101
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O'Leary S, Monksfield P, Kel G, Connolly T, Souter M, Chang A, Marovic P, O'Leary J, Richardson R, Eastwood H. Relations between cochlear histopathology and hearing loss in experimental cochlear implantation. Hear Res 2013; 298:27-35. [DOI: 10.1016/j.heares.2013.01.012] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Revised: 01/17/2013] [Accepted: 01/18/2013] [Indexed: 12/21/2022]
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102
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Lee J, Ismail H, Lee JH, Kel G, O'Leary J, Hampson A, Eastwood H, O'Leary SJ. Effect of Both Local and Systemically Administered Dexamethasone on Long-Term Hearing and Tissue Response in a Guinea Pig Model of Cochlear Implantation. ACTA ACUST UNITED AC 2013; 18:392-405. [DOI: 10.1159/000353582] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Accepted: 06/06/2013] [Indexed: 12/13/2022]
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103
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Bas E, Dinh CT, Garnham C, Polak M, Van de Water TR. Conservation of hearing and protection of hair cells in cochlear implant patients' with residual hearing. Anat Rec (Hoboken) 2012; 295:1909-27. [DOI: 10.1002/ar.22574] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 07/24/2012] [Indexed: 12/13/2022]
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104
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Richard C, Fayad JN, Doherty J, Linthicum FH. Round window versus cochleostomy technique in cochlear implantation: histologic findings. Otol Neurotol 2012; 33:1181-7. [PMID: 22892806 PMCID: PMC3425957 DOI: 10.1097/mao.0b013e318263d56d] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
HYPOTHESIS Cochleostomy or round window enlargement techniques for cochlear implant electrode insertion result in more abnormal tissue formation in the basal cochlea and are more apt to produce endolymphatic hydrops than round window electrode insertion. METHODS Twelve temporal bones from implanted patients were examined under light microscopy and reconstructed with 3-dimensional reconstruction software to determine cochlear damage and volume of neo-ossification and fibrosis after electrode insertion. Amount of new tissue was compared between 3 groups of bones: insertion through the round window (RW), after enlarging the RW (RWE) and cochleostomy (Cochl). The probable role of the electrode was evaluated in each case with hydrops. RESULTS More initial damage occurred in the Cochl and RWE groups than in the RW group, and the difference was significant between RWE and RW in cochlear segment I (p < 0.026). The volume of new bone in Segment I differed significantly between groups (p < 0.012) and was greater in the RWE group than in either the Cochl or RW groups (post hoc p's < 0.035 and 0.019, respectively). Hydrops was seen in 5 cases, all in the Cochl and RWE groups. Blockage of the duct was because of new tissue formation in 4 of the 5 hydrops cases. CONCLUSION With the electrodes in this series, implantation through the RW minimized initial intracochlear trauma and subsequent new tissue formation, whereas the RW extension technique used at the time of these implantations produced the greatest damage. Future studies may clarify whether today's techniques and electrodes will produce these same patterns of damage.
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Affiliation(s)
- Céline Richard
- Research Scholar, House Research Institute, Los Angeles; CHU of St Etienne, University of Saint -Etienne, France
| | - Jose N. Fayad
- House Clinic and House Research Institute; Keck School of Medicine of the University of Southern California
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105
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Souter M, Eastwood H, Marovic P, Kel G, Wongprasartsuk S, Ryan AF, O’Leary SJ. Systemic immunity influences hearing preservation in cochlear implantation. Otol Neurotol 2012; 33:532-8. [PMID: 22470051 PMCID: PMC3897157 DOI: 10.1097/mao.0b013e31824bac44] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
HYPOTHESIS To determine whether a systemic immune response influences hearing thresholds and tissue response after cochlear implantation of hearing guinea pigs. METHODS Guinea pigs were inoculated with sterile antigen (Keyhole limpet hemocyanin) 3 weeks before cochlear implantation. Pure-tone auditory brainstem response thresholds were performed before implantation and 1 and 4 weeks later. Dexamethasone phosphate 20% was adsorbed onto a hyaluronic acid carboxymethylcellulose sponge and was applied to the round window for 30 minutes before electrode insertion. Normal saline was used for controls. Cochlear histology was performed at 4 weeks after implantation to assess the tissue response to implantation. To control for the effect of keyhole limpet hemocyanin priming, a group of unprimed animals underwent cochlear implantation with a saline-soaked pledget applied to the round window. RESULTS Keyhole limpet hemocyanin priming had no significant detrimental effect on thresholds without implantation. Thresholds were elevated after implantation across all frequencies tested (2-32 kHz) in primed animals but only at higher frequencies (4-32 kHz) in unprimed controls. In primed animals, dexamethasone treatment significantly reduced threshold shifts at 2 and 8 kHz. Keyhole limpet hemocyanin led to the more frequent observation of lymphocytes in the tissue response to the implant. CONCLUSION Systemic immune activation at the time of cochlear implantation broadened the range of frequencies experiencing elevated thresholds after implantation. Local dexamethasone provides partial protection against this hearing loss, but the degree and extent of protection are less compared to previous studies with unprimed animals.
