Restriction Operations
Restriction operations are the surgeries most often used for producing weight loss. Food intake is restricted by creating a small pouch at the top of the stomach where the food enters from the esophagus. The pouch initially holds about 1 ounce of food and expands to 2-3 ounces with time. The pouch's lower outlet usually has a diameter of about 1/4 inch. The small outlet delays the emptying of food from the pouch and causes a feeling of fullness.
After an operation, the person usually can eat only a half to a whole cup of food without discomfort or nausea. Also, food has to be well chewed. For most people, the ability to eat a large amount of food at one time is lost, but some patients do return to eating modest amounts of food without feeling hungry.
Restriction operations for obesity include gastric banding and vertical banded gastroplasty. Both operations serve only to restrict food intake. They do not interfere with the normal digestive process.
 | The AGB - Adjustable Gastric Band (Commonly known as the LapBand®)
In this procedure a silicone elastomer band is placed around the upper part of the stomach to create a small stomach pouch which can hold only a small amount of food. The lower, larger part of the stomach is below the band. These two parts are connected by a small outlet created by the band. Food will pass through the outlet (stoma in medical terms) from the upper stomach pouch to the lower part more slowly, and one will feel full longer. The diameter of the band outlet is adjustable to meet individual needs, which can change as one loses weight. The inner surface of the band can be inflated with liquid (saline solution) or deflated to modify the size of the stoma. This can be done in the surgeon's office.
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| Vertical banded gastroplasty (VBG). This procedure is the most frequently used restrictive operation for weight control. As figure 3 illustrates, both a band and staples are used to create a small stomach pouch.
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Restrictive operations lead to weight loss in almost all patients. However, weight regain does occur in some patients. About 30 percent of persons undergoing vertical banded gastroplasty achieve normal weight, and about 80 percent achieve some degree of weight loss. However, some patients are unable to adjust their eating habits and fail to lose the desired weight. In all weight-loss operations, successful results depend on your motivation and behaviors.
A common risk of restrictive operations is vomiting caused by the small stomach being overly stretched by food particles that have not been chewed well. Other risks of VBG include erosion of the band, breakdown of the staple line, and, in a small number of cases, leakage of stomach juices into the abdomen. The latter requires an emergency operation. In a very small number of cases (less than 1 percent) infection or death from complications can occur.
Gastric Bypass Operations
These operations combine creation of small stomach pouches to restrict food intake and construction of bypasses of the duodenum and other segments of the small intestine to cause malabsorption.
Gastric bypass operations (figures 4 and 5) that cause malabsorption and restrict food intake produce more weight loss than restriction operations (figures 2 and 3) that only decrease food intake. Patients who have bypass operations generally lose two-thirds of their excess weight within 2 years.
The risks for pouch stretching, band erosion, breakdown of staple lines, and leakage of stomach contents into the abdomen are about the same for gastric bypass as for vertical banded gastroplasty. However, because gastric bypass operations cause food to skip the duodenum, where most iron and calcium are absorbed, risks for nutritional deficiencies are higher in these procedures. Anemia may result from malabsorption of vitamin B12 and iron in menstruating women, and decreased absorption of calcium may bring on osteoporosis and metabolic bone disease. Patients are required to take nutritional supplements that usually prevent these deficiencies.
Gastric bypass operations also may cause "dumping syndrome," whereby stomach contents move too rapidly through the small intestine. Symptoms include nausea, weakness, sweating, faintness, and, occasionally, diarrhea after eating, as well as the inability to eat sweets without becoming so weak and sweaty that the patient must lie down until the symptoms pass.
The more extensive the bypass operation, the greater is the risk for complications and nutritional deficiencies. Patients with extensive bypasses of the normal digestive process require not only close monitoring, but also life-long use of special foods and medications.
Explore Benefits and Risks
Surgery to produce weight loss is a serious undertaking. Each individual should clearly understand what the proposed operation involves. Patients and physicians should carefully consider the following benefits and risks:
Benefits
| Immediately following surgery, most patients lose weight rapidly and continue to do so until 18 to 24 months after the procedure. Although most patients then start to regain some of their lost weight, few regain it all. |
| Surgery improves most obesity-related conditions. For example, in one study blood sugar levels of most obese patients with diabetes returned to normal after surgery. Nearly all patients whose blood sugar levels did not return to normal were older or had had diabetes for a long time. |
Risks
| Ten to 20 percent of patients who have weight-loss operations require followup operations to correct complications. Abdominal hernias are the most common complications requiring followup surgery. Less common complications include breakdown of the staple line and stretched stomach outlets. |
| More than one-third of obese patients who have gastric surgery develop gallstones. Gallstones are clumps of cholesterol and other matter that form in the gallbladder. During rapid or substantial weight loss a person's risk of developing gallstones is increased. Gallstones can be prevented with supplemental bile salts taken for the first 6 months after surgery. |
| Nearly 30 percent of patients who have weight-loss surgery develop nutritional deficiencies such as anemia, osteoporosis, and metabolic bone disease. These deficiencies can be avoided if vitamin and mineral intakes are maintained. |
| Women of childbearing age should avoid pregnancy until their weight becomes stable because rapid weight loss and nutritional deficiencies can harm a developing fetus. |
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