Metabolic/Bariatric Surgery Types
Gastric bypass surgery is currently considered the gold standard for surgical treatment of obesity. Studies have shown that patients tend to experience 50-80% excess weight loss (EWL) over a two year period following surgery. In addition, gastric bypass offers sustainable weight loss, and has a better record in this regard than does gastric banding. Weight regain is not unknown, however, and has been reported to be as high as 25-30%, depending on the type of procedure and the patient’s dedication to changing. Patients must follow significant, permanent diet and lifestyle modifications following surgery, which is one reason that patients are usually required to undergo psychiatric testing and counseling prior to having the surgery. If weight is regained, then factors such as psychiatric challenges, the patient’s degree of adherence to the new diet, and general health must all be reviewed. Once these have been dealt with, then surgical revision may be considered. Bariatric surgery falls into one of three categories, depending upon the type of procedure: restrictive, malabsorptive or a combination of these. ‘Restrictive’ refers to restricting the size of the stomach, so that the patient feels full on less food. This may be achieved using gastric stapling, gastric banding or by surgically removing a large part of the stomach. ‘Malabsorptive’ surgery involves making significant surgical changes to the digestive tract by bypassing most of the stomach and intestines, thereby shortening the absorptive surface area of the bowel. Because so much absorptive area is lost, the patient must take vitamins and minerals for the rest of his or her life. In the US and European Union, bariatric surgeons generally perform the following major procedures:
- Gastric bypass, including a variation known as vertical banded gastroplasty (VBG); the latter is both malabsorptive and restrictive.
- Roux-en-Y (vertical division)
- Sleeve gastrectomy independent of biliopancreatic diversion.
- Biliopancreatic diversion with duodenal switch (both malabsorptive and restrictive)
- Gastric banding (restrictive)
These may be performed using either open surgery or laparoscopically, but are usually done via laparoscope.