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Bariatric surgery is done on people who:
This type of surgery promotes weight loss by restricting food intake or by interrupting the digestive process. It may be a good option for people who are unable to lower their weight by other means. But even after surgery, the best long-term results are achieved by eating appropriately and participating in a regular physical activity program.
A thorough evaluation, particularly of your nutritional status, will precede any discussion of obesity surgery. An additional requirement is that you have made multiple attempts to lose weight by nonsurgical means. Before deciding if surgery is the right option for you, you will probably meet with a dietitian who will help you to prepare for the dramatic change in your eating habits that will occur after surgery. You will learn how to balance sound nutrition with smaller portions. This is because after surgery you will not be able to eat very much at each sitting.
The two main types of weight loss surgery are:
Restrictive operations restrict food intake and do not interfere with the normal digestive process. To do the surgery, doctors create a small pouch at the top of the stomach where food enters from the esophagus. Initially, the pouch holds about 1 ounce of food and later expands to 2-3 ounces. As a result of this surgery, most people lose the ability to eat large amounts of food at one time and food must be well chewed.
Although restrictive operations lead to weight loss in almost all patients, they are less successful than malabsorptive operations in achieving substantial, long-term weight loss. About 30% of those who undergo VBG achieve normal weight, and about 80% achieve some degree of weight loss. Some patients regain weight. Others are unable to adjust their eating habits and fail to lose the desired weight. Successful results depend on your willingness to adopt a long-term plan of healthy eating and regular physical activity.
Restrictive operations for obesity include:
RGB is the most common and successful type of malabsorptive surgery. First, a small stomach pouch is created to restrict food intake. Next, a Y-shaped section of the small intestine is attached to the pouch to allow food to bypass the lower stomach, the duodenum (the first segment of the small intestine), and the first portion of the jejunum (the second segment of the small intestine). This bypass reduces the amount of calories and nutrients the body absorbs.
In this procedure, a hollow band made of special material is placed around the stomach near its upper end, creating a small pouch and a narrow passage into the larger remainder of the stomach. The band is then inflated with a salt solution. It can be tightened or loosened over time to change the size of the passage by increasing or decreasing the amount of salt solution. After this procedure, weight loss averages 50% of excess body weight.
VBG has been the most common restrictive operation for weight control. Both a band and staples are used to create a small stomach pouch. Excess body weight loss between 38% to 47% is expected after this procedure.
A common complication of restrictive operations is vomiting. This is caused when the small stomach is overly stretched by food particles that have not been chewed well. After laparoscopic AGB, up to 89% of patients complained of side effects, including abdominal pain, heartburn, nausea, band slippage, or band erosion. Moreover, 25% wanted the procedure reversed either due to side effects or inadequate weight loss. Risks of VBG include wearing away of the band and breakdown of the staple line. In a small number of cases, stomach juices may leak into the abdomen, requiring emergency surgery. In less than 1% of all cases, infection or death may occur.
Malabsorptive operations are the most common gastrointestinal surgeries for weight loss. They restrict both food intake and the amount of calories and nutrients the body absorbs.
Malabsorptive operations produce more weight loss than restrictive operations and are more effective in reversing the health problems associated with severe obesity. Patients who have malabsorptive operations generally lose two-thirds of their excess weight within two years.
Malabsorptive operations for weight loss include:
In this more complicated malabsorptive operation, portions of the stomach are removed. The small pouch that remains is connected directly to the final segment of the small intestine, completely bypassing the duodenum and the jejunum. Although this procedure successfully promotes weight loss, it is less frequently used than other types of surgery because of the high risk of nutritional deficiencies. A variation of BPD includes a “duodenal switch,” which leaves a larger portion of the stomach intact, including the pyloric valve that regulates the release of stomach contents into the small intestine. It also keeps a small part of the duodenum in the digestive pathway.
In addition to the risks of restrictive surgeries, malabsorptive operations also carry greater risk for dietary deficiencies. This is because the procedure causes food to bypass the duodenum and jejunum, where most iron, calcium, and other nutrients are absorbed. Menstruating women may develop anemia because not enough vitamin B12 and iron are absorbed. Decreased absorption of calcium may also lead to osteoporosis and metabolic bone disease. Patients are required to take nutritional supplements that help prevent these deficiencies. Patients who have the BPD must also take fat-soluble (dissolved by fat) vitamins A, D, E, and K supplements.
RGB and BPD operations may also cause “dumping syndrome,” which means that stomach contents move too rapidly through the small intestine. Symptoms include nausea, weakness, sweating, faintness, and sometimes diarrhea after eating. Because the duodenal switch operation keeps the pyloric valve intact, it may reduce the likelihood of dumping syndrome.
The more extensive the bypass, the greater the risk of complications and nutritional deficiencies. Patients with extensive bypasses of the normal digestive process require close monitoring and life-long use of special foods, supplements, and medicines.
Surgery is only the beginning of your weight loss program. Expect to be in close touch with your healthcare team for years afterward. There may come a time when the surgical changes can be or must be returned to normal, either because of your successful weight reduction and behavior changes or because of complications.
References:
American Obesity Association website. Available at: http://www.obesity.org/.
American Society of Bariatric Physicians website. Available at: http://www.asbp.org/.
Beers MH, Berkow R. The Merck Manual of Diagnosis and Therapy . 17th ed. Whitehouse Station, NJ: Merck & Co; 1999.
Fauci A. Harrison's Principles of Internal Medicine . 14th ed. New York, NY: McGraw-Hill; 1998.
Mechanick JI, Kushner RF, Sugerman HJ, et al. American Assocaition of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic & Bariatric Surgery medical guidelines for clinical practice for the perioperative nautritional, metabolic, and nonsurgical support of the bariatric surgery patient. Endocrine Practice. 2008;(Suppl 1).
National Institute of Diabetes & Digestive & Kidney Diseases website. Available at: http://www2.niddk.nih.gov/ .
Snow V, Barry P, Fitteman N, Qaseem A, et al. Pharmacologic and surgical management of obesity in primary care: a clinical practice guideline from the American College of Physicians. Ann Intern Med. 2005;142:525-531.
Way LW, Doherty GM. CURRENT Surgical Diagnosis and Treatment . 15th ed. New York, NY: Lange; 2002
2/19/2010 DynaMed's Systematic Literature Surveillance DynaMed's Systematic Literature Surveillance: Picot J, Jones J, Colquitt JL, et al. The clinical effectiveness and cost-effectiveness of bariatric (weight loss) surgery for obesity: a systematic review and economic evaluation. Health Technol Assess. 2009;13:1-190, 215-357, iii-iv.
Last reviewed November 2009 by David Juan, MD
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