An anal fistula is a connection (opening) between the skin around the anus and the rectum. Anal fistula usually occurs as a result of an infection or an abscess (collection of pus) in the anus. It can also be caused by conditions that affect the bowel such as inflammatory bowel disease or Crohn's disease.
There are different types of fistula. Some have a single connection running from the rectum to the skin. Others branch into more than one opening. Sometimes they cross the muscles that control the opening and closing of the anus (sphincter muscles).
Symptoms and signs of an anal fistula include:
Anal fistula is usually diagnosed by physical examination of the anus and rectum. Your surgeon may also ask you to have a magnetic resonance imaging (MRI) scan. The scan can help find out how the fistula is linked to the sphincter muscles.
Surgery is usually the only option. The type of surgery you have will be tailored to your individual needs.