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Hosoya M, Kurihara S, Koyama H, Komune N. Recent advances in Otology: Current landscape and future direction. Auris Nasus Larynx 2024; 51:605-616. [PMID: 38552424 DOI: 10.1016/j.anl.2024.02.009] [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: 08/22/2023] [Revised: 11/24/2023] [Accepted: 02/21/2024] [Indexed: 05/12/2024]
Abstract
Hearing is an essential sensation, and its deterioration leads to a significant decrease in the quality of life. Thus, great efforts have been made by otologists to preserve and recover hearing. Our knowledge regarding the field of otology has progressed with advances in technology, and otologists have sought to develop novel approaches in the field of otologic surgery to achieve higher hearing recovery or preservation rates. This requires knowledge regarding the anatomy of the temporal bone and the physiology of hearing. Basic research in the field of otology has progressed with advances in molecular biology and genetics. This review summarizes the current views and recent advances in the field of otology and otologic surgery, especially from the viewpoint of young Japanese clinician-scientists, and presents the perspectives and future directions for several topics in the field of otology. This review will aid next-generation researchers in understanding the recent advances and future challenges in the field of otology.
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Affiliation(s)
- Makoto Hosoya
- Department of Otolaryngology, Head and Neck Surgery, Keio University School of Medicine, Shinanomachi 35, Shinjuku-ku, Tokyo, 160-8582, Japan.
| | - Sho Kurihara
- Department of Otorhinolaryngology, The Jikei University School of Medicine, 3-25-8 Nishishimbashi Minato-ku, Tokyo, 105-8471, Japan
| | - Hajime Koyama
- Department of Otolaryngology and Head and Neck Surgery, Graduate School of Medicine, The University of Tokyo, Tokyo, 113-8654, Japan
| | - Noritaka Komune
- Department of Otorhinolaryngology, Graduate School of Medical Sciences, Kyushu University, 3-1-1Maidashi Higashi-ku, Fukuoka 812-8582, Japan
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Kataria T, Sharma S, Lakhawat RS, Grover M, Sharma S, Kanodia A, Agarwal S, Samdani S. A Study of Round Window and its Adjacent Anatomy to Guide the Cochlear Implant Electrode Insertion. Indian J Otolaryngol Head Neck Surg 2023; 75:163-169. [PMID: 37206735 PMCID: PMC10188745 DOI: 10.1007/s12070-022-03288-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 11/18/2022] [Indexed: 12/14/2022] Open
Abstract
Introduction Residual hearing preservation has gained attention now which has brought round window membrane into the light, as a port for cochlear implantation. Atraumatic insertion of electrodes can be achieved by study of anatomical variations of round window and its forms which can guide the surgeon. Objective This study was undertaken to examine the anatomical variations of round window and its adjacent structures and their impact on surgical approach during cochlear implantation. Methods A series of 40 adult human temporal bones underwent high-resolution CT scanning and were further dissected for microscopic study of the round window. Results The antero posterior dimensions of RW ranged from 1.22 to 2.51 mm on radiology and on dissection 1.76 mm +/- 0.3 mm. Shape of round window in 72.5% of bones was oval, and in 27.5% bones it was round shaped. As per Saint Thomas hospital classification for Round window visualization we found 82.5% bones had type I RW visualization and 17.5% had type IIa RW visualization. Area of crista fenestra on dissection was ranging from 0.41 to 0.69 mm2. Conclusion Residual hearing preservation has become a new motto for surgeons. Therefore thorough anatomic knowledge of round window is must for careful insertion, as round window is closely related to the sensitive inner ear structures.
