Basal meningiomas. A retrospective study of 139 surgical cases.

BACKGROUND: Basal meningiomas represent a significant group of intracranial tumours. Their surgical treatment presents still today several difficulties since these tumours, as it is well known, may involve critical neurovascular structures. METHODS: This is a retrospective study of 139 consecutive cases of basal meningioma operated on in our institution during the last two decades. Meningiomas location: olfactory groove 20 cases; suprasellar region 22; anterior cranial fossa 6; sphenoid wing 37; cerebellopontine angle/clivus 21; tentorium 26. In most cases the meningioma was larger than 5 cm. The tumour was completely removed (grade I-II of Simpson classification) in 111 cases (79.9%). The authors dwell upon some clinical and surgical aspects of prevailing groups (olfactory, suprasellar, sphenoidal, petroclival and tentorial meningiomas); regarding to operative procedures, the authors in particular emphasise the usefulness of the pterional approach to remove olfactory groove meningiomas and of the combined supra- and infratentorial approach, with preservation of transverse and sigmoid sinuses, to remove petroclival meningiomas. RESULTS: The surgery was followed by excellent or good results in 115 cases (82.7%): patients having a normal life with a score 80-100 of Karnofsky scale; poor outcome occurred in 5.8% of cases, postoperatively died 16 patients (mortality rate 11.5%). Tumour recurrence occurred in 7 cases. CONCLUSIONS: Based on their experience and on analysis of the reviewed literature, the authors conclude that advances in microsurgical techniques and in neuroradiological imaging have radically improved the outcome so that today basal meningiomas can be successfully treated in most cases.