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Yancey KL, Patro A, Smetak M, Perkins EL, Isaacson B, Bennett ML, O'Malley M, Haynes DS, Hunter JB. Evaluating calcium channel blockers and bisphosphonates as otoprotective agents in cochlear implantation hearing preservation candidates. Cochlear Implants Int 2024:1-9. [PMID: 38738388 DOI: 10.1080/14670100.2024.2338003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2024]
Abstract
OBJECTIVES Evaluate potential effects of calcium channel blockers (CCB) and bisphosphonates (BP) on residual hearing following cochlear implantation. METHODS Medications of 303 adult hearing preservation (HP) candidates (low frequency pure tone average [LFPTA] of 125, 250, and 500 Hz ≤80 dB HL) were reviewed. Postimplantation LFPTA of patients taking CCBs and BPs were compared to controls matched by age and preimplantation LFPTA. RESULTS Twenty-six HP candidates were taking a CCB (N = 14) or bisphosphonate (N = 12) at implantation. Median follow-up was 1.37 years (range 0.22-4.64y). Among subjects with initial HP, 29% (N = 2 of 7) CCB users compared to 50% (N = 2 of 4) controls subsequently lost residual hearing 3-6 months later (OR = 0.40, 95% CI = 0.04-4.32, p = 0.58). None of the four BP patients with initial HP experienced delayed loss compared to 50% (N = 2 of 4) controls with initial HP (OR = 0.00, 95% CI = 0.00-1.95, P = 0.43). Two CCB and one BP patients improved to a LFPTA <80 dB HL following initial unaided thresholds that suggested loss of residual hearing. DISCUSSION There were no significant differences in the odds of delayed loss of residual hearing with CCBs or BPs. CONCLUSION Further investigation into potential otoprotective adjuvants for maintaining residual hearing following initial successful hearing preservation is warranted, with larger cohorts and additional CCB/BP agents.
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Affiliation(s)
- Kristen L Yancey
- Department of Otolaryngology-Head and Neck Surgery, Weill Cornell Medical Center/New York Presbyterian Hospital, New York, NY, USA
| | - Ankita Patro
- Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Miriam Smetak
- Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Elizabeth L Perkins
- Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Brandon Isaacson
- Department of Otolaryngology-Head and Neck Surgery, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Marc L Bennett
- Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Matthew O'Malley
- Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - David S Haynes
- Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Jacob B Hunter
- Department of Otolaryngology-Head and Neck Surgery, Thomas Jefferson University Hospital, Philadelphia, PA, USA
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Sriperumbudur KK, Appali R, Gummer AW, van Rienen U. Understanding the impact of modiolus porosity on stimulation of spiral ganglion neurons by cochlear implants. Sci Rep 2024; 14:9593. [PMID: 38671022 PMCID: PMC11053021 DOI: 10.1038/s41598-024-59347-2] [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: 09/29/2023] [Accepted: 04/09/2024] [Indexed: 04/28/2024] Open
Abstract
Moderate-to-profound sensorineural hearing loss in humans is treatable by electrically stimulating the auditory nerve (AN) with a cochlear implant (CI). In the cochlea, the modiolus presents a porous bony interface between the CI electrode and the AN. New bone growth caused by the presence of the CI electrode or neural degeneration inflicted by ageing or otological diseases might change the effective porosity of the modiolus and, thereby, alter its electrical material properties. Using a volume conductor description of the cochlea, with the aid of a 'mapped conductivity' method and an ad-hoc 'regionally kinetic' equation system, we show that even a slight variation in modiolus porosity or pore distribution can disproportionately affect AN stimulation. Hence, because of porosity changes, an inconsistent CI performance might occur if neural degeneration or new bone growth progress after implantation. Appropriate electrical material properties in accordance with modiolar morphology and pathology should be considered in patient-specific studies. The present first-of-its-kind in-silico study advocates for contextual experimental studies to further explore the utility of modiolus porous morphology in optimising the CI outcome.
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Affiliation(s)
- Kiran K Sriperumbudur
- Institute of General Electrical Engineering, University of Rostock, Rostock, Germany.
- Research and Development, MED-EL Medical Electronics GmbH, Innsbruck, Austria.
| | - Revathi Appali
- Institute of General Electrical Engineering, University of Rostock, Rostock, Germany
- Ageing of Individuals and Society, Interdisciplinary Faculty, University of Rostock, Rostock, Germany
| | - Anthony W Gummer
- Department of Otolaryngology, University of Tübingen, Tübingen, Germany.
- Department of Otolaryngology, University of Melbourne, Melbourne, Australia.
