You are in: eMedicine Specialties > General Surgery > Abdomen Bariatric SurgeryArticle Last Updated: Apr 3, 2008AUTHOR AND EDITOR INFORMATIONSection 1 of 10
  Author: Alan A Saber, MD, MS, FACS, Chief, Minimally Invasive Surgery and Bariatric Surgery, Associate Professor, Department of Surgery, Michigan State University Alan A Saber is a member of the following medical societies: American College of Surgeons, American Society for Bariatric Surgery, and American Society for Gastrointestinal Endoscopy Coauthor(s): Ollie J Jackson III, MD, Department of General Surgery, Michigan State University, Kalamazoo Center for Medical Studies Editors: Brian James Daley, MD, MBA, FACS, Associate Program Director, Professor, Department of Surgery, Division of Trauma and Critical Care, University of Tennessee School of Medicine; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Paolo Zamboni, MD, Professor of Surgery, Chief of Day Surgery Unit, Chair of Vascular Diseases Center, University of Ferrara, Italy; John Geibel, MD, DSc, MA, Vice Chairman, Professor, Department of Surgery, Section of Gastrointestinal Medicine and Department of Cellular and Molecular Physiology, Yale University School of Medicine; Director of Surgical Research, Department of Surgery, Yale-New Haven Hospital Author and Editor Disclosure Synonyms and related keywords: weight loss surgery, obesity, body mass index, BMI, gastric banding, Roux-en-Y gastric bypass, biliopancreatic diversion with duodenal switch INTRODUCTIONSection 2 of 10
  Obesity is a major health problem worldwide and has reached epidemic proportions in the Western society. Evidence continues to accumulate that obesity is a major risk factor for many diseases and is associated with significant morbidity and mortality. History of the ProcedureIn 1954, Kremen and Linner introduced jejunoileal bypass, the first effective surgery for obesity in the United States. In this procedure, the proximal jejunum was connected directly to the distal ileum, bypassing 90% of the small intestine out of the intestinal stream of ingested nutrients (blind loop). The procedure induced a state of malabsorption, which led to significant weight loss. However, many patients developed complications secondary to malabsorption (eg, steatorrhea, diarrhea, vitamin deficiencies, oxalosis) or due to the toxic overgrowth of bacteria in the bypassed intestine (eg, liver failure, severe arthritis, skin problems). Consequently, many patients have required reversal of the procedure, and the procedure has been abandoned. This led to a search for better operations. Modifications in the original procedures and the development of new techniques have led to 3 basic concepts for bariatric surgery, as follows: (1) gastric restriction by gastric banding (vertical-banded gastroplasty and adjustable banding), (2) gastric restriction with mild malabsorption (Roux-en-Y gastric bypass), and (3) a combination of mild gastric restriction and malabsorption (duodenal switch). ProblemThe most widely accepted measure of obesity is the body mass index (BMI). This number is calculated by dividing a patient's mass (in kilograms) by his or her height (in meters, squared). A normal BMI is considered in the range of 18.5-24.9 kg/m2. A BMI of 25-29.9 kg/m2 is considered overweight. A BMI of 30 kg/m2 or greater is classified as obese; this classification is further subdivided into class I, II, or III obesity. Considering other factors (eg, total muscle mass, waist circumference) besides the BMI may be important. For example, an extremely muscular individual may have an elevated BMI without being considered overweight. Waist circumference has been shown to be an excellent indicator of abdominal fat mass. A circumference of greater than 88 cm (35 in) in women or greater than 102 cm (40 in) in men strongly correlates with an increased risk of obesity-related disease. FrequencyThe number of overweight individuals in the world is estimated at 1.7 billion. In the EtiologyObesity is a complex, multifactorial chronic disease influenced by the interaction of several factors, such as genetic, endocrine, metabolic, environmental (social and cultural), behavioral, and psychological components, but the basic mechanism occurs when energy intake exceeds energy output. PathophysiologyObesity occurs as the result of an imbalance between energy expenditure and caloric intake. This imbalance has been thought to be under genetic and environmental influence. The discovery of immunological abnormalities in obesity that are related to the leptin-proopiomelanocortin system and elevated tumor necrosis factor-alpha brought a new perspective to the understanding of obesity. Leptin is a hormone made primarily in adipocytes. Leptin is from the Greek word leptos for thin. The circulating leptin levels reflect the amount of stored body fat. Leptin is a negative feedback signal that acts on the hypothalamus to alter the expression of several neuroendocrine peptides that regulate energy intake and expenditure. Central resistance to leptin is a prominent feature of obesity. Increased leptin levels in individuals who are obese are independent of the lipid profile but strongly correlate with the BMI. Leptin exhibits direct effects on monocytes that results in secretion of the interleukin-1 receptor antagonist (IL-1RA). This cytokine antagonist has anti-inflammatory properties. Although leptin treatment works very well in patients who are leptin deficient, the use of leptin in patients who are obese and who already have high levels of leptin has shown limited efficacy. ClinicalMorbid obesity is the harbinger of many other diseases that affect essentially every organ system.
