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Caillaud E, Kerneis S, Bakhos D. Atypical cochleovestibular syndrome in a child. Eur Ann Otorhinolaryngol Head Neck Dis 2024; 141:181-184. [PMID: 37838599 DOI: 10.1016/j.anorl.2023.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2023]
Affiliation(s)
- E Caillaud
- Service ORL et chirurgie cervico-faciale, CHU de Tours, boulevard Tonnellé, 37044 Tours, France.
| | - S Kerneis
- Service ORL et chirurgie cervico-faciale, CHU de Tours, boulevard Tonnellé, 37044 Tours, France
| | - D Bakhos
- Service ORL et chirurgie cervico-faciale, CHU de Tours, boulevard Tonnellé, 37044 Tours, France; CHRU de Tours, université François-Rabelais de Tours, Inserm UMR 1253 I-Brain, 2, boulevard Tonnellé, 37044 Tours, France; Faculté de médecine de Tours, université François-Rabelais de Tours, CHRU de Tours, 2, boulevard Tonnellé, 37044 Tours, France; House Institute Foundation, 2100 W 3rd Street, Suite 111, Los Angeles, CA, 90057, United States
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2
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Flahat B, Bonnard Å, Arebro J. Bilateral intracochlear hemorrhage: A rare onset of chronic myelogenous leukemia. Clin Case Rep 2024; 12:e8741. [PMID: 38645606 PMCID: PMC11031744 DOI: 10.1002/ccr3.8741] [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: 11/18/2023] [Revised: 02/14/2024] [Accepted: 02/20/2024] [Indexed: 04/23/2024] Open
Abstract
Acute onset of vertigo and hearing loss is rare in leukemic disorders. MRI can diagnose intracochlear hemorrhage as the underlying cause. The hearing can improve but if severe hearing loss preserves, cochlear implantation can be considered.
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Affiliation(s)
- Babak Flahat
- Department of NeuroradiologyKarolinska University HospitalStockholmSweden
| | - Åsa Bonnard
- Division of Otorhinolaryngology, Department of Clinical Science, Intervention and TechnologyKarolinska InstitutetStockholmSweden
- Department of Otorhinolaryngology, Head and Neck SurgeryKarolinska University HospitalStockholmSweden
| | - Julia Arebro
- Division of Otorhinolaryngology, Department of Clinical Science, Intervention and TechnologyKarolinska InstitutetStockholmSweden
- Department of Otorhinolaryngology, Head and Neck SurgeryKarolinska University HospitalStockholmSweden
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Razmovski T, Brody KM, Stathopoulos D, Zhang D, Cho E, Hampson AJ, Collins A, Bester C, O'Leary S. Intra-cochlear Flushing Reduces Tissue Response to Cochlear Implantation. Laryngoscope 2024; 134:1410-1416. [PMID: 37694764 DOI: 10.1002/lary.31022] [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: 03/15/2023] [Revised: 07/02/2023] [Accepted: 08/14/2023] [Indexed: 09/12/2023]
Abstract
INTRODUCTION Intraoperative trauma leading to bleeding during cochlear implantation negatively impacts residual hearing of cochlear implant recipients. There are no clinical protocols for the removal of blood during implantation, to reduce the consequential effects such as inflammation and fibrosis which adversely affect cochlear health and residual hearing. This preclinical study investigated the implementation of an intra-cochlear flushing protocol for the removal of blood. METHODS Three groups of guinea pigs were studied for 28 days after cochlear implantation; cochlear implant-only (control group); cochlear implant with blood injected into the cochlea (blood group); and cochlear implant, blood injection, and flushing of the blood from the cochlea intraoperatively (flush group). Auditory brainstem responses (ABRs) in addition to tissue response volumes were analyzed and compared between groups. RESULTS After implantation, the blood group exhibited the highest ABR thresholds when compared to the control and flush group, particularly in the high frequencies. On the final day, the control and blood group had similar ABR thresholds across all frequencies tested, whereas the flush group had the lowest thresholds, significantly lower at 24 kHz than the blood and control group. Analysis of the tissue response showed the flush group had significantly lower tissue responses in the basal half of the array when compared with the blood and control group. CONCLUSIONS Flushing intra-cochlear blood during surgery resulted in better auditory function and reduced subsequent fibrosis in the basal region of the cochlea. This finding prompts the implementation of a flushing protocol in clinical cochlear implantation. LEVEL OF EVIDENCE N/A Laryngoscope, 134:1410-1416, 2024.
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Affiliation(s)
- Tayla Razmovski
- Otolaryngology, Department of Surgery, Royal Victorian Eye and Ear Hospital, University of Melbourne, East Melbourne, Victoria, Australia
| | - Kate M Brody
- Otolaryngology, Department of Surgery, Royal Victorian Eye and Ear Hospital, University of Melbourne, East Melbourne, Victoria, Australia
| | - Dimitra Stathopoulos
- Otolaryngology, Department of Surgery, Royal Victorian Eye and Ear Hospital, University of Melbourne, East Melbourne, Victoria, Australia
| | - Dongcheng Zhang
- Otolaryngology, Department of Surgery, Royal Victorian Eye and Ear Hospital, University of Melbourne, East Melbourne, Victoria, Australia
| | - Ellie Cho
- Biological Optical Microscopy Platform, University of Melbourne, Parkville, Victoria, Australia
| | - Amy J Hampson
- Otolaryngology, Department of Surgery, Royal Victorian Eye and Ear Hospital, University of Melbourne, East Melbourne, Victoria, Australia
| | - Aaron Collins
- Otolaryngology, Department of Surgery, Royal Victorian Eye and Ear Hospital, University of Melbourne, East Melbourne, Victoria, Australia
| | - Christofer Bester
- Otolaryngology, Department of Surgery, Royal Victorian Eye and Ear Hospital, University of Melbourne, East Melbourne, Victoria, Australia
| | - Stephen O'Leary
- Otolaryngology, Department of Surgery, Royal Victorian Eye and Ear Hospital, University of Melbourne, East Melbourne, Victoria, Australia
- The Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia
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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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Zhang D, Chen D, Wang K, Pan J, Tang J, Zhang H. Electrical stimulation of cochlear implant promotes activation of macrophages and fibroblasts under inflammation. Laryngoscope Investig Otolaryngol 2023; 8:1390-1400. [PMID: 37899874 PMCID: PMC10601573 DOI: 10.1002/lio2.1149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 07/28/2023] [Accepted: 08/08/2023] [Indexed: 10/31/2023] Open
Abstract
Objectives The implanted electrodes deliver electric signals to spiral ganglion neurons, conferring restored hearing of cochlear implantation (CI) recipients. Postimplantation intracochlear fibrosis, which is observed in most CI recipients, disturbs the electrical signals and impairs the long-term outcome of CI. The macrophages and fibroblasts activation is critical for the development of intracochlear fibrosis. However, the effect of electric stimulation of cochlear implant (ESCI) on the activity of macrophages and fibroblasts was unclear. In the present study, a human cochlear implant was modified to stimulate cultured macrophages and fibroblasts. Methods By measuring cellular marker and the expression level of cytokine production, the polarization and activity of macrophages and fibroblasts were examined with or without ESCI. Results Our data showed that ESCI had little effects on the morphology, density, and distribution of culturing macrophages and fibroblasts. Furthermore, ESCI alone did not affect the polarization of macrophages or the function of fibroblasts without the treatment of inflammatory factors. However, in the presence of LPS or IL-4, ESCI further promoted the polarization of macrophages, and increased the expression of pro-inflammatory or anti-inflammatory factors, respectively. For fibroblasts, ESCI further increased the collagen I synthesis induced by TGF-β1 treatment. Nifedipine inhibited ESCI induced calcium influx, and hereby abolished the promoted polarization and activation of macrophages and fibroblasts. Conclusion Our results suggest that acute inflammation should be well inhibited before the activation of cochlear implants to control the postoperative intracochlear fibrosis. The voltage-gated calcium channels could be considered as the targets for reducing postimplantation inflammation and fibrosis. Level of Evidence NA.
