Duodenal Switch (DS)
The Duodenal Switch procedure (also called Vertical Gastrectomy with Duodenal Switch, Biliopancreatic Diversion with Duodenal Switch, DS or BPD-DS) is performed by approximately 50 surgeons worldwide. It generates weight loss by restricting the amount of food that can be eaten (removal of stomach or vertical gastrectomy) and by limiting the amount of food (specifically fat) that is absorbed into the body (intestinal bypass or duodenal switch). It is more controversial because it has a significant component of malabsorption (bypass of the intestinal tract), which seems to augment and help maintain long-term weight loss. Of the procedures that are currently performed for the treatment of obesity, it seems to be the most powerful and effective, but may also be associated with more side effects.
In the Duodenal Switch, the stomach is restricted in size by dividing it vertically and removing more than 85%. This part of the procedure is not reversible. The stomach that remains is shaped like a thin banana and measures from 4-7 ounces (120-250 cc) depending on the surgeon performing the procedure. The nerves to the stomach and the outlet valve (pylorus) remain intact with the idea of preserving the functions of the stomach while reducing the volume. By comparison, in a Roux-en-Y gastric bypass, the stomach is divided to bypass most of the stomach, but not removed, and the pylorus is excluded. As an added benefit, normal gastric emptying is maintained with Duodenal Switch. In the Roux-en-Y Gastric Bypass procedure, the pyloric valve is bypassed, causing Dumping Syndrome to occur. In addition, gastritis and "marginal ulcers" are absent in the Duodenal Switch since the stomach is not connected directly to the small intestine.
In the Duodenal Switch, the intestines are divided and rearranged to separate food from the digestive juices, thereby creating malabsorption. The food limb is attached to the duodenum and receives food from the stomach. This limb is 150 cm long. The digestive juices are now separated from the food and travel for over 500 cm in the bypassed small intestine. Both food and digestive juices mix together and travel together for 100 cm in the common limb. Thus, food and digestive juices are separated for most of the length of the intestines. This prevents patients who have undergone this surgery from absorbing all of the calories that are eaten. By comparison, the intestinal bypass in a Roux-en-Y gastric bypass is much less extensive, and the common limb for digestive juices and food to mix is approximately 5 times longer. The Roux-en-Y gastric bypass therefore has minimal malabsorption compared to the Duodenal Switch procedure.