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Cramer J, Böttcher-Rebmann G, Lenarz T, Rau TS. A method for accurate and reproducible specimen alignment for insertion tests of cochlear implant electrode arrays. Int J Comput Assist Radiol Surg 2024; 19:1883-1893. [PMID: 37204650 DOI: 10.1007/s11548-023-02930-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 04/19/2023] [Indexed: 05/20/2023]
Abstract
PURPOSE The trajectory along which the cochlear implant electrode array is inserted influences the insertion forces and the probability for intracochlear trauma. Controlling the trajectory is especially relevant for reproducible conditions in electrode insertion tests. Using ex vivo cochlear specimens, manual alignment of the invisibly embedded cochlea is imprecise and hardly reproducible. The aim of this study was to develop a method for creating a 3D printable pose setting adapter to align a specimen along a desired trajectory toward an insertion axis. METHODS Planning points of the desired trajectory into the cochlea were set using CBCT images. A new custom-made algorithm processed these points for automated calculation of a pose setting adapter. Its shape ensures coaxial positioning of the planned trajectory to both the force sensor measuring direction and the insertion axis. The performance of the approach was evaluated by dissecting and aligning 15 porcine cochlear specimens of which four were subsequently used for automated electrode insertions. RESULTS The pose setting adapter could easily be integrated into an insertion force test setup. Its calculation and 3D printing was possible in all 15 cases. Compared to planning data, a mean positioning accuracy of 0.21 ± 0.10 mm at the level of the round window and a mean angular accuracy of 0.43° ± 0.21° were measured. After alignment, four specimens were used for electrode insertions, demonstrating the practical applicability of our method. CONCLUSION In this work, we present a new method, which enables automated calculation and creation of a ready-to-print pose setting adapter for alignment of cochlear specimens in insertion test setups. The approach is characterized by a high level of accuracy and reproducibility in controlling the insertion trajectory. Therefore, it enables a higher degree of standardization in force measurement when performing ex vivo insertion tests and thereby improves reliability in electrode testing.
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Affiliation(s)
- Jakob Cramer
- Department of Otolaryngology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
| | - Georg Böttcher-Rebmann
- Department of Otolaryngology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Thomas Lenarz
- Department of Otolaryngology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
- Cluster of Excellence EXC 2177/1 "Hearing4all", Hannover Medical School, Hannover, Germany
| | - Thomas S Rau
- Department of Otolaryngology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
- Cluster of Excellence EXC 2177/1 "Hearing4all", Hannover Medical School, Hannover, Germany
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Torres R, Daoudi H, Gu W, Breil E, Ferrary E, Sterkers O, Nguyen Y, Mosnier I. Exploring Trauma Patterns and Contributing Factors With Slim Straight Electrode Array After Cochlear Implantation. Otolaryngol Head Neck Surg 2024; 171:521-529. [PMID: 38532540 DOI: 10.1002/ohn.737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 02/09/2024] [Accepted: 02/29/2024] [Indexed: 03/28/2024]
Abstract
OBJECTIVE To assess trauma patterns associated with the insertion of lateral wall electrode arrays. The study focused on 3 categories-scala tympani (ST), intermediate, and scala vestibuli (SV)-to identify traumatic patterns and contributing factors. STUDY DESIGN Retrospective study. SETTING Data from 106 cochlear implant recipients at a tertiary otologic center. METHODS Demographic and surgical data were collected from recipients who underwent cochlear implantation manually and with RobOtol®. Measurements included cochlear dimensions, angular depth of insertion, and position of the first electrode. Three-dimensional reconstructions were used to analyze the electrode array location relative to the basilar membrane, categorized into ST, intermediate, and SV electrodes. Nontraumatic insertion was defined as all electrodes in the ST, while traumatic insertions had 1 or more electrodes in intermediate or SV locations. RESULTS Out of 106 cases, 44% had nontraumatic and 56% had traumatic insertions. Demographic and surgical characteristics showed no association with traumatic insertions. A deeper position of the first electrode, relative to the round window, was associated with traumatic insertions (P = .03). Three trauma patterns were observed: distal (facing the apical electrodes), proximal (facing the middle electrodes around 180°), and distal/proximal. CONCLUSION This study considers the intermediate position which could be associated with basilar membrane lesions. Risk zones for intracochlear trauma with lateral wall arrays were identified distally and proximally. Traumatic insertions were independently linked to deeper array placement. Future studies should explore whether gentler insertion, without insisting on further electrode array insertion depth, could reduce the trauma during cochlear implantation.
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Affiliation(s)
- Renato Torres
- Unité Fonctionnelle Implants Auditifs et Explorations Fonctionnelles, Service ORL, GHU Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris (AP-HP)/Sorbonne Université, Paris, France
- Technologies et Thérapie Génique Pour la Surdité, Institut de l'Audition, Institut Pasteur/Inserm/Université Paris Cité, Paris, France
| | - Hannah Daoudi
- Unité Fonctionnelle Implants Auditifs et Explorations Fonctionnelles, Service ORL, GHU Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris (AP-HP)/Sorbonne Université, Paris, France
- Technologies et Thérapie Génique Pour la Surdité, Institut de l'Audition, Institut Pasteur/Inserm/Université Paris Cité, Paris, France
| | - Wenxi Gu
- Unité Fonctionnelle Implants Auditifs et Explorations Fonctionnelles, Service ORL, GHU Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris (AP-HP)/Sorbonne Université, Paris, France
- Technologies et Thérapie Génique Pour la Surdité, Institut de l'Audition, Institut Pasteur/Inserm/Université Paris Cité, Paris, France
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases (14DZ2260300), Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Eugénie Breil
- Unité Fonctionnelle Implants Auditifs et Explorations Fonctionnelles, Service ORL, GHU Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris (AP-HP)/Sorbonne Université, Paris, France
| | - Evelyne Ferrary
- Unité Fonctionnelle Implants Auditifs et Explorations Fonctionnelles, Service ORL, GHU Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris (AP-HP)/Sorbonne Université, Paris, France
- Technologies et Thérapie Génique Pour la Surdité, Institut de l'Audition, Institut Pasteur/Inserm/Université Paris Cité, Paris, France
| | - Olivier Sterkers
- Unité Fonctionnelle Implants Auditifs et Explorations Fonctionnelles, Service ORL, GHU Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris (AP-HP)/Sorbonne Université, Paris, France
- Technologies et Thérapie Génique Pour la Surdité, Institut de l'Audition, Institut Pasteur/Inserm/Université Paris Cité, Paris, France
| | - Yann Nguyen
- Unité Fonctionnelle Implants Auditifs et Explorations Fonctionnelles, Service ORL, GHU Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris (AP-HP)/Sorbonne Université, Paris, France
- Technologies et Thérapie Génique Pour la Surdité, Institut de l'Audition, Institut Pasteur/Inserm/Université Paris Cité, Paris, France
| | - Isabelle Mosnier
- Unité Fonctionnelle Implants Auditifs et Explorations Fonctionnelles, Service ORL, GHU Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris (AP-HP)/Sorbonne Université, Paris, France
- Technologies et Thérapie Génique Pour la Surdité, Institut de l'Audition, Institut Pasteur/Inserm/Université Paris Cité, Paris, France
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Hrnčiřík F, Nagy L, Grimes HL, Iftikhar H, Muzaffar J, Bance M. Impact of Insertion Speed, Depth, and Robotic Assistance on Cochlear Implant Insertion Forces and Intracochlear Pressure: A Scoping Review. SENSORS (BASEL, SWITZERLAND) 2024; 24:3307. [PMID: 38894099 PMCID: PMC11174543 DOI: 10.3390/s24113307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 05/13/2024] [Accepted: 05/14/2024] [Indexed: 06/21/2024]
Abstract
Cochlear implants are crucial for addressing severe-to-profound hearing loss, with the success of the procedure requiring careful electrode placement. This scoping review synthesizes the findings from 125 studies examining the factors influencing insertion forces (IFs) and intracochlear pressure (IP), which are crucial for optimizing implantation techniques and enhancing patient outcomes. The review highlights the impact of variables, including insertion depth, speed, and the use of robotic assistance on IFs and IP. Results indicate that higher insertion speeds generally increase IFs and IP in artificial models, a pattern not consistently observed in cadaveric studies due to variations in methodology and sample size. The study also explores the observed minimal impact of robotic assistance on reducing IFs compared to manual methods. Importantly, this review underscores the need for a standardized approach in cochlear implant research to address inconsistencies and improve clinical practices aimed at preserving hearing during implantation.
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Affiliation(s)
- Filip Hrnčiřík
- Cambridge Hearing Group, Cambridge CB2 7EF, UK; (F.H.)
- Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0QQ, UK
| | - Leo Nagy
- Clinical School, University of Cambridge, Cambridge CB2 0QQ, UK
| | | | - Haissan Iftikhar
- Department of Otolaryngology, University Hospitals Birmingham, Birmingham B15 2TT, UK
| | - Jameel Muzaffar
- Cambridge Hearing Group, Cambridge CB2 7EF, UK; (F.H.)
- Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0QQ, UK
- Department of Otolaryngology, University Hospitals Birmingham, Birmingham B15 2TT, UK
| | - Manohar Bance
- Cambridge Hearing Group, Cambridge CB2 7EF, UK; (F.H.)
- Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0QQ, UK
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Rau TS, Böttcher-Rebmann G, Schell V, Cramer J, Artukarslan E, Baier C, Lenarz T, Salcher R. First clinical implementation of insertion force measurement in cochlear implantation surgery. Front Neurol 2024; 15:1400455. [PMID: 38711559 PMCID: PMC11070539 DOI: 10.3389/fneur.2024.1400455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Accepted: 04/08/2024] [Indexed: 05/08/2024] Open
Abstract
Purpose The significance of atraumatic electrode array (EA) insertion in cochlear implant (CI) surgery is widely acknowledged, with consensus that forces due to EA insertion are directly correlated with insertion trauma. Unfortunately, the manual perception of these forces through haptic feedback is inherently limited, and techniques for in vivo force measurements to monitor the insertion are not yet available. Addressing this gap, we developed of a force-sensitive insertion tool capable of capturing real-time insertion forces during standard CI surgery. Methods This paper describes the tool and its pioneering application in a clinical setting and reports initial findings from an ongoing clinical study. Data and experiences from five patients have been evaluated so far, including force profiles of four patients. Results The initial intraoperative experiences are promising, with successful integration into the conventional workflow. Feasibility of in vivo insertion force measurement and practicability of the tool's intraoperative use could be demonstrated. The recorded in vivo insertion forces show the expected rise with increasing insertion depth. Forces at the end of insertion range from 17.2 mN to 43.6 mN, while maximal peak forces were observed in the range from 44.8 mN to 102.4 mN. Conclusion We hypothesize that this novel method holds the potential to assist surgeons in monitoring the insertion forces and, thus, minimizing insertion trauma and ensuring better preservation of residual hearing. Future data recording with this tool can form the basis of ongoing research into the causes of insertion trauma, paving the way for new and improved prevention strategies.
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Affiliation(s)
- Thomas S. Rau
- Department of Otolaryngology and Cluster of Excellence EXC 2177/1 “Hearing4all”, Hannover Medical School, Hannover, Germany
| | - Georg Böttcher-Rebmann
- Department of Otolaryngology and Cluster of Excellence EXC 2177/1 “Hearing4all”, Hannover Medical School, Hannover, Germany
| | - Viktor Schell
- Department of Otolaryngology and Cluster of Excellence EXC 2177/1 “Hearing4all”, Hannover Medical School, Hannover, Germany
| | - Jakob Cramer
- Department of Otolaryngology and Cluster of Excellence EXC 2177/1 “Hearing4all”, Hannover Medical School, Hannover, Germany
| | - Eralp Artukarslan
- Department of Otolaryngology and Cluster of Excellence EXC 2177/1 “Hearing4all”, Hannover Medical School, Hannover, Germany
| | - Claas Baier
- Institute for Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
| | - Thomas Lenarz
- Department of Otolaryngology and Cluster of Excellence EXC 2177/1 “Hearing4all”, Hannover Medical School, Hannover, Germany
| | - Rolf Salcher
- Department of Otolaryngology and Cluster of Excellence EXC 2177/1 “Hearing4all”, Hannover Medical School, Hannover, Germany
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Geerardyn A, Zhu M, Verhaert N, Quesnel AM. Intracochlear Trauma and Local Ossification Patterns Differ Between Straight and Precurved Cochlear Implant Electrodes. Otol Neurotol 2024; 45:245-255. [PMID: 38270168 PMCID: PMC10922381 DOI: 10.1097/mao.0000000000004102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2024]
Abstract
HYPOTHESIS Trauma to the osseous spiral lamina (OSL) or spiral ligament (SL) during cochlear implant (CI) insertion segregates with electrode type and induces localized intracochlear ossification and fibrosis. BACKGROUND The goal of atraumatic CI insertion is to preserve intracochlear structures, limit reactive intracochlear tissue formation, and preserve residual hearing. Previous qualitative studies hypothesized a localized effect of trauma on intracochlear tissue formation; however, quantitative studies failed to confirm this. METHODS Insertional trauma beyond the immediate insertion site was histologically assessed in 21 human temporal bones with a CI. Three-dimensional reconstructions were generated and virtually resectioned perpendicular to the cochlear spiral at high resolution. The cochlear volume occupied by ossification or fibrosis was determined at the midpoint of the trauma and compared with regions proximal and distal to this point. RESULTS Seven cases, all implanted with precurved electrodes, showed an OSL fracture beyond the immediate insertion site. Significantly more intracochlear ossification was observed at the midpoint of the OSL fracture, compared with the -26 to -18 degrees proximal and 28 to 56 degrees distal to the center. No such pattern was observed for fibrosis. In the 12 cases with a perforation of the SL (9 straight and 3 precurved electrodes), no localized pattern of ossification or fibrosis was observed around these perforations. CONCLUSION OSL fractures were observed exclusively with precurved electrodes in this study and may serve as a nidus for localized intracochlear ossification. Perforation of the SL, in contrast, predominantly occurred with straight electrodes and was not associated with localized ossification.
