Positive and negative post stapedotomy effects on cervical VEMP recordings; a STROBE analysis

The primary goal of the present study was to compare the pre- and post-stapedotomy elicitation and waveform characteristics of both air- and bone-conduction (AC-, BC-) cervical vestibular evoked myogenic potentials (cVEMPs) through an individualized approach. A possible association between audiological characteristics, such as AC- and BC- pure tone audiometry thresholds and air-bone gap and the production of cVEMPs before and after stapedotomy was also investigated.

Twenty-five ears were subjected to full audiological evaluation as well as AC- and BC-cVEMPs pre- and post-stapedotomy. Four subgroups were studied; consistently present/absent, post-operatively disappeared and restored cVEMPs.

Post-stapedotomy changes in cVEMP elicitability did not reach significance for either AC-cVEMP (OR=5.41, 95% CI 0.88-33.36, P=0.06) or BC-cVEMP (OR=2.40, 95% CI 0.42-13.60, P=0.3). Normal or abnormal AC-cVEMPs were equally subject to post-operative changes (OR=1.95, 95% CI 0.32-12.01, P=0.5), as were BC-cVEMPs (OR=3.75, 95% CI 0.66-21.25, P=0.1). Neither the audiological characteristics nor the surgical outcome, in terms of ABG results, were relevant to the presence or absence of AC- and BC-cVEMPs before or after stapedotomy.

The presumed changes brought to the sacculus by stapedotomy are minor and beyond the diagnostic abilities of either AC-cVEMPs or BC-cVEMPs, both in terms of cVEMPs elicitability and waveform characteristics. In individual cases, however, which may deserve further investigation, cVEMPs may reappear or disappear after stapedotomy probably following minor changes toward a lower or higher vestibular system resistance for pressure and sound transmission.