An anal fistula typically is the result of a previous abscess. It is a tunnel connecting the anal gland, from which the abscess arose, to the skin where the abscess was drained.
After an abscess has been drained, a passage may remain between the anal gland and the skin, resulting in a fistula. If the gland does not heal, there will be persistent drainage through this passage. Overall this happens in a third of patients with an anal abscess.
Fistulas are associated with drainage of liquid (blood, pus, or mucus) around the affected area. Generally, fistulas are not painful unless pus builds up inside the tract. If the outside opening of the fistula heals first, a recurrent abscess may develop.
Diagnosis & Treatment
Surgery is generally necessary to treat an anal fistula. Usually the procedure involves cutting a small portion of the anal sphincter muscle to open the passage, joining the external and internal opening, and converting the passage into a groove that will then heal from the inside out. Sometimes a more complicated procedure is necessary if too much sphincter muscle is involved.
Most fistula surgery can be performed on an outpatient basis in our Surgery Center. If the fistula involves too much sphincter muscle, a two-stage procedure or more complicated repair may be necessary. This includes an endorectal advancement flap, the LIFT procedure (ligation of intersphincteric fistula tract), or a fistula plug.