| | - Ursula van Rienen
- Institute of General Electrical Engineering, University of Rostock, Rostock, Germany
- Ageing of Individuals and Society, Interdisciplinary Faculty, University of Rostock, Rostock, Germany
- Life, Light and Matter, Interdisciplinary Faculty, University of Rostock, Rostock, Germany
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3
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Boukhzer S, Eliezer M, Boubaker F, Hossu G, Blum A, Teixeira P, Parietti-Winkler C, Gillet R. Ultra-high-resolution CT of the temporal bone: The end of stapes prosthesis dimensional error and correlation with patient symptoms. Eur J Radiol 2024; 175:111467. [PMID: 38636410 DOI: 10.1016/j.ejrad.2024.111467] [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: 12/19/2023] [Revised: 03/23/2024] [Accepted: 04/11/2024] [Indexed: 04/20/2024]
Abstract
PURPOSE To describe the reliability of ultra-high-resolution computed tomography (UHR-CT) in the measurement of titanium stapes prostheses using manufacturer data as a reference. MATERIALS AND METHODS This retrospective study included patients treated by stapedectomy with titanium prostheses who underwent UHR-CT between January 2020 and October 2023. Images were acquired using an ultra-high-resolution mode (slice thickness: 0.25 mm; matrix, 1024 × 1024). Two radiologists independently evaluated the length, diameter, and intra-vestibular protrusion of the prosthesis. Post-operative air-bone gaps (ABGs) were recorded. RESULTS Fourteen patients were enrolled (mean age, 44.3 ± 13.8 [SD] years, 9 females), resulting in 16 temporal bone UHR-CTs. The exact length was obtained in 81.3 % (n = 13/16) and underestimated by 0.1 to 0.3 mm in the remaining 18.7 % (n = 3/16) CT scans for both readers (mean misestimation: -0.02 ± 0.06 [SD] mm, overall underestimation of 0.43 %). The exact diameter was reported in 75 % (n = 12/16) and 87.5 % (n = 14/16) of the CT scans for readers 1 and 2, respectively, and was off by 0.1 mm in all discrepancies (mean misestimation: 0.01 ± 0.04 [SD] mm, overall overestimation of 2.43 %). Intravestibular prosthesis protrusion was of 0.5 ± 0.43 [SD] mm (range: 0-1) and 0.49 ± 0.44 [SD] mm (range: 0-1.1) for readers 1 and 2, respectively, and did not correlate with ABGs (r = 0.25 and 0.22; P = 0.39 and 0.47 for readers 1 and 2, respectively). Intra and interobserver agreements were excellent. CONCLUSION UHR-CT provides 99.6 % and 97.6 % accuracy for prosthesis length and diameter measurements, respectively.
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Affiliation(s)
- Sara Boukhzer
- Guilloz Imaging Department, Central Hospital, University Hospital Center of Nancy, Nancy, France
| | - Michael Eliezer
- Department of Radiology, Lariboisière Hospital, Paris, France
| | - Fatma Boubaker
- Guilloz Imaging Department, Central Hospital, University Hospital Center of Nancy, Nancy, France
| | - Gabriela Hossu
- Université de Lorraine, INSERM, IADI, Nancy, France; Université de Lorraine, CIC, Innovation Technologique, University Hospital Center of Nancy, Nancy, France
| | - Alain Blum
- Guilloz Imaging Department, Central Hospital, University Hospital Center of Nancy, Nancy, France; Université de Lorraine, INSERM, IADI, Nancy, France; Université de Lorraine, CIC, Innovation Technologique, University Hospital Center of Nancy, Nancy, France
| | - Pedro Teixeira
- Guilloz Imaging Department, Central Hospital, University Hospital Center of Nancy, Nancy, France; Université de Lorraine, INSERM, IADI, Nancy, France; Université de Lorraine, CIC, Innovation Technologique, University Hospital Center of Nancy, Nancy, France
| | - Cécile Parietti-Winkler
- ENT Surgery Department, Central Hospital, University Hospital Center of Nancy, Nancy, France
| | - Romain Gillet
- Guilloz Imaging Department, Central Hospital, University Hospital Center of Nancy, Nancy, France; Université de Lorraine, INSERM, IADI, Nancy, France; Université de Lorraine, CIC, Innovation Technologique, University Hospital Center of Nancy, Nancy, France.
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Du H, Li J, Chen Z, Gao Y, Yang X, Yuan S, Wang Q, Guo W, Chen W, Dai P, Yang S. Changes in hearing function and intracochlear morphology after electrode array insertion in minipigs. Acta Otolaryngol 2024; 144:159-167. [PMID: 38742731 DOI: 10.1080/00016489.2024.2341122] [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: 01/17/2024] [Accepted: 04/04/2024] [Indexed: 05/16/2024]
Abstract
BACKGROUND In temporal bone specimens from long-term cochlear implant users, foreign body response within the cochlea has been demonstrated. However, how hearing changes after implantation and fibrosis progresses within the cochlea is unknown. OBJECTIVES To investigate the short-term dynamic changes in hearing and cochlear histopathology in minipigs after electrode array insertion. MATERIAL AND METHODS Twelve minipigs were selected for electrode array insertion (EAI) and the Control. Hearing tests were performed preoperatively and on 0, 7, 14, and 28 day(s) postoperatively, and cochlear histopathology was performed after the hearing tests on 7, 14, and 28 days after surgery. RESULTS Electrode array insertion had a significant effect for the frequency range tested (1 kHz-20kHz). Exudation was evident one week after electrode array insertion; at four weeks postoperatively, a fibrous sheath formed around the electrode. At each time point, the endolymphatic hydrops was found; no significant changes in the morphology and packing density of the spiral ganglion neurons were observed. CONCLUSIONS AND SIGNIFICANCE The effect of electrode array insertion on hearing and intracochlear fibrosis was significant. The process of fibrosis and endolymphatic hydrops seemed to not correlate with the degree of hearing loss, nor did it affect spiral ganglion neuron integrity in the 4-week postoperative period.
