Anal fistula at roof of ischiorectal fossa inside levator-ani muscle (RIFIL): a new highly complex anal fistula diagnosed on MRI.

RIFIL are highly complex fistulas. Proper diagnosis by MRI, surgical access, and subsequent management of these fistulas is quite challenging and they are associated with poor prognosis. Missing their diagnosis would lead to higher recurrence rate. These have not been described previously and were perhaps confused with high transsphincteric infralevator fistulas in ischiorectal fossa.