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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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Zagabathuni A, Padi KK, Kameswaran M, Subramani K. Development of Automated Tool for Electrode Array Insertion and its Study on Intracochlear Pressure. Laryngoscope 2024; 134:1388-1395. [PMID: 37584398 DOI: 10.1002/lary.30966] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 06/05/2023] [Accepted: 07/14/2023] [Indexed: 08/17/2023]
Abstract
Cochlear implantation is the most successful approach for people with profound sensorineural hearing loss. Manual insertion of the electrode array may result in damaging the soft tissue structures and basilar membrane. An automated electrode array insertion device is reported to be less traumatic in cochlear implant surgery. OBJECTIVES The present work develops a simple, reliable, and compact device for automatically inserting the electrode array during cochlear implantation and test the device to observe intracochlear pressure during simulated electrode insertion. METHODS The device actuates the electrode array by a roller mechanism. For testing the automated device, a straight cochlea having the dimension of the scala tympani and a model electrode is developed using a 3D printer. A pressure sensor is utilized to observe the pressure change at different insertional conditions. RESULTS The electrode is inserted into a prototype cochlea at different speeds without any pause, and it is noticed that the pressure is increased with the depth of insertion of the electrode irrespective of the speed of electrode insertion. The rate of pressure change is observed to be increased exponentially with the speed of insertion. CONCLUSION At an insertion speed of 0.15 mm/s, the peak pressure is observed to be 133 Pa, which can be further evaluated in anatomical models for clinical scenarios. LEVEL OF EVIDENCE N/A Laryngoscope, 134:1388-1395, 2024.
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Affiliation(s)
- Aparna Zagabathuni
- School of Materials Science and Engineering, National Institute of Technology Calicut, Calicut, India
| | - Kishore Kumar Padi
- Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati, India
| | | | - Kanagaraj Subramani
- Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati, India
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Wang T, Li H, Pu T, Yang L. Microsurgery Robots: Applications, Design, and Development. SENSORS (BASEL, SWITZERLAND) 2023; 23:8503. [PMID: 37896597 PMCID: PMC10611418 DOI: 10.3390/s23208503] [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: 09/24/2023] [Revised: 10/07/2023] [Accepted: 10/09/2023] [Indexed: 10/29/2023]
Abstract
Microsurgical techniques have been widely utilized in various surgical specialties, such as ophthalmology, neurosurgery, and otolaryngology, which require intricate and precise surgical tool manipulation on a small scale. In microsurgery, operations on delicate vessels or tissues require high standards in surgeons' skills. This exceptionally high requirement in skills leads to a steep learning curve and lengthy training before the surgeons can perform microsurgical procedures with quality outcomes. The microsurgery robot (MSR), which can improve surgeons' operation skills through various functions, has received extensive research attention in the past three decades. There have been many review papers summarizing the research on MSR for specific surgical specialties. However, an in-depth review of the relevant technologies used in MSR systems is limited in the literature. This review details the technical challenges in microsurgery, and systematically summarizes the key technologies in MSR with a developmental perspective from the basic structural mechanism design, to the perception and human-machine interaction methods, and further to the ability in achieving a certain level of autonomy. By presenting and comparing the methods and technologies in this cutting-edge research, this paper aims to provide readers with a comprehensive understanding of the current state of MSR research and identify potential directions for future development in MSR.
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Affiliation(s)
- Tiexin Wang
- ZJU-UIUC Institute, International Campus, Zhejiang University, Haining 314400, China; (T.W.); (H.L.); (T.P.)
- School of Mechanical Engineering, Zhejiang University, Hangzhou 310058, China
| | - Haoyu Li
- ZJU-UIUC Institute, International Campus, Zhejiang University, Haining 314400, China; (T.W.); (H.L.); (T.P.)
| | - Tanhong Pu
- ZJU-UIUC Institute, International Campus, Zhejiang University, Haining 314400, China; (T.W.); (H.L.); (T.P.)
| | - Liangjing Yang
- ZJU-UIUC Institute, International Campus, Zhejiang University, Haining 314400, China; (T.W.); (H.L.); (T.P.)