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Affiliation(s)
- Haiqiao Du
- Senior Department of Otolaryngology-Head and Neck Surgery, the Sixth Medical Center of Chinese PLA General Hospital, Chinese PLA Medical School, Beijing, China
- State Key Laboratory of Hearing and Balance Science, Beijing, China
- National Clinical Research Center for Otolaryngologic Diseases, Beijing, China
- Key Laboratory of Hearing Science, Ministry of Education, Beijing, China
- Beijing Key Laboratory of Hearing Impairment Prevention and Treatment, Beijing, China
| | - Jianan Li
- Senior Department of Otolaryngology-Head and Neck Surgery, the Sixth Medical Center of Chinese PLA General Hospital, Chinese PLA Medical School, Beijing, China
- State Key Laboratory of Hearing and Balance Science, Beijing, China
- National Clinical Research Center for Otolaryngologic Diseases, Beijing, China
- Key Laboratory of Hearing Science, Ministry of Education, Beijing, China
- Beijing Key Laboratory of Hearing Impairment Prevention and Treatment, Beijing, China
| | - Zhifeng Chen
- Senior Department of Otolaryngology-Head and Neck Surgery, the Sixth Medical Center of Chinese PLA General Hospital, Chinese PLA Medical School, Beijing, China
- State Key Laboratory of Hearing and Balance Science, Beijing, China
- National Clinical Research Center for Otolaryngologic Diseases, Beijing, China
- Key Laboratory of Hearing Science, Ministry of Education, Beijing, China
- Beijing Key Laboratory of Hearing Impairment Prevention and Treatment, Beijing, China
- Department of Otolaryngology Head and Neck Surgery, The 940th Hospital of Joint Logistics Support Force of Chinese PLA, Lanzhou, China
| | - Yun Gao
- Kunming Institute of Zoology, The Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Xiao Yang
- Kunming Institute of Zoology, The Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Shuolong Yuan
- Senior Department of Otolaryngology-Head and Neck Surgery, the Sixth Medical Center of Chinese PLA General Hospital, Chinese PLA Medical School, Beijing, China
- State Key Laboratory of Hearing and Balance Science, Beijing, China
- National Clinical Research Center for Otolaryngologic Diseases, Beijing, China
- Key Laboratory of Hearing Science, Ministry of Education, Beijing, China
- Beijing Key Laboratory of Hearing Impairment Prevention and Treatment, Beijing, China
| | - Qian Wang
- Senior Department of Otolaryngology-Head and Neck Surgery, the Sixth Medical Center of Chinese PLA General Hospital, Chinese PLA Medical School, Beijing, China
- State Key Laboratory of Hearing and Balance Science, Beijing, China
- National Clinical Research Center for Otolaryngologic Diseases, Beijing, China
- Key Laboratory of Hearing Science, Ministry of Education, Beijing, China
- Beijing Key Laboratory of Hearing Impairment Prevention and Treatment, Beijing, China
| | - Weiwei Guo
- Senior Department of Otolaryngology-Head and Neck Surgery, the Sixth Medical Center of Chinese PLA General Hospital, Chinese PLA Medical School, Beijing, China
- State Key Laboratory of Hearing and Balance Science, Beijing, China
- National Clinical Research Center for Otolaryngologic Diseases, Beijing, China
- Key Laboratory of Hearing Science, Ministry of Education, Beijing, China
- Beijing Key Laboratory of Hearing Impairment Prevention and Treatment, Beijing, China
| | - Wei Chen
- Senior Department of Otolaryngology-Head and Neck Surgery, the Sixth Medical Center of Chinese PLA General Hospital, Chinese PLA Medical School, Beijing, China
- State Key Laboratory of Hearing and Balance Science, Beijing, China
- National Clinical Research Center for Otolaryngologic Diseases, Beijing, China
- Key Laboratory of Hearing Science, Ministry of Education, Beijing, China
- Beijing Key Laboratory of Hearing Impairment Prevention and Treatment, Beijing, China
| | - Pu Dai
- Senior Department of Otolaryngology-Head and Neck Surgery, the Sixth Medical Center of Chinese PLA General Hospital, Chinese PLA Medical School, Beijing, China
- State Key Laboratory of Hearing and Balance Science, Beijing, China
- National Clinical Research Center for Otolaryngologic Diseases, Beijing, China
- Key Laboratory of Hearing Science, Ministry of Education, Beijing, China
- Beijing Key Laboratory of Hearing Impairment Prevention and Treatment, Beijing, China
| | - Shiming Yang
- Senior Department of Otolaryngology-Head and Neck Surgery, the Sixth Medical Center of Chinese PLA General Hospital, Chinese PLA Medical School, Beijing, China
- State Key Laboratory of Hearing and Balance Science, Beijing, China
- National Clinical Research Center for Otolaryngologic Diseases, Beijing, China
- Key Laboratory of Hearing Science, Ministry of Education, Beijing, China
- Beijing Key Laboratory of Hearing Impairment Prevention and Treatment, Beijing, China
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Mussoi BS, Meibos A, Woodson E, Sydlowski S. The association between electrode impedance and short-term outcomes in cochlear implant recipients of slim modiolar and slim straight electrode arrays. Cochlear Implants Int 2024; 25:59-68. [PMID: 38081181 DOI: 10.1080/14670100.2023.2290768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/17/2024]
Abstract
OBJECTIVES Electrode impedance measurements from cochlear implants (CI) reflect the status of the electrode array as well as the surrounding cochlear environment, and could provide a clinical index of functional changes with the CI. The goals of this study were to examine (1) the impact of electrode array type on electrode impedance, and (2) the relationship between electrode impedance and short-term hearing preservation and speech recognition outcomes. METHODS Retrospective study of 115 adult hearing preservation CI recipients of a slim modiolar or slim straight array. Common ground electrode impedances, pre- and post-operative hearing thresholds and CNC word recognition scores were retrieved. RESULTS Electrode impedances were significantly higher for recipients of the straight electrode array. Within individuals, electrode impedances were stable after the first week post-activation. However, increased standard deviation of electrode impedances was associated with greater loss of low frequency hearing at initial activation, and with poorer speech recognition at 6 months post-implantation. CONCLUSIONS Results demonstrate that electrode impedances depend on the type of implanted array. Findings also suggest that there may be a role for the variability in electrode impedance across electrodes as an indicator of changes in the intracochlear environment that contribute to outcomes with a CI.
