Abdominoperineal resection is a surgical operation to treat disease of the rectum or anal canal, and it involves removal of the anus, the rectum, and part of the sigmoid colon along with their draining lymph nodes, through incisions made in the abdomen and perineum. The end of the remaining sigmoid colon is brought out permanently as an opening on the surface of the abdomen, called a colostomy. Fecal matter from the colostomy is collected in a disposable bag that covers the colostomy.