SURGICAL-TREATMENT OF ANTERIOR BASAL MENINGIOMAS

Meningiomas of the anterior skull base account for 40% of all intracra nial meningiomas. Of these, almost half are sphenoid wing meningiomas; the other half are tuberculum sella tumors or olfactory groove tumors . Anterior clinoidal (medial sphenoid wing) meningiomas are a subcateg ory of the sphenoid wing meningiomas; they fall into one of three cate gories according to the presence of an interfacing arachnoidal membran e between the tumor and the cerebral vessels. Meningiomas of the tuber culum sella arise from the tuberculum sella, chiasmatic sulcus, limbus sphenoidale, and the diaphragma sella; they may extend into both opti c canals. Olfactory groove meningiomas arise more anteriorly than do t he tuberculum sella meningiomas and may be symmetrical around the midl ine or extend to one side or the other; at least 15% grow into the eth moid sinuses. This paper addresses the clinical presentation, preopera tive evaluation, and surgical procedures used for treating tumors of t he tuberculum sella, the olfactory groove, and the anterior clinoid.