Treating an anal fistula

Many anal fistulas will require some kind of surgery as very few heal on their own. There are a few different types of surgery which can be used. The type of surgery you may have will depend on where your fistula is and whether it is a simple or complex fistula.

You can learn more about what fistulas are in this article.

Surgery to treat an anal fistula

In general surgery to treat anal fistulas is done under general anaesthetic (where you are unconscious), however some procedures are done under local anaesthetic where you are still awake but the area being treated is numbed.

Some of the types of surgery include:


It is thought fistulotomy surgery is used to treat 85-95% of cases of anal fistulas. To do this the whole length of the fistula is cut open. It is then cleaned and flattened. In the months following the surgery it will heal into a flat scar.

If your fistula is near the anal sphincter muscle then the surgeon may need to cut into the muscle to access the fistula. This can carry some risk of causing bowel incontinence, but your surgeon will try to minimise this.

It is unlikely you will need to stay in hospital following the procedure.

Seton techniques

It may be decided that you need a seton inserted to help drain the fistula properly. A seton is a piece of surgical threat left in the fistula. Pus and infected tissue from the fistula can then flow down the seton. A seton may be left in place for several months and, if your fistula is complex, you may need to have several operations using setons before your fistula heals.

It is usually inserted under general anaesthetic and afterwards the wound will be covered by a dressing to absorb the fluid draining out of the fistula. This will need to be regularly changed and the area kept clean. You will be shown how to do this.

Advancement flap procedures

This procedure may be used if the fistula is complex. During an advancement flap procedure a piece of tissue is removed from the rectum or skin taken from the anus. After carrying out a fistulotomy this piece of tissue or skin (the advancement flap) is attached to where the internal opening of the fistula was.

Bioprosthetic plug

This is a cone-shaped plug that can be used to block the opening of the fistula inside your body (the internal plug). The external opening of the fistula is left unblocked so that it can continue to drain. Over time new tissue grows around the plug to heal the fistula. Complications such as pain and an abscess forming or the plug being pushed out of place have been associated with this procedure.


In a fistulectomy the fistula is completely cut out. It is most commonly performed on anal fistulas. It is often considered to be more effective than a fistulotomy, however recovery times and potential for complications are higher.

Other treatments (non-surgical)

Fibrin glue

In this procedure fibrin glue is injected into the fistula and it is then stitched closed. It is a simple, safe and painless procedure, however the long-term results for fibrin glue are low.

Medical treatments

Medical treatment via drugs such as antibiotics, immunosuppressive drug such as Azathioprine or Mercaptopurine to try to close the fistula may be used before turning to surgical options. If these don’t work then you may be prescribed a biologic (or anti-TNF) drug such as Infliximab or Adalimumab.

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