Brainstem auditory evoked potentials in microvascular decompression for hemifacial spasm: A prospective study

Objective: The aim of this prospective study is to identify the factors influencing postoperative hearing loss (HL) and explore effective strategies for reducing postoperative hearing complications following microvascular decompression (MVD) for hemifacial spasm (HFS).Methods: From January 2018 to January 2023, we enrolled a total of 55 patients who underwent MVD for HFS at our institution. Intraoperative monitoring of brainstem auditory evoked potentials (BAEPs) was conducted in all surgeries, beginning from the induction of general anesthesia and continuing until skin closure. Prior to surgery and one month after, pure-tone audiometry (PTA) evaluations were performed to evaluate HL. We conducted an analysis to identify factors that influenced postoperative HL. Our examination focused on the occurrence of postoperative HL, considering changes in BAEPs, and we evaluated the diagnostic accuracy of significant warning criteria.Results: In this study, a total of 55 patients (37 women and 18 men) with a mean age of 52.5 +/- 13.4 years (range 24-80) were included. Among them, 5 patients (9.1 %) experienced postoperative HL. The variations in other risk factors based on the pattern of HL were not statistically significant (p > 0.05), whereas surgical experience showed significance (p = 0.028). Notably, the group of patients who showed wave V loss in intraoperative BAEPs was found to be significantly associated with postoperative HL.Conclusion: Surgical experience is a factor influencing postoperative HL. Intraoperative changes in BAEPs, particularly loss of wave V, were found to be a significant indicator of poorer recovery of hearing capacity after MVD for HFS.