High complex anal fistula managed by the modified transanal opening of the intersphincteric space via the inter-sphincteric approach: A case report

High complex anal fistulas are epithelialized tunnels, with the main fistula piercing above the deep external sphincter and the internal opening approaching the dentate line. Conventional surgical procedures for high complex anal fistulas remove most of the external sphincter and damage the anorectal ring. Postoperative loss of anal function can cause physical and mental damage. Transanal opening of the intersphincteric space (TROPIS) is an effective procedure that completely preserves the external anal sphincter. However, its clinical application is limited by challenges in the localization of the internal opening of a fistula and the high risk of complications. On the basis of our clinical experience, we modified the TROPIS procedure for the treatment of treating high complex anal fistulas.