- School of Mechanical Engineering, Zhejiang University, Hangzhou 310058, China
- Department of Mechanical Engineering, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA
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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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Robotic pullback technique of a precurved cochlear-implant electrode array using real-time impedance sensing feedback. Int J Comput Assist Radiol Surg 2023; 18:413-421. [PMID: 36331796 DOI: 10.1007/s11548-022-02772-3] [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: 05/26/2022] [Accepted: 10/04/2022] [Indexed: 11/06/2022]
Abstract
PURPOSE During traditional insertion of cochlear implant (CI) electrode arrays (EAs), surgeons rely on limited tactile feedback and visualization of the EA entering the cochlea to control the insertion. One insertion approach for precurved EAs involves slightly overinserting the EA and then retracting it slightly to achieve closer hugging of the modiolus. In this work, we investigate whether electrical impedance sensing could be a valuable real-time feedback tool to advise this pullback technique. METHODS Using a to-scale 3D-printed scala tympani model, a robotic insertion tool, and a custom impedance sensing system, we performed experiments to assess the bipolar insertion impedance profiles for a cochlear CI532/632 precurved EA. Four pairs of contacts from the 22 electrode contacts were chosen based on preliminary testing and monitored in real time to halt the robotic insertion once the closest modiolar position had been achieved but prior to when the angular insertion depth (AID) would be reduced. RESULTS In this setting, the open-loop robotic insertion impedance profiles were very consistent between trials. The exit of each contact from the external stylet of this EA was clearly discernible on the impedance profile. In closed-loop experiments using the pullback technique, the average distance from the electrode contacts to the modiolus was reduced without greatly affecting the AID by using impedance feedback in real time to determine when to stop EA retraction. CONCLUSION Impedance sensing, and specifically the access resistance component of impedance, could be a valuable real-time feedback tool in the operating room during CI EA insertion. Future work should more thoroughly analyze the effects of more realistic operating room conditions and inter-patient variability on this technique.
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Smetak MR, Riojas KE, Sharma RK, Labadie RF. Beyond the phantom: Unroofing the scala vestibuli in a fresh temporal bone as a model for cochlear implant insertion experiments. J Neurosci Methods 2022; 382:109710. [PMID: 36207005 DOI: 10.1016/j.jneumeth.2022.109710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 09/06/2022] [Accepted: 09/13/2022] [Indexed: 11/07/2022]
Affiliation(s)
- Miriam R Smetak
- Department of Otolaryngology - Head and Neck Surgery, Vanderbilt University Medical Center, 1215 21st Ave S, Nashville, TN 37232, United States.
| | - Katherine E Riojas
- Department of Mechanical Engineering, Vanderbilt University, 2301 Vanderbilt Place PMB 401592, Nashville, TN 37240-1592, United States
| | - Rahul K Sharma
- Department of Otolaryngology - Head and Neck Surgery, Vanderbilt University Medical Center, 1215 21st Ave S, Nashville, TN 37232, United States
| | - Robert F Labadie
- Department of Otolaryngology - Head and Neck Surgery, Vanderbilt University Medical Center, 1215 21st Ave S, Nashville, TN 37232, United States; Department of Mechanical Engineering, Vanderbilt University, 2301 Vanderbilt Place PMB 401592, Nashville, TN 37240-1592, United States
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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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Deng N, Li J, Lyu H, Huang R, Liu H, Guo C. Degradable silk-based soft actuators with magnetic responsiveness. J Mater Chem B 2022; 10:7650-7660. [PMID: 36128873 DOI: 10.1039/d2tb01328b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Soft actuators with stimuli-responsiveness have great potential in biomedical applications such as drug delivery and minimally invasive surgery. In this study, protein-based soft actuators with magnetic actuation are fabricated using naturally occurring silk proteins and synthesized Fe3O4 magnetic nanoparticles (NPs). Briefly, magnetic silk films are first prepared by solution casting of a mixture containing silk proteins, synthesized Fe3O4 NPs, and glycerol. The molecular structures of the magnetic silk films are characterized by FTIR spectroscopy, which show that the β-sheet content in the films is about 20%. The mechanical tests show that the magnetic silk films can be stretched to over 200% under wet conditions and Young's modulus is estimated to be 4.89 ± 0.69 MPa, matching the stiffness of soft tissues. Furthermore, the enzymatic degradability, good biocompatibility, and in vivo X-ray visibility of the films are demonstrated by the in vitro enzymatic degradation test, in vivo biocompatibility test, and micro-CT imaging, respectively. Degradable silk-based soft actuators with magnetic responsiveness are successfully prepared by thermal forming or plastic molding of the magnetic silk films. The fabricated soft actuators can be actuated and move with precise locomotive gaits in solutions using a magnet. In addition, the retention of the soft actuators and localized drug delivery in gastrointestinal tracts by attaching a magnet to the abdominal skin are demonstrated using model systems. The degradable silk-based soft actuators provide many opportunities for improving current therapeutic strategies in biomedicine.
