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Cochlear implantation in an animal model documents cochlear damage at the tip of the implant

INTRODUCTION: Electrocochleography has recently emerged as a diagnostic tool in cochlear implant surgery, purposing hearing preservation and optimal electrode positioning. OBJECTIVE: In this experimental study, extra-cochlear potentials were obtained during cochlear implant surgery in guinea pigs. T...

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Autores principales: Andrade, José Santos Cruz de, Baumhoff, Peter, Cruz, Oswaldo Laércio Mendonça, Lenarz, Thomas, Kral, Andrej
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Elsevier 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9422412/
https://www.ncbi.nlm.nih.gov/pubmed/33039317
http://dx.doi.org/10.1016/j.bjorl.2020.07.017
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author Andrade, José Santos Cruz de
Baumhoff, Peter
Cruz, Oswaldo Laércio Mendonça
Lenarz, Thomas
Kral, Andrej
author_facet Andrade, José Santos Cruz de
Baumhoff, Peter
Cruz, Oswaldo Laércio Mendonça
Lenarz, Thomas
Kral, Andrej
author_sort Andrade, José Santos Cruz de
collection PubMed
description INTRODUCTION: Electrocochleography has recently emerged as a diagnostic tool in cochlear implant surgery, purposing hearing preservation and optimal electrode positioning. OBJECTIVE: In this experimental study, extra-cochlear potentials were obtained during cochlear implant surgery in guinea pigs. The aim was to determine electrophysiological changes indicating cochlear trauma after cochleostomy and after electrode implantation in different insertion depths. METHODS: Normal-hearing guinea pigs (n = 14) were implanted uni- or bilaterally with a multichannel electrode. The extra-cochlear cochlear nerve action potentials were obtained in response to acoustic stimuli at specific frequencies before and after cochleostomy, and after introduction of the electrode bundle. After the electrophysiological experiments, the guinea pigs were euthanized and microtomography was performed, in order to determine the position of the electrode and to calculate of the depth of insertion. Based on the changes of amplitude and thresholds in relation to the stimulus frequency, the electrophysiological data and the position obtained by the microtomography reconstruction were compared. RESULTS: Cochleostomy promoted a small electrophysiological impact, while electrode insertion caused changes in the amplitude of extra-cochlear electrophysiological potentials over a wide range of frequencies, especially in the deepest insertions. There was, however, preservation of the electrical response to low frequency stimuli in most cases, indicating a limited auditory impact in the intraoperative evaluation. The mean insertion depth of the apical electrodes was 5339.56 μm (±306.45 – 6 inserted contacts) and 4447.75 μm (±290.23 – 5 inserted contacts). CONCLUSIONS: The main electrophysiological changes observed during surgical procedures occurred during implantation of the electrode, especially the deepest insertions, whereas the cochleostomy disturbed the potentials to a lesser extent. While hearing loss was often observed apical to the cochlear implant, it was possible to preserve low frequencies after insertion.
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spelling pubmed-94224122022-08-31 Cochlear implantation in an animal model documents cochlear damage at the tip of the implant Andrade, José Santos Cruz de Baumhoff, Peter Cruz, Oswaldo Laércio Mendonça Lenarz, Thomas Kral, Andrej Braz J Otorhinolaryngol Original Article INTRODUCTION: Electrocochleography has recently emerged as a diagnostic tool in cochlear implant surgery, purposing hearing preservation and optimal electrode positioning. OBJECTIVE: In this experimental study, extra-cochlear potentials were obtained during cochlear implant surgery in guinea pigs. The aim was to determine electrophysiological changes indicating cochlear trauma after cochleostomy and after electrode implantation in different insertion depths. METHODS: Normal-hearing guinea pigs (n = 14) were implanted uni- or bilaterally with a multichannel electrode. The extra-cochlear cochlear nerve action potentials were obtained in response to acoustic stimuli at specific frequencies before and after cochleostomy, and after introduction of the electrode bundle. After the electrophysiological experiments, the guinea pigs were euthanized and microtomography was performed, in order to determine the position of the electrode and to calculate of the depth of insertion. Based on the changes of amplitude and thresholds in relation to the stimulus frequency, the electrophysiological data and the position obtained by the microtomography reconstruction were compared. RESULTS: Cochleostomy promoted a small electrophysiological impact, while electrode insertion caused changes in the amplitude of extra-cochlear electrophysiological potentials over a wide range of frequencies, especially in the deepest insertions. There was, however, preservation of the electrical response to low frequency stimuli in most cases, indicating a limited auditory impact in the intraoperative evaluation. The mean insertion depth of the apical electrodes was 5339.56 μm (±306.45 – 6 inserted contacts) and 4447.75 μm (±290.23 – 5 inserted contacts). CONCLUSIONS: The main electrophysiological changes observed during surgical procedures occurred during implantation of the electrode, especially the deepest insertions, whereas the cochleostomy disturbed the potentials to a lesser extent. While hearing loss was often observed apical to the cochlear implant, it was possible to preserve low frequencies after insertion. Elsevier 2020-09-20 /pmc/articles/PMC9422412/ /pubmed/33039317 http://dx.doi.org/10.1016/j.bjorl.2020.07.017 Text en © 2020 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. https://creativecommons.org/licenses/by/4.0/This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Original Article
Andrade, José Santos Cruz de
Baumhoff, Peter
Cruz, Oswaldo Laércio Mendonça
Lenarz, Thomas
Kral, Andrej
Cochlear implantation in an animal model documents cochlear damage at the tip of the implant
title Cochlear implantation in an animal model documents cochlear damage at the tip of the implant
title_full Cochlear implantation in an animal model documents cochlear damage at the tip of the implant
title_fullStr Cochlear implantation in an animal model documents cochlear damage at the tip of the implant
title_full_unstemmed Cochlear implantation in an animal model documents cochlear damage at the tip of the implant
title_short Cochlear implantation in an animal model documents cochlear damage at the tip of the implant
title_sort cochlear implantation in an animal model documents cochlear damage at the tip of the implant
topic Original Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9422412/
https://www.ncbi.nlm.nih.gov/pubmed/33039317
http://dx.doi.org/10.1016/j.bjorl.2020.07.017
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