INDICATIONSSection 3 of 10
Surgery for obesity should be considered as a treatment of last resort after dieting, exercise, psychotherapy, and drug treatments have failed. CONTRAINDICATIONSSection 4 of 10
Contraindications to bariatric surgery include illnesses that greatly reduce life expectancy and are unlikely to be improved with weight reduction, including cancer and end-stage renal, hepatic, or cardiopulmonary disease. WORKUPSection 5 of 10
Lab Studies
Imaging Studies
Diagnostic Procedures
TREATMENTSection 6 of 10
Medical therapyA preoperative trial of weight loss is beneficial to ensure patient compliance with the postoperative diet protocol. Also, a preoperative liquid diet can shrink the liver, thus facilitating the surgical procedure. Surgical therapyTypes of bariatric surgery include the following:
Bariatric surgery can be performed by both an open technique and a laparoscopic technique. The laparoscopic technique has currently become the more popular approach. Gastric bypass Gastric bypass is currently the most popular procedure performed in the The gastric bypass provides a substantial amount of dietary restriction. The restriction is created by the small stomach pouch, which gives the patient a feeling of satiety after eating a small meal. The restrictive element of the operation consists of the creation of a small gastric pouch (approximately 20 mL in volume) with a small outlet that, on distention by food, causes the sensation of satiety. In addition, the gastric bypass provides a small-to-moderate degree of intentional malabsorption due to the separation of food, which passes through the alimentary limb of the Y, from the biliopancreatic secretions, which pass through the biliopancreatic limb of the Y. The degree of malabsorption can be adjusted by modifying the length of the alimentary and biliopancreatic limbs. The malabsorptive element is a result of bypassing the distal stomach, the entire duodenum, and varying the length of the jejunum. The extent of the bypass of the intestine determines the degree of macronutrient malabsorption. The standard Roux limb is about 75 cm. More extensive malabsorptive variations consist of gastric bypasses with a 150-cm Roux limb (long-limb) or with a very long-limb (distal gastric bypass). In addition to restricting food intake, causing some degree of malabsorption, it also causes dumping syndrome in response to a high-sugar liquid meal. Weight loss after a standard 75-cm Roux gastric bypass usually exceeds 100 lb or about 65-70% of excess body weight and about 35% of BMI. The longer-limb bypasses are used to obtain comparable weight reductions in patients who are super obese (BMI >50 kg/m2). Weight loss generally levels off in 1-2 years, and a regain of up to 20 lb from the weight loss nadir to a long-term plateau is common. Reversal For all bariatric procedures, pure reversal without conversion to another bariatric procedure is almost certainly followed by a return to morbid obesity. Gastric bypass can be reversed, though this is rarely required. Revision A standard Roux gastric bypass with failed weight loss can be revised to a very long-limb Roux-en-Y procedure or the dilated gastric pouch can be revised. After gastric bypass surgery, some patients may experience dumping syndrome upon ingestion of sweets. This is caused by the rapid passage of gastric pouch contents directly into the small bowel, unimpeded by a pyloric valve. The presence of concentrated simple sugars in the Roux limb presents a substantial osmotic load that may result in cramping and abdominal discomfort; additionally, the ensuing rapid release of insulin by the pancreas may cause symptomatic hypoglycemia. This unpleasant reaction to sugar is considered to be a desired effect of gastric bypass surgery, and it has been referred to by patients as the postoperative police officer. Weight loss after gastric bypass has been shown to be greater than that obtained by dietary, medical, behavioral, or combined approaches to weight loss. A long-term follow-up study performed by MacLean et al defined postoperative success as a reduction in weight to a BMI of less than 35 kg/m2.1 By this criterion, a successful outcome was achieved in 93% of patients with an initial BMI of less than 50 kg/m2 and in 57% of