Abdominoperineal resection (APR) is an operation in which a surgeon removes the anus, rectum and part of the sigmoid colon using incisions in your abdomen and between your buttocks (perineum). It is most commonly performed for rectal and anal cancers, in particular in the situation where the rectal cancer being removed is very low in the rectum and it is not possible to get an adequate clearance of the tumour when removing and preserving enough sphincter muscle to maintain continence.
At the completion of the surgery, the end of the residual colon will be brought to the skin on the left hand side of the abdomen, allowing faecal material to drain in to a bag. This arrangement is known as a colostomy or stoma. Unlike the anus, the stoma has no sphincter muscles. Faecal material will thus drain in to the bag as the colon contracts.
Abdominoperineal resection is major surgery and will require the patient to be in hospital for around a week postoperatively to recover, and learn the basics of managing their colostomy.