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Affiliation(s)
- Melanie Souter
- Department of Otolaryngology, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
- Department of Otolaryngology, Christchurch Hospital, Christchurch, New Zealand
| | - Hayden Eastwood
- Department of Otolaryngology, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
| | - Paul Marovic
- Department of Otolaryngology, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
- Department of Surgery, Monash University, Clayton, Australia
| | - Gordana Kel
- Department of Otolaryngology, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
| | - Sarin Wongprasartsuk
- Department of Otolaryngology, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
- Department of Surgery, Monash University, Clayton, Australia
| | - Allen F. Ryan
- Departments of Otolaryngology and Neurosciences, University of California at San Diego
- San Diego VA Healthcare System, San Diego, California, U.S.A
| | - Stephen John O’Leary
- Department of Otolaryngology, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
- Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
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106
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Landry TG, Wise AK, Fallon JB, Shepherd RK. Spiral ganglion neuron survival and function in the deafened cochlea following chronic neurotrophic treatment. Hear Res 2011; 282:303-13. [PMID: 21762764 PMCID: PMC3205216 DOI: 10.1016/j.heares.2011.06.007] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Revised: 06/28/2011] [Accepted: 06/28/2011] [Indexed: 12/26/2022]
Abstract
Cochlear implants electrically stimulate residual spiral ganglion neurons (SGNs) to provide auditory cues for the severe-profoundly deaf. However, SGNs gradually degenerate following cochlear hair cell loss, leaving fewer neurons available for stimulation. Providing an exogenous supply of neurotrophins (NTs) has been shown to prevent SGN degeneration, and when combined with chronic intracochlear electrical stimulation (ES) following a short period of deafness (5 days), may also promote the formation of new neurons. The present study assessed the histopathological response of guinea pig cochleae treated with NTs (brain-derived neurotrophic factor and neurotrophin-3) with and without ES over a four week period, initiated two weeks after deafening. Results were compared to both NT alone and artificial perilymph (AP) treated animals. AP/ES treated animals exhibited no evidence of SGN rescue compared with untreated deafened controls. In contrast, NT administration showed a significant SGN rescue effect in the lower and middle cochlear turns (two-way ANOVA, p < 0.05) compared with AP-treated control animals. ES in combination with NT did not enhance SGN survival compared with NT alone. SGN function was assessed by measuring electrically-evoked auditory brainstem response (EABR) thresholds. EABR thresholds following NT treatment were significantly lower than animals treated with AP (two-way ANOVA, p = 0.033). Finally, the potential for induced neurogenesis following the combined treatment was investigated using a marker of DNA synthesis. However, no evidence of neurogenesis was observed in the SGN population. The results indicate that chronic NT delivery to the cochlea may be beneficial to cochlear implant patients by increasing the number of viable SGNs and decreasing activation thresholds compared to chronic ES alone.
