Tentorial dural flap for transtentorial surgery.

For a subtemporal transtentorial approach to the anterior part of the posterior fossa a tentorial dural flap is described. An incision is begun at the free edge of the tentorium at the level of the posterior edge of the cerebral peduncle and is then directed anterolaterally towards the superior petrosal sinus. A triangular flap of the tentorial dura is everted over the superior petrosal sinus. The flap has the advantage of being simple and safe, and provides a wide window to the infratentorial structures. In addition the occasional troublesome bleeding from the superior petrosal sinus and the petrosal vein is avoided. The fourth and fifth cranial nerves are protected and exposed widely.