Bariatric surgical anatomy and mechanisms of action.

Because bariatric surgery is becoming increasingly common, gastroenterologists need to be familiar with the surgical and endoscopic anatomy of the operations in use today. This review focuses on the 4 most commonly performed bariatric operations in the United States: Roux-en-Y gastric bypass, adjustable gastric band, sleeve gastrectomy, and biliopancreatic diversion with duodenal switch. The anatomy and mechanism of action of each procedure is discussed and illustrated. Emphasis is placed on the endoscopic anatomy, with review of the commonly encountered complications. Emerging techniques and devices are reviewed.