The role of the blink reflex in predicting facial nerve outcomes following vestibular schwannoma surgery: a 4-year retrospective review

OBJECTIVE: The objective of this study was to evaluate the prognostic value of intraoperative blink reflex (BR) monitoring in predicting postoperative facial nerve outcomes following vestibular schwannoma (VS) resection. Given the limitations of existing intraoperative neuromonitoring (IONM) techniques, this study aimed to determine whether BR loss correlates with worsened facial nerve function, and to assess its potential as an adjunctive tool for surgical decision-making. METHODS: The authors conducted a retrospective review of adult patients who underwent VS resection between January 2021 and January 2025 at a single academic institution. Demographics, surgical and imaging features, and IONM data were extracted from the electronic medical record. BR monitoring involved supraorbital nerve stimulation with orbicularis oculi recording. Facial nerve outcomes were measured via House-Brackmann (HB) grade at postoperative day (POD) 1, discharge, and ≥ 6 months. A generalized estimating equation (GEE) model was used to evaluate associations between BR loss and longitudinal facial nerve outcomes, adjusting for tumor size, fundal fluid cap, age, and brainstem compression. RESULTS: Of 165 patients, 154 (93.3%) underwent BR monitoring; 43 (27.9%) of the 154 experienced intraoperative ipsilateral BR loss. GEE analysis of 122 patients and 324 observations revealed that BR loss independently predicted worsened facial nerve outcomes across time points (OR 2.40, 95% CI 1.02-5.66; p = 0.045). No significant associations were found between facial nerve function and tumor size, fundal fluid cap, age, or brainstem compression. At ≥ 6 months, the odds of a worse HB grade improved significantly compared to POD1 (OR 0.177, 95% CI 0.056-0.554; p = 0.003). CONCLUSIONS: Intraoperative BR loss is significantly associated with postoperative facial nerve dysfunction following VS surgery and is a more reliable predictor than tumor-related variables. BR monitoring provides a nondisruptive, physiologically integrative, and robust adjunct to existing IONM methods. Its use may enhance intraoperative decision-making and improve long-term functional outcomes.