Figure 1.

Gastric and foregut anatomy of RYGB, VSG, AGB, and BPD. (a) Normal upper GI anatomy. (b) RYGB surgically transforms the stomach into a small pouch, then bypasses most of the stomach and duodenum by attaching the distal jejunum directly to the stomach. (c) VSG surgically removes most of the stomach, turning the gastric pouch into a tight sleeve. (d) AGB applies an adjustable band to the proximal portion of the stomach to restrict food entry. (e) BPD surgically modifies the stomach in a manner similar to RYGB and connects the duodenum directly to the jejunum, bypassing most of the intestine. (f) BPD-DS includes surgical modification of the stomach much like a VSG coupled with the intestinal rerouting of a BPD.