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Affiliation(s)
| | - MengYu Zhu
- Otopathology Laboratory, Massachusetts Eye and Ear, Boston, Massachusetts, USA
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Kashani RG, Kocharyan A, Bennion DM, Scheperle RA, Etler C, Oleson J, Dunn CC, Claussen AD, Gantz BJ, Hansen MR. Combining Intraoperative Electrocochleography with Robotics-Assisted Electrode Array Insertion. Otol Neurotol 2024; 45:143-149. [PMID: 38206061 PMCID: PMC10786337 DOI: 10.1097/mao.0000000000004094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
OBJECTIVE To describe the use of robotics-assisted electrode array (EA) insertion combined with intraoperative electrocochleography (ECochG) in hearing preservation cochlear implant surgery. STUDY DESIGN Prospective, single-arm, open-label study. SETTING All procedures and data collection were performed at a single tertiary referral center. PATIENTS Twenty-one postlingually deaf adult subjects meeting Food and Drug Administration indication criteria for cochlear implantation with residual acoustic hearing defined as thresholds no worse than 65 dB at 125, 250, and 500 Hz. INTERVENTION All patients underwent standard-of-care unilateral cochlear implant surgery using a single-use robotics-assisted EA insertion device and concurrent intraoperative ECochG. MAIN OUTCOME MEASURES Postoperative pure-tone average over 125, 250, and 500 Hz measured at initial activation and subsequent intervals up to 1 year afterward. RESULTS Twenty-two EAs were implanted with a single-use robotics-assisted insertion device and simultaneous intraoperative ECochG. Fine control over robotic insertion kinetics could be applied in response to changes in ECochG signal. Patients had stable pure-tone averages after activation with normal impedance and neural telemetry responses. CONCLUSIONS Combining robotics-assisted EA insertion with intraoperative ECochG is a feasible technique when performing hearing preservation implant surgery. This combined approach may provide the surgeon a means to overcome the limitations of manual insertion and respond to cochlear feedback in real-time.
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Affiliation(s)
- Rustin G. Kashani
- Department of Otolaryngology–Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa
| | - Armine Kocharyan
- Department of Otolaryngology–Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa
| | - Douglas M. Bennion
- Department of Otolaryngology–Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa
| | - Rachel A. Scheperle
- Department of Otolaryngology–Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa
| | - Christine Etler
- Department of Otolaryngology–Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa
| | - Jacob Oleson
- Department of Otolaryngology–Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa
| | - Camille C. Dunn
- Department of Otolaryngology–Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa
| | - Alexander D. Claussen
- Department of Otolaryngology–Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa
| | - Bruce J. Gantz
- Department of Otolaryngology–Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa
| | - Marlan R. Hansen
- Department of Otolaryngology–Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa
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Kashani RG, Henslee A, Nelson RF, Hansen MR. Robotic assistance during cochlear implantation: the rationale for consistent, controlled speed of electrode array insertion. Front Neurol 2024; 15:1335994. [PMID: 38318440 PMCID: PMC10839068 DOI: 10.3389/fneur.2024.1335994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 01/05/2024] [Indexed: 02/07/2024] Open
Abstract
Cochlear implants (CI) have revolutionized the treatment of patients with severe to profound sensory hearing loss by providing a method of bypassing normal hearing to directly stimulate the auditory nerve. A further advance in the field has been the introduction of "hearing preservation" surgery, whereby the CI electrode array (EA) is carefully inserted to spare damage to the delicate anatomy and function of the cochlea. Preserving residual function of the inner ear allows patients to receive maximal benefit from the CI and to combine CI electric stimulation with acoustic hearing, offering improved postoperative speech, hearing, and quality of life outcomes. However, under the current paradigm of implant surgery, where EAs are inserted by hand, the cochlea cannot be reliably spared from damage. Robotics-assisted EA insertion is an emerging technology that may overcome fundamental human kinetic limitations that prevent consistency in achieving steady and slow EA insertion. This review begins by describing the relationship between EA insertion speed and generation of intracochlear forces and pressures. The various mechanisms by which these intracochlear forces can damage the cochlea and lead to worsened postoperative outcomes are discussed. The constraints of manual insertion technique are compared to robotics-assisted methods, followed by an overview of the current and future state of robotics-assisted EA insertion.
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Affiliation(s)
- Rustin G. Kashani
- Department of Otolaryngology – Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, IA, United States
| | | | | | - Marlan R. Hansen
- Department of Otolaryngology – Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, IA, United States
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Böttcher-Rebmann G, Schell V, Zuniga MG, Salcher R, Lenarz T, Rau TS. Preclinical evaluation of a tool for insertion force measurements in cochlear implant surgery. Int J Comput Assist Radiol Surg 2023; 18:2117-2124. [PMID: 37310560 PMCID: PMC10589184 DOI: 10.1007/s11548-023-02975-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 05/23/2023] [Indexed: 06/14/2023]
Abstract
PURPOSE Trauma that may be inflicted to the inner ear (cochlea) during the insertion of an electrode array (EA) in cochlear implant (CI) surgery can significantly decrease the hearing outcome of patients with residual hearing. Interaction forces between the EA and the cochlea are a promising indicator for the likelihood of intracochlear trauma. However, insertion forces have only been measured in laboratory setups. We recently developed a tool to measure the insertion force during CI surgery. Here, we present the first ex vivo evaluation of our tool with a focus on usability in the standard surgical workflow. METHODS Two CI surgeons inserted commercially available EAs into three temporal bone specimens. The insertion force and the orientation of the tool were recorded together with camera footage. The surgeons answered a questionnaire after each insertion to evaluate the surgical workflow with respect to CI surgery. RESULTS The EA insertion using our tool was rated successful in all 18 trials. The surgical workflow was evaluated to be equivalent to standard CI surgery. Minor handling challenges can be overcome through surgeon training. The peak insertion forces were 62.4 mN ± 26.7 mN on average. Peak forces significantly correlated to the final electrode insertion depth, supporting the assumption that the measured forces mainly correspond to intracochlear events and not extracochlear friction. Gravity-induced forces of up to 28.8 mN were removed from the signal, illustrating the importance of the compensation of such forces in manual surgery. CONCLUSION The results show that the tool is ready for intraoperative use. In vivo insertion force data will improve the interpretability of experimental results in laboratory settings. The implementation of live insertion force feedback to surgeons could further improve residual hearing preservation.
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Affiliation(s)
- Georg Böttcher-Rebmann
- Department of Otolaryngology and Cluster of Excellence EXC 2177/1 "Hearing4all", Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
| | - Viktor Schell
- Department of Otolaryngology and Cluster of Excellence EXC 2177/1 "Hearing4all", Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - M Geraldine Zuniga
- Department of Otolaryngology and Cluster of Excellence EXC 2177/1 "Hearing4all", Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Rolf Salcher
- Department of Otolaryngology and Cluster of Excellence EXC 2177/1 "Hearing4all", Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Thomas Lenarz
- Department of Otolaryngology and Cluster of Excellence EXC 2177/1 "Hearing4all", Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Thomas S Rau
- Department of Otolaryngology and Cluster of Excellence EXC 2177/1 "Hearing4all", Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
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Choi G, Ha Y, Kim DH, Shin S, Hyun J, Kim S, Oh SH, Min KS. Assessing the manufacturable 32-channel cochlear electrode array: evaluation results for clinical trials. Biomed Microdevices 2023; 25:41. [PMID: 37870619 DOI: 10.1007/s10544-023-00681-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/05/2023] [Indexed: 10/24/2023]
Abstract
Reliability evaluation results of a manufacturable 32-channel cochlear electrode array are reported in this paper. Applying automated laser micro-machining process and a layer-by-layer silicone deposition scheme, authors developed the manufacturing methods of the electrode array for fine patterning and mass production. The developed electrode array has been verified through the requirements specified by the ISO Standard 14708-7. And the insertion trauma of the electrode array has been evaluated based on human temporal bone studies. According to the specified requirements, the electrode array was assessed through elongation & insulation, flexural, and fatigue tests. In addition, Temporal bone study was performed using eight fresh-frozen cadaver temporal bones with the electrode arrays inserted via the round window. Following soaking in saline condition, the impedances between conducting wires of the electrode array were measured over 100 kΩ (the pass/fail criterion). After each required test, it was shown that the electrode array maintained the electrical continuity and insulation condition. The average insertion angle of the electrode array inside the scala tympani was 399.7°. The human temporal bone studies exhibited atraumatic insertion rate of 60.3% (grade 0 or 1). The reliability of the manufacturable electrode array is successfully verified in mechanical, electrical, and histological aspects. Following the completion of a 32-channel cochlear implant system, the performance and stability of the 32-channel electrode array will be evaluated in clinical trials.
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Affiliation(s)
| | - Yoonhee Ha
- TODOC Co., Ltd., Seoul, 08394, South Korea
| | | | | | | | | | - Seung-Ha Oh
- Department of Otorhinolaryngology, Seoul National University Hospital, Seoul, 03080, South Korea
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Hrncirik F, Roberts I, Sevgili I, Swords C, Bance M. Models of Cochlea Used in Cochlear Implant Research: A Review. Ann Biomed Eng 2023; 51:1390-1407. [PMID: 37087541 PMCID: PMC10264527 DOI: 10.1007/s10439-023-03192-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 03/20/2023] [Indexed: 04/24/2023]
Abstract
As the first clinically translated machine-neural interface, cochlear implants (CI) have demonstrated much success in providing hearing to those with severe to profound hearing loss. Despite their clinical effectiveness, key drawbacks such as hearing damage, partly from insertion forces that arise during implantation, and current spread, which limits focussing ability, prevent wider CI eligibility. In this review, we provide an overview of the anatomical and physical properties of the cochlea as a resource to aid the development of accurate models to improve future CI treatments. We highlight the advancements in the development of various physical, animal, tissue engineering, and computational models of the cochlea and the need for such models, challenges in their use, and a perspective on their future directions.
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Affiliation(s)
- Filip Hrncirik
- Cambridge Hearing Group, Cambridge, UK.
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0QQ, UK.
| | - Iwan Roberts
- Cambridge Hearing Group, Cambridge, UK
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - Ilkem Sevgili
- Cambridge Hearing Group, Cambridge, UK
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - Chloe Swords
- Cambridge Hearing Group, Cambridge, UK
- Department of Physiology, Development and Neurosciences, University of Cambridge, Cambridge, CB2 3DY, UK
| | - Manohar Bance
- Cambridge Hearing Group, Cambridge, UK
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0QQ, UK
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Iso-Mustajärvi M, Silvast T, Heikka T, Tervaniemi J, Calixto R, Linder PH, Dietz A. Trauma After Cochlear Implantation: The Accuracy of Micro-Computed Tomography and Cone-Beam Fusion Computed Tomography Compared With Histology in Human Temporal Bones. Otol Neurotol 2023; 44:339-345. [PMID: 36843083 PMCID: PMC10022666 DOI: 10.1097/mao.0000000000003835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
HYPOTHESIS Micro-computed tomography (micro-CT) and cone-beam computed tomography (CBCT), in conjunction with the image fusion technique, may provide similar results for trauma assessment after cochlear implantation, with respect to the trauma evaluation in preclinical cochlear implant (CI) studies, as the histology. BACKGROUND Before clinical use, novel cochlear implant (CI) designs are tested in temporal bone (TB) studies for usability and risk evaluation. The criterion standard for evaluating intracochlear insertion trauma and electrode location has historically been with histological samples. Progress of modern imaging technology has created alternatives to classic histology. This study compares the micro-CT and CBCT fusion images between histological samples in a preclinical CI study. METHODS Fourteen freshly frozen TBs were inserted with a lateral wall research CI electrode. All TBs were scanned with CBCT preoperatively and postoperatively. After insertion, the TBs were prepared for micro-CT and histology. Twelve TBs underwent first a micro-CT and then the histological process. The CBCTs were used for image fusion, and all three different methods were used for intracochlear trauma evaluation. The results were compared between methods. RESULTS There were 4 of 14 translocations detected with the fusion image method and 3 of 12 with the micro-CT and histology. When compared, the trauma grades converged and were not statistically significant. CONCLUSION The trauma grading based on micro-CT is comparable to the histology. The image fusion technique based on CBCT is less accurate because it relies on an empirical assumption of the basal membrane localization, but it is clinically applicable.
