The Duodenal Switch (biliopancreatic diversion) combines restrictive and malabsorptive elements to help people achieve and maintain the best reported weight loss observed with modern weight-loss surgery procedures.
The restrictive part of the Duodenal Switch procedure is achieved via partial gastrectomy (removal of part of the stomach), which reduces the size of the stomach. The distal or pouch like portion of the stomach is removed. Some scientists think this helps reduce chemicals produced by the stomach that trigger hunger and eating.
Unlike the Roux-n-Y the Duodenal Switch keeps the pyloric valve between stomach and small intestine intact eliminating dumping syndrome, marginal ulcers, stoma closures, and blockages, all of which are possible side effects observed in patients who have had other gastric bypass procedures.
The malabsorptive component of the duodenal switch procedure is achieved by rearranging the small intestine so as to separate the flow of food from the flow of bile and pancreatic juices. Reducing the amount of bile and pancreatic juices the food comes in contact with reduces the amount of food that is digested and decreases absorption of some calories and nutrients.
Further down the digestive tract, the separated portions of the small intestinal are rejoined; food and digestive juices begin to mix, and limited fat absorption, essential for good health, occurs.
While the duodenal switch produces the greatest degree of weight loss of the bariatric procedures in use today, it also carries some additional risks which should be carefully evaluated when selecting this procedure.