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Affiliation(s)
- Thomas G. Landry
- The Bionic Ear Institute, Daly Wing, St. Vincent’s Hospital, Fitzroy, Victoria, 3065, Australia
- The University of Melbourne, Parkville, Victoria, 3052, Australia
| | - Andrew K. Wise
- The Bionic Ear Institute, Daly Wing, St. Vincent’s Hospital, Fitzroy, Victoria, 3065, Australia
- The University of Melbourne, Parkville, Victoria, 3052, Australia
| | - James B. Fallon
- The Bionic Ear Institute, Daly Wing, St. Vincent’s Hospital, Fitzroy, Victoria, 3065, Australia
- The University of Melbourne, Parkville, Victoria, 3052, Australia
| | - Robert K. Shepherd
- The Bionic Ear Institute, Daly Wing, St. Vincent’s Hospital, Fitzroy, Victoria, 3065, Australia
- The University of Melbourne, Parkville, Victoria, 3052, Australia
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107
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Jia H, Venail F, Piron JP, Batrel C, Pelliccia P, Artières F, Uziel A, Mondain M. Effect of surgical technique on electrode impedance after cochlear implantation. Ann Otol Rhinol Laryngol 2011; 120:529-34. [PMID: 21922977 DOI: 10.1177/000348941112000807] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVES We compare the evolution of electrode impedance values (IVs) following either conventional cochlear implantation or implantation by the soft surgery (SS) technique. METHODS We performed a retrospective chart review of 20 consecutive adult patients who underwent implantation with the Nucleus CA 24 device between 2004 and 2007. Five patients with preoperative residual hearing at the frequencies 256, 512, and 1,024 Hz underwent implantation by an SS cochlear implantation technique (SS group), and the 15 other patients underwent a conventional implantation technique (conventional cochleostomy [CC] group). The active electrodes were classified as distal (17 to 22), middle (10 to 16), or proximal (3 to 9) according to their position in relation to the tip of the electrode array. Their IVs were collected at 1, 3, 12, 24, and 36 months after implantation. Changes in auditory thresholds at 3 and 24 months were reported for patients in the SS group. RESULTS The postoperative IVs of both the CC and SS groups decreased significantly between 1 and 3 months after implantation (p < 0.05) and then remained stable. The IVs after 12 months were significantly lower (p < 0.05) in the SS group than in the CC group. CONCLUSIONS Patients who underwent the SS technique displayed lower long-term electrode IVs than did their counterparts in the CC group. If electrode IVs are indeed an indirect representation of cochlear fibrosis, the use of the SS technique in lieu of the CC technique could reduce fibrotic development.
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Affiliation(s)
- Huan Jia
- Ear, Nose, and Throat Department and Cochlear Implant Center, Gui de Chauliac, University Hospital, Montpellier, France
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108
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Lee A, Jiang D, McLaren S, Nunn T, Demler JM, Tysome JR, Connor S, Fitzgerald O'Connor A. Electric acoustic stimulation of the auditory system: experience and results of ten patients using MED-EL's M and FlexEAS electrodes. Clin Otolaryngol 2010; 35:190-7. [PMID: 20636737 DOI: 10.1111/j.1749-4486.2010.02140.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To evaluate the hearing preservation rate and speech perception scores in patients with profound high frequency hearing loss and acoustically aidable low frequency hearing, managed with the MED-EL electric acoustic stimulation system referenced to the insertion depth of the electrode array. STUDY DESIGN Retrospective data analysis. PARTICIPANTS AND SETTING Ten patients implanted at the Auditory Implant Centre, Guy's and St Thomas's Hospital, London, UK. MAIN OUTCOME MEASURES Pure tone audiometry, speech perception tests and electrode insertion depth angle. RESULTS Postoperatively, functional hearing preservation allowing electric acoustic stimulation was achieved in eight patients and total preservation of residual hearing in five patients with follow-up periods of more than 12 months. Three of four (75%) patients with an insertion depth of >360 degrees had a threshold shift of >25 dB, and all four patients had a threshold shift of >10 dB. All patients with total hearing preservation had the electrode inserted up to 360 degrees at maximum. Overall, speech perception outcomes increased significantly and hearing impairment was significantly reduced after electric acoustic stimulation or electric stimulation alone as compared with the preoperative scores. CONCLUSION Electric acoustic stimulation provides significant benefit to individuals with profound high frequency hearing loss. Studies with larger number of patients are needed to establish the optimal electrode insertion angle as well as to further analyse the benefit of electric acoustic stimulation.