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Affiliation(s)
- Niping Deng
- School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China.,School of Engineering, Westlake University, Hangzhou 310024, China.
| | - Jinghang Li
- School of Engineering, Westlake University, Hangzhou 310024, China.
| | - Hao Lyu
- School of Engineering, Westlake University, Hangzhou 310024, China.
| | - Ruochuan Huang
- School of Engineering, Westlake University, Hangzhou 310024, China.
| | - Haoran Liu
- School of Engineering, Westlake University, Hangzhou 310024, China.
| | - Chengchen Guo
- School of Engineering, Westlake University, Hangzhou 310024, China. .,Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou 310024, China
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Dupont PE, Simaan N, Choset H, Rucker C. Continuum Robots for Medical Interventions. PROCEEDINGS OF THE IEEE. INSTITUTE OF ELECTRICAL AND ELECTRONICS ENGINEERS 2022; 110:847-870. [PMID: 35756186 PMCID: PMC9231641 DOI: 10.1109/jproc.2022.3141338] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Continuum robots are not constructed with discrete joints but, instead, change shape and position their tip by flexing along their entire length. Their narrow curvilinear shape makes them well suited to passing through body lumens, natural orifices, or small surgical incisions to perform minimally invasive procedures. Modeling and controlling these robots are, however, substantially more complex than traditional robots comprised of rigid links connected by discrete joints. Furthermore, there are many approaches to achieving robot flexure. Each presents its own design and modeling challenges, and to date, each has been pursued largely independently of the others. This article attempts to provide a unified summary of the state of the art of continuum robot architectures with respect to design for specific clinical applications. It also describes a unifying framework for modeling and controlling these systems while additionally explaining the elements unique to each architecture. The major research accomplishments are described for each topic and directions for the future progress needed to achieve widespread clinical use are identified.
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Affiliation(s)
- Pierre E Dupont
- Department of Cardiovascular Surgery, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115 USA
| | - Nabil Simaan
- Department of Mechanical Engineering, the Department of Computer Science, and the Department of Otolaryngology, Vanderbilt University, Nashville, TN 37235 USA
| | - Howie Choset
- Mechanical Engineering Department, the Biomedical Engineering Department, and the Robotics Institute, Carnegie Mellon, Pittsburgh, PA 15213 USA
| | - Caleb Rucker
- Department of Mechanical, Aerospace, and Biomedical Engineering, The University of Tennessee, Knoxville, TN 37996 USA
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Abstract
In conventional classification, soft robots feature mechanical compliance as the main distinguishing factor from traditional robots made of rigid materials. Recent advances in functional soft materials have facilitated the emergence of a new class of soft robots capable of tether-free actuation in response to external stimuli such as heat, light, solvent, or electric or magnetic field. Among the various types of stimuli-responsive materials, magnetic soft materials have shown remarkable progress in their design and fabrication, leading to the development of magnetic soft robots with unique advantages and potential for many important applications. However, the field of magnetic soft robots is still in its infancy and requires further advancements in terms of design principles, fabrication methods, control mechanisms, and sensing modalities. Successful future development of magnetic soft robots would require a comprehensive understanding of the fundamental principle of magnetic actuation, as well as the physical properties and behavior of magnetic soft materials. In this review, we discuss recent progress in the design and fabrication, modeling and simulation, and actuation and control of magnetic soft materials and robots. We then give a set of design guidelines for optimal actuation performance of magnetic soft materials. Lastly, we summarize potential biomedical applications of magnetic soft robots and provide our perspectives on next-generation magnetic soft robots.
