Surgical Strategies for Aggressive Skull Base Meningiomas

Objective: Skull base meningiomas occasionally show aggressive growth particularly when they recur. Recurrent cranial base meningiomas extending widely into skull base and craniofacial structures are one of the most challenging tumors to treat surgically. We reviewed our experience of treatment in a series of patients with those aggressive meningiomas to analyze factors potentially affecting the long-term clinical outcome.

Patients and Methods: Clinical records of a total of 152 patients with cranial base meningiomas, who had been followed for more than 5 years, were retrospectively reviewed. The mean follow-up time period was 90.4 ± 21.2 months (range, 61–124). Of 152 patients, 13 patients experienced recurrence after variety periods of time following initial surgery. Based on the location of recurrence, the 13 patients were divided into the lateral (n = 6) and the central (n = 7) skull base groups.

Results: Since the lateral skull base type occasionally extended widely into craniofacial structures such as paranasal sinuses, nasal cavity, orbit, and infratemporal and pterygopalatinere fossae, two or more approaches including transnasal endoscopic surgery were combined. Since the central skull base type often involved critical structures such as the brainstem, radical resection was not feasible.

Among several variables analyzed using a multivariate logistic regression model, an increased proliferative potential (odd ratio 3.7, 95% CI 1.9 – 8.5, p = 0.0018) as indicated by biological parameters such as high MIB-1 index was an independent variable predicting the deterioration of the long-term functional outcomes. Recurrence at the central skull base (Odd ratio 2.5, 95% CI 1.2 – 12.5, p = 0.037) was also a strong predictor of poor long-term outcome.

Conclusions: Highly proliferative potentials induced repeated recurrences, eventually leading to worsening of functional outcomes of patients with central skull base meningiomas. In the lateral skull base type, on the other hand, a relatively good performance status was maintained for several years even after repeated surgeries. Therefore, radical resection of the tumors should be planned for this type. Endoscopic endonasal approach was efficacious particularly in skull base meningiomas with large craniofacial extension since it can provide a wide surgical view to the midline skull base in a less invasive way. This approach can obviate the need for traditional transfacial approach with facial skin incisions.