[Intraoperative monitoring of cochlear nerve function during cerebello-pontine angle surgery]

Abstract

Background: Surgical procedures in the cerebello-pontine angle (CPA), e. g. for vestibular schwannoma, have an increased risk for damage to the cochlear nerve. Consequently, hearing deterioration up to complete deafness may result with severe impact on quality of life. Methods for intraoperative monitoring of function may minimize such risks.

Objective: Review of current methods for intraoperative monitoring of the cochelar nerve and summary of new developments.

Materials and methods: Analysis and summary of literature, discussion of new methods.

Results: Early auditory evoked potentials using click stimuli remain the standard method for intraoperative monitoring of cochlear nerve function. Amplitude and latency changes indicate a risk of postoperative hearing deterioration; however demonstrate only limited further differentiation of hearing quality. As novel methods, near-field recordings may allow faster feedback and auditory steady state responses potentially enable frequency specific testing.

Conclusions: Intraoperative monitoring of the cochlear nerve is an integral component of CPA surgery. It enables detection of potential nerve damage and thus contributes to avoiding postoperative functional deficits. Development and implementation of novel and additional approaches may further improve its clinical value.

Keywords: Acoustic nerve; Cerebellopontine angle tumor; Intraoperative neurophysiological monitoring; Vestibular schwannoma; Vestibulocochlear nerve diseases.