An anal fistula is a small tunnel that develops between the end of the bowel and the skin near the anus.

They’re usually the result of an infection near the anus causing a collection of pus (abscess) in the nearby tissue. When the pus drains away, it can leave a small channel behind.

Anal fistulascan cause unpleasant symptoms, such as discomfort and skin irritation, and won’t usually get better on their own. Surgery is recommended in most cases.

  • Treatment

    Surgery is usually necessary to treat an anal fistula as very few heal by themselves.

    The best option for you will depend on the position of your fistula and whether it’s a single channel or branches off in different directions.

    Sometimes you may need to have an initial examination of the area under general anaesthetic (where you’re asleep) to help determine the best treatment.

    Your surgeon will talk to you about the options available and which one they feel is the most suitable for you.

    Surgery for an anal fistula is usually carried out under general anaesthetic. In many cases, it’s not necessary to stay in hospital overnight afterwards.

    The aim of surgery is to heal the fistula while avoiding damage to the sphincter muscles, the ring of muscles that open and close the anus, which could potentially result in loss of bowel control bowel incontinence).

  • Fistulotomy

    The most common type of surgery for anal fistulas is a fistulotomy. This involves cutting along the whole length of the fistula to open it up so it heals as a flat scar.
    A fistulotomy is the most effective treatment for many anal fistulas, although it’s usually only suitable for fistulas that don’t pass through much of the sphincter muscles, as the risk of incontinence is lowest in these cases.
    If your surgeon has to cut a small portion of anal sphincter muscle during the procedure, they will make every attempt to reduce the risk of incontinence.
    In cases where the risk of incontinence is considered too high, one of the procedures below may be recommended instead.

  • Risks

    Like any type of treatment, treatment for anal fistulas carries a number of risks.

    The main risks are:

    • infection – this may require a course of antibiotics; severe cases may need to be treated in hospital
    • recurrence of the fistula – the fistula can sometimes recur despite surgery
    • bowel incontinence – this is a potential risk with most types of anal fistula treatment, although severe incontinence is rare and every effort will be made to prevent it

    The level of risk will depend on things like where your fistula is located and the specific procedure you have. Speak to your surgeon about the potential risks of the procedure they recommend.