Anal fistula treatment

An anal fistula does not heal by itself and can only be treated with surgery.

We give you a medicine called a general anaesthetic. This means that you are asleep and do not feel anything during the procedure.

Most people do not need to stay in hospital overnight, unless the surgery is more complex.

Before surgery

You go to a pre-assessment clinic before surgery. At this clinic, we can:

  • check your health
  • ask you questions about your medical history (your past and present conditions and treatment)
  • ask you about your medicines
  • talk to you about the surgery in more detail

Having surgery

During surgery, we cut the infected tunnel to stop unhealed pockets of infection from being trapped inside. If we find an abscess, we cut open and drain this first.

Before surgery, it is not always possible to tell if the fistula runs through your anal sphincter muscles. These muscles open and close the anus. If they are damaged, this can cause problems controlling when you poo (bowel incontinence).

To prevent any damage, the surgeon puts a stitch in your fistula rather than cutting the anal sphincter muscles. This is called a ‘seton’.

A seton is a thread that the surgeon puts through the fistula tunnel, out of the bottom and then ties in a knot outside. This allows the infection to drain and heal, without damaging your anal sphincter muscles. The stitch remains in place for several months to allow drainage and heeling of the tunnel.

Your surgeon might cut the part of your fistula that does not involve the anal sphincter muscles. Then, they might put in a seton for the section that lies within the anal sphincter muscles. This means that you might have a wound and a seton after surgery.

After surgery

If your surgeon puts in a seton, it should not be painful and you can bathe and go to the toilet as normal. It does not interfere with sex or pregnancy. 

Resource number: 0908/VER7
Last reviewed: June 2023
Next review: June 2026

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