Gastric Bypass

Gastric bypass procedures are any of a group of similar operations used to treat morbid obesity—the severe accumulation of excess weight as fatty tissue—and the health problems it causes. Bariatric surgery is the term encompassing all of the surgical treatments for morbid obesity, not just gastric bypasses, which make up only one class of such operations.

A gastric bypass first divides the stomach into a small upper pouch and a much larger, lower remnant pouch and then re-arranges the small intestine to allow both pouches to stay connected to it. Surgeons have developed several different ways to reconnect the intestine, thus leading to several different by pass names. Any BY PASS leads to a marked reduction in the functional volume of the stomach, accompanied by an altered physiological and psychological response to food. The resulting weight loss, typically dramatic, markedly reduces comorbidities. The long-term mortality rate of gastric bypass patients has reduction of up to 40%.

The gastric bypass, in its various forms, accounts for a large majority of the bariatric surgical procedures performed. An increasing number of these operations are by limited access techniques, termed laparoscopy.

Laparoscopic surgery uses several small incisions, or ports, one of which conveys a surgical telescope connected to a video camera, and others permit access of specialized operating instruments. The surgeon actually views his operation on a video screen. The method is limited access surgery, reflecting both the limitation on handling and feeling tissues, and also the limited resolution and two-dimensionality of the video image. With experience, a skilled laparoscopic surgeon can perform most procedures as expeditiously as with an open incision—with the option of using an incision should the need arise.

The gastric bypass reduces the size of the stomach by well over 90%. A normal stomach can stretch, sometimes to over 1000 ml, while the pouch of the gastric bypass may be 15 ml in size. The Gastric Bypass pouch formed from the part of the stomach, which is least susceptible to stretching. That, and its small original size, prevents any significant long-term change in pouch volume. What does change, over time, is the size of the connection between stomach and bowel, and the ability of the small bowel to hold a greater volume of food. Over time, the functional capacity of the pouch increases, by that time, weight loss has occurred, and the increased capacity serves to allow maintenance of a lower body weight.

When the patient ingests just a small amount of food, the first response is a stretching of the wall of the stomach pouch, stimulating nerves, which tell the brain that the stomach is full. The patient feels a sensation of fullness, as if they had just eaten a large meal—but with just a thumbful of food.