A Voxel-based Risk Stratification for Cranial Nerve Function Deterioration in Skull Base Meningioma

Introduction: Deterioration of cranial nerve function (CNF) after surgical resection is a major concern in any skull base meningioma. Functional outcome depends on several predictors such as tumor size and location. However, the exact anatomic origin of the meningioma can be obscured in large tumors crossing compartments. The present study sought to apply unbiased lesion symptom mapping to evaluate the predictors of CNFD in skull base meningioma.

Methods: Clinical details (e.g. histologic subtypes, WHO grading) and magnetic resonance images features (e.g. tumor size and location) were obtained in 225 treatment-naïve meningioma patients. Stepwise linear regression analysis was performed to determine significant predictors of CNFD. Additionally, we performed a multivariate voxel-based symptom lesion mapping (VLSM) to evaluate the exact spatial profile of meningioma dural attachment zone (DAZ) associated with CNFD.

Results: 47/225 (21%) of patients demonstrated a transient and 29/225 (13%) a permanent CFND after surgery. In 23/47 (49%) more than one CN was affected. CNVIII function was most likely to deteriorate (n=16, 6.7%). VLSM determined a high risk of CNFD at the petroclival junction (PCJ) and the anterior tentorial notch. This cluster was overlapping with a significant higher likelihood for subtotal resection (PCJ and cavernous sinus). Multivariate analysis failed to detect other significant predictors of CNFD (e.g. tumor size, subtype or WHO grading). Gross-total-resection was achieved in 158/225 (70%). The mean follow-up was 40±38 months. The recurrence rate was 31/194 (14%) with a mean-time-to-recurrence of 42±25 months. Notably, there was no spatial cluster for higher recurrence risk in the VLSM.

Conclusion : Meningioma DAZ at the PCJ and anterior temporal notch is the most important predictor for CNFD independent of tumor size and histologic subtype of the meningioma. While extent-of-resection is often limited in these areas, there was no increase of recurrence risk. VLSM might help to provide a better preoperative risk stratification in skull base meningioma surgery.