Intracranial meningioma resection using frameless stereotaxy.

Thirty-four consecutive patients with intracranial meningiomas underwent 35 resections aided by an interactive surgical navigation system (ISN; "frameless stereotaxy"). System capabilities include real-time display of wand location, orientation, and relationship to nearby structures using multiplanar and three-dimensional presentation of magnetic resonance imaging (MRI) and/or computed tomography (CT) data obtained perioperatively. There were 16 patients with convexity tumors, five patients with sphenoid wing tumors, five patients with falx or parasagittal tumors, and eight patients with skull base tumors (two each: petroclival, cavernous sinus, olfactory groove, and planum sphenoidale). the ISN system was used to locate a minimal craniotomy (i.e., trephine) in 11 (32%) patients, to optimize bone flap design in 13 (38%) patients, to identify the location of parasagittal draining veins in five (15%) patients, and to locate the carotid or basilar arteries in 11 (32%) patients. The techniques provided limited benefit in cranial nerve preservation. No patient had permanent central neurologic morbidity. Where intended preoperatively, tumor resection was complete (i.e., > 98%) in all patients as determined via postoperative MRI. Interactive surgical navigation is a useful adjunct in the operative management of some patients with intracranial meningiomas.