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Affiliation(s)
- Dingling Zhang
- Department of Otolaryngology Head and Neck SurgeryZhujiang Hospital of Southern Medical UniversityGuangzhouChina
| | - Dongxiu Chen
- Department of Otolaryngology Head and Neck SurgeryZhujiang Hospital of Southern Medical UniversityGuangzhouChina
| | - Kaiye Wang
- Department of Otolaryngology Head and Neck SurgeryZhujiang Hospital of Southern Medical UniversityGuangzhouChina
| | - Jing Pan
- Department of Otolaryngology Head and Neck SurgeryZhujiang Hospital of Southern Medical UniversityGuangzhouChina
| | - Jie Tang
- Department of Otolaryngology Head and Neck SurgeryZhujiang Hospital of Southern Medical UniversityGuangzhouChina
- Department of PhysiologySouthern Medical University School of Basic Medical SciencesGuangzhouChina
- Key Laboratory of Mental Health of the Ministry of EducationSouthern Medical UniversityGuangzhouChina
- Hearing Research CenterSouthern Medical UniversityGuangzhouChina
| | - Hongzheng Zhang
- Department of Otolaryngology Head and Neck SurgeryZhujiang Hospital of Southern Medical UniversityGuangzhouChina
- Hearing Research CenterSouthern Medical UniversityGuangzhouChina
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Braack KJ, Miles T, Amat F, Brown DJ, Atlas MD, Kuthubutheen J, Mulders WH, Prêle CM. Using x-ray micro computed tomography to quantify intracochlear fibrosis after cochlear implantation in a Guinea pig model. Heliyon 2023; 9:e19343. [PMID: 37662829 PMCID: PMC10474428 DOI: 10.1016/j.heliyon.2023.e19343] [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: 02/23/2023] [Revised: 08/07/2023] [Accepted: 08/18/2023] [Indexed: 09/05/2023] Open
Abstract
Cochlear implants (CIs) allow individuals with profound hearing loss to understand speech and perceive sounds. However, not all patients obtain the full benefits that CIs can provide and the cause of this disparity is not fully understood. One possible factor for the variability in outcomes after cochlear implantation, is the development of fibrotic scar tissue around the implanted electrode. It has been hypothesised that limiting the extent of fibrosis after implantation may improve overall CI function, and longevity of the device. Currently, histology is often used to quantify the extent of intracochlear tissue growth after implantation however this method is labour intensive, time-consuming, often involves significant user bias, and causes physical distortion of the fibrosis. Therefore, this study aimed to evaluate x-ray micro computed tomography (μCT) as a method to measure the amount and distribution of fibrosis in a guinea pig model of cochlear implantation. Adult guinea pigs were implanted with an inactive electrode, and cochleae harvested eight weeks later (n = 7) and analysed using μCT, to quantify the extent of tissue reaction, followed by histological analysis to confirm that the tissue was indeed fibrotic. Cochleae harvested from an additional six animals following implantation were analysed by μCT, before and after contrast staining with osmium tetroxide (OsO4), to enhance the visualisation of soft tissues within the cochlea, including the tissue reaction. Independent analysis by two observers showed that the quantification method was robust and provided additional information on the distribution of the response within the cochlea. Histological analysis revealed that μCT visualised dense collagenous material and new bone formation but did not capture loose, areolar fibrotic tissue. Treatment with OsO4 significantly enhanced the visible tissue reaction detected using μCT. Overall, μCT is an alternative and reliable method that can be used to quantify the extent of the CI-induced intracochlear tissue response and will be a useful tool for the in vivo assessment of novel anti-fibrotic treatments.
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Affiliation(s)
- Kady J. Braack
- School of Human Sciences, University of Western Australia, Crawley, WA 6009, Australia
| | - Tylah Miles
- Institute for Respiratory Health, University of Western Australia, Nedlands, WA 6009, Australia
| | - Farah Amat
- School of Human Sciences, University of Western Australia, Crawley, WA 6009, Australia
| | - Daniel J. Brown
- Curtin Medical School, Curtin University, Bentley, WA 6102, Australia
| | - Marcus D. Atlas
- Curtin Medical School, Curtin University, Bentley, WA 6102, Australia
- Medical School, University of Western Australia, Crawley, WA 6009, Australia
- Ear Science Institute Australia, Subiaco, WA 6008, Australia
| | - Jafri Kuthubutheen
- Medical School, University of Western Australia, Crawley, WA 6009, Australia
- Department of Otolaryngology Head and Neck Surgery, Sir Charles Gairdner Hospital, Hospital Avenue, Nedlands, WA 6009, Australia
| | | | - Cecilia M. Prêle
- Institute for Respiratory Health, University of Western Australia, Nedlands, WA 6009, Australia
- Ear Science Institute Australia, Subiaco, WA 6008, Australia
- School of Medical, Molecular and Forensic Sciences, Murdoch University, Murdoch, WA 6150, Australia
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Creber NJ, Eastwood HT, Hampson AJ, O'Leary SJ. Cochlear implant surgery facilitates intracochlear distribution of perioperative systemic steroids. Acta Otolaryngol 2023; 143:647-654. [PMID: 37603289 DOI: 10.1080/00016489.2023.2241877] [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: 05/11/2023] [Revised: 07/17/2023] [Accepted: 07/18/2023] [Indexed: 08/22/2023]
Abstract
BACKGROUND Systemically administered steroids are widely utilised for hearing preservation therapies. More recently, steroids have been administered to achieve hearing protection after cochlear implant surgery. Currently there is a lack of understanding as to which administration route offers most therapeutic efficacy, local or systemic administration. Paramount to this are observations in animal studies that systemic administration following implantation offers hearing protection and reduced cochlear fibrosis, despite observations that perilymphatic levels are up to 10-fold higher after local administration in non-implanted cochleae. AIMS/OBJECTIVES This paper explores the impact that cochlear implantation and associated acute inflammation has on steroid distribution and uptake following systemic administration of dexamethasone. MATERIAL AND METHODS Eight guinea pigs received systemic dexamethasone 60 min prior to cochlear implantation. Implanted and contralateral non-implanted cochlea were harvested for tissue immunohistochemistry and detection of dexamethasone. RESULTS Cochleostomy with scala tympani implantation resulted in a significant increase in cochlear dexamethasone signal. This was most notable at the organ of Corti, stria vascularis, and blood product in the scala tympani. CONCLUSIONS AND SIGNIFICANCE This study demonstrates that the inner ear distribution of systemically administered steroids is enhanced following surgery for cochlear implantation and provides rationale for systemic perioperative steroids in hearing preservation surgery.
