Cranial base surgical techniques for large sphenocavernous meningiomas: technical note.

Abstract

Large meningiomas arising from the dura covering the sphenoid ridge present surgical challenges because of frequent involvement of the carotid artery and its branches, the optic nerve and tract, the superior orbital fissure, and cavernous sinus structures. To circumvent the inherent difficulties of a traditional approach strategy, cranial base approaches were applied to: 1) isolate and interrupt the major blood supply as an initial step, 2) minimize brain retraction, and 3) isolate the neurovascular structures exiting the tumor at the cranial base to protect and better separate them. Six patients were treated with such a strategy in the past 2 years (five women and one man, ages 34-69 yr). All tumors measured at least 5 cm in their greatest diameter and arose at the sphenoid ridge. All tumors extended posteriorly to involve the cavernous sinus to varying degrees. In two patients a frontotemporal bone flap was used; in two patients, a transzygomatic approach was used; and in the remaining two patients, an orbitozygomatic strategy was used. Extensive bone removal at the cranial base was performed in all cases. Four patients had gross total resections, and two were subtotal owing to invasion of the cavernous sinus or the middle cerebral artery. There were no permanent cranial nerve deficits; however, two patients sustained transient IIIrd nerve paresis. Two patients postoperatively developed transient cerebral edema that required intensive treatment. All six patients had good outcomes, resuming independent activity by 3 months after surgery. Contemporary cranial base surgical techniques have a role in the treatment of large sphenoid ridge meningiomas. These strategies result in safe resection with low morbidity and obviate the need in most cases for preoperative embolization. The anatomic foundation for using these approaches is discussed.