Thanks to advances in minimally invasive surgery, most weight loss procedures are now performed laparoscopically. These techniques require much smaller incisions than open surgery, reducing tissue damage, pain and risk for complications while also facilitating quicker recoveries.
Chilton surgeons perform two kinds of weight loss procedures, each of which carries its own risks and benefits:
Malabsorptive operations are the most common weight loss surgeries. They restrict both food intake and the amount of calories and nutrients the body absorbs.
Roux-en-Y gastric bypass (RGB), illustrated in Figure 1, is the most successful form of malabsorptive surgery. A small stomach pouch is created to restrict food intake. Then 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 part of the jejunum (the second segment of the small intestine).
Malabsorptive operations can produce greater weight loss than restrictive operations, and are considered more effective in reversing the serious health problems associated with severe obesity. Patients who have malabsorptive surgery generally lose two-thirds of their excess weight within two years.
In general, malabsorptive operations carry more risks than restrictive surgeries. In addition to risks common to both techniques, malabsorptive operations place patients at greater risk for nutritional deficiencies because foods bypass the duodenum and jejunum, where most iron and calcium are absorbed. Patients are required to take nutritional supplements, which will usually prevent these deficiencies. RGB operations may also cause "dumping syndrome," which occurs when the stomach contents move too rapidly through the small intestine. Symptoms include nausea, weakness, sweating and faintness, and sometimes diarrhea after eating.
Restrictive operations, or gastric banding, severely limit food intake without otherwise interfering with the normal digestive process. In these procedures, physicians create a small pouch at the top of the stomach where food enters from the esophagus. Initially, the pouch holds about one ounce of food, eventually expanding to hold two to three 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 results in a feeling of fullness.
Adjustable gastric banding involves placing a hollow band made of specialized material around the stomach near its upper end, creating a small pouch and a narrow passage into the remainder of the stomach. The band is then inflated with a saline solution. It can be tightened or loosened over time to change the size of the passage by increasing or decreasing the amount of solution.
Although restrictive operations lead to weight loss in about 80 percent of patients, they are less successful than malabsorptive operations in achieving substantial, long-term weight loss. Successful results depend on the patient's willingness to adopt a long-term plan of healthy eating and regular physical activity.
Common risks of restrictive operations include: vomiting, caused by the small stomach being overly stretched by too much food or food that has not been sufficiently chewed; band slippage; and saline leakage.
Source: NIDDK: Gastrointestinal Surgery for Severe Obesity