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Affiliation(s)
- A Lee
- Auditory Implant Centre, Guy's and St. Thomas' NHS Trust, London, UK
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109
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Permanent and transient effects of locally delivered n-acetyl cysteine in a guinea pig model of cochlear implantation. Hear Res 2010; 259:24-30. [DOI: 10.1016/j.heares.2009.08.010] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2009] [Revised: 08/28/2009] [Accepted: 08/29/2009] [Indexed: 12/14/2022]
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110
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Histopathologic assessment of fibrosis and new bone formation in implanted human temporal bones using 3D reconstruction. Otolaryngol Head Neck Surg 2009; 141:247-52. [PMID: 19643260 DOI: 10.1016/j.otohns.2009.03.031] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2008] [Revised: 02/10/2009] [Accepted: 03/31/2009] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To evaluate new bone formation and fibrosis in implanted human temporal bones and relate that to neurosensory elements preservation. STUDY DESIGN Human temporal bone histopathology study. SETTING Temporal bone laboratory. SUBJECTS AND METHODS Ten human temporal bones from eight patients with multichannel cochlear implants and one single-electrode implant were examined under light microscopy and reconstructed with AMIRA 4.1 3D reconstruction software. Volumes of new bone formation, fibrosis, and patent area were calculated in each bone. RESULTS The amount of fibrosis and new bone formation postimplantation varied among bones. There were no statistically significant relationships between age at implantation or duration of implantation and the overall amount of new tissue in the implanted ear. There was a relationship between total amount of new tissue and preservation of neurosensory elements only in segment I of the cochlea (Rho=-0.75, P<or=0.013). Most of the new tissue was located in segments I and II, segment III had little to no new tissue formation, and segment IV was clear in all of the subjects. CONCLUSION New tissue formation postimplantation was related to preservation of neurosensory elements primarily in segment I of the cochlea. In an era of hearing preservation surgery and hybrid cochlear implants, soft surgical techniques are advocated as a means to decrease surgical trauma.
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111
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Abstract
Recent advances in cochlear implant technology have focused renewed attention on the preservation of residual hearing. The focus on preservation of residual hearing is driven by the concept of electroacoustic stimulation. This option depends on the insertion of a short cochlear implant electrode into the basal region of the cochlea while preserving native function in the apical region. The desire to preserve residual hearing has led to the development of the soft-surgery cochlear implantation technique. Here, the authors evaluate its various components. Avoiding entry of blood into the cochlea and the use of hyaluronate seem to be reasonably supported, whereas the use of topical steroids is unlikely to be beneficial. The site of entry into the cochlea, the use of contoured or straight devices, and the depth of insertion are also evaluated. The authors highlight the importance of systematic recording of outcomes and surgical events.
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Affiliation(s)
- David R Friedland
- Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, 9200 W. Wisconsin Avenue, Milwaukee, WI 53226, USA.
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112
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Gstoettner >W, Helbig S, Settevendemie C, Baumann U, Wagenblast J, Arnoldner C, Gstoettner >W, Helbig S, Settevendemie C, Baumann U, Wagenblast J, Arnoldner C. A new electrode for residual hearing preservation in cochlear implantation: first clinical results. Acta Otolaryngol 2009; 129:372-9. [PMID: 19140036 DOI: 10.1080/00016480802552568] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
CONCLUSION A so far unattained high rate (100%) of residual hearing preservation in cochlear implantation for electric-acoustic stimulation could be achieved using sophisticated surgical techniques in combination with the MedEl Flex EAS electrode. OBJECTIVES This study aimed to gather first audiological and surgical results from the experience gained with the new MedEl Flex EAS electrode array. PATIENTS AND METHODS Nine patients (aged 7.62-71.32 years) with profound high frequency hearing loss were supplied with this atraumatic electrode, which was designed to preserve residual hearing despite intracochlear insertion of an electrode array. All patients were implanted by the same surgeon. RESULTS Hearing preservation was achieved in all patients (complete preservation 44.44%) after a mean follow-up period of 9.73 months. Mean monosyllabic test scores improved from 9% correct with the hearing aid alone to 48% with the cochlear implant and to 65% in the electric-acoustic mode.
