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Gastrointestinal Surgery |
People who may consider gastrointestinal surgery include those with a body mass index (BMI) above 40—about 100 pounds of overweight for men and 80 pounds for women (see table 1 for a BMI conversion chart). People with a BMI between 35 and 40 who suffer from type 2 diabetes or life-threatening cardiopulmonary problems such as severe sleep apnea or obesity-related heart disease may also be candidates for surgery. The concept of gastrointestinal surgery to control obesity grew out of results of operations for cancer or severe ulcers that removed large portions of the stomach or small intestine. Because patients undergoing these procedures tended to lose weight after surgery, some physicians began to use such operations to treat severe obesity. The first operation that was widely used for severe obesity was the intestinal bypass. This operation, first used 40 years ago, produced weight loss by causing malabsorption. The idea was that patients could eat large amounts of food, which would be poorly digested or passed along too fast for the body to absorb many calories. The problem with this surgery was that it caused a loss of essential nutrients and its side effects were unpredictable and sometimes fatal. The original form of the intestinal bypass operation is no longer used.
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The Normal Digestive Process |
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How Does Surgery Promote Weight Loss? |
Gastrointestinal
surgery for obesity, also called bariatric surgery, alters the digestive
process. The operations promote weight loss by closing off parts of the
stomach to make it smaller. Operations that only reduce stomach size are
known as “restrictive operations” because they restrict the amount of food
the stomach can hold.
Some operations combine stomach restriction with a partial bypass of the small intestine. These procedures create a direct connection from the stomach to the lower segment of the small intestine, literally bypassing portions of the digestive tract that absorb calories and nutrients. These are known as malabsorptive operations. Table 1. Body Mass Index
Automatic BMI Calculator: Click here. |
What Are the Surgical Options? |
There
are several types of restrictive and malabsorptive operations. Each one
carries its own benefits and risks.
Restrictive Operations Restrictive operations serve only to restrict food intake and do not interfere with the normal digestive process. To perform 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. The lower outlet of the pouch usually has a diameter of only about ¾ inch. This small outlet delays the emptying of food from the pouch and causes a feeling of fullness. As a result of this surgery, most people lose the ability to eat large amounts of food at one time. After an operation, the person usually can eat only ¾ to 1 cup of food without discomfort or nausea. Also, food has to be well chewed. Restrictive operations for obesity include adjustable gastric banding (AGB) and vertical banded gastroplasty (VBG).
A
common risk of restrictive operations is vomiting, which is caused when
the small stomach is overly stretched by food particles that have not been
chewed well. Band slippage and saline leakage have been reported after
AGB. 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 an emergency operation. In less than 1 percent of all
cases, infection or death from complications may occur.
Malabsorptive Operations 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.
In addition to the risks of restrictive surgeries, malabsorptive operations also carry greater risk for nutritional deficiencies. This is because the procedure causes food to bypass the duodenum and jejunum, where most iron and calcium are absorbed. Menstruating women may develop anemia because not enough vitamin B12 and iron are absorbed. Decreased absorption of calcium may also bring on osteoporosis and metabolic bone disease. Patients are required to take nutritional supplements that usually prevent these deficiencies. Patients who have the biliopancreatic diversion surgery must also take fat-soluble (dissolved by fat) vitamins A, D, E, and K supplements. RGB and BPD operations may also cause “dumping syndrome.” This 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 for 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 medications.
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Explore Benefits and Risks |
Surgery
to produce weight loss is a serious undertaking. Anyone thinking about
surgery should understand what the operation involves. Patients and physicians
should carefully consider the following benefits and risks:
Benefits
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Medical Costs |
Gastrointestinal
surgery costs about $15,000. Medical insurance coverage varies by state
and insurance provider. If you are considering gastrointestinal surgery,
contact your regional Medicare or Medicaid office or insurance plan to
find out if the procedure is covered.
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Is the Surgery for You? | Gastrointestinal
surgery may be the next step for people who remain severely obese after
trying nonsurgical approaches, or for people who have an obesity-related
disease. Candidates for surgery have:
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Additional Reading |
Gastrointestinal
Surgery for Severe Obesity. Consensus Statement, NIH Consensus Development
Conference, March 25-27, 1991; Public Health Service, National Institutes
of Health, Office of Medical Applications of Research. This publication,
written for health professionals, summarizes the findings of a conference
discussing treatments for severe obesity. Available from WIN.
Weight Loss for Life. NIH Publication No. 00-3700. This booklet describes how we lose weight, healthy eating habits, the importance of physical activity, and behavior change. Available from WIN.
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Additional Resource |
American
Society for Bariatric Surgery
140 NW 75th Drive, Suite C Gainesville, FL 32607 Phone: (352) 331-4900 Fax: (352) 331-4975 Website: http://www.asbs.org/
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