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Affiliation(s)
- Bruna S Mussoi
- Speech Pathology and Audiology, Kent State University, Kent, OH, USA
| | - Alex Meibos
- School of Speech-Language Pathology and Audiology, The University of Akron, Akron, OH, USA
| | - Erika Woodson
- Head and Neck Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Sarah Sydlowski
- Head and Neck Institute, Cleveland Clinic, Cleveland, OH, USA
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Tang R, Li J, Zhao P, Zhang Z, Yin H, Ding H, Xu N, Yang Z, Wang Z. Utility of machine learning for identifying stapes fixation on ultra-high-resolution CT. Jpn J Radiol 2024; 42:69-77. [PMID: 37561264 DOI: 10.1007/s11604-023-01475-2] [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: 04/06/2023] [Accepted: 07/18/2023] [Indexed: 08/11/2023]
Abstract
PURPOSE Imaging diagnosis of stapes fixation (SF) is challenging owing to a lack of definite evidence. We developed a comprehensive machine learning (ML) model to identify SF on ultra-high-resolution CT. MATERIALS AND METHODS We retrospectively enrolled 109 participants (143 ears) and divided them into the training set (115 ears) and test set (28 ears). Stapes mobility (SF or non-SF) was determined by surgical inspection. In the ML analysis, rectangular regions of interest were placed on consecutive axial slices in the training set. Radiomic features were extracted and fed into the training session. The test set was analyzed using 7 ML models (support vector machine, k nearest neighbor, decision tree, random forest, extra trees, eXtreme Gradient Boosting, and Light Gradient Boosting Machine) and by 2 dedicated neuroradiologists. Diagnostic performance (sensitivity, specificity and accuracy, with surgical findings as the reference) was compared between the radiologists and the optimal ML model by using the McNemar test. RESULTS The mean age of the participants was 42.3 ± 17.5 years. The Light Gradient Boosting Machine (LightGBM) model showed the highest sensitivity (0.83), specificity (0.81), accuracy (0.82) and area under the curve (0.88) for detecting SF among the 7 ML models. The neuroradiologists achieved good sensitivities (0.75 and 0.67), moderate-to-good specificities (0.63 and 0.56) and good accuracies (0.68 and 0.61). This model showed no statistical differences with the neuroradiologists (P values 0.289-1.000). CONCLUSIONS Compared to the neuroradiologists, the LightGBM model achieved competitive diagnostic performance in identifying SF, and has the potential to be a supportive tool in clinical practice.
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Affiliation(s)
- Ruowei Tang
- Department of Radiology, Beijing Friendship Hospital, Capital Medical University, 95 Yong'an Road, Xicheng District, Beijing, 100050, People's Republic of China
| | - Jia Li
- Department of Radiology, Beijing Friendship Hospital, Capital Medical University, 95 Yong'an Road, Xicheng District, Beijing, 100050, People's Republic of China
| | - Pengfei Zhao
- Department of Radiology, Beijing Friendship Hospital, Capital Medical University, 95 Yong'an Road, Xicheng District, Beijing, 100050, People's Republic of China.
| | - Zhengyu Zhang
- Department of Radiology, Beijing Friendship Hospital, Capital Medical University, 95 Yong'an Road, Xicheng District, Beijing, 100050, People's Republic of China
| | - Hongxia Yin
- Department of Radiology, Beijing Friendship Hospital, Capital Medical University, 95 Yong'an Road, Xicheng District, Beijing, 100050, People's Republic of China
| | - Heyu Ding
- Department of Radiology, Beijing Friendship Hospital, Capital Medical University, 95 Yong'an Road, Xicheng District, Beijing, 100050, People's Republic of China
| | - Ning Xu
- Department of Radiology, Beijing Friendship Hospital, Capital Medical University, 95 Yong'an Road, Xicheng District, Beijing, 100050, People's Republic of China
| | - Zhenghan Yang
- Department of Radiology, Beijing Friendship Hospital, Capital Medical University, 95 Yong'an Road, Xicheng District, Beijing, 100050, People's Republic of China
| | - Zhenchang Wang
- Department of Radiology, Beijing Friendship Hospital, Capital Medical University, 95 Yong'an Road, Xicheng District, Beijing, 100050, People's Republic of China.
