The subtemporal interdural approach to dumbbell-shaped trigeminal schwannomas: cadaveric prosection.
OBJECTIVE
Successful resection of dumbbell-shaped trigeminal schwannomas via a subtemporal interdural approach requires an understanding of both the anatomy related to the bone dissection of the petrous apex (Kawase's triangle or quadrilateral) and meningeal anatomy. We studied the meningeal anatomy related to this approach and describe the dural incisions and stepwise mobilization.


METHODS
Meningeal anatomy around Meckel's cave and porus trigeminus was examined during the subtemporal interdural anterior transpetrosal approach in both sides of 15 cadaveric heads. Histological study of the Meckel's cave region was performed in two cadaveric heads.


RESULTS
The Gasserian ganglion and trigeminal roots have two layers of dura propria on their dorsolateral surface: an inner layer from the posterior fossa dura propria that constitutes the dorsolateral wall of Meckel's cave and an outer layer from the dura propria of the middle fossa. The cleavage plane between these two layers continues distally as the cleavage plane between the epineural sheaths of the trigeminal divisions and the dura propria of the middle fossa. This cleavage plane serves as the anatomic landmark for the interdural exposure of the contents of Meckel's cave. The superior petrosal sinus is sectioned at the medial aspect of Kawase's triangle and reflected along with the porus trigeminus roof.


CONCLUSIONS
Understanding the critical meningeal architecture in and around Meckel's cave allows experienced cranial neurosurgeons to develop a subtemporal interdural approach to dumbbell-shaped trigeminal schwannomas that effectively converts a multiple-compartment tumor into a single-compartment tumor. Dural incisions and stepwise mobilization complements our previous description of the bony dissection for this approach.
Youssef
Samy
S
Department of Neurosurgery, University of South Florida, Tampa, Florida, USA.
Kim
Eun-Young
EY
Aziz
Khaled M A
KM
Hemida
Salah
S
Keller
Jeffrey T
JT
van Loveren
Harry R
HR
D002102:Cadaver; D003390:Cranial Nerve Neoplasms / Q000473:pathology* / Q000601:surgery*; D004388:Dura Mater / Q000473:pathology* / Q000601:surgery*; D006801:Humans; D066298:In Vitro Techniques; D009442:Neurilemmoma / Q000473:pathology* / Q000601:surgery*; D019635:Neurosurgical Procedures / Q000379:methods; D013702:Temporal Lobe / Q000473:pathology / Q000601:surgery; D020433:Trigeminal Nerve Diseases / Q000473:pathology* / Q000601:surgery*