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Affiliation(s)
- Yoonho Kim
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Xuanhe Zhao
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Bruns TL, Riojas KE, Labadie RF, Webster RJ. Real-Time Localization of Cochlear-Implant Electrode Arrays Using Bipolar Impedance Sensing. IEEE Trans Biomed Eng 2022; 69:718-724. [PMID: 34379586 PMCID: PMC8918040 DOI: 10.1109/tbme.2021.3104104] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Surgeons have no direct objective feedback on cochlear-implant electrode array (EA) positioning during insertion, yet optimal hearing outcomes are contingent on placing the EA as close as feasible to viable neural endings. This paper describes a system to non-invasively determine intracochlear positioning of an EA, without requiring any modifications to existing commercial EAs themselves. METHODS Electrical impedance has been suggested as a way to measure EA proximity to the inner wall of the cochlea that houses auditory nerve endings-the modiolus. In this paper, we extend prior work and demonstrate for the first time the relationship between bipolar access resistance and proximity of the EA to the modiolus (E-M proximity). We also evaluate two methods for producing direct, real-time estimates of E-M proximity from bipolar impedance measurements. RESULTS We show that bipolar access resistance is highly correlated with E-M proximity and can be approximately modeled by a power law function. This one dimensional model is shown to be capable of producing accurate real-time estimates of E-M proximity, but its simplicity also limits the potential for future improvement. To address this challenge, we propose a new prediction approach based on a recurrent neural network, which generated an overall prediction accuracy of 93.7%. CONCLUSION Bipolar access resistance is highly correlated with E-M proximity, and can be used to estimate EA positioning. SIGNIFICANCE This work shows how impedance sensing can be used to localize an EA during insertion into the small, enclosed cochlear environment, without requiring any modifications to existing clinically used EAs.
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Affiliation(s)
- Trevor L. Bruns
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN, USA
| | - Katherine E. Riojas
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN, USA
| | - Robert F. Labadie
- Department of Otolaryngology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Robert J. Webster
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN, USA
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Usevitch DE, Park AH, Scheper V, Abbott JJ. Estimating the Pose of a Guinea-pig Cochlea Without Medical Imaging. Otol Neurotol 2021; 42:e1219-e1226. [PMID: 34224546 PMCID: PMC8715751 DOI: 10.1097/mao.0000000000003250] [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: 11/26/2022]
Abstract
HYPOTHESIS The pose (i.e., position and orientation) of a guinea-pig cochlea can be accurately estimated using externally observable features, without requiring computed-tomography (CT) scans. BACKGROUND Guinea pigs are frequently used in otologic research as animal models of cochlear-implant surgery. In robot-assisted surgical insertion of cochlear-implant electrode arrays, knowing the cochlea pose is required. A preoperative CT scan of the guinea-pig anatomy can be labeled and registered to the surgical system, however, this process can be expensive and time consuming. METHODS Anatomical features from both sides of 11 guinea-pig CT scans were labeled and registered, forming sets. Using a groupwise point-set registration algorithm, errors in cochlea position and modiolar-axis orientation were estimated for 11 iterations of registration where each feature set was used as a hold-out set containing a reduced number of features that could all be touched by a motion-tracking probe intraoperatively. The method was validated on 2000 simulated guinea-pig cochleae and six physical guinea-pig-skull cochleae. RESULTS Validation on simulated cochleae resulted in cochlea-position estimates with a maximum error of 0.43 mm and modiolar-axis orientation estimates with a maximum error of 8.1 degrees for 96.7% of cochleae. Physical validation resulted in cochlea-position estimates with a maximum error of 0.80 mm and modiolar-axis orientation estimates with a maximum error of 12.4 degrees. CONCLUSIONS This work enables researchers conducting robot-assisted surgical insertions of cochlear-implant electrode arrays using a guinea-pig animal model to estimate the pose of a guinea-pig cochlea by locating six externally observable features on the guinea pig, without the need for CT scans.
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Affiliation(s)
| | - Albert H Park
- Division of Otolaryngology, Department of Surgery, University of Utah, Salt Lake City, Utah
| | - Verena Scheper
- Department of Otolaryngology, Hannover Medical School, and Cluster of Excellence Hearing4all, Hannover, Germany
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Esmailie F, Francoeur M, Ameel T. Experimental Validation of a Three-Dimensional Heat Transfer Model Within the Scala Tympani With Application to Magnetic Cochlear Implant Surgery. IEEE Trans Biomed Eng 2021; 68:2821-2832. [PMID: 33523803 PMCID: PMC8415572 DOI: 10.1109/tbme.2021.3055976] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Magnetic guidance of cochlear implants is a promising technique to reduce the risk of physical trauma during surgery. In this approach, a magnet attached to the tip of the implant electrode array is guided within the scala tympani using a magnetic field. After surgery, the magnet must be detached from the implant electrode array via localized heating, which may cause thermal trauma, and removed from the scala tympani. OBJECTIVES The objective of this work is to experimentally validate a three-dimensional (3D) heat transfer model of the scala tympani which will enable accurate predictions of the maximum safe input power to avoid localized hyperthermia when detaching the magnet from the implant electrode array. METHODS Experiments are designed using a rigorous scale analysis and performed by measuring transient temperatures in a 3D-printed scala tympani phantom subjected to a sudden change in its isothermal environment and localized heating via a small heat source. RESULTS The measured and predicted temperatures are in good agreement with an error less than 6 % ( p= 0.84). For the most conservative case where all boundaries of the model except the insertion opening are adiabatic, the power required to release the magnet attached to the implant electrode array by 1 mm 3 of paraffin is approximately half of the predicted maximum safe input power. CONCLUSIONS A 3D heat transfer model of the scala tympani is successfully validated and enables predicting the maximum safe input power required to detach the magnet from the implant electrode array. SIGNIFICANCE This work will enable the design of a thermally safe magnetic cochlear implant surgery procedure.
