Sewing an anal fistula plug or patch of biologic tissue into the fistula to allow your tissue to grow into the patch and heal the fistula.Using a tissue graft taken from a nearby part of your body or folding a flap of healthy tissue over the fistula opening.Repairing the anal sphincter muscles if they've been damaged by the fistula or by scarring or tissue damage from radiation or Crohn's disease.