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Zhang N, Tang R, Zhao P, Xu N, Meng F, Wang Z, Zhang T, Zhang Z, Yin H, Ding H, Qiu X, Dai C, Huang Y, Yang Z, Huang X, Wang Z. Potential of ultra-high-resolution CT in detecting osseous changes of temporomandibular joint: experiences in temporomandibular disorders. BMC Oral Health 2023; 23:737. [PMID: 37814269 PMCID: PMC10563235 DOI: 10.1186/s12903-023-03449-2] [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: 07/10/2023] [Accepted: 09/24/2023] [Indexed: 10/11/2023] Open
Abstract
BACKGROUND Osseous changes of the temporomandibular joint (TMJ) are related to the progression of temporomandibular disorders (TMD), and computed tomography (CT) plays a vital role in disease evaluation. OBJECTIVE The aims of this study were to evaluate the image quality and diagnostic value of ultra-high-resolution CT (U-HRCT) in TMD compared to cone-beam CT (CBCT). METHODS TMD patients who underwent both CBCT and U-HRCT between November 2021 and September 2022 were retrospectively included. Image quality scores were assigned for four osseous structures (the cortical and trabecular bones of the condyle, articular eminence, and glenoid fossa) by two independent observers from Score 1 (unacceptable) to Score 5 (excellent). Diagnostic classification of TMD was categorized as follows: Class A (no evident lesion), Class B (indeterminate condition) and Class C (definitive lesion). Image quality scores and diagnostic classifications were compared between CBCT and U-HRCT. The Cohen's Kappa test, Wilcoxon signed-rank test, Chi-square test and Fisher's exact test were conducted for statistical analysis. RESULTS Thirty TMD patients (median age, 30 years; interquartile range, 26-43 years; 25 females) with 60 TMJs were enrolled. Image quality scores were higher for U-HRCT than for CBCT by both observers (all Ps < 0.001). Definitive diagnoses (Class A and C) were achieved in more cases with U-HRCT than with CBCT (93.3% vs. 65.0%, Fisher's exact value = 7.959, P = 0.012). Among the 21 cases which were ambiguously diagnosed (Class B) by CBCT, definitive diagnosis was achieved for 17 cases (81.0%) using U-HRCT. CONCLUSIONS U-HRCT can identify osseous changes in TMD, providing improved image quality and a more definitive diagnosis, which makes it a feasible diagnostic imaging method for TMD.
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Affiliation(s)
- Ning Zhang
- Department of Stomatology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Ruowei Tang
- Department of Radiology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Pengfei Zhao
- Department of Radiology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Ning Xu
- Department of Radiology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Fanhao Meng
- Department of Stomatology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Zhen Wang
- Department of Stomatology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Tingting Zhang
- Department of Radiology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Zhengyu Zhang
- Department of Radiology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Hongxia Yin
- Department of Radiology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Heyu Ding
- Department of Radiology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Xiaoyu Qiu
- Department of Radiology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Chihang Dai
- Department of Radiology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Yan Huang
- Department of Radiology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Zhenghan Yang
- Department of Radiology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Xiaofeng Huang
- Department of Stomatology, Beijing Friendship Hospital, Capital Medical University, Beijing, China.
| | - Zhenchang Wang
- Department of Radiology, Beijing Friendship Hospital, Capital Medical University, Beijing, China.
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de Rijk SR, Boys AJ, Roberts IV, Jiang C, Garcia C, Owens RM, Bance M. Tissue-Engineered Cochlear Fibrosis Model Links Complex Impedance to Fibrosis Formation for Cochlear Implant Patients. Adv Healthc Mater 2023; 12:e2300732. [PMID: 37310792 DOI: 10.1002/adhm.202300732] [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: 03/07/2023] [Revised: 05/30/2023] [Indexed: 06/15/2023]
Abstract
Cochlear implants are a life-changing technology for those with severe sensorineural hearing loss, partially restoring hearing through direct electrical stimulation of the auditory nerve. However, they are known to elicit an immune response resulting in fibrotic tissue formation in the cochlea that is linked to residual hearing loss and suboptimal outcomes. Intracochlear fibrosis is difficult to track without postmortem histology, and no specific electrical marker for fibrosis exists. In this study, a tissue-engineered model of cochlear fibrosis is developed following implant placement to examine the electrical characteristics associated with fibrotic tissue formation around electrodes. The model is characterized using electrochemical impedance spectroscopy and an increase in the resistance and a decrease in capacitance of the tissue using a representative circuit are found. This result informs a new marker of fibrosis progression over time that is extractable from voltage waveform responses, which can be directly measured in cochlear implant patients. This marker is tested in a small sample size of recently implanted cochlear implant patients, showing a significant increase over two postoperative timepoints. Using this system, complex impedance is demonstrated as a marker of fibrosis progression that is directly measurable from cochlear implants to enable real-time tracking of fibrosis formation in patients, creating opportunities for earlier treatment intervention to improve cochlear implant efficacy.