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Affiliation(s)
| | - Tuomo Silvast
- SIB Labs Infrastructure Unit, Faculty of Science and Forestry, University of Eastern Finland
| | - Tuomas Heikka
- Department of Otorhinolaryngology, Kuopio University Hospital
| | - Jyrki Tervaniemi
- Department of Radiology, Kuopio University Hospital, Kuopio, Finland
| | | | - Pia H. Linder
- Department of Otorhinolaryngology, Kuopio University Hospital
| | - Aarno Dietz
- Department of Otorhinolaryngology, Kuopio University Hospital
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12
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Gantz JA, Gantz BJ, Kaufmann CR, Henslee AM, Dunn CC, Hua X, Hansen MR. A Steadier Hand: The First Human Clinical Trial of a Single-Use Robotic-Assisted Surgical Device for Cochlear Implant Electrode Array Insertion. Otol Neurotol 2023; 44:34-39. [PMID: 36509435 PMCID: PMC9757840 DOI: 10.1097/mao.0000000000003749] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVE To evaluate the safety and utility of an investigational robotic-assisted cochlear implant insertion system. STUDY DESIGN Prospective, single-arm, open-label study under abbreviated Investigational Device Exemption requirements. SETTING All procedures were performed, and all data were collected, at a single tertiary referral center. PATIENTS Twenty-one postlingually deafened adult subjects that met Food and Drug Administration indication criteria for cochlear implantation. INTERVENTION All patients underwent standard-of-care surgery for unilateral cochlear implantation with the addition of a single-use robotic-assisted insertion device during cochlear electrode insertion. MAIN OUTCOME MEASURES Successful insertion of cochlear implant electrode array, electrode array insertion time, postoperative implant function. RESULTS Successful robotic-assisted insertion of lateral wall cochlear implant electrode arrays was achieved in 20 (95.2%) of 21 patients. One insertion was unable to be achieved by either robotic-assisted or manual insertion methods, and the patient was retrospectively found to have a preexisting cochlear fracture. Mean intracochlear electrode array insertion time was 3 minutes 15 seconds. All implants with successful robotic-assisted electrode array insertion (n = 20) had normal impedance and neural response telemetry measures for up to 6 months after surgery. CONCLUSIONS Here we report the first human trial of a single-use robotic-assisted surgical device for cochlear implant electrode array insertion. This device successfully and safely inserted lateral wall cochlear implant electrode arrays from the three device manufacturers with devices approved but he Food and Drug Administration.
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Affiliation(s)
- Jay A. Gantz
- Department of Otolaryngology – Head and Neck Surgery, The University of Iowa Carver College of Medicine, 200 Hawkins Drive, Iowa City, IA 52242-1089, USA
| | - Bruce J. Gantz
- Department of Otolaryngology – Head and Neck Surgery, The University of Iowa Carver College of Medicine, 200 Hawkins Drive, Iowa City, IA 52242-1089, USA
- Department of Neurosurgery, The University of Iowa Carver College of Medicine, 200 Hawkins Drive, Iowa City, IA 52242-1089, USA
| | | | | | - Camille C Dunn
- Department of Otolaryngology – Head and Neck Surgery, The University of Iowa Carver College of Medicine, 200 Hawkins Drive, Iowa City, IA 52242-1089, USA
| | - Xiaoyang Hua
- Department of Otolaryngology – Head and Neck Surgery, The University of Iowa Carver College of Medicine, 200 Hawkins Drive, Iowa City, IA 52242-1089, USA
| | - Marlan R. Hansen
- Department of Otolaryngology – Head and Neck Surgery, The University of Iowa Carver College of Medicine, 200 Hawkins Drive, Iowa City, IA 52242-1089, USA
- Department of Neurosurgery, The University of Iowa Carver College of Medicine, 200 Hawkins Drive, Iowa City, IA 52242-1089, USA
- iotaMotion Inc, 14 ½ South Clinton St. Iowa City, IA 52240, USA
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13
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Ren LJ, Yu Y, Zhang YH, Liu XD, Sun ZJ, Yao WJ, Zhang TY, Wang C, Li CL. Three-dimensional finite element analysis on cochlear implantation electrode insertion. Biomech Model Mechanobiol 2022; 22:467-478. [PMID: 36513945 DOI: 10.1007/s10237-022-01657-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 11/19/2022] [Indexed: 12/14/2022]
Abstract
Studying the insertion process of cochlear implant (CI) electrode array (EA) is important to ensure successful, sufficient, and safe implantation. A three-dimensional finite element (FE) model was developed to simulate the insertion process. The cochlear structures were reconstructed from an average statistical shape model (SSM) of human cochlea. The electrode is simplified as a long and tapered beam of homogeneous elastic materials, contacting and interacting with the stiff cochlear structures. A quasi-static insertion simulation was conducted, the insertion force and the contact pressure between the electrode and the cochlear wall, were calculated to evaluate the smoothness of insertion and the risk of potential cochlear trauma. Based on this model, different EA designs were analyzed, including the Young's modulus, the straight or bended shape, the normal or a more tapped section size. The influence of the insertion angle was also discussed. Our simulations indicate that reducing the EA Young's modulus, tapering and pre-bending are effective ways to ensure safe and successful EA implantation. This model is beneficial for optimizing EA designs and is potentially useful for designing patient-specific CI surgery.
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Affiliation(s)
- Liu-Jie Ren
- Department of Facial Plastic Reconstructive Surgery, ENT Institute, Eye and ENT Hospital, NHC Key Laboratory of Hearing Medicine (Fudan University), Shanghai, 200031, China
| | - Yi Yu
- School of Medical Instrumentation, Shanghai University of Medicine and Health Sciences, Shanghai, 201318, China
| | - Yu-Heng Zhang
- Shanghai Engineering Research Center of Cochlear Implants, Shanghai, 201318, China
| | - Xin-Dong Liu
- Shanghai Engineering Research Center of Cochlear Implants, Shanghai, 201318, China
| | - Zeng-Jun Sun
- Shanghai Engineering Research Center of Cochlear Implants, Shanghai, 201318, China
| | - Wen-Juan Yao
- School of Mechanics and Engineering Science, Shanghai Institute of Applied Mathematics and Mechanics, Shanghai University, Shanghai, 200444, China
| | - Tian-Yu Zhang
- Department of Facial Plastic Reconstructive Surgery, ENT Institute, Eye and ENT Hospital, NHC Key Laboratory of Hearing Medicine (Fudan University), Shanghai, 200031, China
| | - Cheng Wang
- Shanghai Engineering Research Center of Cochlear Implants, Shanghai, 201318, China.
| | - Chen-Long Li
- Department of Facial Plastic Reconstructive Surgery, ENT Institute, Eye and ENT Hospital, NHC Key Laboratory of Hearing Medicine (Fudan University), Shanghai, 200031, China.
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14
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Hrncirik F, Roberts IV, Swords C, Christopher PJ, Chhabu A, Gee AH, Bance ML. Impact of Scala Tympani Geometry on Insertion Forces during Implantation. BIOSENSORS 2022; 12:999. [PMID: 36354508 PMCID: PMC9688204 DOI: 10.3390/bios12110999] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 10/25/2022] [Accepted: 11/05/2022] [Indexed: 05/07/2023]
Abstract
(1) Background: During a cochlear implant insertion, the mechanical trauma can cause residual hearing loss in up to half of implantations. The forces on the cochlea during the insertion can lead to this mechanical trauma but can be highly variable between subjects which is thought to be due to differing anatomy, namely of the scala tympani. This study presents a systematic investigation of the influence of different geometrical parameters of the scala tympani on the cochlear implant insertion force. The influence of these parameters on the insertion forces were determined by testing the forces within 3D-printed, optically transparent models of the scala tympani with geometric alterations. (2) Methods: Three-dimensional segmentations of the cochlea were characterised using a custom MATLAB script which parametrised the scala tympani model, procedurally altered the key shape parameters (e.g., the volume, vertical trajectory, curvature, and cross-sectional area), and generated 3D printable models that were printed using a digital light processing 3D printer. The printed models were then attached to a custom insertion setup that measured the insertion forces on the cochlear implant and the scala tympani model during a controlled robotic insertion. (3) Results: It was determined that the insertion force is largely unaffected by the overall size, curvature, vertical trajectory, and cross-sectional area once the forces were normalised to an angular insertion depth. A Capstan-based model of the CI insertion forces was developed and matched well to the data acquired. (4) Conclusion: By using accurate 3D-printed models of the scala tympani with geometrical alterations, it was possible to demonstrate the insensitivity of the insertion forces to the size and shape of the scala tympani, after controlling for the angular insertion depth. This supports the Capstan model of the cochlear implant insertion force which predicts an exponential growth of the frictional force with an angular insertion depth. This concludes that the angular insertion depth, rather than the length of the CI inserted, should be the major consideration when evaluating the insertion force and associated mechanical trauma caused by cochlear implant insertion.
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Affiliation(s)
- Filip Hrncirik
- Cambridge Hearing Group, Cambridge, UK
- Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0QQ, UK
| | - Iwan V. Roberts
- Cambridge Hearing Group, Cambridge, UK
- Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0QQ, UK
| | - Chloe Swords
- Cambridge Hearing Group, Cambridge, UK
- Department of Physiology, Development and Neurosciences, University of Cambridge, Cambridge CB2 3DY, UK
| | | | - Akil Chhabu
- Clinical School, University of Cambridge, Cambridge CB2 0SP, UK
| | - Andrew H. Gee
- Department of Physiology, Development and Neurosciences, University of Cambridge, Cambridge CB2 3DY, UK
| | - Manohar L. Bance
- Cambridge Hearing Group, Cambridge, UK
- Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0QQ, UK
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15
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The effect of the surgical approach and cochlear implant electrode on the structural integrity of the cochlea in human temporal bones. Sci Rep 2022; 12:17068. [PMID: 36224234 PMCID: PMC9556579 DOI: 10.1038/s41598-022-21399-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 09/27/2022] [Indexed: 12/30/2022] Open
Abstract
Cochlear implants (CI) restore hearing of severely hearing-impaired patients. Although this auditory prosthesis is widely considered to be very successful, structural cochlear trauma during cochlear implantation is an important problem, reductions of which could help to improve hearing outcomes and to broaden selection criteria. The surgical approach in cochlear implantation, i.e. round window (RW) or cochleostomy (CO), and type of electrode-array, perimodiolar (PM) or lateral wall (LW), are variables that might influence the probability of severe trauma. We investigated the effect of these two variables on scalar translocation (STL), a specific type of severe trauma. Thirty-two fresh frozen human cadaveric ears were evenly distributed over four groups receiving either RW or CO approach, and either LW or PM array. Conventional radiological multiplanar reconstruction (MPR) was compared with a reconstruction method that uncoils the spiral shape of the cochlea (UCR). Histological analysis showed that RW with PM array had STL rate of 87% (7/8), CO approach with LW array 75% (6/8), RW approach with LW array 50% (4/8) and CO approach with PM array 29% (2/7). STL assessment using UCR showed a higher inter-observer and histological agreement (91 and 94% respectively), than that using MPR (69 and 74% respectively). In particular, LW array positions were difficult to assess with MPR. In conclusion, the interaction between surgical approach and type of array should be preoperatively considered in cochlear implant surgery. UCR technique is advised for radiological assessment of CI positions, and in general it might be useful for pathologies involving the inner ear or other complex shaped bony tubular structures.
