Ileoanal anastomosis surgery is often used to treat chronic ulcerative colitis or sometimes colon and rectal cancer. Commonly referred to as a J-pouch, the large intestine (colon) is removed and the lower end of the small intestine (ileum) is attached to the opening of the anus. A surgeon creates a pouch from the ileum to hold faecal material, which allows the patient to have fairly normal bowel movements.