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Affiliation(s)
- Nathan J Creber
- Otolaryngology, Department of Surgery, University of Melbourne, East Melbourne, Victoria, Australia
| | - Hayden T Eastwood
- Otolaryngology, Department of Surgery, University of Melbourne, East Melbourne, Victoria, Australia
| | - Amy J Hampson
- Otolaryngology, Department of Surgery, University of Melbourne, East Melbourne, Victoria, Australia
| | - Stephen J O'Leary
- Otolaryngology, Department of Surgery, University of Melbourne, East Melbourne, Victoria, Australia
- Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia
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Razmovski T, Collins A, Bester C, O'Leary S. Using Four-Point Impedance to Detect and Locate Blood during Cochlear Implantation . ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2023; 2023:1-4. [PMID: 38083677 DOI: 10.1109/embc40787.2023.10340312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
Biosensing technologies are emerging as an important consideration when designing implantable medical devices. For cochlear implants, biosensors may help preserve the natural hearing a patient has prior to implantation by detecting blood in the cochlea during insertion. If blood enters the cochlea, it creates a hostile environment leading to further hearing loss and reduced device function. Here we present four-point impedance, measured directly from a commercial cochlear implant, as a biosensor for real-time detection of blood in the cochlea. The four-point impedance of different concentrations of whole blood in saline were measured using the impedance-measuring capabilities of a cochlear implant with a square-wave stimulation. Impedance derived from a cochlear implant succeeded in differentiating concentrations of blood in saline with results from a sensitivity analysis showing the lowest concentration the system could detect was between 12 % to 21 % of whole blood. In a subsequent in-vitro study, continuous four-point impedance was measured from a cochlear implant while it was inserted into a 3D printed cochlear model, followed by an injection of blood to emulate surgical events. These results demonstrated four-point impedance from a cochlear implant can instantaneously detect the addition of blood within the cochlea and localize it along the electrode array. The adaptation of a biosensing tool using a cochlear implant provides more information that can be relayed to the surgeon intraoperatively to potentially enhance hearing outcomes with the implant.Clinical Relevance - Using the cochlear implant itself to detect intra-cochlear bleeding may open therapeutic avenues to prevent further hearing loss.
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Tan E, Bester C, Collins A, Razmovski T, O'Leary S. Four-Point Impedance and Utricular Dysfunction Is Associated with Postoperative Dizziness after Cochlear Implantation. Otol Neurotol 2023:00129492-990000000-00330. [PMID: 37400267 DOI: 10.1097/mao.0000000000003935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2023]
Abstract
INTRODUCTION Postimplantation dizziness is common, affecting approximately 50% of patients. Theories for dizziness include utricular inflammation, endolymphatic hydrops, and loss of perilymph. Four-point impedance (4PI) is a novel impedance measurement in cochlear implantation that shows potential to predict hearing loss, inflammation, and fibrotic tissue response. Here, we associate 4PI with dizziness after implantation and explore the link with utricular function. METHODS Subjective visual vertical (SVV) as a measure of utricular function was recorded preoperatively as a baseline. 4PI was measured immediately postinsertion. Ongoing follow-up was performed at 1 day, 1 week, and 1 month, postoperatively. At each follow-up, 4PI, SVV, and the patients' subjective experience of dizziness were assessed. DISCUSSION Thirty-eight adults were recruited. One-day 4PI was significantly higher in patients dizzy within the next week (254 Ω vs 171 Ω, p = 0.015). The optimum threshold on receiver operating characteristic curve was 190 Ω, above which patients had 10 times greater odds of developing dizziness (Fisher exact test, OR = 9.95, p = 0.0092). This suggests that 4PI varies with changes in the intracochlear environment resulting in dizziness, such as inflammation or hydrops. SVV significantly deviated away from the operated ear at 1 day (fixed effect estimate = 2.6°, p ≤ 0.0001) and 1 week (fixed effect estimate 2.7°, p ≤ 0.001). CONCLUSION One-day 4PI is a potentially useful marker for detecting postoperative dizziness after cochlear implantation. Of the current theories for postoperative dizziness, inflammation might explain the findings seen here, as would changes in hydrostatic pressure. Future research should focus on detecting and exploring these labyrinthine changes in further detail.
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Affiliation(s)
- Eren Tan
- Department of Otolaryngology, The University of Melbourne, Victoria, Australia
| | - Christofer Bester
- Department of Otolaryngology, The University of Melbourne, Victoria, Australia
| | - Aaron Collins
- Department of Otolaryngology, The University of Melbourne, Victoria, Australia
| | - Tayla Razmovski
- Department of Otolaryngology, The University of Melbourne, Victoria, Australia
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Schvartz-Leyzac KC, Colesa DJ, Swiderski DL, Raphael Y, Pfingst BE. Cochlear Health and Cochlear-implant Function. J Assoc Res Otolaryngol 2023; 24:5-29. [PMID: 36600147 PMCID: PMC9971430 DOI: 10.1007/s10162-022-00882-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 11/24/2022] [Indexed: 01/06/2023] Open
Abstract
The cochlear implant (CI) is widely considered to be one of the most innovative and successful neuroprosthetic treatments developed to date. Although outcomes vary, CIs are able to effectively improve hearing in nearly all recipients and can substantially improve speech understanding and quality of life for patients with significant hearing loss. A wealth of research has focused on underlying factors that contribute to success with a CI, and recent evidence suggests that the overall health of the cochlea could potentially play a larger role than previously recognized. This article defines and reviews attributes of cochlear health and describes procedures to evaluate cochlear health in humans and animal models in order to examine the effects of cochlear health on performance with a CI. Lastly, we describe how future biologic approaches can be used to preserve and/or enhance cochlear health in order to maximize performance for individual CI recipients.
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Affiliation(s)
- Kara C Schvartz-Leyzac
- Department of Otolaryngology-Head and Neck Surgery, Michigan Medicine, Kresge Hearing Research Institute, University of Michigan, 1150 Medical Center Drive, Ann Arbor, MI, 48109-5616, USA
- Department of Otolaryngology-Head and Neck Surgery, Medical University of South Carolina, 135 Rutledge Ave, Charleston, SC, 29425, USA
| | - Deborah J Colesa
- Department of Otolaryngology-Head and Neck Surgery, Michigan Medicine, Kresge Hearing Research Institute, University of Michigan, 1150 Medical Center Drive, Ann Arbor, MI, 48109-5616, USA
| | - Donald L Swiderski
- Department of Otolaryngology-Head and Neck Surgery, Michigan Medicine, Kresge Hearing Research Institute, University of Michigan, 1150 Medical Center Drive, Ann Arbor, MI, 48109-5616, USA
| | - Yehoash Raphael
- Department of Otolaryngology-Head and Neck Surgery, Michigan Medicine, Kresge Hearing Research Institute, University of Michigan, 1150 Medical Center Drive, Ann Arbor, MI, 48109-5616, USA
| | - Bryan E Pfingst
- Department of Otolaryngology-Head and Neck Surgery, Michigan Medicine, Kresge Hearing Research Institute, University of Michigan, 1150 Medical Center Drive, Ann Arbor, MI, 48109-5616, USA.