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16
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Henslee AM, Kaufmann CR, Andrick MD, Reineke PT, Tejani VD, Hansen MR. Development and Characterization of an Electrocochleography-Guided Robotics-Assisted Cochlear Implant Array Insertion System. Otolaryngol Head Neck Surg 2022; 167:334-340. [PMID: 34609909 PMCID: PMC9969559 DOI: 10.1177/01945998211049210] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
OBJECTIVE Electrocochleography (ECochG) is increasingly being used during cochlear implant (CI) surgery to detect and mitigate insertion-related intracochlear trauma, where a drop in ECochG signal has been shown to correlate with a decline in hearing outcomes. In this study, an ECochG-guided robotics-assisted CI insertion system was developed and characterized that provides controlled and consistent electrode array insertions while monitoring and adapting to real-time ECochG signals. STUDY DESIGN Experimental research. SETTING A research laboratory and animal testing facility. METHODS A proof-of-concept benchtop study evaluated the ability of the system to detect simulated ECochG signal changes and robotically adapt the insertion. Additionally, the ECochG-guided insertion system was evaluated in a pilot in vivo sheep study to characterize the signal-to-noise ratio and amplitude of ECochG recordings during robotics-assisted insertions. The system comprises an electrode array insertion drive unit, an extracochlear recording electrode module, and a control console that interfaces with both components and the surgeon. RESULTS The system exhibited a microvolt signal resolution and a response time <100 milliseconds after signal change detection, indicating that the system can detect changes and respond faster than a human. Additionally, animal results demonstrated that the system was capable of recording ECochG signals with a high signal-to-noise ratio and sufficient amplitude. CONCLUSION An ECochG-guided robotics-assisted CI insertion system can detect real-time drops in ECochG signals during electrode array insertions and immediately alter the insertion motion. The system may provide a surgeon the means to monitor and reduce CI insertion-related trauma beyond manual insertion techniques for improved CI hearing outcomes.
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Affiliation(s)
| | | | | | | | - Viral D. Tejani
- iotaMotion, Inc, Iowa City, Iowa, USA,Department of Otolaryngology–Head and Neck Surgery, University of Iowa, Iowa City, Iowa, USA
| | - Marlan R. Hansen
- iotaMotion, Inc, Iowa City, Iowa, USA,Department of Otolaryngology–Head and Neck Surgery, University of Iowa, Iowa City, Iowa, USA
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17
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Sismono F, Leblans M, Mancini L, Veneziano A, Zanini F, Dirckx J, Bernaerts A, de Foer B, Offeciers E, Zarowski A. 3D-localisation of cochlear implant electrode contacts in relation to anatomical structures from in vivo cone-beam computed tomography. Hear Res 2022; 426:108537. [DOI: 10.1016/j.heares.2022.108537] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 03/18/2022] [Accepted: 05/23/2022] [Indexed: 12/11/2022]
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18
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Dohr D, Wulf K, Grabow N, Mlynski R, Schraven SP. A PLLA Coating Does Not Affect the Insertion Pressure or Frictional Behavior of a CI Electrode Array at Higher Insertion Speeds. MATERIALS 2022; 15:ma15093049. [PMID: 35591381 PMCID: PMC9104964 DOI: 10.3390/ma15093049] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 04/14/2022] [Accepted: 04/14/2022] [Indexed: 01/27/2023]
Abstract
To prevent endocochlear insertion trauma, the development of drug delivery coatings in the field of CI electrodes has become an increasing focus of research. However, so far, the effect of a polymer coating of PLLA on the mechanical properties, such as the insertion pressure and friction of an electrode array, has not been investigated. In this study, the insertion pressure of a PLLA-coated, 31.5-mm long standard electrode array was examined during placement in a linear cochlear model. Additionally, the friction coefficients between a PLLA-coated electrode array and a tissue simulating the endocochlear lining were acquired. All data were obtained at different insertion speeds (0.1, 0.5, 1.0, 1.5, and 2.0 mm/s) and compared with those of an uncoated electrode array. It was shown that both the maximum insertion pressure generated in the linear model and the friction coefficient of the PLLA-coated electrode did not depend on the insertion speed. At higher insertion speeds above 1.0 mm/s, the insertion pressure (1.268 ± 0.032 mmHg) and the friction coefficient (0.40 ± 0.15) of the coated electrode array were similar to those of an uncoated array (1.252 ± 0.034 mmHg and 0.36 ± 0.15). The present study reveals that a PLLA coating on cochlear electrode arrays has a negligible effect on the electrode array insertion pressure and the friction when higher insertion speeds are used compared with an uncoated electrode array. Therefore, PLLA is a suitable material to be used as a coating for CI electrode arrays and can be considered for a potential drug delivery system.
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Affiliation(s)
- Dana Dohr
- Department of Otorhinolaryngology, Head and Neck Surgery “Otto Körner”, Rostock University Medical Center, 18057 Rostock, Germany; (R.M.); (S.P.S.)
- Correspondence: author
| | - Katharina Wulf
- Institute for Biomedical Engineering, Rostock University Medical Center, 18119 Rostock, Germany; (K.W.); (N.G.)
| | - Niels Grabow
- Institute for Biomedical Engineering, Rostock University Medical Center, 18119 Rostock, Germany; (K.W.); (N.G.)
| | - Robert Mlynski
- Department of Otorhinolaryngology, Head and Neck Surgery “Otto Körner”, Rostock University Medical Center, 18057 Rostock, Germany; (R.M.); (S.P.S.)
| | - Sebastian P. Schraven
- Department of Otorhinolaryngology, Head and Neck Surgery “Otto Körner”, Rostock University Medical Center, 18057 Rostock, Germany; (R.M.); (S.P.S.)
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19
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Intracochlear New Fibro-Ossification and Neuronal Degeneration Following Cochlear Implant Electrode Translocation: Long-Term Histopathological Findings in Humans. Otol Neurotol 2022; 43:e153-e164. [PMID: 35015749 DOI: 10.1097/mao.0000000000003402] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
OBJECTIVE We aim to assess the histopathology of human temporal bones (TBs) with evidence of cochlear implantation (CI) electrode scalar translocation. STUDY DESIGN Otopathology study. SETTING Otopathology laboratory. PATIENTS TBs from patients who had a history of CI and histopathological evidence of interscalar translocation. Specimens with electrode placed entirely within the ST served as controls. INTERVENTION Histopathological assessment of human TBs. MAIN OUTCOME MEASURES TBs from each patient were harvested postmortem and histologically analyzed for intracochlear changes in the context of CI electrode translocation and compared to controls. Intracochlear new fibro-ossification, and spiral ganglion neuron (SGN) counts were assessed. Postoperative word recognition scores (WRS) were also compared. RESULTS Nineteen human TBs with electrode translocation and eight controls were identified. The most common site of translocation was the ascending limb of the basal turn (n = 14 TBs). The average angle of insertion at the point of translocation was 159° ± 79°. Eighteen translocated cases presented moderate fibroosseous changes in the basal region of the cochlea, extending to the translocation point and/or throughout the electrode track in 42%. Lower SGN counts were more pronounced in translocated cases compared to controls, with a significant difference for segment II (p = 0.019). Although final postoperative hearing outcomes were similar between groups, translocated cases had slower rate of improvement in WRS (p = 0.021). CONCLUSIONS Cochlear implant electrode translocation was associated with greater fibroosseous formation and lower SGN population. Our findings suggest that scalar translocations may slow the rate of improvement in WRS overtime as compared to atraumatic electrode insertions.Level of evidence: IV.
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20
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Hartl RMB, Greene NT. Measurement and Mitigation of Intracochlear Pressure Transients During Cochlear Implant Electrode Insertion. Otol Neurotol 2022; 43:174-182. [PMID: 34753876 PMCID: PMC10260290 DOI: 10.1097/mao.0000000000003401] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
HYPOTHESIS High intracochlear pressure transients associated with cochlear implant placement are reduced with smaller, non-styleted arrays, and longer insertion durations. BACKGROUND With increasing focus on hearing preservation during cochlear implant surgery, atraumatic technique is of the utmost importance. Previous studies revealed that high intensity pressure transients can be generated during the insertion of implant electrodes. Resulting acoustic trauma may be one contributing factor to postoperative loss of residual hearing. METHODS Thirty ears in cadaveric specimens were surgically prepared with placement of intracochlear pressure sensors. Sequential implant insertions were made over 10, 30, or 60 seconds using seven randomly ordered electrode styles. Pressures were also measured during common post-insertion electrode manipulations and removal. Measurements were compared between electrode styles and characteristics using analysis of variance (ANOVA) and Pearson correlation. RESULTS Implant insertion and post-insertion manipulations produced high-intensity pressure transients with all electrodes tested, with some measurements exceeding 170 dB peak SPL. Average peak pressures were significantly lower for straight, non-stylet electrodes (p << 0.001). The likelihood of generating transients was lowest with the slowest insertions (p << 0.001). CONCLUSIONS Cochlear implant insertion can generate transients in intralabyrinthine pressure levels equivalent to high intensity, impulsive acoustic stimuli known to cause hearing loss. Although transients were observed in all conditions, exposure may be mitigated by using non-styleted electrodes and slow insertion speeds. Additional surgical manipulations can also produce similar high-pressure events. Results from this investigation suggest that use of non-styleted electrodes, slow but steady insertion speeds, and avoidance of post-insertional manipulations are important to reduce cochlear trauma.
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Affiliation(s)
- Renee M. Banakis Hartl
- Department of Otolaryngology, University of Colorado School of Medicine, Aurora, CO
- Department of Otolaryngology-Head and Neck Surgery, University of Michigan, Ann Arbor, MI
| | - Nathaniel T. Greene
- Department of Otolaryngology, University of Colorado School of Medicine, Aurora, CO
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21
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Partouche E, Adenis V, Gnansia D, Stahl P, Edeline JM. Increased Threshold and Reduced Firing Rate of Auditory Cortex Neurons after Cochlear Implant Insertion. Brain Sci 2022; 12:brainsci12020205. [PMID: 35203968 PMCID: PMC8870646 DOI: 10.3390/brainsci12020205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 01/25/2022] [Accepted: 01/28/2022] [Indexed: 12/10/2022] Open
Abstract
The cochlear implant (CI) is the most successful neuroprosthesis allowing thousands of patients with profound hearing loss to recover speech understanding. Recently, cochlear implants have been proposed to subjects with residual hearing and, in these cases, shorter CIs were implanted. To be successful, it is crucial to preserve the patient’s remaining hearing abilities after the implantation. Here, we quantified the effects of CI insertion on the responses of auditory cortex neurons in anesthetized guinea pigs. The responses of auditory cortex neurons were determined before and after the insertion of a 300 µm diameter CI (six stimulating electrodes, length 6 mm). Immediately after CI insertion there was a 5 to 15 dB increase in the threshold for cortical neurons from the middle to the high frequencies, accompanied by a decrease in the evoked firing rate. Analyzing the characteristic frequency (CF) values revealed that in large number of cases, the CFs obtained after insertion were lower than before. These effects were not detected in the control animals. These results indicate that there is a small but immediate cortical hearing loss after CI insertion, even with short length CIs. Therefore, efforts should be made to minimize the damages during CI insertion to preserve the cortical responses to acoustic stimuli.
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Affiliation(s)
- Elie Partouche
- Paris-Saclay Institute of Neurosciences (Neuro-PSI), CNRS UMR 9197, Universite Paris-Saclay, 91400 Saclay, France; (E.P.); (V.A.)
| | - Victor Adenis
- Paris-Saclay Institute of Neurosciences (Neuro-PSI), CNRS UMR 9197, Universite Paris-Saclay, 91400 Saclay, France; (E.P.); (V.A.)
| | - Dan Gnansia
- Department of Scientific and Clinical Research, Oticon Medical, 06224 Vallauris, France; (D.G.); (P.S.)
| | - Pierre Stahl
- Department of Scientific and Clinical Research, Oticon Medical, 06224 Vallauris, France; (D.G.); (P.S.)
| | - Jean-Marc Edeline
- Paris-Saclay Institute of Neurosciences (Neuro-PSI), CNRS UMR 9197, Universite Paris-Saclay, 91400 Saclay, France; (E.P.); (V.A.)
- Correspondence:
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22
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Robotics, automation, active electrode arrays, and new devices for cochlear implantation: A contemporary review. Hear Res 2022; 414:108425. [PMID: 34979455 DOI: 10.1016/j.heares.2021.108425] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 12/16/2021] [Accepted: 12/23/2021] [Indexed: 01/14/2023]
Abstract
In the last two decades, cochlear implant surgery has evolved into a minimally invasive, hearing preservation surgical technique. The devices used during surgery have benefited from technological advances that have allowed modification and possible improvement of the surgical technique. Robotics has recently gained popularity in otology as an effective tool to overcome the surgeon's limitations such as tremor, drift and accurate force control feedback in laboratory testing. Cochlear implantation benefits from robotic assistance in several steps during the surgical procedure: (i) during the approach to the middle ear by automated mastoidectomy and posterior tympanotomy or through a tunnel from the postauricular skin to the middle ear (i.e. direct cochlear access); (ii) a minimally invasive cochleostomy by a robot-assisted drilling tool; (iii) alignment of the correct insertion axis on the basal cochlear turn; (iv) insertion of the electrode array with a motorized insertion tool. In recent years, the development of bone-attached parallel robots and image-guided surgical robotic systems has allowed the first successful cochlear implantation procedures in patients via a single hole drilled tunnel. Several other robotic systems, new materials, sensing technologies applied to the electrodes, and smart devices have been developed, tested in experimental models and finally some have been used in patients with the aim of reducing trauma in cochleostomy, and permitting slow and more accurate insertion of the electrodes. Despite the promising results in laboratory tests in terms of minimal invasiveness, reduced trauma and better hearing preservation, so far, no clinical benefits on residual hearing preservation or better speech performance have been demonstrated. Before these devices can become the standard approach for cochlear implantation, several points still need to be addressed, primarily cost and duration of the procedure. One can hope that improvement in the cost/benefit ratio will expand the technology to every cochlear implantation procedure. Laboratory research and clinical studies on patients should continue with the aim of making intracochlear implant insertion an atraumatic and reversible gesture for total preservation of the inner ear structure and physiology.
