Surgery for anal fistula is performed under a general anaesthetic. To lessen the risk of bowel incontinence (when you pass a motion without wanting to), your treatment may involve several operations over a number of months. The type of surgery you need will depend on where the fistula is.

If the fistula is below, or crosses, the lower part of the sphincter muscles, your surgeon will cut it open to the skin and leave the wound open, so that it can heal with healthy tissue.  This is referred to as laying open the fistula.

If the fistula has branches that pass through the upper part of the sphincter muscles, your surgeon may place a special stitch, called a Seton stitch, in the fistula to allow pus to drain easily. This may be followed by further operations in future, including insertion of a fistula plug.