Intraoperative Monitoring of Hearing During Ossiculoplasty

Abstract

Krzysztof Morawski Department of Otolaryngology, Medical University of Warsaw, Warsaw, Poland Email: morawski@neurotology.pl Phone: +48 502 043 162 Website: www.otolaryngology.pl www.wum.edu.pl Objective: To evaluate the utility of electrocochleography recorded from the round window (RW-ECochG) and auditory brainstem responses (ABR) for assessment of hearing improvement during ossicular reconstruction performed during second look operation. Study Design: A prospective study of 20 patients undergoing two-stage canal wall-up tympanoplasty with intraoperative RW-ECochG and ABR recording during the second look operation to improve hearing results. Setting: This study was performed in a tertiary referral center. Subjects and Methods: Twenty patients 18 to 50 years of age underwent two stage canal wall-up tympanoplasty and followed for at least 6 months. During the second look operation RW-ECochG and ABR were measured intraoperatively. Needle electrode for RW-ECochG was placed at RW niche via posterior tympanotomy. Various options of ossiculoplasty were evaluated. Auditory thresholds defined by N1-peak in RW-ECochG and ABR wave V were evaluated for various prostheses types and orientations. Results: Intraoperatively measured thresholds demonstrated a good improvement for click and tonebursts. RW-ECochG appeared more sensitive than ABR during ossicular prostheses manipulations. The largest changes in measurements occurred during TORP placement procedures. In two cases intraoperative bleeding from tympanic mucosa made impossible effective testing. For all the others a good correspondence between intraoperative recordings and postoperative hearing results were achieved. Conclusions: Intraoperative evoked potentials using RW-ECochG and, to some extent, ABR were found to be good predictors of postoperative hearing after second stage ossicular reconstruction and good tool for intraoperative evaluation of ossicular reconstruction efficacy. Bleeding from mucosa limited intraoperative application of both RW-ECochG and ABR. Support: NCBiR Poland, Grant N R13 0040 06/2009 Intraoperative Monitoring of Hearing During Ossiculoplasty Krzysztof Morawski, MD, PhD1; Kazimierz Niemczyk, MD, PhD1; Fred Telischi, MEE, MD, FACS2 1Department of Otolaryngology, Medical University of Warsaw, Poland; 2Department of Otolaryngology, University of Miami Miller School of Medicine, FL, USA