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Razmovski T, Bester C, Collins A, Tan E, O'Leary SJ. Four-Point Impedance Changes After Cochlear Implantation for Lateral Wall and Perimodiolar Implants. Otol Neurotol 2022; 43:e1107-e1114. [PMID: 36351225 DOI: 10.1097/mao.0000000000003732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
OBJECTIVE Monitor four-point impedance in cochlear implant recipients over time and determine if implant type, surgical approach, and electrode positioning affected impedance measurements. STUDY DESIGN Prospective observational. SETTING Hospital. PATIENTS Adult cochlear implant recipients implanted with a perimodiolar or lateral wall cochlear implant. MAIN OUTCOME MEASURES Mean values for four-point impedances were calculated for all electrode contacts at perioperative and 3 months after surgery. Linear mixed models were applied to the impedance data to compare between implant types and time points. The angular insertion depth and electrode position relative to the medial and lateral wall, commonly termed the Intracochlear Position Index (ICPI), were collected and compared with impedance measurements. RESULTS Perioperatively, the four-point impedance was similar between implant types, with perimodiolar implants having marginally higher impedance values in the basal region. At 3 months after surgery, impedances significantly increased in the basal half of the electrode array for both implants, with higher impedance values for CI532 implants. There were no significant differences in insertion angle depth between implant types. The ICPI values for the seven most basal electrodes were similar for both implants; however, CI532 arrays were significantly more medially placed along the remaining apical portion of the array, which is expected. ICPI values did not correlate with impedance measurements for either implant. CONCLUSIONS Four-point impedance increases at 3 months after surgery may reflect fibrous tissue formation after cochlear implantation. The higher impedance values in perimodiolar implants may reflect a more extensive fibrosis formation as a result of surgical approaches used, requiring drilling of the cochlea bone.
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Affiliation(s)
- Tayla Razmovski
- Department of Surgery (Otolaryngology), The University of Melbourne
| | | | - Aaron Collins
- Department of Surgery (Otolaryngology), The University of Melbourne
| | - Eren Tan
- Department of Surgery (Otolaryngology), The University of Melbourne
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The Augmented Cochlear Implant: a Convergence of Drugs and Cochlear Implantation for the Treatment of Hearing Loss. CURRENT OTORHINOLARYNGOLOGY REPORTS 2022. [DOI: 10.1007/s40136-022-00426-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Rahman MT, Chari DA, Ishiyama G, Lopez I, Quesnel AM, Ishiyama A, Nadol JB, Hansen MR. Cochlear implants: Causes, effects and mitigation strategies for the foreign body response and inflammation. Hear Res 2022; 422:108536. [PMID: 35709579 PMCID: PMC9684357 DOI: 10.1016/j.heares.2022.108536] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 04/20/2022] [Accepted: 05/23/2022] [Indexed: 12/15/2022]
Abstract
Cochlear implants provide effective auditory rehabilitation for patients with severe to profound sensorineural hearing loss. Recent advances in cochlear implant technology and surgical approaches have enabled a greater number of patients to benefit from this technology, including those with significant residual low frequency acoustic hearing. Nearly all cochleae implanted with a cochlear implant electrode array develop an inflammatory and fibrotic response. This tissue reaction can have deleterious consequences for implant function, residual acoustic hearing, and the development of the next generation of cochlear prosthetics. This article reviews the current understanding of the inflammatory/foreign body response (FBR) after cochlear implant surgery, its impact on clinical outcome, and therapeutic strategies to mitigate this response. Findings from both in human subjects and animal models across a variety of species are highlighted. Electrode array design, surgical techniques, implant materials, and the degree and type of electrical stimulation are some critical factors that affect the FBR and inflammation. Modification of these factors and various anti-inflammatory pharmacological interventions have been shown to mitigate the inflammatory/FBR response. Ongoing and future approaches that seek to limit surgical trauma and curb the FBR to the implanted biomaterials of the electrode array are discussed. A better understanding of the anatomical, cellular and molecular basis of the inflammatory/FBR response after cochlear implantation has the potential to improve the outcome of current cochlear implants and also facilitate the development of the next generation of neural prostheses.
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Affiliation(s)
- Muhammad T Rahman
- Department of Otolaryngology-Head & Neck Surgery, University of Iowa, Iowa City, IA, USA
| | - Divya A Chari
- Department of Otolaryngology-Head & Neck Surgery, Harvard University, Boston, MA, USA
| | - Gail Ishiyama
- Department of Head & Neck Surgery, University of California Los Angeles, LA, USA
| | - Ivan Lopez
- Department of Head & Neck Surgery, University of California Los Angeles, LA, USA
| | - Alicia M Quesnel
- Department of Otolaryngology-Head & Neck Surgery, Harvard University, Boston, MA, USA
| | - Akira Ishiyama
- Department of Head & Neck Surgery, University of California Los Angeles, LA, USA
| | - Joseph B Nadol
- Department of Otolaryngology-Head & Neck Surgery, Harvard University, Boston, MA, USA
| | - Marlan R Hansen
- Department of Otolaryngology-Head & Neck Surgery, University of Iowa, Iowa City, IA, USA.
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Anacker A, Esser KH, Lenarz T, Paasche G. Purification of Fibroblasts From the Spiral Ganglion. Front Neurol 2022; 13:877342. [PMID: 35493807 PMCID: PMC9051338 DOI: 10.3389/fneur.2022.877342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 03/21/2022] [Indexed: 11/15/2022] Open
Abstract
Using cultures of freshly isolated spiral ganglion cells (SGC) is common to investigate the effect of substances on spiral ganglion neurons (SGN) in vitro. As these cultures contain more cell types than just neurons, and it might be beneficial to have cochlear fibroblasts available to further investigate approaches to reduce the growth of fibrous tissue around the electrode array after cochlear implantation, we aimed at the purification of fibroblasts from the spiral ganglion in the current study. Subcultivation of the primary SGC culture removed the neurons from the culture and increased the fibroblast to glial cell ratio in the preparations, which was revealed by staining for vimentin, the S100B-protein, and the 200-kD neurofilament. We performed direct immunolabeling for the Thy1-glycoprotein and the p75NGFR-enabled fluorescence-based cell sorting. This procedure resulted in a cell culture of cochlear fibroblasts with a purity of more than 99%. The received fibroblasts can be subcultivated for up to 10 passages before proliferation rates drop. Additionally, 80% of the cells survived the first attempt of cryopreservation and exhibited a fibroblast-specific morphology. Using the described approach provides a purified preparation of cochlear fibroblasts, which can now be used in vitro for further investigations.
