Long head of biceps femoris flap in anal fistula treatment: anatomical study and case report.

In case of complex anal fistulae, the treatment can include muscular flaps. The gracilis transposition flap is the gold-standard in perineal reconstructive surgery, with wide use during the past decades. However, in some cases, this flap is too short to reach difficult locations such as the posterior perineum. The long head of the biceps femoris, which has already been studied in the electrically stimulated neosphincter formation, could be more appropriate in such clinical situations. Furthermore, its potential advantages, amongst which an excellent functional outcome, would be to allow persistent prone position, during both treatment and reconstruction, as well as a more favorable intramuscular vascularisation. We report the case of a 39-year-old man with a complex recurrent transphincteric posterior anal fistula with an external orifice in the right buttock and complicated with a severe cellulitis, treated with an endo-anal flap combined with a long head of biceps femoris pediculised flap.