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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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Hendricks CM, Cavilla MS, Usevitch DE, Bruns TL, Riojas KE, Leon L, Webster RJ, Warren FM, Abbott JJ. Magnetic Steering of Robotically Inserted Lateral-wall Cochlear-implant Electrode Arrays Reduces Forces on the Basilar Membrane In Vitro. Otol Neurotol 2021; 42:1022-1030. [PMID: 33859137 PMCID: PMC8282696 DOI: 10.1097/mao.0000000000003129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
HYPOTHESIS Undesirable forces applied to the basilar membrane during surgical insertion of lateral-wall cochlear-implant electrode arrays (EAs) can be reduced via robotic insertion with magnetic steering of the EA tip. BACKGROUND Robotic insertion of magnetically steered lateral-wall EAs has been shown to reduce insertion forces in vitro and in cadavers. No previous study of robot-assisted insertion has considered force on the basilar membrane. METHODS Insertions were executed in an open-channel scala-tympani phantom. A force plate, representing the basilar membrane, covered the channel to measure forces in the direction of the basilar membrane. An electromagnetic source generated a magnetic field to steer investigational EAs with permanent magnets at their tips, while a robot performed the insertion. RESULTS When magnetic steering was sufficient to pull the tip of the EA off of the lateral wall of the channel, it resulted in at least a 62% reduction of force on the phantom basilar membrane at insertion depths beyond 14.4 mm (p < 0.05), and these beneficial effects were maintained beyond approximately the same depth, even with 10 degrees of error in the estimation of the modiolar axis of the cochlea. When magnetic steering was not sufficient to pull the EA tip off of the lateral wall, a significant difference from the no-magnetic-steering case was not found. CONCLUSIONS This in vitro study suggests that magnetic steering of robotically inserted lateral-wall cochlear-implant EAs, given sufficient steering magnitude, can reduce forces on the basilar membrane in the first basilar turn compared with robotic insertion without magnetic steering.
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Affiliation(s)
- Cameron M Hendricks
- Department of Mechanical Engineering, University of Utah, Salt Lake City, Utah
| | - Matt S Cavilla
- Department of Mechanical Engineering, University of Utah, Salt Lake City, Utah
| | - David E Usevitch
- Department of Mechanical Engineering, University of Utah, Salt Lake City, Utah
| | - Trevor L Bruns
- Department of Mechanical Engineering, Vanderbilt University, Nashville, Tennessee
| | - Katherine E Riojas
- Department of Mechanical Engineering, Vanderbilt University, Nashville, Tennessee
| | | | - Robert J Webster
- Department of Mechanical Engineering, Vanderbilt University, Nashville, Tennessee
| | | | - Jake J Abbott
- Department of Mechanical Engineering, University of Utah, Salt Lake City, Utah
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Atkinson D, D'Souza T, Rajput JS, Tasnim N, Muthuswamy J, Marvi H, Pancrazio JJ. Advances in Implantable Microelectrode Array Insertion and Positioning. Neuromodulation 2021; 25:789-795. [PMID: 33438369 DOI: 10.1111/ner.13355] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 12/14/2020] [Accepted: 12/21/2020] [Indexed: 11/29/2022]
Abstract
OBJECTIVES Microelectrode arrays offer a means to probe the functional circuitry of the brain and the promise of cortical neuroprosthesis for individuals suffering from paralysis or limb loss. These devices are typically comprised of one or more shanks incorporating microelectrode sites, where the shanks are positioned by inserting the devices along a straight path that is normal to the brain surface. The lack of consistent long-term chronic recording technology has driven interest in novel probe design and approaches that go beyond the standard insertion approach that is limited to a single velocity or axis. This review offers a description of typical approaches and associated limitations and surveys emergent methods for implantation of microelectrode arrays, in particular those new approaches that leverage embedded microactuators and extend the insertion direction beyond a single axis. MATERIALS AND METHODS This review paper surveys the current technologies that enable probe implantation, repositioning, and the capability to record/stimulate from a tissue volume. A comprehensive literature search was performed using PubMed, Web of Science, and Google Scholar. RESULTS There has been substantial innovation in the development of microscale and embedded technology that enables probe repositioning to maintain quality recordings in the brain. Innovations in material science have resulted in novel strategies for deployable structures that can record from or stimulate a tissue volume. Moreover, new developments involving magnetically steerable catheters and needles offer an alternative approach to "pull" rather than "push" a probe into the tissue. CONCLUSION We envision the emergence of a new generation of probes and insertion methodologies for neuromodulation applications that enable reliable chronic performance from devices that can be positioned virtually anywhere in the brain.
