An anal fistula is an abnormal tunnel-like passageway which forms between the lining of the anal canal and the skin around the anus.

Anal fistulas usually occur when an anal abscess doesn’t heal properly after the fluid from the abscess drains, leaving a small channel behind.

Fistulas can also be caused by Crohn’s Disease, diverticulitis, tuberculosis (TB) or because of a complication during surgery near the anus.

The main treatment options for an anal fistula include a fistulotomy, which involves cutting down the length of the fistula so that it heals into a flat scar.

Fistulotomy

A fistulotomy is usually only suitable for fistulas that don’t pass through too much of the anal sphincter muscle, to reduce the risk of incontinence.

Your Consultant will assess whether they need to cut into the muscle and how high the risk of incontinence is. If the risk is considered too high, they may recommend another procedure, such as seton techniques.

Seton techniques

Seton techniques involve placing a piece of surgical thread (a seton) in the fistula and leaving it there for several weeks to keep it open. This allows the fistula to drain and heal without the need to cut into the sphincter muscle. A loose seton won’t cure the fistula and your Surgeon may need a tighter seton to cut through the fistula slowly and cure it.

Your Consultant will discuss the options available, and which one would be most suitable for you.

Your Consultant will explain how you should prepare for anal fistula surgery. This includes asking you to stop smoking.

If you’re having a general anaesthetic, you’ll need to stop eating and drinking for a few hours before your operation.

On the day of your operation, your Consultant will meet with you before they carry out the procedure. You may need to wear compression stockings to help prevent deep vein thrombosis (DVT).

Once you’re asleep, your Consultant will insert a thin metal probe into the opening of the fistula. If you require a fistulotomy, they’ll cut through the skin and tissue to open the top of the fistula. The wound will be left open to heal (i.e. no stitches will be used but a dressing will be applied).

During surgery, your Consultant may decide that a more complex procedure, e.g. seton technique is required. In this case you’ll have both a wound and a seton after surgery.

After your procedure, it's important to rest until the effects of the general anaesthetic have worn off. If you experience any pain, the nursing staff will provide appropriate pain relief.

Once the anaesthetic has worn off, the nursing staff will help you to get up and move around. We'll offer you refreshments as soon as you feel ready to eat and drink again.

Most patients can go home the same day. We recommend having someone stay with you overnight until the effects of the anaesthetic fully wear off. Before you leave, we'll give you detailed advice on wound care, pain relief, and laxatives, as you may experience constipation.

When you get home, you should bathe or shower regularly to keep the wound clean. Avoid using highly perfumed bath oils, bath salts or shower gels, as they can irritate the wound. You should also avoid any heavy lifting, exercise or running for the first week of your recovery and don’t go swimming until your wound has healed.

Your wound should heal within approximately six weeks, depending on its size. If you begin feeling sick, develop headaches, a fever or heart palpitations, you should contact us urgently using the number on your discharge letter.

To find out the cost of treatment for an anal fistula, please see the colorectal surgery section of our pricing page.