Clinical significance of wave I in brainstem auditory evoked potentials during microvascular decompression surgery for hemifacial spasm: a case report

Abstract

Hemifacial spasm (HFS) is an involuntary contraction of muscles on one side of the face. It is caused by compression of the facial nerve by blood vessels. Microvascular decompression (MVD) is an effective treatment for HFS. However, complications such as hearing loss and dizziness may occur due to nerve deficits during surgery. To prevent this, neural monitoring is performed with brainstem auditory evoked potentials (BAEPs). In most hospitals, the presence or absence of BAEPs V waveform is used as an indicator for monitoring. Also, it tends to be intensively implemented only during the main procedure. In this report, we compare three cases in which there were differences in postoperative hearing complications depending on the presence of wave I. This suggests the importance of attention on wave I of BAEPs monitoring during MVD surgery and the need for acquiring wave I data until closing time as well during the main procedure.