Analysis of Venous Drainage from Sylvian Veins in Clinoidal Meningioma(<SPECIAL ISSUES>Veins of the Skull Base (1): Cavernous Sinus)

Abstract

Skull base meningiomas can occasionally obstruct the basal venous sinuses as the tumor growth. We therefore analyzed the venous draining pattern from sylvian veins in clinoidal meningiomas. Between 1995 and 2007, twenty patients with clinoidal meningioma underwent surgical intervention at our institute. Venous drainage from sylvian veins was categorized into three patterns, including cortical type, sphenobasal type and sphenoparietal type, according to the main draining vein. Preoperative angiographic evaluation showed 14 patients (70%) as cortical type, 5 patients (25%) as sphenobasal type and 1 patient (5%) as sphenoparietal type. Postoperative clinical courses revealed that dominant sphenobasal sinuses were successfully preserved by skull base techniques in all of the sphenobasal type patients. One sphenoparietal type patient developed a brain contusion conceivably, by the obstruction of the dominant sphenoparietal sinus during tumor resection. Drainers from sylvian veins to the skull base should be carefully evaluated preoperatively and must be preserved, if dominant, in the surgery of clinoidal meningioma.