Intraoperative Recording of Auditory Brainstem Responses for Monitoring of Floating Mass Transducer Coupling Efficacy During Revision Surgery-Proof of Concept.

Abstract

OBJECTIVE\nThe objective of the study was to measure auditory brainstem responses elicited by stimulation via a semi-implantable active middle ear implant with an electromagnetically driven floating mass transducer to quantify the coupling efficacy (=vibroplasty in situ thresholds\u200a-\u200abone conduction thresholds) in a patient during a revision surgery.\n\n\nPATIENTS\nOne patient, reimplanted with an active middle ear implant in a revision surgery.\n\n\nINTERVENTION(S)\nDiagnostic.\n\n\nMAIN OUTCOME MEASURE(S)\nIntraoperative auditory brainstem responses evoked by stimulation via an active middle ear implant in a calibrated set-up directly indicating the coupling efficacy magnitude (auditory brainstem response threshold\u200a=\u200acoupling efficacy), as well as pre- and postoperative bone conduction and vibroplasty in situ thresholds.\n\n\nRESULTS\nThe intraoperative auditory brainstem response threshold was detected at 0\u200adB nHL, i.e., the magnitude of coupling efficacy was determined intraoperatively to be 0\u200adB. The actual postoperative coupling efficacy (=postoperative vibroplasty in situ\u200a-\u200apostoperative bone conduction thresholds) was -2.5\u200adB.\n\n\nCONCLUSIONS\nThe coupling efficacy determined intraoperatively was consistent with the postoperative coupling efficacy. The described method seems to be a promising tool to objectively quantify the magnitude of coupling efficacy in active middle ear implant surgeries.