What is an anal fistula?
An anal fistula is an abnormal tunnel connecting the inside of the anal canal to the skin around the anus. It often follows an anal abscess. Fistulas do not usually heal on their own and generally need surgery.
Symptoms & when to see a doctor
Common symptoms include discharge, recurrent swelling or pain near the anus, and irritation of the surrounding skin. Assessment includes a clinical examination and, in some cases, an MRI to map the tunnel before treatment.
Treatment options
The right operation depends on how the fistula relates to the anal muscles, with the aim of curing the fistula while protecting continence.
- Fistulotomy: opening a simple, low fistula to heal
- Seton: a thread placed to drain and gradually treat the tract
- Sphincter-preserving techniques such as LIFT
- Laser treatment of the fistula tract in selected cases
Recovery
Recovery depends on the type of fistula and operation; wound care and follow-up are an important part of healing.
Where suitable, this may be carried out using minimally invasive techniques. See Minimally Invasive Surgery.
Frequently asked questions
Can an anal fistula heal without surgery?
Fistulas rarely heal on their own and usually need surgery. The aim is to cure the fistula while protecting the muscles that control continence.
Will fistula surgery affect continence?
Protecting continence is a key priority. The choice of operation depends on how the fistula relates to the anal muscles, and sphincter-preserving techniques are used where appropriate.
Is an MRI needed for a fistula?
In some cases, yes. An MRI can map the fistula tract and help plan the safest treatment, especially for complex fistulas.