Complications are when problems occur during or after the operation. Specific complications of anal fistula operation are uncommon, but can include: infection - this can result in an anal abscess and further surgery may be needed; damage to the sphincter muscles - this may affect your bowel control and can lead to faecal incontinence; narrowing of the anal canal (the short, muscular tube that connects the rectum with the anus); or reoccurrence - there is a chance that the fistula may come back.
Attribution: BUPA