Weight Loss Surgery Options
While these operations also reduce the size of the stomach, the stomach pouch created is much larger than with other procedures. The goal is to restrict the amount of food consumed and alter the normal digestive process, but to a much greater degree. The anatomy of the small intestine is changed to divert the bile and pancreatic juices so they meet the ingested food closer to the middle or the end of the small intestine.With the three approaches discussed below, absorption of nutrients and calories is also reduced, but to a much greater degree than with previously discussed procedures. Each of the three differs in how and when the digestive juices (i.e., bile) come into contact with the food.
Since food bypasses the duodenum, all the
risk considerations discussed in the gastric bypass section regarding
the malabsorption of some minerals and vitamins also apply to these techniques,
only to a greater degree.
Biliopancreatic Diversion (BPD):
removes approximately 3/4 of the stomach to produce both restriction of
food intake and reduction of acid output. Leaving enough upper stomach
is important to maintain proper nutrition. The small intestine is then
divided with one end attached to the stomach pouch to create what is called
an "alimentary limb." All the food moves through this segment,
however, not much is absorbed. The bile and pancreatic juices move through
the "biliopancreatic limb," which is connected to the side of
the intestine close to the end. This supplies digestive juices in the
section of the intestine now called the "common limb." The surgeon
is able to vary the length of the common limb to regulate the amount of
absorption of protein, fat and fat-soluble vitamins.
Extended (Distal) Roux-en-Y Gastric Bypass (RYGBP-E):
RYGBP-E is an alternative means of achieving malabsorption by creating a stapled or divided small gastric pouch, leaving the remainder of stomach in place. A long limb of the small intestine is attached to the stomach to divert the bile and pancreatic juices. This procedure carries with it fewer operative risks by avoiding removal of the lower 3/4 of the stomach. Gastric pouch size and the length of the bypassed intestine determine the risks for ulcers, malnutrition and other effects.
Biliopancreatic Diversion with "Duodenal Switch"
This procedure is a variation of BPD in which stomach removal is restricted to the outer margin, leaving a sleeve of stomach with the pylorus and the beginning of the duodenum at its end. The duodenum, the first portion of the small intestine, is divided so that pancreatic and bile drainage is bypassed. The near end of the "alimentary limb" is then attached to the beginning of the duodenum, while the "common limb" is created in the same way as described above.