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Affiliation(s)
- Annett Anacker
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany
| | | | - Thomas Lenarz
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany
- Cluster of Excellence Hearing4all, Hannover Medical School, Hannover, Germany
| | - Gerrit Paasche
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany
- Cluster of Excellence Hearing4all, Hannover Medical School, Hannover, Germany
- *Correspondence: Gerrit Paasche
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A Micro-Computed Tomography Study of Round Window Anatomy and Implications for Atraumatic Cochlear Implant Insertion. Otol Neurotol 2021; 42:327-334. [PMID: 33290359 DOI: 10.1097/mao.0000000000002924] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
HYPOTHESIS The goal of this study was to interrogate high-resolution three-dimensional reconstructions of round window anatomy to illustrate and characterize structural variability with implications for atraumatic cochlear implant insertion. BACKGROUND Cochlear implants are increasingly used to improve sound detection in patients with substantial residual hearing. However, traumatic cochlear implant insertion through the round window involving upward deviation of the electrode into the spiral ligament, basilar membrane, and osseous spiral lamina, medial impaction on the modiolus, or interscalar excursion into the scala vestibuli are associated with lower rates of hearing preservation and poorer speech perception.Successful atraumatic insertion is dependent on an anatomical understanding of the middle and inner ear. The round window bony niche lacks distinct demonstrable anatomical landmarks for the position of the round window membrane, and there is limited guidance on the amount of bony overhang that can be safely drilled away. A greater understanding of the anatomical variation around the round window could enhance treatment efficacy. METHODS Fourteen human cadaver temporal bones were imaged using microcomputed tomography. Resulting scans were digitally reconstructed, segmented, and measured. RESULTS Round window niche walls vary substantially in size and projection. Round window average short diameter measured 1.30 mm (range 1.07-1.44), and is limited by the crista fenestrae at the inferoanterior margin of the round window. Crista fenestrae size and morphology varied considerably. Reconstructions with solid and translucent panels are presented. CONCLUSION Anatomical heterogeneity should be considered in cochlear implant selection, drilling, and choice of insertion vector.
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Abstract
Intra-cochlear fibrous tissue formation around the electrode following cochlear implantation affects the electrode impedance as well as electrode explantation during reimplantation surgeries. Applying corticosteroids in cochlear implantation is one way of minimizing the intra-cochlear fibrous tissue formation around the electrode. It were J. Kiefer, C. von Ilberg, and W. Gstöttner who proposed the first idea on drug delivery application in cochlear implantation to MED-EL in the year 2000. During the twenty years of translational research efforts at MED-EL in collaboration with several clinics and research institutions from across the world, preclinical safety and efficacy of corticosteroids were performed leading to the final formulation of the electrode design. In parallel to the drug eluting CI electrode development, MED-EL also invested research efforts into developing tools enabling delivery of pharmaceutical agents of surgeon's choice inside the cochlea. The inner ear catheter designed to administer drug substances into the cochlea was CE marked in 2020. A feasibility study in human subjects with MED-EL CI featuring dexamethasone-eluting electrode array started in June 2020. This article covers the milestones of translational research towards the drug delivery in CI application that took place in association with MED-EL.
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Affiliation(s)
| | - Ingeborg Hochmair
- MED-EL Elektromedizinische Geraete Gesellschaft m.b.H., Innsbruck, Austria
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Konerding W, Arenberg JG, Kral A, Baumhoff P. Late electrically-evoked compound action potentials as markers for acute micro-lesions of spiral ganglion neurons. Hear Res 2020; 413:108057. [PMID: 32883545 DOI: 10.1016/j.heares.2020.108057] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 07/13/2020] [Accepted: 08/11/2020] [Indexed: 12/20/2022]
Abstract
Cochlear implants (CIs) are the treatment of choice for profoundly hearing impaired people. It has been proposed that speech perception in CI users is influenced by the neural health (deafferentation, demyelination and degeneration) of the cochlea, which may be heterogeneous along an individual cochlea. Several options have been put forward to account for these local differences in neural health when fitting the speech processor settings, however with mixed results. The interpretation of the results is hampered by the fact that reliable markers of locally restricted changes in spiral ganglion neuron (SGN) health are lacking. The aim of the study was (i) to establish mechanical micro-lesions in the guinea pig as a model of heterogeneous SGN deafferentation and degeneration and (ii) to assess potential electrophysiological markers that can also be used in human subjects. First, we defined the extent of micro-lesions in normal hearing animals using acoustically-evoked compound action potentials (aCAPs); second, we measured electrically-evoked CAPs (eCAPs) before and after focal lesioning in neomycin-deafened and implanted animals. Therefore, we inserted guinea pig adjusted 6-contact CIs through a cochleostomy in the scala tympani. The eCAP was recorded from a ball electrode at the round window niche in response to monopolar or bipolar, 50 µs/phase biphasic pulses of alternating anodic- and cathodic-leading polarity. To exclude the large electrical artifact from the analysis, we focused on the late eCAP component. We systematically isolated the eCAP parameter that showed local pre- versus post-lesion changes and lesion-target specificity. Histological evaluation of the cleared cochleae revealed focal damage of an average size of 0.0036 mm3 with an apical-basal span of maximal 440 µm. We found that the threshold of the late N2P2 eCAP component was significantly elevated after lesioning when stimulating at basal (near the lesion), but not apical (distant to the lesion) CI contacts. To circumvent the potentially conflicting influence of the apical-basal gradient in eCAP thresholds, we used the polarity effect (PE=cathodic-anodic) as a relative measure. During monopolar stimulation, but not bipolar stimulation, the PE was sensitive to the lesion target and showed significantly better cathodic than anodic thresholds after soma lesions. We conclude that the difference in N2P2 thresholds in response to cathodic versus anodic-leading monopolar stimulation corresponds to the presence of SGN soma damage, and may therefore be a marker for SGN loss. We consider this electrophysiological estimate of local neural health a potentially relevant tool for human applications because of the temporal separation from the stimulation artifact and possible implementation into common eCAP measurements.
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Affiliation(s)
- Wiebke Konerding
- Department of Experimental Otology, Hannover Medical School, Stadtfelddamm 34, 30625 Hannover, Germany.
| | - Julie G Arenberg
- Massachusetts Eye and Ear Infirmary, Harvard Medical School, 25 Shattuck Street, Boston, MA 02115, USA.
| | - Andrej Kral
- Department of Experimental Otology, Hannover Medical School, Stadtfelddamm 34, 30625 Hannover, Germany; Cluster of Excellence "Hearing4all", Germany.
| | - Peter Baumhoff
- Department of Experimental Otology, Hannover Medical School, Stadtfelddamm 34, 30625 Hannover, Germany.
