Biliopancreatic Diversion: A surgical procedure which diverts pancreatobiliary secretions via the duodenum and the jejunum into the colon, the remaining small intestine being anastomosed to the stomach after antrectomy. The procedure produces less diarrhea than does jejunoileal bypass.Obesity, Morbid: The condition of weighing two, three, or more times the ideal weight, so called because it is associated with many serious and life-threatening disorders. In the BODY MASS INDEX, morbid obesity is defined as having a BMI greater than 40.0 kg/m2.Vagotomy, Truncal: Bilateral dissection of the abdominal branches of the vagus nerve. It is used frequently in the surgical management of duodenal and gastric ulcers, as well as in physiologic studies of gastrointestinal secretion and motility.Bariatric Surgery: Surgical procedures aimed at affecting metabolism and producing major WEIGHT REDUCTION in patients with MORBID OBESITY.Gastric Bypass: Surgical procedure in which the STOMACH is transected high on the body. The resulting small proximal gastric pouch is joined to any parts of the SMALL INTESTINE by an end-to-side SURGICAL ANASTOMOSIS, depending on the amounts of intestinal surface being bypasses. This procedure is used frequently in the treatment of MORBID OBESITY by limiting the size of functional STOMACH, food intake, and food absorption.Urinary Diversion: Temporary or permanent diversion of the flow of urine through the ureter away from the URINARY BLADDER in the presence of a bladder disease or after cystectomy. There is a variety of techniques: direct anastomosis of ureter and bowel, cutaneous ureterostomy, ileal, jejunal or colon conduit, ureterosigmoidostomy, etc. (From Campbell's Urology, 6th ed, p2654)Weight Loss: Decrease in existing BODY WEIGHT.Jejunoileal Bypass: A procedure consisting of the SURGICAL ANASTOMOSIS of the proximal part of the JEJUNUM to the distal portion of the ILEUM, so as to bypass the nutrient-absorptive segment of the SMALL INTESTINE. Due to the severe malnutrition and life-threatening metabolic complications, this method is no longer used to treat MORBID OBESITY.Bile Ducts, Extrahepatic: Passages external to the liver for the conveyance of bile. These include the COMMON BILE DUCT and the common hepatic duct (HEPATIC DUCT, COMMON).