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23
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Areias B, Parente MPL, Gentil F, Natal Jorge RM. Finite element modelling of the surgical procedure for placement of a straight electrode array: Mechanical and clinical consequences. J Biomech 2021; 129:110812. [PMID: 34688063 DOI: 10.1016/j.jbiomech.2021.110812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 09/07/2021] [Accepted: 10/07/2021] [Indexed: 11/16/2022]
Abstract
A cochlear implant is an electronic device implanted into the cochlea to directly stimulate the auditory nerve. Such device is used in patients with severe-to-profound hearing loss. The cochlear implant surgery is safe, but involves some risks, such as infections, device malfunction or damage of the facial nerve and it can result on a poor hearing outcome, due to the destruction of any present residual hearing. Future improvements in cochlear implant surgery will necessarily involve the decrease of the intra-cochlear damage. Several implant related variables, such as materials, geometrical design, processor and surgical techniques can be optimized in order for the patients to partially recover their hearing capacities The straight electrode is a type of cochlear implant that many authors indicate as being the less traumatic. From the finite element analysis conducted in this work, the influence of the insertion speed, the friction coefficient between the cochlear wall and the electrode array, and several configurations of the cochlear implant tip were studied. The numerical simulations of the implantation showed the same pattern of the insertion force against insertion depth, thus indicating the different phases of the insertion. Results demonstrated that lower insertion speeds, friction coefficients and tip stiffness, led to a reduction on the contact pressures and insertion force. It is expected that these improved configurations will allow to preserve the residual hearing while reducing surgical complications.
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Affiliation(s)
- B Areias
- INEGI, Institute of Science and Innovation in Mechanical and Industrial Engineering, Porto, Portugal.
| | - M P L Parente
- INEGI, Institute of Science and Innovation in Mechanical and Industrial Engineering, Porto, Portugal; FEUP, Faculty of Engineering, University of Porto, Porto, Portugal.
| | - F Gentil
- Escola Superior de Saúde - Politécnico do Porto, Porto, Portugal; Clínica ORL - Dr. Eurico de Almeida, Porto, Portugal; WIDEX, Porto, Portugal.
| | - R M Natal Jorge
- INEGI, Institute of Science and Innovation in Mechanical and Industrial Engineering, Porto, Portugal; FEUP, Faculty of Engineering, University of Porto, Porto, Portugal.
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Hafeez N, Du X, Boulgouris N, Begg P, Irving R, Coulson C, Tourrel G. Electrical impedance guides electrode array in cochlear implantation using machine learning and robotic feeder. Hear Res 2021; 412:108371. [PMID: 34689069 DOI: 10.1016/j.heares.2021.108371] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 09/22/2021] [Accepted: 10/05/2021] [Indexed: 10/20/2022]
Abstract
Cochlear Implant provides an electronic substitute for hearing to severely or profoundly deaf patients. However, postoperative hearing outcomes significantly depend on the proper placement of electrode array (EA) into scala tympani (ST) during cochlear implant surgery. Due to limited intra-operative methods to access array placement, the objective of the current study was to evaluate the relationship between EA complex impedance and different insertion trajectories in a plastic ST model. A prototype system was designed to measure bipolar complex impedance (magnitude and phase) and its resistive and reactive components of electrodes. A 3-DoF actuation system was used as an insertion feeder. 137 insertions were performed from 3 different directions at a speed of 0.08 mm/s. Complex impedance data of 8 electrode pairs were sequentially recorded in each experiment. Machine learning algorithms were employed to classify both the full and partial insertion lengths. Support Vector Machine (SVM) gave the highest 97.1% accuracy for full insertion. When a real-time prediction was tested, Shallow Neural Network (SNN) model performed better than other algorithms using partial insertion data. The highest accuracy was found at 86.1% when 4 time samples and 2 apical electrode pairs were used. Direction prediction using partial data has the potential of online control of the insertion feeder for better EA placement. Accessing the position of the electrode array during the insertion has the potential to optimize its intraoperative placement that will result in improved hearing outcomes.
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Affiliation(s)
- Nauman Hafeez
- Institute of Environment, Health and Societies, Brunel University, London, UB8 3PH, UK.
| | - Xinli Du
- Institute of Environment, Health and Societies, Brunel University, London, UB8 3PH, UK
| | - Nikolaos Boulgouris
- Institute of Environment, Health and Societies, Brunel University, London, UB8 3PH, UK
| | - Philip Begg
- University Hospitals Birmingham NHS Foundation Trust, Birmingham, B15 2GW, UK
| | - Richard Irving
- University Hospitals Birmingham NHS Foundation Trust, Birmingham, B15 2GW, UK
| | - Chris Coulson
- University Hospitals Birmingham NHS Foundation Trust, Birmingham, B15 2GW, UK
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Hou L, Du X, Boulgouris NV, Hafeez N, Coulson C, Irving R, Begg P, Brett P. A Capacitive Cochlear Implant Electrode Array Sensing System to Discriminate Fold-Over Pattern. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2021; 64:3685-3696. [PMID: 34407380 DOI: 10.1044/2021_jslhr-21-00067] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Purpose During insertion of the cochlear implant electrode array, the tip of the array may fold back on itself and can cause serious complications to patients. This article presents a sensing system for cochlear implantation in a cochlear model. The electrode array fold-over behaviors can be detected by analyzing capacitive information from the array tip. Method Depending on the angle of the array tip against the cochlear inner wall when it enters the cochlear model, different insertion patterns of the electrode array could occur, including smooth insertion, buckling, and fold-over. The insertion force simulating the haptic feedback for surgeons and bipolar capacitance signals during the insertion progress were collected and compared. The Pearson correlation coefficient (PCC) was applied to the collected capacitive signals to discriminate the fold-over pattern. Results Forty-six electrode array insertions were conducted and the deviation of the measured insertion force varies between a range of 20% and 30%. The capacitance values from electrode pair (1, 2) were recorded for analyzing. A threshold for the PCC is set to be 0.94 that can successfully discriminate the fold over insertions from the other two types of insertions, with a success rate of 97.83%. Conclusions Capacitive measurement is an effective method for the detection of faulty insertions and the maximization of the outcome of cochlear implantation. The proposed capacitive sensing system can be used in other tissue implants in vessels, spinal cord, or heart.
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Affiliation(s)
- Lei Hou
- Brunel University London, United Kingdom
| | - Xinli Du
- Brunel University London, United Kingdom
| | | | | | - Chris Coulson
- Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham, United Kingdom
| | - Richard Irving
- Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham, United Kingdom
| | - Philip Begg
- Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham, United Kingdom
| | - Peter Brett
- University of Southern Queensland, Toowoomba, Australia
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Eser MB, Atalay B, Kalcıoğlu MT. Is Cochlear Length Related to Congenital Sensorineural Hearing Loss: Preliminary Data. J Int Adv Otol 2021; 17:1-8. [PMID: 32147598 DOI: 10.5152/iao.2020.7863] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVES This study used the data from patients with congenital sensorineural hearing loss (CSNHL) and those with normal hearing to measure and compare the length of the cochlea with high-resolution computed tomography (HRCT). MATERIALS AND METHODS HRCT images of patients who were diagnosed with CSNHL and were candidates for cochlear implantation were evaluated retrospectively. Sixty-three ears of 33 patients were included in the study. The control group comprised 66 ears of 33 individuals. The measurements were conducted by an experienced radiologist, using three-dimensional curved multiplanar reconstruction. All the measurements were performed thrice, and the average was calculated. RESULTS The data were distributed normally. The lengths of the cochlear components for the CSNHL and control groups were as follows: basal turn 21.66±1.01 (21.30-22.02) and 22.57±0.68 (22.32-22.81) mm, middle turn 11.58±0.69 (11.34-11.83) and 12.39±0.46 (12.23-12.56) mm, and apical turn 6.45±0.92 (6.12-6.77) and 7.12±0.65 (6.89-7.35) mm, respectively. The mean cochlear lateral wall (LW) length was significantly shorter in the CSNHL patients [39.71±1.32 (39.25-40.18) mm] than in the controls [42.09±1.17 (41.67-42.51) mm], (p<0.001). The intra-rater reliability was 0.878 (confidence interval 95%: 0.841-0.908 p<0.001). The cut-off value was 40.81 mm (sensitivity: 0.91, specificity: 0.94, and accuracy: 0.90). CONCLUSION There were microanatomic dissimilarities between the length of the cochlea in subjects from the CSNHL group and those from the control group.
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Affiliation(s)
- Mehmet Bilgin Eser
- Department of Radiology, Istanbul Medeniyet University School of Medicine, Istanbul, Turkey
| | - Başak Atalay
- Department of Radiology, Istanbul Medeniyet University School of Medicine, Istanbul, Turkey
| | - Mahmut Tayyar Kalcıoğlu
- Department of Otorhinolaryngology - Head and Neck Surgery, Istanbul Medeniyet University School of Medicine, İstanbul, Turkey
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Riojas KE, Tran ET, Freeman MH, Noble JH, Webster RJ, Labadie RF. Clinical Translation of an Insertion Tool for Minimally Invasive Cochlear Implant Surgery. J Med Device 2021; 15:031001. [PMID: 33995757 PMCID: PMC8086187 DOI: 10.1115/1.4050203] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 01/22/2021] [Indexed: 11/08/2022] Open
Abstract
The objective of this paper is to describe the development of a minimally invasive cochlear implant surgery (MICIS) electrode array insertion tool concept to enable clinical translation. First, analysis of the geometric parameters of potential MICIS patients (N = 97) was performed to inform tool design, inform MICIS phantom model design, and provide further insight into MICIS candidacy. Design changes were made to the insertion tool based on clinical requirements and parameter analysis results. A MICIS phantom testing model was built to evaluate insertion force profiles in a clinically realistic manner, and the new tool design was evaluated in the model and in cadavers to test clinical viability. Finally, after regulatory approval, the tool was used for the first time in a clinical case. Results of this work included first, in the parameter analysis, approximately 20% of the population was not considered viable MICIS candidates. Additionally, one 3D printed tool could accommodate all viable candidates with polyimide sheath length adjustments accounting for interpatient variation. The insertion tool design was miniaturized out of clinical necessity and a disassembly method, necessary for removal around the cochlear implant, was developed and tested. Phantom model testing revealed that the force profile of the insertion tool was similar to that of traditional forceps insertion. Cadaver testing demonstrated that all clinical requirements (including complete disassembly) were achieved with the tool, and the new tool enabled 15% deeper insertions compared to the forceps approach. Finally, and most importantly, the tool helped achieve a full insertion in its first MICIS clinical case. In conclusion, the new insertion tool provides a clinically viable solution to one of the most difficult aspects of MICIS.
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Affiliation(s)
- Katherine E. Riojas
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37212
| | - Emily T. Tran
- Department of Mechanical Engineering, The University of Tulsa, Tulsa, OK 74104
| | - Michael H. Freeman
- Department of Otolaryngology–Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, TN 37232
| | - Jack H. Noble
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN 37212
| | - Robert J. Webster
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37212
| | - Robert F. Labadie
- Department of Otolaryngology–Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, TN 37232
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Riemann C, Sudhoff H, Todt I. Influence of Intracochlear Air on Experimental Pressure Measurements. Audiol Neurootol 2021; 27:34-39. [PMID: 34130281 DOI: 10.1159/000516142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 03/25/2021] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION Intracochlear pressure changes have been assumed to play a central role in hearing preservation during cochlear implantation. The pressure in different settings has been evaluated (temporal bones vs. cochlea models) and was found to have advantages and disadvantages. Experimentally, problems have been discussed to influence the results substantially. OBJECTIVE The aim of the present study was to evaluate the effect of intracochlear air on the measurements in a cochlea model by using a fiber optic pressure sensor. MATERIALS AND METHODS The experiments were performed in an uncurled 3D printed full cochlea model. A microfiber-optic pressure sensor was inserted, and intracochlear pressures were evaluated under 3 conditions: (1) cochlea model filled to 100% with fluid, (2) cochlea model filled with air, and (3) cochlea model filled to approximately 50% with fluid. Since the cochlea model is transparent, a direct visualization of air under the microscope was possible when performing the insertions. RESULTS In the first condition, the mean intracochlear pressure at the end of the insertion was 0.044 psi (SD 0.012, 95% CI). In the second setting, the results were similar. In the last scenario, with 50% filling, the mean intracochlear pressure was statistically significantly different with a mean value of 0.074 psi (SD 0.013, 95% CI) (p < 0.0044, ANOVA). Besides this, in the last condition with 50% fluid, a plateau was formed when the fiber optic reached the air portion. CONCLUSION The results obtained in a 3D printed full cochlea model show the importance of a direct evaluation of air inside the experimental setting. The exclusion of intracochlear air should be an important factor for the choice of the model for intracochlear pressure measurement (temporal bone vs. cochlea model).