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Affiliation(s)
- Simone R de Rijk
- Cambridge Hearing Group, Cambridge, CB2 8AF, UK
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 3 EB, UK
| | - Alexander J Boys
- Cambridge Hearing Group, Cambridge, CB2 8AF, UK
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, CB3 0AS, UK
| | - Iwan V Roberts
- Cambridge Hearing Group, Cambridge, CB2 8AF, UK
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 3 EB, UK
| | - Chen Jiang
- Cambridge Hearing Group, Cambridge, CB2 8AF, UK
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 3 EB, UK
- Department of Electronic Engineering, Tsinghua University, Beijing, 100190, P. R. China
| | - Charlotte Garcia
- Cambridge Hearing Group, Cambridge, CB2 8AF, UK
- Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, CB2 7EF, UK
| | - Róisín M Owens
- Cambridge Hearing Group, Cambridge, CB2 8AF, UK
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, CB3 0AS, UK
| | - Manohar Bance
- Cambridge Hearing Group, Cambridge, CB2 8AF, UK
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 3 EB, UK
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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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10
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Human cochlear microstructures at risk of electrode insertion trauma, elucidated in 3D with contrast-enhanced microCT. Sci Rep 2023; 13:2191. [PMID: 36750646 PMCID: PMC9905077 DOI: 10.1038/s41598-023-29401-6] [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: 10/14/2022] [Accepted: 02/03/2023] [Indexed: 02/09/2023] Open
Abstract
Cochlear implant restores hearing loss through electrical stimulation of the hearing nerve from within the cochlea. Unfortunately, surgical implantation of this neuroprosthesis often traumatizes delicate intracochlear structures, resulting in loss of residual hearing and compromising hearing in noisy environments and appreciation of music. To avoid cochlear trauma, insertion techniques and devices have to be adjusted to the cochlear microanatomy. However, existing techniques were unable to achieve a representative visualization of the human cochlea: classical histology damages the tissues and lacks 3D perspective; standard microCT fails to resolve the cochlear soft tissues; and previously used X-ray contrast-enhancing staining agents are destructive. In this study, we overcame these limitations by performing contrast-enhanced microCT imaging (CECT) with a novel polyoxometalate staining agent Hf-WD POM. With Hf-WD POM-based CECT, we achieved nondestructive, high-resolution, simultaneous, 3D visualization of the mineralized and soft microstructures in fresh-frozen human cochleae. This enabled quantitative analysis of the true intracochlear dimensions and led to anatomical discoveries, concerning surgically-relevant microstructures: the round window membrane, the Rosenthal's canal and the secondary spiral lamina. Furthermore, we demonstrated that Hf-WD POM-based CECT enables quantitative assessment of these structures as well as their trauma.
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11
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Geerardyn A, Zhu M, Wu P, O'Malley J, Nadol JB, Liberman MC, Nakajima HH, Verhaert N, Quesnel AM. Three-dimensional quantification of fibrosis and ossification after cochlear implantation via virtual re-sectioning: Potential implications for residual hearing. Hear Res 2023; 428:108681. [PMID: 36584546 PMCID: PMC10942756 DOI: 10.1016/j.heares.2022.108681] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 12/13/2022] [Accepted: 12/18/2022] [Indexed: 12/24/2022]
Abstract
Hearing preservation may be achieved initially in the majority of patients after cochlear implantation, however, a significant proportion of these patients experience delayed hearing loss months or years later. A prior histological report in a case of delayed hearing loss suggested a potential cochlear mechanical origin of this hearing loss due to tissue fibrosis, and older case series highlight the frequent findings of post-implantation fibrosis and neoosteogenesis though without a focus on the impact on residual hearing. Here we present the largest series (N = 20) of 3-dimensionally reconstructed cochleae based on digitally scanned histologic sections from patients who were implanted during their lifetime. All patients were implanted with multichannel electrodes via a cochleostomy or an extended round window insertion. A quantified analysis of intracochlear tissue formation was carried out via virtual re-sectioning orthogonal to the cochlear spiral. Intracochlear tissue formation was present in every case. On average 33% (SD 14%) of the total cochlear volume was occupied by new tissue formation, consisting of 26% (SD 12%) fibrous and 7% (SD 6%) bony tissue. The round window was completely covered by fibro-osseous tissue in 85% of cases and was associated with an obstruction of the cochlear aqueduct in 100%. The basal part of the basilar membrane was at least partially abutted by the electrode or new tissue formation in every case, while the apical region, corresponding with a characteristic frequency of < 500 Hz, appeared normal in 89%. This quantitative analysis shows that after cochlear implantation via extended round window or cochleostomy, intracochlear fibrosis and neoossification are present in all cases at anatomical locations that could impact normal inner ear mechanics.