patients with an initial BMI of greater than 50 kg/m2. Since its initial description in 1994 by Wittgrove and others, the laparoscopic gastric bypass approach has been shown to combine the efficacy of the open approach with the decreased pain, lower wound morbidity, and shorter convalescence of a minimally invasive procedure.2 Results of several laparoscopic gastric bypass series have paralleled or improved upon those of open surgery. In Higa's series of 400 laparoscopic procedures, patients lost an average of 69% of their initial excess weight by 12 months after their operations.3 Schauer's group reported even better weight loss; in a group of 275 patients undergoing laparoscopic gastric bypass, there was an average loss of excess weight of 83% at 24 months after surgery. A prospective, randomized trial was completed that compared the results of laparoscopic gastric bypass to the results of open gastric bypass. Patients who had undergone laparoscopic gastric bypass were found to have substantially less impairment of pulmonary function after surgery and decreased postoperative pain. In the author's experience, the convalescence after laparoscopic gastric bypass is substantially reduced relative to open procedures, with some patients returning to work in 2 weeks or less. Laparoscopic adjustable gastric banding Laparoscopic adjustable gastric banding is the most common bariatric procedure and is performed in Europe, The device consists of an adjustable inflatable band placed around the proximal part of the stomach. This creates a small gastric pouch (approximately 15 mL in volume) and a small stoma. Band restriction is adjustable by adding or removing saline from the inflatable band by a reservoir system of saline attached to the band and accessible through a port, which is attached by a catheter to the band. The port is placed subcutaneously in the anterior abdominal wall after the band is secured around the stomach. Adjustment of the band through the access port is an essential part of laparoscopic adjustable gastric banding therapy. Appropriate adjustments, performed up to 6 times annually, are critical for successful outcomes. Patients must chew food thoroughly to allow food to pass through the band. Adjusting the inflation of the cuff changes the size of the opening through which food passes but does not change the size of the gastric pouch; deflation of the cuff is useful when the outlet is obstructed. Weight loss after laparoscopic adjustable gastric banding is about 50-60% of excess body weight in approximately 2 years. Laparoscopic adjustable gastric banding can be completely reversed with removal of the band, tubing, and port. Biliopancreatic diversion with duodenal switch The procedure includes the following:
Malabsorption is achieved by separating food from biliopancreatic digestive fluids. More weight loss results from fat malabsorption. Protein absorption is also reduced. This has the best weight loss with the least regain. There is less disruption of eating patterns. Early weight loss is from restriction and malabsorption, and, later, it is mostly from malabsorption; 75-85% of excess body weight loss is at 18 months. Pyloric preservation protects against marginal ulceration and dumping syndrome. The procedure is technically challenging and difficult to reverse. Insurance companies may not cover this procedure because it is still considered investigational. Preoperative detailsThe diversity of clinical and occult obesity-related comorbidities necessitates a multidisciplinary team approach in the preoperative evaluation of the patient who is morbidly obese. This evaluation will enhance the postoperative outcome. Preoperative cardiac, pulmonary, psychiatric, and endocrine evaluations may be necessary. These evaluations help to exclude patients who may not benefit from surgery; at the same time, they optimize those considered being potential good candidates for surgery. Preoperative nutritional consultation helps in obtaining a detailed diet history and in explaining preoperative and postoperative diet protocol. Intraoperative detailsSee Surgical therapy. Postoperative detailsAfter surgery, patients must remain on a high-protein, low-fat diet, and they must supplement their diet with multivitamins, iron, and