In an anterior resection of the rectum, the left side of the colon and upper rectum are taken out, and the ends are joined up whenever possible.
An anterior resection of the rectum is carried out under a general anaesthesia. A cut is made in the skin to the left of the navel about 40 cm (15 inches) long. The left side of the colon loop and the upper rectum are freed from the inside of the stomach. The diseased part is cut out and usually the ends are joined together.
Sometimes it is safer if the ends are not joined together.
Then the bowel waste is channelled through the bowel which opens in the front of the stomach (a colostomy), and the patient needs to wear a bag.
Usually the ends are joined up at a much later date from the anterior resection of the rectum procedure. Sometimes the ends are joined up at the first operation, but a short term colostomy is made as well. This keeps the bowel waste away from the join while it is healing up.