Anal Fistula


An anal fistula is a tunnel joining the skin near the anus to the inside of the bowel (either the anal canal or rectum). This means that the inside of the bowel is connected to the outside of the body through an additional opening. A fistula is usually the result of an infection or abscess in the anus. There are many different kinds of fistula. Some have a single tract (tunnel) running from the bowel to the skin. Others branch into more than one tract. Sometimes they cross the muscles that control the opening and closing of the anus (sphincters).

Anal fistulas are painful and the skin around the anus can swell. They may discharge mucus, pus or blood. The skin may also become itchy and irritated, and the fistula opening may be infected. Surgical treatment is usually needed to treat them and the aim is to “lay open” the tissue over the fistula and take away the infected and inflamed tissue. It is usually done under general anaesthesia as a day case. The exact operation will depend on the type of fistula you have and the surgeon’s findings under anaesthesia.

You will usually have a pre-op assessment in the week before surgery where blood tests, chest X-ray and an ECG (heart recording) may be taken. You will be admitted a few hours before the approximate planned time of surgery having had nothing to eat for six hours before the start time (you may drink water up to two hours before your proposed time of surgery - with any of your regular medications). You will see your surgeon and the anaesthetist before your operation. After your surgery you will wake up in the recovery room, and then be transferred back to the ward. Later the same day you may have something to eat and drink if you wish. Most people are discharged home later the same day.

You will be provided with painkillers before discharge but it is recommended that you take regular paracetamol and ibuprofen (unless you are sensitive to these) after a few days of these. Stronger painkillers such as cocodamol may be necessary but if so it is important to take a laxative such as lactulose at the same time.

If the fistula has simply been laid open then it will heal from within. The time taken depends on the depth of the incision – which relates to the depth of the fistula. You will need regular dressings until it has healed these will be arranged between the hospital and your GP’s surgery prior to discharge.

If a seton has been inserted, then the wound will settle but not completely heal. It will continue to discharge fluid, sometimes blood-stained, as long as it is present. The aim is for the seton to drain away any infection and sometmes slowly work it’s way through the tissues until it is low enough to be laid open at a future time. The surgeon will make recommendations about timing according to the specific circumstances.

You may drive a car when you are able to perform an emergency stop.

You will be seen for follow-up six weeks following your surgery.

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