique over time, a larger number of lower risk patients undergoing surgical intervention, the establishment of high-volume bariatric surgical centers, and the increase in surgeons with extensive experience in bariatric surgery. 41 Long-term survival following bariatric surgery is improved compared to nonsurgical patients according to several studies using matched control patients with morbid obesity. 36,113 Two recent studies utilizing administrative databases have suggested that the complication rate following gastric bypass over a 3-year interval is somewhat higher than previously recognized. 59,112 Conduct of prospective clinically derived follow-up will be necessary to accurately define the incidence of long-term complications requiring intervention. 61 Identification of patients at increased (or decreased) risk of a perioperative complication, including mortality, as well as poor long-term outcome, is critical in the selection of appropriate operative candidates, decision making by patients, and adjustment of programmatic risk by surgical sites. Several individual centers have analyzed their own data and studies of state, regional, or national administrative databases have been conducted Risk factors that most frequently correlate with increased risk are advanced age (especially over 60 years), male gender, and surgeon and/or hospital inexperience. Other risk factors identified on a variable basis have been higher BMI, and the presence of hypertension, pulmonary, and/or cardiac disease. The largest clinical single institution database has found the basis for construction of an Obesity Surgery Mortality Risk Score. 115 Hopefully, the accumulation of multicenter clinical data, such as the proposed Surgical Review Corporation database or the NIH consortium known as the Longitudinal Assessment of Bariatric Surgery, 61 will facilitate refine-

13 May 2007 BARIATRIC SURGERY 2265 ment of risk prediction for individual patients, as well as program risk adjustment. Psychologic and Behavioral Issues Psychologic and behavioral issues are of paramount importance in working with the bariatric surgery patient. Patients must have a thorough understanding of how surgery will affect many areas of their life, such as eating behavior, social and physical functioning, and body image. In addition, pre- and postsurgical regimens involve a multitude of behavioral changes that are necessary for positive outcome and patients need to be prepared for making many lifestyle adjustments (eg, food choices, amounts consumed, eating speed and frequency, exercise). Presurgical Psychologic Assessment Most surgical centers require that patients undergo a presurgical psychologic evaluation, and many third-party payers require this evaluation before approving a patient for surgery. The purpose of the psychologic evaluation is to assess whether a patient is an appropriate candidate for surgery, and if so, whether patients may benefit from receiving additional services prior to or following surgery. Based on their assessment, the psychologic provider makes recommendations to the patient and the surgical team, and provides patients with appropriate referrals when additional services may be beneficial or when surgery is contraindicated. Psychologic evaluation practices are not standard across programs; however, most include assessment of the patient s knowledge about the surgery; motivation and expectations; ability to comply with pre- and postsurgical regimens; barriers to successful outcome; eating, diet, weight, and nutritional history; psychologic status (ie, evaluation of psychiatric disorders) and history of mental health treatment; cognitive functioning; medical history; social history; and current support system. Recent studies have indicated that psychologic assessment practices vary widely across programs Part of the explanation for the lack of standardization in assessment procedures is that studies to date have been equivocal regarding the prognostic value of presurgical behavioral variables (with the possible exception of severe and chronic psychiatric pathology, especially when it requires inpatient treatment) Assessment practices are unlikely to become more uniform until longer term studies identify reliable prognostic indicators of outcome. Until then, many established programs have published detailed descriptions of comprehensive psychologic evaluation procedures or interviews that can be used by practitioners seeking models of assessment protocols. Given the current inconclusive data regarding prognostic variables, the general recommendation is that psychologic evaluations be used to identify patients who could benefit from additional support pre- or postoperatively and make recommendations for further treatment to those patients, rather than to deny them eligibility for surgery. 