Open or laparoscopic colon resection is performed for a variety of conditions, the most common of which are benign or malignant neoplasms (tubular or villoglandular adenomas, adenocarcinoma, carcinoid, lymphoma); complications of diverticular disease (perforation with peritonitis or abscess, stricture, bleeding); extensive traumatic perforations; angiodysplasia or arteriovenous malformation with lower gastrointestinal bleeding; and inflammatory bowel disease (ulcerative colitis, segmental colonic Crohn's disease, toxic megacolon). Less common indications for resection include volvulus of the sigmoid colon or cecum; thrombotic, embolic, or low-flow infarction; and premalignant conditions (familial polyposis, Gardner's syndrome).

Hemicolectomy for malignant neoplasms involves excision of the area of the tumor, at least 10 cm of normal proximal colon or small bowel, and 5 cm of normal distal colon as well as the regional lymphatics that accompany the major vessels. Therefore, a formal right hemicolectomy for carcinoma of the cecum would involve excision of 10 cm of distal ileum, the ascending colon, hepatic flexure, and right half of the transverse colon. In contrast, segmental resection for complications of diverticular disease, Crohn's disease, colonic volvulus, or infarction involves only grossly diseased bowel without excision of regional lymphatics. Subtotal abdominal colectomy with ileorectostomy is performed for patients with non-familial synchronous scattered benign or malignant neoplasms. It is also used in some patients with megacolon secondary to obstructing neoplasms of the sigmoid or rectosigmoid colon or of the upper rectum.