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Swiderski DL, Colesa DJ, Hughes AP, Raphael Y, Pfingst BE. Relationships between Intrascalar Tissue, Neuron Survival, and Cochlear Implant Function. J Assoc Res Otolaryngol 2020; 21:337-352. [PMID: 32691251 DOI: 10.1007/s10162-020-00761-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 07/12/2020] [Indexed: 12/15/2022] Open
Abstract
Fibrous tissue and/or new bone are often found surrounding a cochlear implant in the cochlear scalae. This new intrascalar tissue could potentially limit cochlear implant function by increasing impedance and altering signaling pathways between the implant and the auditory nerve. In this study, we investigated the relationship between intrascalar tissue and 5 measures of implant function in guinea pigs. Variation in both spiral ganglion neuron (SGN) survival and intrascalar tissue was produced by implanting hearing ears, ears deafened with neomycin, and neomycin-deafened ears treated with a neurotrophin. We found significant effects of SGN density on 4 functional measures but adding intrascalar tissue level to the analysis did not explain more variation in any measure than was explained by SGN density alone. These results suggest that effects of intrascalar tissue on electrical hearing are relatively unimportant in comparison to degeneration of the auditory nerve, although additional studies in human implant recipients are still needed to assess the effects of this tissue on complex hearing tasks like speech perception. The results also suggest that efforts to minimize the trauma that aggravates both tissue development and SGN loss could be beneficial.
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Affiliation(s)
- Donald L Swiderski
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, Michigan Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Deborah J Colesa
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, Michigan Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Aaron P Hughes
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, Michigan Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Yehoash Raphael
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, Michigan Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Bryan E Pfingst
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, Michigan Medicine, University of Michigan, Ann Arbor, MI, USA.
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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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Bruns TL, Riojas KE, Ropella DS, Cavilla MS, Petruska AJ, Freeman MH, Labadie RF, Abbott JJ, Webster RJ. Magnetically Steered Robotic Insertion of Cochlear-Implant Electrode Arrays: System Integration and First-In-Cadaver Results. IEEE Robot Autom Lett 2020; 5:2240-2247. [PMID: 34621979 DOI: 10.1109/lra.2020.2970978] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Cochlear-implant electrode arrays (EAs) must be inserted accurately and precisely to avoid damaging the delicate anatomical structures of the inner ear. It has previously been shown on the benchtop that using magnetic fields to steer magnet-tipped EAs during insertion reduces insertion forces, which correlate with insertion errors and damage to internal cochlear structures. This paper presents several advancements toward the goal of deploying magnetic steering of cochlear-implant EAs in the operating room. In particular, we integrate image guidance with patient-specific insertion vectors, we incorporate a new nonmagnetic insertion tool, and we use an electromagnetic source, which provides programmable control over the generated field. The electromagnet is safer than prior permanent-magnet approaches in two ways: it eliminates motion of the field source relative to the patient's head and creates a field-free source in the power-off state. Using this system, we demonstrate system feasibility by magnetically steering EAs into a cadaver cochlea for the first time. We show that magnetic steering decreases average insertion forces, in comparison to manual insertions and to image-guided robotic insertions alone.
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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
| | - Dominick S Ropella
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN, USA
| | - Matt S Cavilla
- Department of Mechanical Engineering, University of Utah, Salt Lake City, UT, USA
| | - Andrew J Petruska
- Department of Mechanical Engineering, Colorado School of Mines, Golden, CO, USA
| | - Michael H Freeman
- Department of Otolaryngology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Robert F Labadie
- Department of Otolaryngology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Jake J Abbott
- Department of Mechanical Engineering, University of Utah, Salt Lake City, UT, USA
| | - Robert J Webster
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN, USA
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Choong JK, Hampson AJ, Brody KM, Lo J, Bester CW, Gummer AW, Reynolds NP, O'Leary SJ. Nanomechanical mapping reveals localized stiffening of the basilar membrane after cochlear implantation. Hear Res 2019; 385:107846. [PMID: 31786442 DOI: 10.1016/j.heares.2019.107846] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 11/02/2019] [Accepted: 11/10/2019] [Indexed: 01/12/2023]
Abstract
Cochlear implantation leads to many structural changes within the cochlea which can impair residual hearing. In patients with preserved low-frequency hearing, a delayed hearing loss can occur weeks-to-years post-implantation. We explore whether stiffening of the basilar membrane (BM) may be a contributory factor in an animal model. Our objective is to map changes in morphology and Young's modulus of basal and apical areas of the BM after cochlear implantation, using quantitative nanomechanical atomic force microscopy (QNM-AFM) after cochlear implant surgery. Cochlear implantation was undertaken in the guinea pig, and the BM was harvested at four time-points: 1 day, 14 days, 28 days and 84 days post-implantation for QNM-AFM analysis. Auditory brainstem response thresholds were determined prior to implantation and termination. BM tissue showed altered morphology and a progressive increase in Young's modulus, mainly in the apex, over time after implantation. BM tissue from the cochlear base demonstrated areas of extreme stiffness which are likely due to micro-calcification on the BM. In conclusion, stiffening of the BM after cochlear implantation occurs over time, even at sites far apical to a cochlear implant.
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Affiliation(s)
- Jessica K Choong
- Otolaryngology, Department of Surgery, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
| | - Amy J Hampson
- Otolaryngology, Department of Surgery, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
| | - Kate M Brody
- Otolaryngology, Department of Surgery, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
| | - Jonathon Lo
- Otolaryngology, Department of Surgery, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
| | - Christofer W Bester
- Otolaryngology, Department of Surgery, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
| | - Anthony W Gummer
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Strasse 5, 72076, Tübingen, Germany
| | - Nicholas P Reynolds
- ARC Training Centre for Biodevices, Swinburne University of Technology, Hawthorn, Australia; Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Australia.
| | - Stephen J O'Leary
- Otolaryngology, Department of Surgery, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia.
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Foggia MJ, Quevedo RV, Hansen MR. Intracochlear fibrosis and the foreign body response to cochlear implant biomaterials. Laryngoscope Investig Otolaryngol 2019; 4:678-683. [PMID: 31890888 PMCID: PMC6929576 DOI: 10.1002/lio2.329] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 10/30/2019] [Indexed: 12/31/2022] Open
Abstract
OBJECTIVE To report current knowledge on the topic of intracochlear fibrosis and the foreign body response following cochlear implantation (CI). METHODS A literature search was performed in PubMed to identify peer-reviewed articles. Search components included "cochlear implant," "Foreign body response (FBR)," and "fibrosis." Original studies and review articles relevant to the topic were included. RESULTS Ninety peer-reviewed articles describing the foreign body response or intracochlear fibrosis following CI were included. CONCLUSIONS Intracochlear fibrosis following CI represents a significant limiting factor for the success of CI users. Several strategies have been employed to mitigate the foreign body response within the cochlea including drug delivery systems and modifications in surgical technique and electrode design. A better understanding of the FBR has the potential to improve CI outcomes and the next generation of cochlear prostheses.