122 However, there are several conditions that are usually considered contraindications for surgery, including severe untreated psychopathology, such as severe major depression, alcohol or substance abuse or dependence, or active bulimia nervosa. 122,127 Other contraindications include suicidal ideation, self-mutilation, active psychosis, or severe cognitive impairment that would significantly interfere with the postoperative self-care regimen. 122,127 Some of these patients may be appropriate candidates once psychiatric symptoms have resolved or stabilized. If a patient is referred to seek additional treatment prior to scheduling surgery, they can be scheduled for a follow-up psychologic visit to reassess their readiness for surgery at a later date. If surgery is clearly contraindicated, the patient should be provided with referrals for alternative treatment. Psychologic Characteristics of Bariatric Surgery Candidates Several studies have found high rates of psychopathology among individuals who present as candidates for bariatric surgery. 23,128 Depressive, anxiety, eating, and adjustment disorders are the most prevalent psychiatric problems reported by patients. 129 A recent study using structured diagnostic interviews reported that 36.8% of bariatric surgery candidates reported at least 1 lifetime Axis I psychiatric disorder, and 24.1% met criteria for a current disorder. 130 Although these data indicate that psychopathology is present among a significant subset of the bariatric patient population, the rates are lower than previous studies that had used less stringent assessment procedures (eg, questionnaires, chart-review diagnoses), and are similar to rates of psychopathology reported in the general population. 131 This finding highlights the importance of using rigorous methods of assessment to establish prevalence of psychiatric disorders and assess for comorbid psychopathology among bariatric surgery patients. Binge eating is a topic of particular interest in studies of bariatric surgery patients as it is common among obese individuals. Approximately 16% 30% of patients seeking treatment for obesity meet Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria for binge eating disorder, 132 and estimates of subsyndromal binge eating are higher. In addition, binge eating may signal the presence of increased psychopathology 130 and the need for additional monitoring of patients to reduce poor outcome following surgery. 133 A review of studies examining bariatric surgery patients indicated that the reported prevalence rates of binge eating vary widely from 10% to 69%. 134 Some of this variability may be due to differences in assessment methods, and further research is needed to establish the best measures to assess binge eating in this patient population. 135,136

14 2266 ELDER AND WOLFE GASTROENTEROLOGY Vol. 132, No. 6 Although initially suspected as a prognostic indicator of poor outcome, studies examining preoperative binge eating have revealed that it is not, in and of itself, a reliable predictor of poor weight loss up to 5 years following surgery However, it appears that the reemergence of binge eating following surgery may be associated with less weight loss or weight regain and poorer outcome in other domains (eg, postoperative complications, eating, and weight-related pathology). 133,138, Further research is necessary to clarify what variables may identify patients who are at risk for reemergence of binge eating postoperatively. In summary, based on the current data, binge eating should not be a contraindication for surgery, but postsurgical monitoring for the redevelopment of binge eating can be useful to identify patients who may benefit from additional treatment to improve outcome. Vomiting may also occur in many patients following surgery, and can occur when patients consume inappropriate foods or amounts, or eat too quickly. One study found that approximately 5 years postoperatively, 79% of patients reported occasional vomiting, and 33% of patients vomited at least weekly, but the presence of vomiting was not associated with presurgical eating pathology. 143 Another study found that years following gastric bypass surgery, 68.8% of patients reported continued problems with involuntary vomiting. 142 Interestingly, a majority of these patients did not view the vomiting as a major concern, nor did they view it as a serious adverse outcome. However, other researchers have suggested that postoperative vomiting in some patients may represent a purging behavior or a failed attempt to binge. 140,143 More research is needed to investigate whether some patients develop pathologic forms of vomiting, for example vomiting that is motivated by a desire to lose weight, or other eating or weight concerns. Postsurgical Psychosocial Outcome In general, quality of life and psychosocial functioning improves following surgery. 