The surgical removal of part or all of the colon. Colectomy is used in severe cases of diverticular disease or to remove a cancerous tumour in the colon or a narrowed part of the intestine that is obstructing the passage of faeces. A total colectomy is carried out when ulcerative colitis cannot be controlled by drugs, and may be used in cases of familial polyposis.
In a partial colectomy, the diseased section of the colon is removed, and the ends of the severed colon are joined. A temporary colostomy may be required until the rejoined colon has healed. In a total colectomy, the whole of the large intestine is removed, with or without the rectum. If the rectum is removed, an ileostomy may be performed. The bowel usually functions normally after a partial colectomy. In a total colectomy, the reduced ability of the intestines to absorb water from the faeces can result in diarrhoea. Antidiarrhoeal drugs may therefore be required.