An anal fistula is a trivial channel that can develop among the end of the bowel and the skin adjacent the anus.
An anal fistula can cause draining and discharge when passing stools - and can be sore.
An anal fistula can occur afterward surgery to drain an anal abscess.
In some cases, an anal fistula reasons persistent drainage. In other cases, where the outside of the network opening closes, the consequence may be recurrent anal abscesses. The only treatment for an anal fistula is surgery.