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Affiliation(s)
- A Geerardyn
- Department of Otolaryngology - Head & Neck Surgery, Harvard Medical School, Boston, MA, USA; Otopathology Laboratory, Massachusetts Eye and Ear, Boston, MA, USA; ExpORL, Department of Neurosciences, Katholieke Universiteit Leuven, Leuven, Belgium
| | - M Zhu
- Otopathology Laboratory, Massachusetts Eye and Ear, Boston, MA, USA
| | - P Wu
- Department of Otolaryngology - Head & Neck Surgery, Harvard Medical School, Boston, MA, USA; Eaton Peabody Laboratories, Massachusetts Eye and Ear, Boston, MA, USA
| | - J O'Malley
- Otopathology Laboratory, Massachusetts Eye and Ear, Boston, MA, USA
| | - J B Nadol
- Department of Otolaryngology - Head & Neck Surgery, Harvard Medical School, Boston, MA, USA; Otopathology Laboratory, Massachusetts Eye and Ear, Boston, MA, USA
| | - M C Liberman
- Department of Otolaryngology - Head & Neck Surgery, Harvard Medical School, Boston, MA, USA; Otopathology Laboratory, Massachusetts Eye and Ear, Boston, MA, USA; Eaton Peabody Laboratories, Massachusetts Eye and Ear, Boston, MA, USA
| | - H H Nakajima
- Department of Otolaryngology - Head & Neck Surgery, Harvard Medical School, Boston, MA, USA; Eaton Peabody Laboratories, Massachusetts Eye and Ear, Boston, MA, USA
| | - N Verhaert
- ExpORL, Department of Neurosciences, Katholieke Universiteit Leuven, Leuven, Belgium
| | - A M Quesnel
- Department of Otolaryngology - Head & Neck Surgery, Harvard Medical School, Boston, MA, USA; Otopathology Laboratory, Massachusetts Eye and Ear, Boston, MA, USA.
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12
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Loureiro RM, Sumi DV, Soares CR. Temporal Bone Imaging Opportunities With Ultra-High-Resolution Computed Tomography. J Audiol Otol 2023; 27:51-53. [PMID: 36254616 PMCID: PMC9884993 DOI: 10.7874/jao.2022.00346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 09/01/2022] [Indexed: 01/31/2023] Open
Affiliation(s)
- Rafael Maffei Loureiro
- Department of Radiology, Hospital Israelita Albert Einstein, São Paulo, Brazil,Address for correspondence Rafael Maffei Loureiro, MD Department of Radiology, Hospital Israelita Albert Einstein, Av. Albert Einstein, 627/701, 05652-900, São Paulo, SP, Brazil Tel +55-11-21512452 / Fax +55-11-21512452 E-mail
| | - Daniel Vaccaro Sumi
- Department of Radiology, Hospital Israelita Albert Einstein, São Paulo, Brazil
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13
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Starovoyt A, Quirk BC, Putzeys T, Kerckhofs G, Nuyts J, Wouters J, McLaughlin RA, Verhaert N. An optically-guided cochlear implant sheath for real-time monitoring of electrode insertion into the human cochlea. Sci Rep 2022; 12:19234. [PMID: 36357503 PMCID: PMC9649659 DOI: 10.1038/s41598-022-23653-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 11/03/2022] [Indexed: 11/12/2022] Open
Abstract
In cochlear implant surgery, insertion of perimodiolar electrode arrays into the scala tympani can be complicated by trauma or even accidental translocation of the electrode array within the cochlea. In patients with partial hearing loss, cochlear trauma can not only negatively affect implant performance, but also reduce residual hearing function. These events have been related to suboptimal positioning of the cochlear implant electrode array with respect to critical cochlear walls of the scala tympani (modiolar wall, osseous spiral lamina and basilar membrane). Currently, the position of the electrode array in relation to these walls cannot be assessed during the insertion and the surgeon depends on tactile feedback, which is unreliable and often comes too late. This study presents an image-guided cochlear implant device with an integrated, fiber-optic imaging probe that provides real-time feedback using optical coherence tomography during insertion into the human cochlea. This novel device enables the surgeon to accurately detect and identify the cochlear walls ahead and to adjust the insertion trajectory, avoiding collision and trauma. The functionality of this prototype has been demonstrated in a series of insertion experiments, conducted by experienced cochlear implant surgeons on fresh-frozen human cadaveric cochleae.
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Affiliation(s)
- Anastasiya Starovoyt
- grid.5596.f0000 0001 0668 7884Department of Neurosciences, ExpORL, KU Leuven, 3000 Leuven, Belgium ,grid.5596.f0000 0001 0668 7884Department of Neurosciences, Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium
| | - Bryden C. Quirk
- grid.1010.00000 0004 1936 7304Australian Research Council Centre of Excellence for Nanoscale BioPhotonics, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, SA 5005 Australia ,grid.1010.00000 0004 1936 7304Institute for Photonics and Advanced Sensing, The University of Adelaide, Adelaide, SA 5005 Australia
| | - Tristan Putzeys
- grid.5596.f0000 0001 0668 7884Department of Neurosciences, ExpORL, KU Leuven, 3000 Leuven, Belgium ,grid.5596.f0000 0001 0668 7884Department of Neurosciences, Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium ,grid.5596.f0000 0001 0668 7884Laboratory for Soft Matter and Biophysics, Department of Physics and Astronomy, KU Leuven, 3000 Leuven, Belgium
| | - Greet Kerckhofs
- grid.7942.80000 0001 2294 713XBiomechanics Laboratory, Institute of Mechanics, Materials, and Civil Engineering, UCLouvain, 1348 Louvain-La-Neuve, Belgium ,grid.5596.f0000 0001 0668 7884Department of Materials Science and Engineering, KU Leuven, 3000 Leuven, Belgium ,grid.7942.80000 0001 2294 713XInstitute of Experimental and Clinical Research, UCLouvain, 1200 Woluwé-Saint-Lambert, Belgium ,grid.5596.f0000 0001 0668 7884Prometheus, Division of Skeletal Tissue Engineering, KU Leuven, 3000 Leuven, Belgium
| | - Johan Nuyts
