Frontotemporal/Subtemporal Interdural Approach to Middle Fossa-Posterior

Abstract

Trigeminal schwannomas arising from the gasserian ganglion many a time consist of two components: the body of the tumor in the interdural space of the Meckel's cave and a posterior extension through the porus trigeminus into the subarachnoid space of the posterior fossa. Recent innovations in skull base surgery have facilitated single-stage interdural removal of these dumbbell tumors. The procedure involves a safe peeling of the dura propria (meningeal layer of dura) of the middle fossa from the divisions of the trigeminal nerve with exposure of the lateral wall of the cavernous sinus, opening of the Meckel's cave, and opening of the porus trigeminus into the posterior fossa. From January 1984 to August 2007, out of the 52 patients with trigeminal schwannomas surgically managed, 19 were dumbbell-shaped with both middle and posterior fossa components. Sixteen of these were operated using the extra/interdural approach. Tumor could be radically removed in most of the patients and there was no operative mortality in this group. When the posterior fossa component was small, it could be easily removed through the expanded porus trigeminus without additional anterior petrosectomy. Operative videos of this novel approach will be shown.