What is a fistula in ano?

A fistula is ano is a hollow track lined with granulation tissue connecting a primary opening inside the anal canal to a secondary opening in the perianal skin. Surgical removal of the abnormal track between the anus and skin is needed. Following the procedure the patient will experience pain and discomfort. This might continue for up to 4 weeks, but generally lasts 2 weeks.


This procedure will require an anaesthetic.

What are the risks of this specific procedure?

There are risks and complications with this procedure.  They include but are not limited to the following:

General risks:

  • Infection can occur, requiring antibiotics and further treatment.
  • Bleeding could occur and may require a return to the operating room.
  • Bleeding is more common if you have been taking blood thinning drugs such as Warfarin, Asprin, Clopidogrel (Plavix or Iscover) or Dipyridamole (Persantin or Asasantin).
  • Small areas of the lung can collapse, increasing the risk of chest infection.
  • This may need antibiotics and physiotherapy.
  • Increased risk in obese people of wound infection, chest infection, heart and lung complications, and thrombosis.
  • Heart attack or stroke could occur due to the strain on the heart.
  • Blood clot in the leg (DVT) causing pain and swelling. In rare cases, part of the clot may break off and go to the lungs.
  • Death as a result of this procedure is possible.

Specific risks:

  • There will be an open wound where the fistula was removed. This will take 2-3 weeks to heal.
  • If the fistula involves an excessive amount of muscle around the anus, the doctor may insert a small plastic marker to assist in drainage until further surgery is possible.
  • The condition may recur, and an abscess about the anal region may occur.
  • Scarring may develop about the anus, and it may be painful or thickened.
  • Rarely the muscles at the anus may be over stretched or over cut with a resultant weakness in the area. This could cause problems with control of the bowels (incontinence).  A pad may need to be worn and/or further surgery may be needed.
  • Increased risk in smokers of wound and chest infections, heart and lung complications and thrombosis.