Obesity surgery is an operation that reduces or bypasses the stomach or small intestine so that severely overweight people can achieve significant and permanent weight loss.
Obesity surgery, also called bariatric surgery, is performed only on severely overweight people who are more than twice their ideal weight. This level of obesity often is refered to as morbid obesity since it can result in many serious, and potentially deadly, health problems, including hypertenison, Type II diabetes mellitus (non-insulin dependent diabetes), increased risk for coronary disease, increased unexplained heart attack, hyperlipidemia, and a higher prevalence of colon, prostate, endometrial, and, possibly, breast cancer. Therefore, this surgery is performed on people whose risk of complications of surgery is outweighed by the need to lose weight to prevent health complications, and for whom supervised weight loss and exercise programs have repeatedly failed. Obesity surgery, however, does not make people thin. Most people lose about 60% of their excess weight through this treatment. Changes in diet and exercise are still required to maintain a normal weight.
The theory behind obesity surgery is that if the volume the stomach holds is reduced and the entrance into the intestine is made smaller to slow stomach emptying, or part of the small intestine is bypassed or shortened, people will not be able to consume and/or absorb as
many calories. With obesity surgery the volume of food the stomach can hold is reduced from about four cups to about 1/2 a cup.
Insurers may consider obesity surgery elective surgery and not cover it under their policy. Documentation of the necessity for surgery and approval from the insurer should be sought before this operation is performed.
Obesity surgery should not be performed on people who are less than twice their ideal weight. It is also not appropriate for people who have substance addictions or who have psychological disorders. Other considerations in choosing candidates for obesity surgery include the general health of the person and his or her willingness to comply with follow-up treatment.
Obesity surgery is usually performed in a hospital by a surgeon who has experience with obesity surgery or at a center that specializes in the procedure. General anesthesia is used, and the operation takes 2–3 hours. The hospital stay lasts about a week.
Three procedures are currently used for obesity surgery:
- Gastric bypass surgery. Probably the most common type of obesity surgery, gastric bypass surgery has been performed in the United States for about 25 years. In this procedure, the volume of the stomach is reduced by four rows of stainless steel staples that separate the main body of the stomach from a small, newly created pouch. The pouch is attached at one end to the esophagus. At the other end is a very small opening into the small intestine. Food flows though this pouch, bypassing the main portion of the stomach and emptying slowly into the small intestine where it is absorbed.
- Vertical banded gastroplasty. In this procedure an artificial pouch is created using staples in a different section of the stomach. Plastic mesh is sutured into part of the pouch to prevent it from dilating. In both surgeries the food enters the small intestine farther along that it would enter if exiting the stomach normally. This reduces the time available for absorption of nutrients.
- Jejuoileal bypass. Now a rarely performed procedure, jejuoileal bypass involves shortening the small intestine. Because of the high occurance of serious complications involving chronic diarrhea and liver disease, it has largely been abandoned for the other, safer procedures
After patients are carefully selected as appropriate for obesity surgery, they receive standard preoperative blood and urine tests and meet with an anesthesiologist to discuss how their health may affect the administration of anesthesia. Pre-surgery counseling is done to help patients anticipate what to expect after the operation.
Immediately after the operation, most patients are restricted to a liquid diet for two to three weeks; however, some may remain on it for up to 12 weeks. Patients then move on to a diet of pureed food for about a month, and, after about two months, most can tolerate solid food. High fat food is restricted because it is hard to digest and causes diarrhea. Patients are expected to work on changing their eating and exercise habits to assist in weight loss. Most people eat three to four small meals a day once they return to solid food. Eating too quickly or too much after obestity surgery can cause nausea and vomiting as well as intestinal "dumping, " a condition in which undigested food is shunted too quickly into the small intestine, causing pain, diarrhea, weakness, and dizziness.
As in any abdominal surgery, there is always a risk of excessive bleeding, infection, and allergic reaction to anesthesia. Specific risks associated with obesity surgery include leaking or stretching of the pouch and loosening of the gastric staples. Although the average death rate associated with this procedure is less than one percent, the rate varies from center to center, ranging from 0–4%. Long term failure rates can reach 50%, sometimes making additional surgery necessary. Other complications of obesity surgery include an intolerance to foods high in fats, lactose intolerance, bouts of vomiting, diarrhea, and intestinal discomfort
Many people lose about 60% of the weight they need to reach their ideal weight through obesity surgery. However, surgery is not a magic weight-loss operation, and success also depends on the patient's willingness to exercise and eat low-calorie foods.
Gallager, Sharon, and R. Armour Forse. "Gastric Bypass." Diabetes Forecast 47 (Dec. 1994): 52.
Sadovsky, Richard. "Surgical Treatments for Obesity: Selection of Patients." American Family Physician 56 (Dec. 1997): 2320.