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Affiliation(s)
- David Atkinson
- Department of Bioengineering, Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas, Richardson, TX, USA
| | - Tania D'Souza
- Department of Bioengineering, Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas, Richardson, TX, USA
| | - Jai Singh Rajput
- Department of Bioengineering, Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas, Richardson, TX, USA
| | - Nishat Tasnim
- Department of Bioengineering, Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas, Richardson, TX, USA
| | - Jit Muthuswamy
- Department of Biomedical Engineering, School of Biological and Health Systems, Engineering, Arizona State University, Tempe, AZ, USA
| | - Hamid Marvi
- School for Engineering of Matter Transport and Energy, Ira A. Fulton Schools of Engineering, Arizona State University, Tempe, AZ, USA
| | - Joseph J Pancrazio
- Department of Bioengineering, Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas, Richardson, TX, USA
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Gafford J, Freeman M, Fichera L, Noble J, Labadie R, Webster RJ. Eyes in Ears: A Miniature Steerable Digital Endoscope for Trans-Nasal Diagnosis of Middle Ear Disease. Ann Biomed Eng 2021; 49:219-232. [PMID: 32458223 PMCID: PMC7688494 DOI: 10.1007/s10439-020-02518-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 04/24/2020] [Indexed: 01/17/2023]
Abstract
The aim of this work is to design, fabricate and experimentally validate a miniature steerable digital endoscope that can provide comprehensive, high-resolution imaging of the middle ear using a trans-nasal approach. The motivation for this work comes from the high incidence of middle ear diseases, and the current reliance on invasive surgery to diagnose and survey these diseases which typically consists of the eardrum being lifted surgically to directly visualize the middle ear using a trans-canal approach. To enable less-invasive diagnosis and surveillance of middle ear disease, we propose an endoscope that is small enough to pass into the middle ear through the Eustachian tube, with a steerable tip that carries a 1 Megapixel image sensor and fiber-optic illumination to provide high-resolution visualization of critical middle ear structures. The proposed endoscope would enable physicians to diagnose middle ear disease using a non-surgical trans-nasal approach instead, enabling such procedures to be performed in an office setting and greatly reducing invasiveness for the patient. In this work, the computational design of the steerable tip based on computed tomography models of real human middle ear anatomy is presented, and these results informed the fabrication of a clinical-scale steerable endoscope prototype. The prototype was used in a pilot study in three cadaveric temporal bone specimens, where high-quality middle ear visualization was achieved as determined by an unbiased cohort of otolaryngologists. This is the first paper to demonstrate cadaveric validation of a digital, steerable, clinical-scale endoscope for middle ear disease diagnosis, and the experimental results illustrate that the endoscope enables the visualization of critical middle ear structures (such as the epitympanum or sinus tympani) that were seldom or never visualized in prior published trans-Eustachian tube endoscopy feasibility studies.
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Affiliation(s)
- Joshua Gafford
- Vanderbilt University Engineering Department, Nashville, TN, USA.
| | | | | | - Jack Noble
- Vanderbilt University Engineering Department, Nashville, TN, USA
- Vanderbilt Institute for Surgery and Engineering (VISE), Nashville, TN, USA
| | - Robert Labadie
- Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Institute for Surgery and Engineering (VISE), Nashville, TN, USA
| | - Robert J Webster
- Vanderbilt University Engineering Department, Nashville, TN, USA
- Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Institute for Surgery and Engineering (VISE), Nashville, TN, USA
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