Introduction: Gamma Knife radiosurgery (GK) is often used for skull base meningiomas due to open surgical risks to cranial nerve (CN) function. In this study, we aimed to evaluate specific CN outcomes following GK and identify predictors of these outcomes.
Methods: We performed a single institution retrospective analysis of GK patients treated from 2015-2023 with at least one CN deficit pre-GK and a minimum follow-up of 6 months. Predictors of CN function changes were assessed using univariate and multivariate regression analysis.
Results: In our cohort of 43 patients (mean age: 62.1 years), most patients had tumors in cavernous sinus (41.9%) and petrous region/cerebellopontine angle (CPA) (27.9%). The mean tumor diameter was 20.8 mm. The most common deficits at presentation were of CN 5 (32.6%), CN 6 (23.3%), CN 2 (18.6%), CN 3 (16.3%), and CN 8 (11.6%). The median total dose was 1500.0 cGy (range: 1500.0-3000.0) and follow-up period was 31.0 months (range: 6-90). At last follow-up, 44.8% had unchanged symptoms, 18.6% experienced improvement, and 25.6% experienced worsening. For patients with CN 5 deficits, 28.6% improved, 71.4% were unchanged, while 28.6% worsened. Among patients with CN 6 deficits, 20.0% improved and 80.0% were unchanged. In patients with CN 2 deficits, 25.0% improved, 25.0% were unchanged, and 50.0% worsened. In patients with cavernous sinus meningiomas, symptoms improved in 22.2%, remained unchanged in 72.2%, and worsened in 5.6%. Among patients with petrous/CPA meningiomas, 8.3% improved, 58.3% were unchanged, and 33.3% worsened. Age, gender, tumor diameter, and type of immobilization (frame vs. mask) did not correlate significantly with symptom worsening in regression analyses.
Conclusion : The majority of patients with CN deficits from skull base meningiomas experienced stable or improved symptoms following GK radiosurgery, with the greatest improvements observed in CN 5 deficits. These findings suggest that GK is a viable option for managing CN symptoms in this patient population.
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