Colectomy is surgery in which all or part of the colon (also called the large intestine) is removed. There are a number of different types of colectomies. They include: right hemicolectomy – in which the right part of the colon is removed, left hemicolectomy – where the left portion of the colon is removed, and other types of partial colectomies – where other segments are removed from the colon. In all colectomies, the bowel is either reconnected afterward (which is called an anastomosis) or the surgeon creates an ostomy, an opening of the bowel on the abdominal wall, to allow the contents of the bowel to exit from the body. Colectomy may be needed for treatment of different types of problems, including diverticulitis, benign polyps of the colon and cancer of the colon. A special variant of colectomy is total colectomy, which is also called proctocolectomy. This is most commonly a treatment considered for people with ulcerative colitis, either because of failure to respond to treatment or because of the cancer risk associated with the disease.