Surgery is necessary to cure an anal fistula. Although fistula surgery is usually relatively straightforward, the potential for complication exists, and is preferably performed by a specialist in colon and rectal surgery. It may be performed at the same time as the abscess surgery, although fistulas often develop four to six weeks after an abscess is drained, sometimes even months or years later.

Fistula surgery usually involves opening up the fistula tunnel. Often this will require cutting a small portion of the anal sphincter, the muscle that helps to control bowel movements. Joining the external and internal openings of the tunnel and con-verting it to a groove will then allow it to heal from the inside out. Most of the time, fistula surgery can be performed on an outpatient basis. Treatment of a deep or extensive fistula may require a short hospital stay.