Basal Meningiomas. A Retrospective Study of 196 Surgical Cases

Background: Basal meningiomas represent a significant group of extrinsic brain tumors. Their surgical treatment presents some difficulties since these tumors usually involve critical neurovascular structures. Methods: This is a retrospective study of 196 consecutive cases of basal meningioma treated in our hospital during the 5 last years. CT, MRI, and cerebral angiography were used to diagnose the tumors. Pre- and postoperative clinical condition was estimated by Karnofsky scale. The influence of tumor size, location, visual deficit, surgical approach, and radicality of surgical resection were analyzed. Result: Meningiomas were located in the following areas: olfactory groove, 32 cases; suprasellar region, 51; sphenoid wing, 50; cerebellopontine angle, 10; clivus, 31; tentorium, 22. In most cases the meningioma was larger than 4 cm. Tumors were completely removed in 142 (72.4%) cases. The surgery was followed by excellent or good results in 150 (76.5%) cases, patients having a normal life with a score of 70 to 90 on the Karnofsky scale; poor outcome occurred in 25 (12.8%) cases; 21 (10.7%) patients died postoperatively. Discussion: Some authors dwell upon clinical and surgical aspects of a prevailing group (olfactory, suprasellar, sphenoidal, petroclival, and tentorial meningiomas); regarding operative procedures, we particularly emphasize the usefulness of the pterional approach for removal of olfactory groove meningiomas and of combined supra- and infratentorial approach, with preservation of transverse and sigmoid sinuses, to remove petroclival meningiomas. According to our experience and analysis, we conclude that advances in microsurgical techniques and neuroradiological imaging have radically improved outcome. Conclusion: Basal meningiomas can be treated successfully in most cases. The outcome depends significantly on complications, involved critical neurovascular structures, and the patient's condition before surgery. The complications depend significantly on the duration of operation, extent of operation, and the invasiveness of the meningiomas' critical neuroanatomic structure.