Evaluation of an impedance-based method to monitor the insertion of the electrode array during cochlear implantation

Timo M Gottfried; Pablo Galeazzi; Aline Föger; Daniel Dejaco; Andrea Tröger; Natalie Fischer; Veronika Innerhofer; Francesco Di Trapani; Nora Weiss; Josef Seebacher; Angelika Dierker; Joachim Schmutzhard

doi:10.1007/s00405-024-08584-2

Evaluation of an impedance-based method to monitor the insertion of the electrode array during cochlear implantation

Eur Arch Otorhinolaryngol. 2024 Apr 2. doi: 10.1007/s00405-024-08584-2. Online ahead of print.

Authors

Affiliations

¹ Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Innsbruck, Anichstr. 35, 6020, Innsbruck, Tyrol, Austria.
² MED-EL Medical Electronics, Worldwide Headquarters, Fürstenweg 77a, Innsbruck, Tyrol, Austria.
³ Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Bochum, North Rhine-Westphalia, Bleichstraße 15, 44787, Bochum, Germany.
⁴ Department of Otorhinolaryngology, TUM School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany.
⁵ Department of Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium.
⁶ Departement of Hearing, Speech and Voice Disorders, Medical University of Innsbruck, Anichstr. 35, 6020, Innsbruck, Tyrol, Austria.
⁷ Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Innsbruck, Anichstr. 35, 6020, Innsbruck, Tyrol, Austria. joachim.schmutzhard@i-med.ac.at.

PMID: 38564010
DOI: 10.1007/s00405-024-08584-2

Abstract

Purpose: Cochlear implantation is a prevalent remedy for severe-to-profound hearing loss. Optimising outcomes and hearing preservation, and minimising insertion trauma, require precise electrode placement. Objective monitoring during the insertion process can provide valuable insights and enhance surgical precision. This study assesses the feasibility and performance of an impedance-based method for monitoring electrode insertion, compared to the surgeon's feedback.

Methods: The study utilised the Insertion Monitoring Tool (IMT) research software, allowing for real-time measurement of impedance and evoked compound action potential (eCAP) during electrode insertion in 20 patient implantations. This enabled an impedance-based method to continuously assess the status of each electrode during the insertion process. The feasibility and performance was evaluated and compared to the surgeon's feedback approach. eCAP measurements focused merely on feasibility without searching specific responses.

Results: The IMT demonstrated feasibility in measuring real-time impedances and eCAP during the insertion of the electrode array. The impedance-based method exhibited potential for accurately monitoring the insertion depth with a high success rate. However, further development is needed to improve the number of usable contacts.

Conclusions: Objective monitoring with the impedance-based method shows promise as a valuable tool to enhance the precision of cochlear implant electrode insertion respecting insertion distance estimation. The IMT research software proved feasible in recording real-time impedances and eCAP during electrode insertion. While this impedance-based method exhibits high success rates, further improvements are required to optimise the number of usable contacts. This study highlights the potential of objective monitoring techniques to enhance cochlear implantation outcomes.

Keywords: Cochlear implant; Electrode impedance; Insertion speed; Real-time measurement.