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Affiliation(s)
- Conrad Riemann
- Department of Otolaryngology, Head and Neck Surgery, Bielefeld University, Campus Mitte, Klinikum Bielefeld, Bielefeld, Germany
| | - Holger Sudhoff
- Department of Otolaryngology, Head and Neck Surgery, Bielefeld University, Campus Mitte, Klinikum Bielefeld, Bielefeld, Germany
| | - Ingo Todt
- Department of Otolaryngology, Head and Neck Surgery, Bielefeld University, Campus Mitte, Klinikum Bielefeld, Bielefeld, Germany
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Aebischer P, Mantokoudis G, Weder S, Anschuetz L, Caversaccio M, Wimmer W. In-Vitro Study of Speed and Alignment Angle in Cochlear Implant Electrode Array Insertions. IEEE Trans Biomed Eng 2021; 69:129-137. [PMID: 34110987 DOI: 10.1109/tbme.2021.3088232] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
OBJECTIVE The insertion of the electrode array is a critical step in cochlear implantation. Herein we comprehensively investigate the impact of the alignment angle and feed-forward speed on deep insertions in artificial scala tympani models with accurate macro-anatomy and controlled frictional properties. METHODS Motorized insertions (n=1033) were performed in six scala tympani models with varying speeds and alignment angles. We evaluated reaction forces and micrographs of the insertion process and developed a mathematical model to estimate the normal force distribution along the electrode arrays. RESULTS Insertions parallel to the cochlear base significantly reduce insertion energies and lead to smoother array movement. Non-constant insertion speeds allow to reduce insertion forces for a fixed total insertion time compared to a constant feed rate. CONCLUSION In cochlear implantation, smoothness and peak forces can be reduced with alignment angles parallel to the scala tympani centerline and with non-constant feed-forward speed profiles. SIGNIFICANCE Our results may help to provide clinical guidelines and improve surgical tools for manual and automated cochlear implantation.
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Frictional Behavior of Cochlear Electrode Array Is Dictated by Insertion Speed and Impacts Insertion Force. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11115162] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Background: During cochlear implantation, the electrode array has significant friction with the sensitive endocochlear lining and causes mutual mechanical trauma while the array is being inserted. Both, the impact of insertion speed on electrode friction and the relationship of electrode insertion force and friction have not been adequately investigated to date. Methods: In this study, friction coefficients between a CI electrode array (31.5 mm) and a tissue simulating the endocochlear lining have been acquired, depending on different insertion speeds (0.1, 0.5, 1.0, 1.5, and 2.0 mm/s). Additionally, the electrode insertion forces during the placing into a scala tympani model were recorded and correlated with the friction coefficient. Results: It was shown that the friction coefficient reached the lowest value at an insertion speed of 0.1 mm/s (0.24 ± 0.13), a maximum occurred at 1.5 mm/s (0.59 ± 0.12), and dropped again at 2 mm/s (0.45 ± 0.11). Similar patterns were observed for the insertion forces. Consequently, a high correlation coefficient (0.9) was obtained between the insertion forces and friction coefficients. Conclusion: The present study reveals a non-linear increase in electrode array friction, when insertion speed raises and reports a high correlation between friction coefficient and electrode insertion force. This dependence is a relevant future parameter to evaluate and reduce cochlear implant insertion trauma. Significance statement: Here, we demonstrated a dependence between cochlear electrode insertion speed and its friction behavior and a high correlation to insertion force. Our study provides valuable information for the evaluation and prevention of cochlear implant insertion trauma and supports the optimization of cochlear electrode arrays regarding friction characteristics.
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Robot-assisted Cochlear Implant Electrode Array Insertion in Adults: A Comparative Study With Manual Insertion. Otol Neurotol 2021; 42:e438-e444. [PMID: 33306661 DOI: 10.1097/mao.0000000000003002] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To describe the first cochlear array insertions using a robot-assisted technique, with different types of straight or precurved electrode arrays, compared with arrays manually inserted into the cochlea. STUDY DESIGN Retrospective review. SETTING Tertiary otologic center. PATIENTS Twenty cochlear implantations in the robot-assisted group and 40 in the manually inserted group. INTERVENTIONS Cochlear implantations using a robot-assisted technique (RobOtol) with straight (eight Cochlear CI522/622, and eight Advanced Bionics Hifocus Slim J) or precurved (four Advanced Bionics Hifocus Mid-Scala) matched to manual cochlear implantations. Three-dimensional reconstruction images of the basilar membrane and the electrode array were obtained from pre- and postimplantation computed tomography. MAIN OUTCOME MEASURES Rate and localization of scalar translocations. RESULTS For straight electrode arrays, scalar translocations occurred in 19% (3/16) of the robot-assisted group and 31% (10/32) of the manually inserted group. Considering the number of translocated electrodes, this was lower in the robot-assisted group (7%) than in the manually inserted group (16%) (p < 0.0001, χ2 test). For precurved electrode arrays, scalar translocations occurred in 50% (2/4) of the robot-assisted group and 38% (3/8) of the manually inserted group. CONCLUSION This study showed a safe and reliable insertion of different electrode array types with a robot-assisted technique, with a less traumatic robotic insertion of straight electrode arrays when compared with manual insertion.
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On the Intracochlear Location of Straight Electrode Arrays After Cochlear Implantation: How Lateral Are Lateral Wall Electrodes? Otol Neurotol 2021; 42:242-250. [PMID: 33026778 DOI: 10.1097/mao.0000000000002880] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
OBJECTIVE Cochlear implants are the gold standard for patients with severe sensorineural hearing loss. A focused electrical stimulation of individual spiral ganglion neurons has not been achieved yet because the scala tympani is a fluid-filled compartment and does not offer a matrix for neuritic outgrowth. Coating of the electrode contacts with swelling hydrogels could fill that gap between the electrode array and the medial wall of the cochlea. Therefore, the exact position of the electrode array within the scala tympani has to be known. STUDY DESIGN Retrospective analysis of patient data sets. SETTING Tertiary referral center. A total of 95 patients with cochlear implants from one manufacturer were included in this study. The lateral wall, the modiolar wall, and the cochlear implant electrode were segmented using OsiriX MD. For repositioning and reconstructing the respective contours and measuring distances, files were analyzed in MATLAB. The distances from the edge of each electrode contact to the cochlear walls showed no significant differences. But between the different contacts within each patient, there were significant differences. Around 180 degree insertion, electrodes start to get in contact with the lateral wall. The tip of the electrode array was always facing toward the modiolar wall independent of the length of the electrode. We established a method to analyze the position of electrodes within the cochlea.
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The Effect of Ultra-slow Velocities on Insertion Forces: A Study Using a Highly Flexible Straight Electrode Array. Otol Neurotol 2021; 42:e1013-e1021. [PMID: 33883518 DOI: 10.1097/mao.0000000000003148] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE The present study sought to 1) characterize insertion forces resulting from a flexible straight electrode array (EA) inserted at slow and ultra-slow insertion velocities, and 2) evaluate if ultra-slow velocities decrease insertion forces independent of other variables. BACKGROUND Low insertion forces are desirable in cochlear implant (CI) surgery to reduce trauma and preserve hearing. Recently, ultra-slow insertion velocities (lower than manually feasible) have been shown to produce significantly lower insertion forces using other EAs. METHODS Five flexible straight EAs were used to record insertion forces into an inelastic artificial scala tympani model. Eleven trial recordings were performed for each EA at five predetermined automated, continuous insertion velocities ranging from 0.03 to 1.6 mm/s. RESULTS An ultra-slow insertion velocity of 0.03 mm/s resulted in a median insertion force of 0.010 N at 20 mm of insertion depth, and 0.026 N at 24.3 mm-the final insertion depth. These forces represent only 24 to 29% of those measured using 1.6 mm/s. After controlling for insertion depth of the EA into the artificial scala tympani model and trial insertion number, decreasing the insertion velocity from 0.4 to 0.03 mm/s resulted in a 50% decrease in the insertion forces. CONCLUSION Using the tested EA ultra-slow velocities can decrease insertion forces, independent of variables like insertion depth. Our results suggest ultra-slow velocities can reduce insertion forces at least 60%, compared with humanly feasible continuous velocities (≥0.9 mm/s).
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Atalay B, Eser MB, Kalcioglu MT, Ankarali H. Comprehensive Analysis of Factors Affecting Cochlear Size: A Systematic Review and Meta-analysis. Laryngoscope 2021; 132:188-197. [PMID: 33764541 DOI: 10.1002/lary.29532] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 03/09/2021] [Accepted: 03/16/2021] [Indexed: 12/14/2022]
Abstract
OBJECTIVES To determine the cochlea's average size in humans and evaluate the relationships between certain covariates and cochlear size. METHODS A systematic search on articles on cochlear size and published in English was conducted using Cochrane, PubMed, Web of Science, and Scopus databases up to September 15, 2020. Data were pooled using random-effects with three models. The effect of demographic, clinical, and measurement-related parameters was specifically analyzed. Meta-regression and subgroup analyses were conducted. The overall effect estimation was made for outcomes. RESULTS The meta-analysis included 4,708 cochleae from 56 studies. The overall length of the organ of Corti was 32.94 mm (95% confidence interval [CI]: 32.51-33.38). The first and second models revealed that age, gender, country, continent, measurement method (direct, indirect), measured structure ("A" value, cochlear lateral wall), origin (in vivo, in vitro), and type (histology specimens, plastic casts, imaging) of the cochlear material did not affect the cochlear size. However, study populations (general population, patients with a cochlear implant, and patients with congenital sensorineural hearing loss [CSNHL]) were found to affect the outcomes. Compared to the other populations, patients with CSNHL had shorter cochleae. Therefore, we developed a third model and found that the general population and patients with cochlear implants did not differ in cochlear size. CONCLUSION This meta-analysis investigated the factors that could affect the cochlear size and found that patients with CSNHL had significantly shorter cochleae, whereas other covariates had no significant effect. Laryngoscope, 2021.
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Affiliation(s)
- Basak Atalay
- Faculty of Medicine, Department of Radiology, Goztepe Training and Research Hospital, Istanbul Medeniyet University, Istanbul, Turkey
| | - Mehmet Bilgin Eser
- Faculty of Medicine, Department of Radiology, Goztepe Training and Research Hospital, Istanbul Medeniyet University, Istanbul, Turkey
| | - Mahmut Tayyar Kalcioglu
- Faculty of Medicine, Department of Otorhinolaryngology-Head and Neck Surgery, Goztepe Training and Research Hospital, Istanbul Medeniyet University, Istanbul, Turkey
| | - Handan Ankarali
- Faculty of Medicine, Department of Biostatistics and Medical Informatics, Istanbul Medeniyet University, Istanbul, Turkey
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Snels C, Roland JT, Treaba C, Jethanamest D, Huinck W, Friedmann DR, Dhooge I, Mylanus E. Force and pressure measurements in temporal bones. Am J Otolaryngol 2021; 42:102859. [PMID: 33440250 DOI: 10.1016/j.amjoto.2020.102859] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 12/22/2020] [Indexed: 10/22/2022]
Abstract
PURPOSE Some cochlear implant (CI) patients lose their residual hearing during surgery. Two factors that might play a role in residual hearing loss are the change in intracochlear hydraulic pressure and force on the cochlear wall during electrode insertion. The aim of this study is to investigate whether a difference in peak hydraulic pressure and peak force on the cochlear wall exists during a CI electrode insertion with different insertion techniques. MATERIALS AND METHODS Twenty fresh frozen temporal bones were used. Hydraulic pressure and force on the cochlear wall were recorded during straight electrode insertions with 1) slow versus fast insertion speed, 2) manual versus automatic insertion method and 3) round window approach (RWA) versus extended RWA (ERWA). RESULTS When inserting with a slow compared to a fast insertion speed, the peak hydraulic pressure is 239% (95% CI: 130-399%) higher with a RWA and 58% (95% CI: 6-137%) higher with an ERWA. However, the peak force on the cochlear wall is a factor 29% less (95% CI: 13-43%) with a slow insertion speed. No effect was found of opening and insertion method. CONCLUSIONS As contradictory findings were found for hydraulic pressure and force on the cochlear wall on insertion speed, it remains unclear which insertion speed (slow versus fast) is less traumatic to inner ear structure.
