Our understanding of the physiological basis underlying biliopancreatic diversion (BPD) has evolved during the last two decades. Initially, 25 years ago, when presented by Scopinaro and his colleagues, the procedure was seen as a simple technique to decrease caloric absorption particularly by decreasing fat absorption. Shortening the gut and controlling the action of bile were the two fundamental mechanisms on which the procedure was based. The reversibility of the procedure and the fact that normal eating habits were preserved made the procedure very appealing. Later, another major mechanism was discovered. Absence of food in the first part of the gut decreases levels of hormones (known to be involved in the development of obesity and diabetes) secreted by this part of the gut. At the same time, food diverted directly into the last part of the gut increases levels of hormones (known to decrease insulin secretion and to help prevent obesity) secreted by this segment. These hormonal changes, which directly affect the cause of obesity, are an additional reason to prefer this approach.1
Convinced from our clinical experience that morbid obesity is a metabolic disease, rather than due to abnormal eating habits, BPD became our procedure of choice and helped demonstrate that obesity is indeed a disease of the gut. BPD is a procedure intended to change the pathology underlying morbid obesity.
Removing bile from the outlet of the stomach is an ulcerogenic procedure.2 To prevent ulcers, it was initially suggested that BPD be accompanied by a partial gastrectomy, which was the classic ulcer preventing procedure at the time, in similar circumstances. Later it was shown that replacing distal gastrectomy by a sleeve gastrectomy (SG) and a duodenal switch better preserved normal gastric physiology, without interfering with the basic function of the procedure. The changes meant same weight loss without compromising the basic function of the procedure and produced fewer side effects. The procedure was called “duodenal switch” and represents a variant of the conventional BPD (Figure 14–1). It has the same fundamental physiologic mechanism with fewer side effects.3–5
BPD has three components, and all three have both positive and negative effects. The components are as follows: (1) the length of gut left in contact with food: the “alimentary channel”; (2) the length of intestine where bile is allowed to be involved in the digestive process: the “common channel”; (3) the size of the remaining stomach: the “gastric remnant.” All three factors individually and concomitantly influence weight loss, side effects, as well as complications.
The ideal construction of a BPD is not yet established. It is not known whether it would be preferable to individualize the construction, according to certain patient characteristics such as age, sex, height, BMI, etc. There are no data relating any of the three components of the ...