Rectal advancement flap
An anal fistula is a tract that connects the inside of the anal canal to the skin adjacent to the anus. Fistulas can cause discharge, pain, itching and lead to recurrent abscess formation; they therefore need treatment.
Simply opening the tract and allowing the area to heal up can treat most fistulas. However, when fistulas run in a course that involves a significant portion of the anal sphincter muscle this is not possible due to the risk of incontinence; in this case a more complex approach is necessary. One option is to perform an advancement flap procedure, whereby part of the rectal wall above the fistula is mobilized and sutured over the hole. The external opening is often excised and the tract left to heal over a few weeks.
Your surgeon will discuss with you what the operation involves, as well as the procedure-specific risks.