Treating Obesity - Biliopancreatic Diversion

A biliopancreatic diversion is surgical procedure performed to treat obesity. It is one of the older bariatric procedures first introduced in 1979. Biliopancreatic diversion is a malabsorptive procedure which means the goal is to interfere with the body's ability to absorb calories consumed in the diet. Biliopancreatic diversion is also known as biliopancreatic bypass and is closely related to the duodenal switch procedure and jejunoileal bypass surgery.

The food we eat travels down the esophagus and collects temporarily in the stomach for digestion. There is very little absorption of nutrients in these two locations, however. The main location for the absorption of calories is in the first part of the small intestine called the duodenum. Digestion and absorption of large food particles is aided greatly by bile salts from the gallbladder (which dissolve fats) and digestive enzymes from the pancreas (which break up proteins and sugars into individual molecules). In addition to its role in nutrient absorption, the duodenum is also were ingested food is mixed with bile and digestive enzymes.

In biliopancreatic diversion surgery, these digestive processes are disrupted. In biliopancreatic diversion (BPD), the bottom portion of the stomach is removed, which, incidentally, could be considered a restrictive rather than malabsorptive procedure. The small intestine is cut at a location other than the duodenum, further along the intestine. This later portion of the small intestine is reconnected to the now smaller stomach. The remaining duodenum, connections from the gallbladder, and connections from the pancreas are diverted farther down the digestive tract, just before the large intestine.

The result of biliopancreatic diversion surgery is that swallowed food passes through the digestive system but absorption into the body is very limited. This leads to a profound and long term weight loss. Patients that have had biliopancreatic diversion surgery usually lose about 70 to 90 % of their excess weight. This is a high degree of weight loss, even when compared to other bariatric surgeries.

There are drawbacks to the biliopancreatic diversion procedure, however. Since nutrient absorption is severely limited in this obesity surgery, swallowed food passes through the GI tract with little to no transformation. Also, digestive enzymes and bile acids are not introduced until late in the food's travel through the system. This often leads to a condition known as dumping syndrome. Dumping syndrome is a state in which food moves too quickly through the digestive system. This causes faintness, weakness, and nausea. Diarrhea, particularly foul-smelling, is also common after biliopancreatic diversion surgery.

The other main complication with biliopancreatic diversion is that nutrient and vitamin deficiencies may develop. While the number of calories absorbed decreases, so do the essential vitamins and minerals. This can lead to health problems. Any person that has biliopancreatic diversion surgery must be vigilant for nutritional deficiencies throughout life. Supplements may be necessary to prevent deficiencies.

While the weight loss experienced with biliopancreatic diversion can be profound, the potential complications outweigh the benefits in many cases. Biliopancreatic diversion surgery is not performed as often in the United States as other types of weight loss surgery. This bariatric surgery remains popular in Italy where a fair number of biliopancreatic diversion procedures are performed each year.