An ileostomy involves attaching the lowest section of the small intestine to an opening in the abdominal wall, known as a stoma, while a colostomy involves an end section of the large intestine, states the National Institute of Diabetes and Digestive and Kidney Diseases. The surgeon completely bypasses the colon, rectum and anus when performing a permanent ileostomy, while a permanent colostomy involves bypassing the lower colon and rectum.
Ileostomy and colostomy are both diversion procedures to provide a pathway for waste to leave the body when a major area of the bowels is impaired, according to MedlinePlus. A colostomy is typically performed after a bowel resection or injury. An ileostomy is often performed alongside a resection surgery in the small intestine or a complete removal of the colon and rectum. The doctor may set up a temporary ileostomy, which is performed after removing part or all of the large intestine while leaving the rectum intact. This option reduces stress on the remaining lower portion, which can be reattached later through surgery.
Surgeons often recommend temporary colostomy for patients with colon or rectal inflammation or injury that can heal with rest, states the NIDDK. Colostomy is most often used to treat diverticulitis, rectal cancer or fecal incontinence, while ileostomy is commonly used to treat rectal cancer or inflammatory bowel disease.