Surgery of the stomach, duodenum, gallbladder, and bile ducts.
D001652:Bile Ducts / Q000601:surgery*; D001660:Biliary Tract Diseases / Q000601:surgery; D004386:Duodenum / Q000601:surgery*; D005704:Gallbladder / Q000601:surgery*; D005767:Gastrointestinal Diseases / Q000601:surgery; D005770:Gastrointestinal Neoplasms / Q000601:surgery; D006801:Humans; D013270:Stomach / Q000601:surgery*