2025 Proffered Presentations
S288: HIGHER RISK OF FACIAL NERVE FUNCTION DECREMENT AFTER RADIOSURGERY IN VESTIBULAR SCHWANNOMAS WITH PRIOR SURGICAL RESECTION
Jun Ma; Pranav Kumar; Alan Gordillo; Anish Kosanam; Juan D Alzate; Pranay Soni; Pablo F Recinos; Varun R Kshettry; Cleveland Clinic Foundation
Objective: Gamma Knife Radiosurgery (GRKS) is a well-established primary, adjuvant, or salvage treatment for vestibular schwannoma (VS) with low rate of complications including facial nerve palsy. Whether prior surgical resection affects the facial nerve risk after GKRS, however, is poorly understood. This study is to investigate post-GKRS facial nerve function in VS patients y who have had prior surgical resection.
Methods: A database of 697 GKRS for adult VS between 2003 – 2024 was screened to identify specifically cases who received open surgical resection of the same tumor before GKRS. Demographic, clinical, and radiological characteristics of each tumor were recorded. Facial nerve function was graded with House Brackmann (HB) scale at multiple time points: pre-surgery, immediate postop, short-term postop (<3 months), pre-GKRS and post-GKRS until last follow-up. Descriptive statistical techniques were used to describe distributions and logistic regression was conducted to assess the relationship between covariates and post-GKRS facial nerve function.
Results: There were 38 patients with 39 tumors in total were included. Median age was 57 years (IQR 45 – 65). The majority (57.9%) of patients were female and tumors were more commonly right-sided (59%). Eight (20.5%) tumors had cystic changes pre-GKRS. Median time interval from prior surgery to GKRS was 3 years [MOU2] [JM3] (IQR 0-9). Median tumor volume at GKRS was 1.96cc (IQR 1.13-3.40), with a median treatment dose of 13Gy. [MOU4] [JM5] Median post-GKRS follow up (f/u) time was 4 years (IQR 2-7), with 1 (2.6%) patient lost to f/u[MOU6] [JM7] . The facial nerve function at GKRS was HB-I in 24 (61.5%), HB-II in 5 (12.8%), HB-III in 4 (10.3%), HB-IV in 2 (5.1%), HB-V in 1 (2.6%), and HB-VI in 3 (7.7%) patients. Facial nerve function was improved in 3 (7.9%), the same in 28 (73.7%), and worsened in 7 (18.4%) patients within 2 years after GKRS. At last follow-up post-GKRS, facial nerve function was improved in 6 (15.8%), unchanged in 25 (65.8%), and worsened in 7 (18.4%) patients. No statistical correlation was observed between change in post-GRKS facial nerve function and age, sex, tumor location, time between surgery and GKRS, tumor volume at GKRS, or facial nerve grade at GKRS.
Conclusions: In patients with prior surgical resection, the rate of worsened facial nerve function was 18.4% after GKRS both at 2 years and long-term follow-up. Compared to historical literature, prior surgical resection appears to be a risk factor [MOU8] [JM9] for post-GKRS new/worsened facial nerve palsy in adult VS. Further investigation with larger samples sizes is needed to further delineate specific patient or tumor specific predictors of worsened facial nerve function post-GKRS.