Prognostic Factors for Facial Nerve Outcome after Vestibular Schwannoma Surgery: A 12-Year Multicentric Retrospective Study

Introduction This study aimed to evaluate facial nerve (FN) impairment in patients undergoing three vestibular schwannoma (VS) surgical techniques and identify variables influencing FN function. Materials and Methods A retrospective multicentric analysis was conducted on patients treated between 2010 and 2022 using retrosigmoid (RS), translabyrinthine (TL), or transcanal transpromontorial surgery (TTS). All participants had normal preoperative FN function and no previous radiotherapy. FN function was evaluated immediately, 6, 12, and 24 months post-surgery using the HB scale. Results Among 234 patients, the median FN grade was HB III immediately post-surgery, improving to HB II at 6, 12, and 24 months. Transient FN palsy occurred in 48%, whereas permanent palsy affected 39%. Higher Koos grades were significantly associated with worse FN outcomes. Older age correlated with poorer recovery at 6, 12, and 24 months (p = 0.03, 0.009, 0.02). In Koos II cases, TL yielded better FN function than RS at 48 hours and 12 months (p = 0.03). Among Koos III patients, FN preservation rates were significantly higher with TL versus RS at all time points (p = 0.003, 0.003, 0.001, 0.004). TTS demonstrated superior FN preservation compared with RS at 12 and 24 months (p = 0.007, 0.001). Multivariate analysis revealed younger age, lower Koos, TL, and TTS as predictors of better FN outcomes. Discussion Younger age, lower Koos grades, and the TL and TTS approaches are significantly linked to improved FN function after VS surgery.