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Affiliation(s)
- Megan J. Foggia
- Department of Otolaryngology—Head & Neck SurgeryUniversity of Iowa Hospitals and ClinicsIowa CityIowa
| | - Rene Vielman Quevedo
- Department of Otolaryngology—Head & Neck SurgeryUniversity of Iowa Hospitals and ClinicsIowa CityIowa
| | - Marlan R. Hansen
- Department of Otolaryngology—Head & Neck SurgeryUniversity of Iowa Hospitals and ClinicsIowa CityIowa
- Department of NeurosurgeryUniversity of Iowa Hospitals and ClinicsIowa CityIowa
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Choong JKL, Lo J, Chambers SA, Hampson AJ, Eastwood HT, O’Leary SJ. Intracochlear tPA infusion may reduce fibrosis caused by cochlear implantation surgery. Acta Otolaryngol 2019; 139:396-402. [PMID: 30950671 DOI: 10.1080/00016489.2019.1587504] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
BACKGROUND Experiments show that the extent of ongoing fibrotic change within the cochlea can be determined by the volume and pattern of bleeding within the first 24 h following cochlear implantation. Tissue-type plasminogen activator (tPA) is effective at reducing thrombus volume when administered both within and external to the systemic circulation. AIMS/OBJECTIVES To determine if tPA delivered into the scala tympani immediately following implantation will reduce thrombus volume within the lower basal turn of the cochlea. MATERIALS AND METHODS Guinea pigs were implanted with either 'soft' or 'hard' arrays and administered tPA or saline via an intra-cochlear infusion immediately after implantation. Hearing was checked prior to, and 2 weeks after implantation. Cochleae were then harvested and imaged. RESULTS Animals implanted with 'soft' arrays had 4.2% less tissue response compared with animals implanted with 'hard' arrays. In animals receiving 'soft' arrays, tPA reduced the volume of tissue response (measured by the percentage of the lower basal turn of the scala tympani occupied by tissue response) compared with saline. CONCLUSIONS AND SIGNIFICANCE tPA may be effective in reducing the overall volume of tissue response in routine 'soft' cochlear implantation and may have a greater effect in the event of significant surgical trauma.
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Affiliation(s)
- Jessica Ky-Lee Choong
- aOtolaryngology, Department of Surgery, University of Melbourne, Melbourne, Australia
| | - Jonathon Lo
- aOtolaryngology, Department of Surgery, University of Melbourne, Melbourne, Australia
| | - Scott Andrew Chambers
- aOtolaryngology, Department of Surgery, University of Melbourne, Melbourne, Australia
| | - Amy Judith Hampson
- aOtolaryngology, Department of Surgery, University of Melbourne, Melbourne, Australia
| | | | - Stephen John O’Leary
- aOtolaryngology, Department of Surgery, University of Melbourne, Melbourne, Australia
- bRoyal Victorian Eye and Ear Hospital, Melbourne, Australia
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Changes of Electrocochleographic Responses During Cochlear Implantation Presented at the Annual Meeting of ADANO 2016 in Berlin. Otol Neurotol 2019; 40:e424-e429. [DOI: 10.1097/mao.0000000000001939] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Effects of dexamethasone on intracochlear inflammation and residual hearing after cochleostomy: A comparison of administration routes. PLoS One 2018; 13:e0195230. [PMID: 29601595 PMCID: PMC5877881 DOI: 10.1371/journal.pone.0195230] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 03/06/2018] [Indexed: 12/20/2022] Open
Abstract
Preservation of residual hearing after cochlear implant is an important issue with regards to hearing performance. Various methods of steroid administration have been widely used in clinical practice to reduce inflammation and preserve residual hearing. Here we compare the effect of different routes of dexamethasone administration on intracochlear inflammation and residual hearing in guinea pig ears. Dexamethasone was delivered into the guinea pigs either through intracochlear, intratympanic or systemic route. The intracochlear concentration of dexamethasone, residual hearing, inflammatory cytokines and histopathologic changes were evaluated over time. A higher intracochlear dexamethasone concentration was observed after intracochlear administration than through the other routes. Residual hearing was better preserved with local dexamethasone administration as was supported by the reduced inflammatory cytokines, more hair cell survival and less severe intracochlear fibrosis and ossification concurrently seen in the local delivery group than in the systemic group. The results demonstrate that local dexamethasone delivery can reduce intracochlear inflammation and preserve residual hearing better than in systemically administered dexamethasone.
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Susceptibility of Diabetic Mice to Noise Trauma. BIOMED RESEARCH INTERNATIONAL 2018; 2018:7601232. [PMID: 29619376 PMCID: PMC5830016 DOI: 10.1155/2018/7601232] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Revised: 12/26/2017] [Accepted: 01/17/2018] [Indexed: 02/07/2023]
Abstract
Diabetes can lead to many end-organ complications. However, the association between diabetes and hearing loss is not well understood. Here, we investigated the effect of noise exposure on diabetic mice compared with wild-type mice. Hearing threshold shifts, histopathologic changes in the cochlea, and inflammatory responses were evaluated over time. After noise exposure, more severe hearing threshold shifts, auditory hair cell loss, and synaptopathies were notable in diabetic mice compared with wild-type mice. Moreover, increased inflammatory responses and reactive oxygen species production were observed in the ears of diabetic mice. The results demonstrated that diabetic mice are more susceptible to noise trauma.
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Drouillard M, Torres R, Mamelle E, De Seta D, Sterkers O, Ferrary E, Nguyen Y. Influence of electrode array stiffness and diameter on hearing in cochlear implanted guinea pig. PLoS One 2017; 12:e0183674. [PMID: 28837630 PMCID: PMC5570298 DOI: 10.1371/journal.pone.0183674] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 08/08/2017] [Indexed: 11/18/2022] Open
Abstract
During cochlear implantation, electrode array translocation and trauma should be avoided to preserve residual hearing. The aim of our study was to evaluate the effect of physical parameters of the array on residual hearing and cochlear structures during insertion. Three array prototypes with different stiffnesses or external diameters were implanted in normal hearing guinea pigs via a motorized insertion tool carried on a robot-based arm, and insertion forces were recorded. Array prototypes 0.4 and 0.4R had 0.4 mm external diameter and prototype 0.3 had 0.3 mm external diameter. The axial stiffness was set to 1 for the 0.4 prototype and the stiffnesses of the 0.4R and 0.3 prototypes were calculated from this as 6.8 and 0.8 (relative units), respectively. Hearing was assessed preoperatively by the auditory brainstem response (ABR), and then at day 7 and day 30 post-implantation. A study of the macroscopic anatomy was performed on cochleae harvested at day 30 to examine the scala location of the array. At day 7, guinea pigs implanted with the 0.4R array had significantly poorer hearing results than those implanted with the 0.3 array (26±17.7, 44±23.4, 33±20.5 dB, n = 7, vs 5±8.7, 1±11.6, 12±11.5 dB, n = 6, mean±SEM, respectively, at 8, 16 and 24 kHz, p<0.01) or those implanted with the 0.4 array (44±23.4 dB, n = 7, vs 28±21.7 dB, n = 7, at 16 kHz, p<0.05). Hearing remained stable from day 7 to day 30. The maximal peak of insertion force was higher with the 0.4R array than with the 0.3 array (56±23.8 mN, n = 7, vs 26±8.7 mN, n = 6). Observation of the cochleae showed that an incorrectly positioned electrode array or fibrosis were associated with hearing loss ≥40 dB (at 16 kHz). An optimal position in the scala tympani with a flexible and thin array and prevention of fibrosis should be the primary objectives to preserve hearing during cochlear implantation.