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Practicable assessment of cochlear size and shape from clinical CT images. Sci Rep 2021; 11:3448. [PMID: 33568727 PMCID: PMC7876007 DOI: 10.1038/s41598-021-83059-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 01/25/2021] [Indexed: 11/08/2022] Open
Abstract
There is considerable interpersonal variation in the size and shape of the human cochlea, with evident consequences for cochlear implantation. The ability to characterize a specific cochlea, from preoperative computed tomography (CT) images, would allow the clinician to personalize the choice of electrode, surgical approach and postoperative programming. In this study, we present a fast, practicable and freely available method for estimating cochlear size and shape from clinical CT. The approach taken is to fit a template surface to the CT data, using either a statistical shape model or a locally affine deformation (LAD). After fitting, we measure cochlear size, duct length and a novel measure of basal turn non-planarity, which we suggest might correlate with the risk of insertion trauma. Gold-standard measurements from a convenience sample of 18 micro-CT scans are compared with the same quantities estimated from low-resolution, noisy, pseudo-clinical data synthesized from the same micro-CT scans. The best results were obtained using the LAD method, with an expected error of 8-17% of the gold-standard sample range for non-planarity, cochlear size and duct length.
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Woodson E, Nelson RC, Smeal M, Haberkamp T, Sydlowski S. Initial hearing preservation outcomes of cochlear implantation with a slim perimodiolar electrode array. Cochlear Implants Int 2021; 22:148-156. [PMID: 33443000 DOI: 10.1080/14670100.2020.1858553] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
OBJECTIVE To assess the slim modiolar array as a hearing preservation electrode. METHODS Retrospective chart review of adult, post-lingual CI recipients implanted with slim modiolar array Sept 2016 to July 2017 in a tertiary referral center. Baseline audiograms were obtained within six months of initial CI evaluation. Patients with low frequency pure tone average (LFPTA) (125, 250, 500 Hz) <80 dB were considered HP candidates. Postoperative audiograms were obtained within 48 h before activation. Successful HP was considered as (1) retention of LFPTA threshold <80 dB and (2) change in threshold from pre- to post-operative. RESULTS Sixty-three patients received the slim perimodiolar array and 42 were HP candidates. Post-operative audiograms were obtained for 39 of 42 patients an average of 28.92 days after surgery. 56.4% of HP candidates retainedLFPTA <80 dB. Mean ΔLFPTA was 24.15 dB (±16.14; p < 0.001). 56.4% of HP candidates experienced Δ LFPTA <20 dB; 69.2% <30 dB. Functional hearing preservation was more successful in lower frequencies where starting thresholds were better - 78% with LFPTA <50 dB retained serviceable hearing at activation. The postoperative change was similar in each low frequency (Δ125 Hz: mean 21.25 +/- 14.76 (N = 28); Δ250 Hz: 26.28 +/- 19.29 (N = 39); Δ500 Hz: 25.00 +/- 17.73 (N = 39)). CONCLUSIONS The slim perimodiolar array is moderately effective at immediate hearing preservation. In subjects with preoperative audiometric profiles similar to those in prior EAS trials, immediate HP is comparable.
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Affiliation(s)
- Erika Woodson
- Cleveland Clinic Head and Neck Institute, Cleveland, OH, USA
| | | | - Molly Smeal
- Cleveland Clinic Head and Neck Institute, Cleveland, OH, USA
| | | | - Sarah Sydlowski
- Cleveland Clinic Head and Neck Institute, Cleveland, OH, USA
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Jwair S, Prins A, Wegner I, Stokroos RJ, Versnel H, Thomeer HGXM. Scalar Translocation Comparison Between Lateral Wall and Perimodiolar Cochlear Implant Arrays - A Meta-Analysis. Laryngoscope 2020; 131:1358-1368. [PMID: 33159469 PMCID: PMC8246990 DOI: 10.1002/lary.29224] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 10/15/2020] [Accepted: 10/16/2020] [Indexed: 12/15/2022]
Abstract
Objectives/Hypothesis Two types of electrode arrays for cochlear implants (CIs) are distinguished: lateral wall and perimodiolar. Scalar translocation of the array can lead to intracochlear trauma by penetrating from the scala tympani into the scala vestibuli or scala media, potentially negatively affecting hearing performance of CI users. This systematic review compares the lateral wall and perimodiolar arrays with respect to scalar translocation. Study Design Systematic review. Methods PubMed, Embase, and Cochrane databases were reviewed for studies published within the last 11 years. No other limitations were set. All studies with original data that evaluated the occurrence of scalar translocation or tip fold‐over (TF) with postoperative computed tomography (CT) following primary cochlear implantation in bilateral sensorineuronal hearing loss patients were considered to be eligible. Data were extracted independently by two reviewers. Results We included 33 studies, of which none were randomized controlled trials. Meta‐analysis of five cohort studies comparing scalar translocation between lateral wall and perimodiolar arrays showed that lateral wall arrays have significantly lower translocation rates (7% vs. 43%; pooled odds ratio = 0.12). Translocation was negatively associated with speech perception scores (weighted mean 41% vs. 55%). Tip fold‐over of the array was more frequent with perimodiolar arrays (X2 = 6.8, P < .01). Conclusions Scalar translocation and tip fold‐overs occurred more frequently with perimodiolar arrays than with lateral wall arrays. In addition, translocation of the array negatively affects hearing with the cochlear implant. Therefore, if one aims to minimize clinically relevant intracochlear trauma, lateral wall arrays would be the preferred option for cochlear implantation. Laryngoscope, 131:1358–1368, 2021
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Affiliation(s)
- Saad Jwair
- Department of Otorhinolaryngology and Head & Neck Surgery, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands.,UMC Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Adrianus Prins
- Department of Otorhinolaryngology and Head & Neck Surgery, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Inge Wegner
- Department of Otorhinolaryngology and Head & Neck Surgery, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Robert J Stokroos
- Department of Otorhinolaryngology and Head & Neck Surgery, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands.,UMC Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Huib Versnel
- Department of Otorhinolaryngology and Head & Neck Surgery, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands.,UMC Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Hans G X M Thomeer
- Department of Otorhinolaryngology and Head & Neck Surgery, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands.,UMC Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
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Fluoroscopy guided electrode-array insertion for cochlear implantation with straight electrode-arrays: a valuable tool in most cases. Eur Arch Otorhinolaryngol 2020; 278:965-975. [PMID: 32588170 DOI: 10.1007/s00405-020-06151-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 06/17/2020] [Indexed: 10/24/2022]
Abstract
PURPOSE To highlight the advantages of real time fluoroscopy guided electrode-array (EA) insertion (FGI) during cochlear implants surgery. METHODS All surgical procedures were performed in a dedicated operating room equipped with a robotic C-arm cone beam device, allowing for intraoperative real time 2D FGI and postoperative 3D imaging. Only straight EAs were used. Patients were sorted out in three groups: ANAT, with anatomical concerns; HP, with residual hearing; NPR: patients with no particular reason for FGI. In all cases the angle of EA-insertion was measured. In the HP group pre and postoperative hearing were compared. The radiation delivered to the patient was recorded. RESULTS Fifty-three cochlear implantation procedures were achieved under fluoroscopy in 50 patients from November 2015 to January 2020 (HP group: n = 10; ANAT group: n = 13; NPR group: n = 27). In the ANAT group, FGI proved to be helpful in 8 cases (61.5%), successfully guiding the surgeon during EA -insertion. On average, the angle of insertion was at 424° ± 55°. In the HP group, a controlled smooth EA-insertion was carried out in all cases but one. The targeted 360° angle of insertion was always reached. Hearing preservation was possible with an eventual average drop of 30 ± 1.5 dB. In the NPR group, FGI helped control the quality of insertion in all cases and appeared very informative in five (17.8%): one EA-misrouting, three stuck EAs, and one case with hidden electrodes out of the cochlea in revision surgery. Final 3D cone beam CT scan double-checked the EA position in all adults. The radiation dose was equivalent to a bit less than four digital subtract radiographs. CONCLUSION The FGI is a very useful adjunct in cochlear implantation in all cases of expected surgical pitfalls, in patients with residual hearing, and even in case without preoperative particular reason, with low irradiation.
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Abstract
INTRODUCTION A modern cochlear implant electrode array design must combine: improved surgical ease of use, structure preservation, particularly important for pediatric application, stable position within the cochlea over time, and a meaningful balance between hearing preservation against addressing sufficient cochlear tissue to support electrical-only hearing. The aim of this study was to investigate a new lateral wall electrode array design from Advanced Bionics on human temporal bones (TBs). METHODS Ten fresh-frozen TBs were implanted with the SlimJ electrode array via the round window. The electrode array is 23 mm long, with a cross-section varying from 0.25 × 0.55 mm at the most apical contact to 0.6 × 0.8 mm at the proximal marker contact. To assess location of the electrode array, the TBs were postoperatively scanned using cone beam computed tomography, and histology was performed to assess intracochlear trauma (Grades 0-4). RESULTS All electrode arrays were considered easy to insert. The average insertion depth was 432 degrees measured from the round window with a range from 411 to 450 degrees azimuth. Nine out of 10 electrode arrays were inserted fully (<0.5 mm out of the cochlea), one electrode array was left 1.5 mm out of the cochlea. No translocations were observed in all 10 cochleae, slight touching of the basilar membrane at the distal portion of the array was observed in 50% of the cases. CONCLUSION The results from the new thin lateral wall electrode array from Advanced Bionics provided consistent scala tympani locations. No translocations were observed and almost all electrode arrays were fully inserted. These results are promising and the new electrode array will be further studied in clinical practice investigating hearing preservation capabilities and speech performance.
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Development of a rapidly made, easily personalized drug-eluting polymer film on the electrode array of a cochlear implant during surgery. Biochem Biophys Res Commun 2020; 526:328-333. [PMID: 32220497 DOI: 10.1016/j.bbrc.2020.02.171] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 02/26/2020] [Indexed: 01/12/2023]
Abstract
OBJECTIVE To develop a drug-eluting polymer film which can be easily personalized and rapidly made on the electrode array of a cochlear implant during surgery. METHODS A precursor solution was prepared with poly lactic-co-glycolic acid (PLGA) and trichloromethane. Using a dip-coating method, the silicone electrode array (HiFocus 1J, Advanced Bionics) was coated in polymer film produced from the precursor solution containing one of three drugs: dexamethasone sodium phosphate (DSP), cytosine arabinoside hydrochloride (Ara-C), or nicotinamide adenine dinucleotide (NAD), and the release of these drugs from the polymer film was studied. The drug-eluting film on the electrode array was analyzed by environmental scanning electron microscopy (ESEM). The water contact angle and the impedance of the electrode array were measured before and after coating. Drug release kinetics was evaluated in a quasi-stationary release model, using high performance liquid chromatography every 24 h for 15 days. RESULTS Five electrode arrays were tested with each of the three drugs in the polymer film coating. Before and after coating, ESEM studies revealed that the drug-loaded PLGA coating yielded a smooth covering with an average thickness of 1.02 ± 0.05 μm. The mass of the coated electrode increased by 1.00 ± 0.03 mg. The water contact angle decreased after coating (102 ± 0.6° vs 77 ± 1.6°, p < 0.01) but there was no significant change in the average impedance of the electrodes after coating (0.9 ± 0.22 kΩ vs 1.0 ± 0.18 kΩ, p > 0.05). An in vitro drug kinetics study revealed a faster release in the first 24 h (63.4 ± 0.6%) and a sustained release over the following 15 days (78.3 ± 1.7% in 2 days, 95.6 ± 1.0% in 7 days and 99.1 ± 0.4% in 14 days). The release rate was not affected by the drug, dose or the thickness of the coating. CONCLUSION The dip-coating method is feasible for rapid casting of a drug-eluting PLGA film on an electrode array during CI surgery. The coated electrode array maintained its original morphology and became more hydrophilic. The loaded drug is released in a sustained manner and is easily regulated, and so the method might represent a potential application for clinical use in cochlear implantation.
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Four-point impedance as a biomarker for bleeding during cochlear implantation. Sci Rep 2020; 10:2777. [PMID: 32066743 PMCID: PMC7026160 DOI: 10.1038/s41598-019-56253-w] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 11/07/2019] [Indexed: 12/24/2022] Open
Abstract
Cochlear implantation has successfully restored the perception of hearing for nearly 200 thousand profoundly deaf adults and children. More recently, implant candidature has expanded to include those with considerable natural hearing which, when preserved, provides an improved hearing experience in noisy environments. But more than half of these patients lose this natural hearing soon after implantation. To reduce this burden, biosensing technologies are emerging that provide feedback on the quality of surgery. Here we report clinical findings on a new intra-operative measurement of electrical impedance (4-point impedance) which, when elevated, is associated with high rates of post-operative hearing loss and vestibular dysfunction. In vivo and in vitro data presented suggest that elevated 4-point impedance is likely due to the presence of blood within the cochlea rather than its geometry. Four-point impedance is a new marker for the detection of cochlear injury causing bleeding, that may be incorporated into intraoperative monitoring protocols during CI surgery.