calcium, usually on a twice-a-day basis. Ursodiol (Actigall) may be given to minimize the risk of developing gallstones during the period of acute weight loss. Patients must modify their eating habits by avoiding chewy meats and other foods that may inhibit normal emptying of their stomach pouch. Nutritional and metabolic blood tests need to be performed on a frequent basis; in the author's practice, these tests are performed at 6 months after surgery, 12 months after surgery, and then annually thereafter. Postbariatric surgery body contouring Massive weight loss is associated with negative consequences for the body, such as flabby skin, abdominal skin overhang, and pendulous breasts. The excess skin does not contract back to its preweight gain tightness. Redundant rolls of tissue may also be associated with intertrigo and significant hygiene problems. Surgical correction of these body deformities can significantly enhance physical and physiological changes. The usual time lapse between gastric bypass and plastic surgery procedures is 12-18 months. Treatment alternatives for body contouring procedures include lipoplasty, conventional surgery, or a combination of the two procedures. Conventional contouring procedures include abdominoplasty, buttock lift, lower body lift, thigh lift, upper arm lift, facelift, breast reduction, mastopexy, and/or augmentation. Multiple procedures are usually required, and a staged approach to body contouring surgery following bariatric surgery seems to improve safety and outcomes. Complications of body contouring procedures include hematomas and seromas, as well as fat necrosis, skin slough, infection, and deep vein thrombosis. In addition, the patient should be involved with a team that assesses nutritional and psychological issues as needed. Follow-upFor excellent patient education resources, visit eMedicine's Public Health Center. Also, see eMedicine's patient education articles Obesity and Surgery in the Treatment of Obesity. COMPLICATIONSSection 7 of 10
Complications of Roux-en-Y gastric bypass are as follows:
Operative (30-day) mortality for gastric bypass when performed by skilled surgeons is about 0.5%. The risk of dying in the first month after a Roux-en-Y gastric bypass from complications of the operation is about 0.2-0.5% in expert centers. Studies have demonstrated that the mortality rate from hospitals with less experience with the procedure is far higher than that reported by expert centers. Compared with open procedures, laparoscopic gastric bypass has a higher rate of intra-abdominal complications, whereas the duration of hospitalization is shorter, wound complications are lower, and the postoperative patient comfort is higher. Lifelong oral or intramuscular vitamin B-12 supplementation and iron, vitamin B, folate, and calcium supplementation are recommended to avoid specific nutrient deficiency conditions, such as anemia. Complications of the adjustable gastric band procedure are as follows:
Because the biliopancreatic diversion with duodenal switch procedure is less well known, the complications are potentially more problematic if the surgeon is unfamiliar with the procedure.
OUTCOME AND PROGNOSISSection 8 of 10
Care of the postoperative bariatric surgery patient is recommended for the lifetime of the patient, with at least 3 follow-up visits with the bariatric surgery team within the first year. Laparoscopic adjustable gastric banding requires more frequent visits for band adjustment. Postoperative dietary changes (including vitamin, mineral, and possibly liquid protein supplementation), exercise, and lifestyle changes should be reinforced by counseling, support groups, and the patient's family physician. Favorable outcomes of bariatric surgery can lead to socioeconomic advancement, which may require patient guidance. Postoperative care may also include planning for reconstructive operations after weight stabilization for certain patients. FUTURE AND CONTROVERSIESSection 9 of 10
Over the past 10 years, the field of bariatric surgery has been enriched by data from numerous clinical investigations and experience. The direction of future clinical investigations is manifold and includes the following:
REFERENCESSection 10 of 10
Article Last Updated: Apr 3, 2008 |