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Affiliation(s)
- Mylène Drouillard
- Sorbonne Universités, Université Pierre et Marie Curie Paris 6, Inserm, Unité “Réhabilitation chirurgicale mini-invasive et robotisée de l'audition”, Paris, France
- AP-HP, GHU Pitié-Salpêtrière, Service ORL, Otologie, implants auditifs et chirurgie de la base du crâne, Paris, France
| | - Renato Torres
- Sorbonne Universités, Université Pierre et Marie Curie Paris 6, Inserm, Unité “Réhabilitation chirurgicale mini-invasive et robotisée de l'audition”, Paris, France
- AP-HP, GHU Pitié-Salpêtrière, Service ORL, Otologie, implants auditifs et chirurgie de la base du crâne, Paris, France
| | - Elisabeth Mamelle
- Sorbonne Universités, Université Pierre et Marie Curie Paris 6, Inserm, Unité “Réhabilitation chirurgicale mini-invasive et robotisée de l'audition”, Paris, France
- AP-HP, GHU Pitié-Salpêtrière, Service ORL, Otologie, implants auditifs et chirurgie de la base du crâne, Paris, France
| | - Daniele De Seta
- Sorbonne Universités, Université Pierre et Marie Curie Paris 6, Inserm, Unité “Réhabilitation chirurgicale mini-invasive et robotisée de l'audition”, Paris, France
- AP-HP, GHU Pitié-Salpêtrière, Service ORL, Otologie, implants auditifs et chirurgie de la base du crâne, Paris, France
| | - Olivier Sterkers
- Sorbonne Universités, Université Pierre et Marie Curie Paris 6, Inserm, Unité “Réhabilitation chirurgicale mini-invasive et robotisée de l'audition”, Paris, France
- AP-HP, GHU Pitié-Salpêtrière, Service ORL, Otologie, implants auditifs et chirurgie de la base du crâne, Paris, France
| | - Evelyne Ferrary
- Sorbonne Universités, Université Pierre et Marie Curie Paris 6, Inserm, Unité “Réhabilitation chirurgicale mini-invasive et robotisée de l'audition”, Paris, France
- AP-HP, GHU Pitié-Salpêtrière, Service ORL, Otologie, implants auditifs et chirurgie de la base du crâne, Paris, France
| | - Yann Nguyen
- Sorbonne Universités, Université Pierre et Marie Curie Paris 6, Inserm, Unité “Réhabilitation chirurgicale mini-invasive et robotisée de l'audition”, Paris, France
- AP-HP, GHU Pitié-Salpêtrière, Service ORL, Otologie, implants auditifs et chirurgie de la base du crâne, Paris, France
- * E-mail:
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Hearing Preservation After Cochlear Implantation May Improve Long-term Word Perception in the Electric-only Condition. Otol Neurotol 2016; 37:1314-9. [DOI: 10.1097/mao.0000000000001193] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Choi JW, Lyu AR, Ryu KA, Kim D, Park YH. Detection of pneumolabyrinth after temporal bone trauma using computed tomography. Acta Otolaryngol 2016; 136:682-6. [PMID: 27007704 DOI: 10.3109/00016489.2016.1157266] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
CONCLUSION Pneumolabyrinth is a very rare condition, even in otic capsule disrupting (OCD) fracture. Hearing was not always impaired, even in cases with OCD fracture. The co-existence of pneumocochlea, regarded as a risk factor for total hearing loss, was extremely rare in cases of pneumolabyrinth. OBJECTIVES The purposes of this study were to analyze the radiological and clinical features in patients with pneumolabyrinth and to overcome the diagnostic pitfalls encountered during pneumocochlea detection. MATERIALS AND METHODS The temporal bone computed tomographies (TBCT) of 402 patients diagnosed with temporal bone fracture along with their clinical records were retrospectively reviewed. RESULTS Only six patients (7% of those with OCD fractures or 1.5% of those with temporal bone fracture) were found to have pneumolabyrinth. Locations of the pneumolabyrinth were in the vestibule in all six cases and three of them showed air densities both in the cochlea and semicircular canal. The size of the air density in the vestibule was 5.38 ± 4.56 mm(2) at the axial view and 6.57 ± 5.67 mm(2) at the coronal view. The mean minimal Hounsfield unit (HU) of air density area in the vestibule was -968.1 ± 22.94 at the axial view and -941 ± 16.88 at the coronal view. Patients with pneumocochlea eventually developed total hearing loss.
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Affiliation(s)
- Jin Woong Choi
- a Department of Otolaryngology-Head and Neck Surgery, Chungnam National University, Daejeon, Republic of Korea
| | - Ah-Ra Lyu
- b Department of Medical Science, Chungnam National Univesersity, Daejeon, Republic of Korea
| | - Kyeung A Ryu
- a Department of Otolaryngology-Head and Neck Surgery, Chungnam National University, Daejeon, Republic of Korea
| | - Dami Kim
- c Department of Radiology, Chungnam National University, Daejeon, Republic of Korea
| | - Yong-Ho Park
- a Department of Otolaryngology-Head and Neck Surgery, Chungnam National University, Daejeon, Republic of Korea
- d Brain Research Insititute, College of Medicine, Chungnam National University, Daejeon, Republic of Korea
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Jin Y, Lyu AR, Park SJ, Xu J, Cui J, Sohn KC, Hur GM, Jin Y, Park YH. Early Postnatal NT-3 Gene Delivery Enhances Hearing Acquisition in the Developmental Period. Laryngoscope 2016; 126:E379-E385. [DOI: 10.1002/lary.26130] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 05/07/2016] [Accepted: 05/11/2016] [Indexed: 12/18/2022]
Affiliation(s)
- Yongde Jin
- Department of Otolaryngology-Head and Neck Surgery; Yanbian University Hospital; Yanji China
| | - Ah-Ra Lyu
- Department of Otolaryngology-Head and Neck Surgery , College of Medicine; Chungnam National University; Daejeon Republic of Korea
- Department of Medical Science; Chungnam National University; Daejeon Republic of Korea
| | - Sung-Jae Park
- Department of Otolaryngology-Head and Neck Surgery , College of Medicine; Chungnam National University; Daejeon Republic of Korea
| | - Jun Xu
- Department of Otolaryngology-Head and Neck Surgery; Yanbian University Hospital; Yanji China
- Department of Otolaryngology-Head and Neck Surgery , College of Medicine; Chungnam National University; Daejeon Republic of Korea
| | - Jie Cui
- Department of Otolaryngology-Head and Neck Surgery; Yanbian University Hospital; Yanji China
| | - Kyung-Cheol Sohn
- Department of Dermatology , College of Medicine; Chungnam National University; Daejeon Republic of Korea
| | - Gang Min Hur
- Department of Pharmacology , College of Medicine; Chungnam National University; Daejeon Republic of Korea
| | - Yulian Jin
- Department of Otolaryngology-Head and Neck Surgery; Yanbian University Hospital; Yanji China
| | - Yong-Ho Park
- Department of Otolaryngology-Head and Neck Surgery , College of Medicine; Chungnam National University; Daejeon Republic of Korea
- Brain Research Institute , College of Medicine; Chungnam National University; Daejeon Republic of Korea
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