Introduction: Meningiomas surgery involving the Tentorium is technically challenging. Varoius classifications were proposed in order to optimize handling strategy(1,2). Our institute policy is to operate all tumors of the posterior fossa as well as petroclival tumors under intraoperative monitoring protocol containing SEP’s. MEP’s, EMG of cranial nerves and BAEP’s (3)

Methods: We retrospectively reviewed 93 patients (68 with tentorial and 25 with petroclival meningiomas with tentorial involvement) treated surgically between 1996-2010. Data collected contained patient's characteristics (gender, age etc.), symptoms and signs at presentation, Histology, operative complications, GOS at follow up and Simpson’s resections-Grade.

Results: Female/Male ratio was 74/19, Age ranged from 26 to 87 years (Mean 58). Mean follow-up was 17,8 months (range 3-80). Seven patients presented with atypical meningioma (WHO Grade 2), while the rest had various hythological combinations of WHO Grade 1 meningiomas. Gross-Total resection (Simpson Grade 1/2) was achieved in 70 cases (76.1%), whereas partial resection (Simpson Grade 3/4) was achieved in 23 cases. One patient died due to generalized brain edema (1%). 13 patients (14%) needed a second procedure due to complication. Tumor recurrence occurred in 17 cases (14 where primarily graded as Simpson 4 and 3 as Simpson 1/2). On follow up 64, 23 and 5 patients have reached Glasgow Outcome Scale of 5, 4 and 3 respectively. When asked subjectively of their outcome, 82 patients (88%) where satisfied with the operative results.) while only 11 patients were not satisfied with the operative results.

Conclusions: Meningioma resection in the tentorial region is challenging, and can be very hazardous. Our operative strategy containing an obligatory intaoperative neurophysiological monitoring is in our opinion justified in order to reduce the risk of postoperative complications. This case series shows that Gross-Total resection is possible with good results. Caution should be taken not to force Gross-Total resection on costs of morbidity or mortality.

Patient Care: The routinely application of intraoperative neurophysiological monitoring as we suggest could improve operative outcome.

Learning Objectives: By the conclusion of this session, participants should be familiar with the complicated management of meningiomas of the posterior fossa and the implication of intraoperative neuorophysiological monitoring.

References: 1. Al-Mefty O: Meningiomas. Lippincott Williams and Wilkins, 1991 2. Guidetti B, Ciappetta P, Domenicucci M: Tentorial meningiomas: surgical experience with 61 cases and long-term results. J Neurosurg 69:183-7, 1988 3. Krammer MJ, Wolf S, Schul DB, Gerstner W, Lumenta CB. Significance of intraoperative motor function monitoring using transcranial electrical motor evoked potentials (MEP) in patients with spinal and cranial lesions near the motor pathways.