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Gonzalez JR, Cass ND, Banakis Hartl RM, Peacock J, Cass SP, Greene NT. Characterizing Insertion Pressure Profiles During Cochlear Implantation: Simultaneous Fluoroscopy and Intracochlear Pressure Measurements. Otol Neurotol 2020; 41:e46-e54. [PMID: 31613835 PMCID: PMC10821719 DOI: 10.1097/mao.0000000000002437] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Combined electrical-acoustical stimulation (EAS) has gained popularity as patients with residual hearing are increasingly undergoing cochlear implantation. Preservation of residual hearing correlates with hearing outcomes, but loss of hearing occurs in a subset of these patients. Several mechanisms have been proposed as causing this hearing loss; we have previously described high amplitude pressure transients, equivalent to high-level noise exposures, in the inner ear during electrode insertion. The source of these transients has not been identified. METHODS Cadaveric human heads were prepared with an extended facial recess. Fiber-optic pressure sensors were inserted into the scala vestibuli and scala tympani to measure intracochlear pressures. Two cochlear implant (CI) electrode styles (straight and perimodiolar) were inserted during time-synced intracochlear pressures and video fluoroscopy measurements. RESULTS CI electrode insertions produced pressure transients in the cochlea up to 160 to 170 dB pSPL equivalent for both styles, consistent with previous results. However, the position of the electrode within the cochlea when transients were generated differed (particularly contact with the medial or lateral walls). CONCLUSIONS These results begin to elucidate the insertion pressure profiles of CI electrodes, which can be used to improve CI electrode designs and facilitate "silent-insertions" to improve chances of hearing preservation.
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Affiliation(s)
- Joseph R. Gonzalez
- Department of Otolaryngology, University of Colorado School of Medicine, Aurora, CO
| | - Nathan D. Cass
- Department of Otolaryngology, University of Colorado School of Medicine, Aurora, CO
| | | | - John Peacock
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, CO
| | - Stephen P. Cass
- Department of Otolaryngology, University of Colorado School of Medicine, Aurora, CO
| | - Nathaniel T. Greene
- Department of Otolaryngology, University of Colorado School of Medicine, Aurora, CO
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Cochlear Implantation With a Novel Long Straight Electrode: the Insertion Results Evaluated by Imaging and Histology in Human Temporal Bones. Otol Neurotol 2019; 39:e784-e793. [PMID: 30199496 DOI: 10.1097/mao.0000000000001953] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
HYPOTHESIS To evaluate the insertion results of a novel straight array (EVO) by detailed imaging and subsequent histology in human temporal bones (TB). BACKGROUND The main focuses of modern cochlear implant surgery are to prevent damage to the intracochlear structures and to preserve residual hearing. This is often achievable with new atraumatic electrode arrays in combination with meticulous surgical techniques. METHODS Twenty fresh-frozen TBs were implanted with the EVO. Pre- and postoperative cone beam computed tomography scans were reconstructed and fused for an artifact-free representation of the electrode. The array's vertical position was quantified in relation to the basilar membrane on basis of which trauma was classified (Grades 0-4). The basilar membrane location was modeled from previous histologic data. The TBs underwent subsequent histologic examination. RESULTS The EVOs were successfully inserted in all TBs. Atraumatic insertion (Grades 0-1) were accomplished in 14 of 20 TBs (70%). There were three apical translocations, and two basal translocations due to electrode bulging. One TB had multiple translocations. The sensitivity and specificity of imaging for detecting insertion trauma (Grades 2-4) was 87.5% and 97.3.0%, respectively. CONCLUSION Comparable insertion results as reported for other arrays were also found for the EVO. Insertion trauma can be mostly avoided with meticulous insertion techniques to prevent bulging and by limiting the insertion depth angle to 360 degrees. The image fusion technique is a reliable tool for evaluating electrode placement and is feasible for trauma grading.
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Rebscher S, Zhou DD, Zeng FG. Development and Clinical Introduction of the Nurotron Cochlear Implant Electrode Array. J Int Adv Otol 2019; 14:392-400. [PMID: 30644380 DOI: 10.5152/iao.2018.6285] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
As the only medical device used in the treatment for deafness, the cochlear implant has benefited to more than half a million individuals worldwide. However, the device has limited penetration due to its high cost, especially in low- and middle-income countries. China alone has 27.8 million deaf people, but less than 100,000 of them have received a cochlear implant. The Nurotron Venus device was developed to address the need for an affordable yet safe and effective cochlear implant. The present study describes the design, development, and evaluation of the Nurotron intracochlear electrode array. The standard array is 22 mm in length from the round window marker to the apical tip of the carrier and has 24 electrodes, with a surface area of 0.32 mm2 and center-to-center spacing of 0.85 mm. The Nurotron array has been tested to meet the mechanical, chemical, and electrical requirements specified by the ISO Standard 14708-07. Human temporal bone and clinical trial results showed that the Nurotron array is easy to insert (7.8/10 rating with 10 indicating the highest ease of use) and has a low complication rate (12.5%) of severe insertion trauma while achieving high device stability and reliability (6 array failures in 43,000 patient years of experience). As a critical component, the Nurotron array has contributed to the high level of Nurotron implant speech performance, equivalent to that produced by other existing devices. The Nurotron device has benefited 10,000 deaf people and helped reduce the unit cost from US$25,000 in 2011 to US$4,620 in 2017 through the Chinese Government Tender Program. New, slim, and micromachined electrodes are being developed to further improve performance and accessibility.
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Affiliation(s)
- Stephen Rebscher
- Department of Otolaryngology, University of California San Francisco, San Francisco, USA
| | | | - Fan-Gang Zeng
- Department of Otolaryngology, University of California Irvine, Irvine, USA
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Cochlear Implant Insertion Axis Into the Basal Turn: A Critical Factor in Electrode Array Translocation. Otol Neurotol 2019; 39:168-176. [PMID: 29194215 DOI: 10.1097/mao.0000000000001648] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
HYPOTHESIS An inappropriate insertion axis leads to intracochlear trauma during cochlear implantation (CI). BACKGROUND Few studies assessed the relationship between the insertion axis and the electrode scalar location. METHODS Preimplantation cone-beam CT (CBCT) was performed on 12 human temporal bones. In five temporal bones, an optimal insertion axis was planned, due to the impossibility to attain the ST centerline from the posterior tympanotomy, because of facial canal position. In the seven other temporal bones, an inaccurate insertion axis was intentionally planned (optimal axis+15 degrees). Automated CI array insertion according to the planned axis was performed with a motorized insertion tool driven by a navigated robot-based arm. The cochlea and basilar membrane were segmented from the preimplantation CBCT and the array segmented from the postimplantation CBCT to construct a merged final three-dimensional (3D) model. Microscopical and 3D analysis were performed to determine the intracochlear trauma at the level of each electrode. RESULTS A good agreement was observed in determining electrode position between microscopic analysis and the 3D model (Cohen's kappa k = 0.67). The angle of approach to the ST centerline was associated with the number of electrodes inserted into the ST (r = -0.65, p = 0.02, [95% CI -0.90 to -0.11] Spearman's rank correlation). CONCLUSION A 3D reconstruction model was effective in determining the array position in the cochlea scalae. Our data indicate that the angle of approach to the ST centerline is a critical factor in intracochlear trauma. Additional studies should be conducted to assess the importance of the insertion axis with other array designs.
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Sosna M, Tacikowska G, Pietrasik K, Skarżyński H, Lorens A, Skarżyński PH. Effect on vestibular function of cochlear implantation by partial deafness treatment-electro acoustic stimulation (PDT-EAS). Eur Arch Otorhinolaryngol 2019; 276:1951-1959. [PMID: 31053967 PMCID: PMC6581932 DOI: 10.1007/s00405-019-05425-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 04/08/2019] [Indexed: 11/26/2022]
Abstract
Purpose Although the cochlear implantation procedure does not interfere with vestibular structures directly, both the vestibulum and the cochlea share the same inner ear fluid space, and this fluid may be responsible for transferring possibly damaging forces from one to the other. The purpose of the study is to assess postoperative vestibular function after partial deafness treatment–electro-acoustic stimulation (PDT–EAS) cochlear implantation. Methods Fifty-five patients were included in the study (30 females, 25 males, age 11–80, mean 41.8 ± 19.35). cVEMP and oVEMP were performed preoperatively and 1–3 months after cochlear implantation. Caloric and vHIT tests were conducted preoperatively and 4–6 months after cochlear implantation. Results Our study shows that, based on a wide range of electrodes, use of PDT–EAS is protective in terms of preserving vestibular function. It gives a rate of saccular damage of 15.79%, utricular damage of 19.04%, and a horizontal semicircular canal response reduction of 15.79%. Conclusions PDT–EAS is protective in terms of preserving vestibular function. Nevertheless, it should be emphasized that the risk of vestibular damage cannot be totally eliminated even when hearing preservation techniques are adopted.
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Affiliation(s)
- Magdalena Sosna
- Otorhinolaryngosurgery Clinic, Institute of Physiology and Pathology of Hearing, Warsaw, Poland
- Department of Otoneurology, Institute of Physiology and Pathology of Hearing, Warsaw, Poland
- World Hearing Center, Institute of Physiology and Pathology of Hearing, Mokra 17 Street, 05-830, Kajetany, Poland
| | - Grażyna Tacikowska
- Department of Otoneurology, Institute of Physiology and Pathology of Hearing, Warsaw, Poland
- World Hearing Center, Institute of Physiology and Pathology of Hearing, Mokra 17 Street, 05-830, Kajetany, Poland
| | - Katarzyna Pietrasik
- Department of Otoneurology, Institute of Physiology and Pathology of Hearing, Warsaw, Poland
- World Hearing Center, Institute of Physiology and Pathology of Hearing, Mokra 17 Street, 05-830, Kajetany, Poland
| | - Henryk Skarżyński
- Otorhinolaryngosurgery Clinic, Institute of Physiology and Pathology of Hearing, Warsaw, Poland
- World Hearing Center, Institute of Physiology and Pathology of Hearing, Mokra 17 Street, 05-830, Kajetany, Poland
| | - Artur Lorens
- Department of Auditory Implant and Perception, Institute of Physiology and Pathology of Hearing, Warsaw, Poland
- World Hearing Center, Institute of Physiology and Pathology of Hearing, Mokra 17 Street, 05-830, Kajetany, Poland
| | - Piotr H Skarżyński
- Otorhinolaryngosurgery Clinic, Institute of Physiology and Pathology of Hearing, Warsaw, Poland.
- World Hearing Center, Institute of Physiology and Pathology of Hearing, Mokra 17 Street, 05-830, Kajetany, Poland.
- Institute of Sensory Organs, Kajetany, Poland.
- Heart Failure and Cardiac Rehabilitation Department, Medical University of Warsaw, Warsaw, Poland.
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Risi F. Considerations and Rationale for Cochlear Implant Electrode Design - Past, Present and Future. J Int Adv Otol 2018; 14:382-391. [PMID: 30644379 PMCID: PMC6354527 DOI: 10.5152/iao.2018.6372] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 12/17/2018] [Indexed: 12/16/2022] Open
Abstract
The electrode array of a cochlear implant forms a permanent, often lifelong interface between the implanted electronics and neural structures of the cochlea. A cochlear implant is primarily prescribed to restore hearing via electrical stimulation of the auditory nerve. As with any neural stimulator intended to either deliver electrical stimulus or record a neural response, the aim is to place the electrodes in close proximity to the target neural structures. The broadening of indications and the concept of preservation of low-frequency residual hearing over the last two decades has resulted in an increased understanding of the mechanisms and implications of intracochlear trauma for both the hearing preservation surgery and electrical stimulation outcomes with cochlear implantation, as well as the influence of many biographic and audiological patient factors correlated with achieving better hearing outcomes. These two goals, the proximity to the cochlear nerve for electrical stimulation and the preservation of cochlear structures, have typically been viewed as mutually exclusive, with perimodiolar electrode arrays being preferred for the former, and lateral wall electrode arrays for the latter. The design evolution of both the lateral wall and perimodiolar electrodes is presented, considering the cochlea anatomy and continued understanding of the mechanics and dynamics of electrode insertion, along with the influence of the ongoing changes to the intracochlear environment to provide a rationale for the electrode design with the intent to provide the greatest patient benefit over their implanted lifetime.
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Affiliation(s)
- Frank Risi
- Group Product Manager, Surgical - Implants, Cochlear Limited, New South Wales, Australia
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