- grid.5596.f0000 0001 0668 7884Department of Imaging and Pathology, Division of Nuclear Medicine, KU Leuven, 3000 Leuven, Belgium ,Nuclear Medicine and Molecular Imaging, Medical Imaging Research Center, 3000 Leuven, Belgium
| | - Jan Wouters
- grid.5596.f0000 0001 0668 7884Department of Neurosciences, ExpORL, KU Leuven, 3000 Leuven, Belgium ,grid.5596.f0000 0001 0668 7884Department of Neurosciences, Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium
| | - Robert A. McLaughlin
- grid.1010.00000 0004 1936 7304Australian Research Council Centre of Excellence for Nanoscale BioPhotonics, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, SA 5005 Australia ,grid.1010.00000 0004 1936 7304Institute for Photonics and Advanced Sensing, The University of Adelaide, Adelaide, SA 5005 Australia ,grid.1012.20000 0004 1936 7910School of Engineering, University of Western Australia, Perth, WA 6009 Australia
| | - Nicolas Verhaert
- grid.5596.f0000 0001 0668 7884Department of Neurosciences, ExpORL, KU Leuven, 3000 Leuven, Belgium ,grid.5596.f0000 0001 0668 7884Department of Neurosciences, Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium ,grid.410569.f0000 0004 0626 3338Department of Otorhinolaryngology, Head and Neck Surgery, University Hospitals of Leuven, 3000 Leuven, Belgium
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14
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Rajendran K, Benson JC, Lane J, Diehn F, Weber N, Thorne J, Larson N, Fletcher J, McCollough C, Leng S. Reply. AJNR Am J Neuroradiol 2022; 43:E44. [PMID: 36202549 PMCID: PMC9731242 DOI: 10.3174/ajnr.a7676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- K Rajendran
- Department of RadiologyMayo ClinicRochester, Minnesota
| | - J C Benson
- Department of RadiologyMayo ClinicRochester, Minnesota
| | - J Lane
- Department of RadiologyMayo ClinicRochester, Minnesota
| | - F Diehn
- Department of RadiologyMayo ClinicRochester, Minnesota
| | - N Weber
- Department of RadiologyMayo ClinicRochester, Minnesota
| | - J Thorne
- Department of RadiologyMayo ClinicRochester, Minnesota
| | - N Larson
- Department of RadiologyMayo ClinicRochester, Minnesota
| | - J Fletcher
- Department of RadiologyMayo ClinicRochester, Minnesota
| | - C McCollough
- Department of RadiologyMayo ClinicRochester, Minnesota
| | - S Leng
- Department of RadiologyMayo ClinicRochester, Minnesota
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15
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Wimmer W, Sclabas L, Caversaccio M, Weder S. Cochlear Implant Electrode Impedance as Potential Biomarker for Residual Hearing. Front Neurol 2022; 13:886171. [PMID: 35832176 PMCID: PMC9271767 DOI: 10.3389/fneur.2022.886171] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 05/31/2022] [Indexed: 11/13/2022] Open
Abstract
Introduction and ObjectivesAmong cochlear implant candidates, an increasing number of patients are presenting with residual acoustic hearing. To monitor the postoperative course of structural and functional preservation of the cochlea, a reliable objective biomarker would be desirable. Recently, impedance telemetry has gained increasing attention in this field. The aim of this study was to investigate the postoperative course of the residual acoustic hearing and clinical impedance in patients with long electrode arrays and to explore the applicability of impedance telemetry for monitoring residual hearing.MethodsWe retrospectively analyzed records of 42 cochlear implant recipients with residual hearing covering a median postoperative follow-up of 25 months with repeated simultaneous pure tone audiometry and impedance telemetry. We used a linear mixed-effects model to estimate the relation between clinical electrode impedance and residual hearing. Besides the clinical impedance, the follow-up time, side of implantation, gender, and age at implantation were included as fixed effects. An interaction term between impedance and follow-up time, as well as subject-level random intercepts and slopes, were included.ResultsLoss of residual hearing occurred either during surgery or within the first 6 post-operative months. Electrode contacts inserted further apically (i.e., deeper) had higher impedances, independent of residual hearing. The highest impedances were measured 1 month postoperatively and gradually decreased over time. Basal electrodes were more likely to maintain higher impedance. Follow-up time was significantly associated with residual hearing. Regardless of the time, we found that a 1 kΩ increase in clinical impedance was associated with a 4.4 dB deterioration of residual hearing (p < 0.001).ConclusionPure tone audiometry is the current gold standard for monitoring postoperative residual hearing. However, the association of clinical impedances with residual hearing thresholds found in our study could potentially be exploited for objective monitoring using impedance telemetry. Further analysis including near-field related impedance components could be performed for improved specificity to local immune responses.
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Affiliation(s)
- Wilhelm Wimmer
- Hearing Research Laboratory, ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
- Department of ENT—Head and Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- *Correspondence: Wilhelm Wimmer
| | - Luca Sclabas
- Department of ENT—Head and Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Marco Caversaccio
- Hearing Research Laboratory, ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
- Department of ENT—Head and Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Stefan Weder
- Hearing Research Laboratory, ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
- Department of ENT—Head and Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
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