Patient Information
Anal Fistula
What is an anal fistula?
An anal fistula is an abnormal communication (“tunnel”) between the internal lining of the anus and the skin outside the anus. A fistula may develop after drainage of an anal abscess but may occur spontaneously. Discharge of pus may be constant or intermittent as the external opening on the skin may heal temporarily.
Causes
Most fistulae are the result of infections in an anal gland. However, patients suffering from inflammatory bowel disease (Ulcerative Colitis and Crohn’s disease) are more likely to develop anal abscesses and fistulae.
Symptoms
Drainage of pus, swelling, itching, minor bleeding.
Surgical Treatment
Surgery is needed to cure a fistula. The course of the tract between the anus and the outside skin has to be identified and exposed. This tract may be treated in one of several ways according to its complexity, and how much sphincter muscle is involved within the fistula tract.
- Fistulotomy opens the length of the tract to the skin’s surface allowing the open wound to heal slowly. Some sphincter muscle is divided. This is the most common treatment employed.
- A Seton is a loop of flexible material placed along the tract to maintain drainage for a period of time.
- Fistula repair closes the internal opening of the tract and preserves anal sphincter muscle. This is a more complex operation.
Examination under anaesthesia may be necessary to assess the process of healing.
Anal fistula can be a difficult and frustrating condition for a patient, as healing rates are variable, and there is often the need for several surgeries in the situation of a complex anal fistula. Please discuss any concerns around this with your surgeon, in particular if the condition is affecting your mood and your ability to carry out your normal daily activities.
Anal Sphincter Control After Surgery
A Fistulotomy divides a varying depth of anal sphincter muscle and this may result in some weakness of the muscle. The effect on continence will depend on the anatomy of the fistula and the amount of intact sphincter remaining after surgical treatment.
