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An In-Vitro Insertion-Force Study of Magnetically Guided Lateral-Wall Cochlear-Implant Electrode Arrays

HYPOTHESIS: Insertion forces can be reduced by magnetically guiding the tip of lateral-wall cochlear-implant electrode arrays during insertion via both cochleostomy and the round window. BACKGROUND: Steerable electrode arrays have the potential to minimize intracochlear trauma by reducing the severi...

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Autores principales: Leon, Lisandro, Warren, Frank M., Abbott, Jake J.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Lippincott Williams & Wilkins 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5763516/
https://www.ncbi.nlm.nih.gov/pubmed/29315180
http://dx.doi.org/10.1097/MAO.0000000000001647
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author Leon, Lisandro
Warren, Frank M.
Abbott, Jake J.
author_facet Leon, Lisandro
Warren, Frank M.
Abbott, Jake J.
author_sort Leon, Lisandro
collection PubMed
description HYPOTHESIS: Insertion forces can be reduced by magnetically guiding the tip of lateral-wall cochlear-implant electrode arrays during insertion via both cochleostomy and the round window. BACKGROUND: Steerable electrode arrays have the potential to minimize intracochlear trauma by reducing the severity of contact between the electrode-array tip and the cochlear wall. However, steerable electrode arrays typically have increased stiffness associated with the steering mechanism. In addition, steerable electrode arrays are typically designed to curve in the direction of the basal turn, which is not ideal for round-window insertions, as the cochlear hook's curvature is in the opposite direction. Lateral-wall electrode arrays can be modified to include magnets at their tips, augmenting their superior flexibility with a steering mechanism. By applying magnetic torque to the tip, an electrode array can be navigated through the cochlear hook and the basal turn. METHODS: Automated insertions of candidate electrode arrays are conducted into a scala-tympani phantom with either a cochleostomy or round-window opening. The phantom is mounted on a multi-degree-of-freedom force sensor. An external magnet applies the necessary magnetic bending torque to the magnetic tip of a modified clinical electrode array, coordinated with the insertion, with the goal of directing the tip down the lumen. Steering of the electrode array is verified through a camera. RESULTS: Statistical t-test results indicate that magnetic guidance does reduce insertion forces by as much as 50% with certain electrode-array models. Direct tip contact with the medial wall through the cochlear hook and the lateral wall of the basal turn is completely eliminated. The magnetic field required to accomplish these insertions varied from 77 to 225 mT based on the volume of the magnet at the tip of the electrode array. Alteration of the tip to accommodate a tiny magnet is minimal and does not change the insertion characteristic of the electrode array unless the tip shape is altered. CONCLUSION: Magnetic guidance can eliminate direct tip contact with the medial walls through the cochlear hook and the lateral walls of the basal turn. Insertion-force reduction will vary based on the electrode-array model, but is statistically significant for all models tested. Successful steering of lateral-wall electrode arrays is accomplished while maintaining its superior flexibility.
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spelling pubmed-57635162018-03-20 An In-Vitro Insertion-Force Study of Magnetically Guided Lateral-Wall Cochlear-Implant Electrode Arrays Leon, Lisandro Warren, Frank M. Abbott, Jake J. Otol Neurotol Cochlear Implants HYPOTHESIS: Insertion forces can be reduced by magnetically guiding the tip of lateral-wall cochlear-implant electrode arrays during insertion via both cochleostomy and the round window. BACKGROUND: Steerable electrode arrays have the potential to minimize intracochlear trauma by reducing the severity of contact between the electrode-array tip and the cochlear wall. However, steerable electrode arrays typically have increased stiffness associated with the steering mechanism. In addition, steerable electrode arrays are typically designed to curve in the direction of the basal turn, which is not ideal for round-window insertions, as the cochlear hook's curvature is in the opposite direction. Lateral-wall electrode arrays can be modified to include magnets at their tips, augmenting their superior flexibility with a steering mechanism. By applying magnetic torque to the tip, an electrode array can be navigated through the cochlear hook and the basal turn. METHODS: Automated insertions of candidate electrode arrays are conducted into a scala-tympani phantom with either a cochleostomy or round-window opening. The phantom is mounted on a multi-degree-of-freedom force sensor. An external magnet applies the necessary magnetic bending torque to the magnetic tip of a modified clinical electrode array, coordinated with the insertion, with the goal of directing the tip down the lumen. Steering of the electrode array is verified through a camera. RESULTS: Statistical t-test results indicate that magnetic guidance does reduce insertion forces by as much as 50% with certain electrode-array models. Direct tip contact with the medial wall through the cochlear hook and the lateral wall of the basal turn is completely eliminated. The magnetic field required to accomplish these insertions varied from 77 to 225 mT based on the volume of the magnet at the tip of the electrode array. Alteration of the tip to accommodate a tiny magnet is minimal and does not change the insertion characteristic of the electrode array unless the tip shape is altered. CONCLUSION: Magnetic guidance can eliminate direct tip contact with the medial walls through the cochlear hook and the lateral walls of the basal turn. Insertion-force reduction will vary based on the electrode-array model, but is statistically significant for all models tested. Successful steering of lateral-wall electrode arrays is accomplished while maintaining its superior flexibility. Lippincott Williams & Wilkins 2018-02 2018-02-26 /pmc/articles/PMC5763516/ /pubmed/29315180 http://dx.doi.org/10.1097/MAO.0000000000001647 Text en © 2017 The Author(s). Published by Wolters Kluwer Health, Inc., on behalf of Otology & Neurotology, Inc. http://creativecommons.org/licenses/by-nc-nd/4.0 This is an open access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal. http://creativecommons.org/licenses/by-nc-nd/4.0
spellingShingle Cochlear Implants
Leon, Lisandro
Warren, Frank M.
Abbott, Jake J.
An In-Vitro Insertion-Force Study of Magnetically Guided Lateral-Wall Cochlear-Implant Electrode Arrays
title An In-Vitro Insertion-Force Study of Magnetically Guided Lateral-Wall Cochlear-Implant Electrode Arrays
title_full An In-Vitro Insertion-Force Study of Magnetically Guided Lateral-Wall Cochlear-Implant Electrode Arrays
title_fullStr An In-Vitro Insertion-Force Study of Magnetically Guided Lateral-Wall Cochlear-Implant Electrode Arrays
title_full_unstemmed An In-Vitro Insertion-Force Study of Magnetically Guided Lateral-Wall Cochlear-Implant Electrode Arrays
title_short An In-Vitro Insertion-Force Study of Magnetically Guided Lateral-Wall Cochlear-Implant Electrode Arrays
title_sort in-vitro insertion-force study of magnetically guided lateral-wall cochlear-implant electrode arrays
topic Cochlear Implants
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5763516/
https://www.ncbi.nlm.nih.gov/pubmed/29315180
http://dx.doi.org/10.1097/MAO.0000000000001647
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