Surgical removal of a part of the sigmoid colon (large bowel) +/- part of the rectum due to a blockage (tumour), perforation or infection. It is either carried with keyhole surgery (laparoscopic) or open (in emergencies). The rectum is usually closed and a colostomy / stoma is formed (the end of the bowel is brought to the surface of the left abdomen. The bowel content is collected in a plastic bag. You will usually be seen by a stoma nurse either prior to the operation or after the operation.