Washington University School of Medicine
Dr. J. Chris Eagon
(314) 454-7224

Surgical Treatment of Morbid Obesity:
Options, Anatomy, Results and Complications

Extreme obesity is a complex chronic health disorder caused by a number of factors including family history (genetics), environment, eating habits, and food choices. This problem is becoming increasingly frequent in the United States, and it is estimated that over 2% of the population have extreme obesity. This causes an even greater burden of co-morbid diseases such as diabetes, high blood pressure, sleep apnea, heart disease and cancer. The additional costs for caring for these health problems exceeds $40 billion dollars in the U.S. each year and increases the costs of yearly health care for each individual by about 50%.

Rationale behind surgical therapy

Increasing degrees of obesity have been shown to be related to increasing risks of death compared with non obese individuals. In cases of extreme obesity, significant weight loss usually cannot be maintained with diet and exercise alone. Unfortunately, only 10% of individuals are able to successfully lose large amounts of weight and keep it off for more than one or two years. The remainder typically regains lost weight or even exceeds their starting weight when they enter a medical treatment program. There is no question that the most effective method for achieving long-term weight management in individuals who are extremely obese is surgery.

Indications for surgery: NIH consensus conference guidelines

Why shouldn’t everyone who is obese have surgery? The answer lies in assessing the risks and benefits of surgery. Surgery for extreme obesity is a major and expensive procedure with significant risks involved including the risk of dying. Therefore, we insist that individuals have exhausted dietary attempts to achieve and maintain weight loss before considering surgery. Persons eligible for gastric bypass surgery must meet the following criteria:

Body Mass Index (BMI) greater than 40 or greater than 35 with serious co-morbidities including diabetes, high blood pressure, sleep apnea or heart disease. BMI can be calculated 703 multiplied by weight in pounds and then divided by height in inches and divided again by height in inches.

Patients must have attempted medical treatment of their weight and failed to maintain weight below the above guideline. The types of medical treatment programs vary, but it should include a behavioral component with frequent follow-up intervals as an integral part.

Patients should be able to show understanding of the relative strengths and weaknesses of medical versus surgical treatment in order to make a decision regarding surgery competently. They must also be able to understand the dietary constraints and lifestyle changes that will be required after surgery. For this reason, behavioral and nutritional assessments and education are critical for the success of surgical therapy.

Mechanisms of surgical weight loss

Several different types of operations have been used since the 1950’s to aid patients in losing weight. Many of these have been discarded over the years because of too many side effects or inadequate long-term weight reduction. Many patients have heard stories from friends or relatives regarding obesity operations in the past that have failed. It is important to realize that the exact procedure performed can make a huge difference in the results. The Roux-Y gastric bypass has been performed close to near its present day form since 1971. It and another procedure, vertical banded gastroplasty, have withstood the test of time and are accepted by the National Institutes of Health Consensus Conference in 1991 as acceptable treatments for extreme obesity. The Lap-band has been FDA approved since 2001 and over 200,000 bands have been placed worldwide. Although it does not have as long a track record and may not produce as much weight loss, the relative simplicity of the surgery and low-risk of complications has made it an increasingly popular choice.

Surgery does not alter the basic laws of energy balance in the body. The only way that weight loss will occur is if the ingestion and absorption of calories are less than the burning of calories by the body. Surgery does not generally affect the rate of calorie burning, so all effects of surgery relate to altering either the ingestion of calories or their absorption by the intestine, or both. The gastric bypass works primarily by decreasing the amount of calories consumed per day. Not all calories consumed are absorbed; however, this is a relatively minor compared to the restriction of calorie intake. Another way that the operation works to affect calorie intake is by an effect called the dumping syndrome. Consuming foods that are high in sugar results in sensations of abdominal pain, lightheadedness, and palpitations in most patients. This leads to a loss of desire for these types of foods and aids in patients’ sense of control over the diet. The Lap-band works entirely by restricting caloric intake and does not affect absorption or cause dumping.