Have you ever had a temporary ostomy during your healing process? maybe this is something your surgeon should consider. Obviously, what has been done...hasn't worked. Are you constipated alot? This is NOT good for fistulas. A serious diet change is in order and daily stool softeners!
I would ask your surgeon if an ostomy would be beneficial for the complete healing or your anal canal to be successful, unless this has been done already.
Good luck to you Tom...I know this cannot be fun :(
Hopefully this link will help.
http://www.mayoclinic.org/anal-fistula/treatment.html