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113
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James DP, Eastwood H, Richardson RT, O’Leary SJ. Effects of Round Window Dexamethasone on Residual Hearing in a Guinea Pig Model of Cochlear Implantation. Audiol Neurootol 2007; 13:86-96. [DOI: 10.1159/000111780] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2006] [Accepted: 07/27/2007] [Indexed: 12/20/2022] Open
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114
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Wenzel GI, Anvari B, Mazhar A, Pikkula B, Oghalai JS. Laser-induced collagen remodeling and deposition within the basilar membrane of the mouse cochlea. JOURNAL OF BIOMEDICAL OPTICS 2007; 12:021007. [PMID: 17477714 PMCID: PMC3651902 DOI: 10.1117/1.2714286] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The cochlea is the mammalian organ of hearing. Its predominant vibratory element, the basilar membrane, is tonotopically tuned, based on the spatial variation of its mass and stiffness. The constituent collagen fibers of the basilar membrane affect its stiffness. Laser irradiation can induce collagen remodeling and deposition in various tissues. We tested whether similar effects could be induced within the basilar membrane. Trypan blue was perfused into the scala tympani of anesthetized mice to stain the basilar membrane. We then irradiated the cochleas with a 694-nm pulsed ruby laser at 15 or 180 Jcm(2). The mice were sacrificed 14 to 16 days later and collagen organization was studied. Polarization microscopy revealed that laser irradiation increased the birefringence within the basilar membrane in a dose-dependent manner. Electron microscopy demonstrated an increase in the density of collagen fibers and the deposition of new fibrils between collagen fibers after laser irradiation. As an assessment of hearing, auditory brainstem response (ABR) thresholds were found to increase moderately after 15 Jcm(2) and substantially after 180 Jcm(2). Our results demonstrate that collagen remodeling and new collagen deposition occurs within the basilar membrane after laser irradiation in a similar fashion to that found in other tissues.
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Affiliation(s)
- Gentiana I. Wenzel
- Baylor College of Medicine, Bobby R. Alford Department of Otolaryngology, Head and Neck Surgery, One Baylor Plaza, NA102, Houston, Texas 77030
| | - Bahman Anvari
- Rice University, Department of Bioengineering, Houston, Texas 77005-1892
| | - Amaan Mazhar
- Rice University, Department of Bioengineering, Houston, Texas 77005-1892
| | - Brian Pikkula
- Rice University, Department of Bioengineering, Houston, Texas 77005-1892
| | - John S. Oghalai
- Baylor College of Medicine, Bobby R. Alford Department of Otolaryngology, Head and Neck Surgery, One Baylor Plaza, NA102, Houston, Texas 77030, and Rice University, Department of Bioengineering, Houston, Texas 77005-1892,
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115
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Lenarz T, Stover T, Buechner A, Paasche G, Briggs R, Risi F, Pesch J, Battmer RD. Temporal Bone Results and Hearing Preservation with a New Straight Electrode. Audiol Neurootol 2006; 11 Suppl 1:34-41. [PMID: 17063009 DOI: 10.1159/000095612] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2006] [Accepted: 04/24/2006] [Indexed: 11/19/2022] Open
Abstract
Due to improved technology, cochlear implant (CI) candidacy has been widened towards patients with usable residual hearing in the low frequency range. These patients might benefit from additional acoustic amplification provided that residual hearing can be preserved with cochlear implantation. To provide a high probability of hearing preservation, a new electrode array was designed and developed at the Medizinische Hochschule Hannover. This 'Hybrid-L' electrode array has 22 electrodes spread over 15 mm with an overall insertion depth of 16 mm. The straight electrode with modiolus facing contacts is designed for a round window insertion. It shall provide the full range of the currently most advanced Nucleus CI system. A temporal bone study demonstrated the favorable insertion characteristics and minimized trauma to intracochlear structures. Compared to standard CI electrodes especially no basilar membrane perforation could be found. So far, 4 patients have been implanted and residual hearing could be preserved. One patient was fitted and showed a marked additional benefit from the electroacoustic stimulation compared to either acoustic or electrical stimulation alone. These results are very encouraging towards a concept of reliable hearing preservation with cochlear implantation.
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Affiliation(s)
- Thomas Lenarz
- Department of Otolaryngology, Medical University of Hannover, Hannover, Germany.
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