Anal Fistula (Fistula in Ano)

What is an anal fistula?

An anal fistula is a track between the skin on the outside of the buttock/anal area and the anal canal on the inside.

What causes an anal fistula?

An anal fistula is almost always the result of a previous anal abscess (an infected cavity filled with pus). Just inside the anus are small anal glands. When these glands get clogged, they may become infected and an anal abscess can develop. After an abscess discharges or has been surgically drained, a track may persist connecting the anal gland from which the abscess arose to the skin. If this occurs, persistent drainage from the outside opening may indicate the persistence of this track. If the outside opening of the track heals, recurrent abscess may develop.

What are the symptoms of an anal fistula?

Symptoms related to the fistula include irritation of skin around the anus, drainage of pus (which often relieves the pain) sometimes associated with recurrent intermittent anal margin swelling.

How is a fistula treated?

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 an accredited specialist colorectal surgeon. It may be performed at the same time as the abscess surgery, although fistulas sometimes develop many months after an initial abscess is drained.

Fistula surgery usually involves opening up the fistula track. This may 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 track and converting it to a groove will then allow it to heal from the inside out. To avoid causing faecal incontinence a stitch (called a Seton) may be inserted to avoid dividing the anal muscle. Mr Tsavellas will explain this to you in more detail during your consultation. Most of the time, fistula surgery can be performed on a day case basis. Treatment of a deep or extensive fistula may require a slightly longer hospital stay.

How long does it take before patients feel better?

Discomfort after fistula surgery can be mild to moderate for the first week and can be controlled with simple painkillers. The amount of time lost from work is usually minimal. Treatment of an abscess or fistula is followed by a period of time at home, when soaking the affected area in warm water (sitz bath) is recommended three or four times a day. Stool softeners or a bulk fibre laxative may also be recommended. It may be necessary to wear a protective pad to prevent the drainage from soiling underclothes. Bowel movements will not affect healing.