142, However, the results are mixed, with some studies indicating no improvement or a reversion to baseline levels of psychosocial distress. 129, The variability in results may be representative of methodologic issues, such as differences in assessment measures, outcome variables studied, or time frame used for follow-up. Further research designed to address these methodologic issues is needed to more fully elucidate psychosocial outcome of bariatric surgery. However, it appears that at least in the short-term, bariatric surgery may improve quality of life and psychosocial outcome in a substantial proportion of patients. Bariatric Surgery in Adolescents The obesity epidemic among children and adolescents has accelerated as fast, if not faster, than the epidemic among adults. 150 The pattern of obesity-related comorbid disease among adolescents is as prevalent and severe as among adults. Specifically, dramatic increase in the incidence of obesity-related glucose intolerance/diabetes, 151 metabolic syndrome, 152 premature coronary artery disease and stroke, 153 and impaired quality of life 154,155 all indicate that severe obesity constitutes a major health problem for adolescents as well as adults. The medical treatment of severe obesity in adolescents has proved to be as futile as among adults, such that the vast majority of obese adolescents carry their obesity into adulthood. 156 Surgical intervention among these obese adolescents has been actively considered as the result of these observations. 157 Limited early experience with bariatric surgery in adolescents indicates that the surgery is safe and associated with weight loss, correction of obesity comorbidity, and improved self-image and socialization among adolescents as well as adults. 158 Further research is clearly needed and guidelines regarding specific criteria, indications, and indicated procedures continue to evolve in this population. 157 Role of Bariatric Surgery in the Treatment of Severe Obesity An unresolved issue that is faced by primary care physicians and patients on a daily basis is whether surgical intervention for all patients with severe (Class III) obesity should be advised. At present, the application of bariatric surgery to morbidly obese patients is limited to approximately 1% of the eligible population in any given year. 41 This situation is most remarkable given the clear identification of the pathology associated with obesity and the increasing evidence that bariatric surgery prolongs longevity, as well as leads to resolution of comorbidites including diabetes, obstructive sleep apnea, hypertension, and dyslipidema, among others. 33,113 Possible factors involved in the hesitancy to apply bariatric surgery to a larger number of eligible patients include fear of postoperative complications, increased cost in the short term associated with bariatric surgery, and a lack of current knowledge of the evolving literature as it pertains to bariatric surgery. Access to surgical care is limited to a variable extent on a regional basis in the United States. Frequency of obesity is disproportionately high relative to the number of bariatric surgical procedures performed among disadvantaged persons in the United States, suggesting inequity in the availability of treatment. 159 An adequately powered, prospective, randomized trial comparing surgical intervention to continued nonsurgical intervention has not been reported and is currently impractical to conduct. 61 Until efficacy of nonsurgical treatment is demonstrated to be durable (ie, lasting more than 2 years), continued reporting of the outcomes of bariatric surgery in relation to their status at baseline is an acceptable basis for formulation of appropriate medical coverage policies. At such time as weight loss comparable to that accom-

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19 May 2007 BARIATRIC SURGERY Whitaker RC, Wright JA, Pepe MS, Seidel KD, Dietz WH. Predicting obesity in young adulthood from childhood and parental obesity. N Engl J Med 1997;337: Inge TH, Krebs NF, Garcia VF, Skelton JA, Guice KS, Strauss RS, Albanese CT, Brandt ML, Hammer LD, Harmon CM, Kane TD, Klish WJ, Oldham KT, Rudolph CD, Helmrath MA, Donovan E, Daniels SR. Bariatric surgery for severely overweight adolescents: concerns and recommendations. Pediatrics 2004;114: Sugerman HJ, Sugerman EL, DeMaria EJ, Kellum JM, Kennedy C, Mowery Y, Wolfe LG. Bariatric surgery for severely obese adolescents. J Gastrointest Surg 2003;7: Liu JH, Zingmond DS, McGory ML, SooHoo NF, Ettner SL, Brook RH, Ko CY. Disparities in the utilization of high-volume hospitals for complex surgery. JAMA 2006;296: Received January 31, Accepted February 26, Address requests for reprints to: Bruce M. Wolfe, MD, Oregon Health & Science University, Division of General Surgery, 3181 SW Sam Jackson Park Road, BTE 223, Portland, Oregon wolfeb@ohsu.edu; fax: (503)