Biliopancreatic diversion bypass

The biliopancreatic diversion bypass is performed through open surgery with one long incision, leaving a permanent scar. It is less common and more complicated than the Roux-en-Y-gastric bypass. In the biliopancreatic diversion, portions of
the stomach are removed and the bypass is attached to the distal illium. This procedure is not widely used, because there is more risk of nutritional deficiencies.

The pancreas and gall bladder have ducts that carry digestive juices and enzymes to the duodenum. These enzymes and digestive juices allow for the breakdown of the food we eat. Once food is broken down it can be absorbed in the
duodenum and jejunum of the lower intestine.

Since this procedure prevents the digestive juices and enzymes in the duodenum and jejunum from making contact with food until almost the end of the ileum, calories from food are simply not absorbed effectively. This allows dramatic weight loss to occur, but it also results in a number of complications.