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Affiliation(s)
- Tanmaya Kataria
- Department of Otorhinolaryngology, SMS Medical college, Jaipur, Rajasthan India
| | - Shitanshu Sharma
- Department of Otorhinolaryngology, SMS Medical college, Jaipur, Rajasthan India
| | - Rajendra Singh Lakhawat
- Department of Otorhinolaryngology, RVRS Government Medical College, Bhilwara, Rajasthan India
| | - Mohnish Grover
- Department of Otorhinolaryngology, SMS Medical college, Jaipur, Rajasthan India
- 8/250, Sector 8, Malviya Nagar Jaipur, Rajasthan 302017 Jaipur, India
| | - Shivam Sharma
- Department of Otorhinolaryngology, SMS Medical college, Jaipur, Rajasthan India
| | | | - Srishti Agarwal
- Department of Otorhinolaryngology, SMS Medical college, Jaipur, Rajasthan India
| | - Sunil Samdani
- Department of Otorhinolaryngology, SMS Medical college, Jaipur, Rajasthan India
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Optical Coherence Tomography-Based Atlas of the Human Cochlear Hook Region. J Clin Med 2022; 12:jcm12010238. [PMID: 36615042 PMCID: PMC9820872 DOI: 10.3390/jcm12010238] [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: 11/25/2022] [Revised: 12/22/2022] [Accepted: 12/23/2022] [Indexed: 12/30/2022] Open
Abstract
Advancements in intracochlear diagnostics, as well as prosthetic and regenerative inner ear therapies, rely on a good understanding of cochlear microanatomy. The human cochlea is very small and deeply embedded within the densest skull bone, making nondestructive visualization of its internal microstructures extremely challenging. Current imaging techniques used in clinical practice, such as MRI and CT, fall short in their resolution to visualize important intracochlear landmarks, and histological analysis of the cochlea cannot be performed on living patients without compromising their hearing. Recently, optical coherence tomography (OCT) has been shown to be a promising tool for nondestructive micrometer resolution imaging of the mammalian inner ear. Various studies performed on human cadaveric tissue and living animals demonstrated the ability of OCT to visualize important cochlear microstructures (scalae, organ of Corti, spiral ligament, and osseous spiral lamina) at micrometer resolution. However, the interpretation of human intracochlear OCT images is non-trivial for researchers and clinicians who are not yet familiar with this novel technology. In this study, we present an atlas of intracochlear OCT images, which were acquired in a series of 7 fresh and 10 fresh-frozen human cadaveric cochleae through the round window membrane and describe the qualitative characteristics of visualized intracochlear structures. Likewise, we describe several intracochlear abnormalities, which could be detected with OCT and are relevant for clinical practice.
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Singh J, Singh RK, Mishra SK, Jha S. Effect of the vertical facial canal to round window distance concerning neural response telemetry during cochlear implantation in children. Int J Pediatr Otorhinolaryngol 2022; 163:111349. [PMID: 36308882 DOI: 10.1016/j.ijporl.2022.111349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Revised: 05/29/2022] [Accepted: 10/11/2022] [Indexed: 11/07/2022]
Abstract
OBJECTIVE To assess the correlation of the distance from the round window (RW) to the vertical facial canal (VFC) with neural response telemetry thresholds (T-NRT), which may have an influence on the insertion trajectory and aid in preoperative surgical planning and electrode selection. METHODS An observational study was conducted on 30 prelingually deaf children under five years diagnosed with bilateral severe to profound hearing loss and received a cochlear implant. The preoperative high resolution computed tomography (HRCT) images in the axial cut bone window setting at the round window level was used to calculate the distance from the RW to the VFC on the RadiAnt DICOM Viewer. The intraoperative distance was measured with ScopyDoc version 8.2.4 software. In Auto-NRT mode, software-based recordings (Cochlear's Custom Sound EP 6.0) were used to measure and evaluate the T-NRT current level. RESULTS A statistically significant positive correlation of the RW to VFC distance with the average T-NRT p = 0.02, r = -0.4 and with the mid-frequency, T-NRT p = 0.003, r = -0.5 was found. CONCLUSION The insertion trajectory can be ascertained by a statistically significant correlation between average T-NRT and mid-frequency T-NRT with RW and VFC distance, and this reliable factor can be taken into account in future surgical technique modulation, electrode selection, and electrode design.
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Affiliation(s)
- Jyoti Singh
- Department of ENT, Indira Gandhi Institute of Medical Sciences, Patna, India
| | - Rakesh Kumar Singh
- Department of ENT, Indira Gandhi Institute of Medical Sciences, Patna, India.
| | | | - Shruti Jha
- Department of ENT, Indira Gandhi Institute of Medical Sciences, Patna, India
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Conversations in Cochlear Implantation: The Inner Ear Therapy of Today. Biomolecules 2022; 12:biom12050649. [PMID: 35625577 PMCID: PMC9138212 DOI: 10.3390/biom12050649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Revised: 04/27/2022] [Accepted: 04/28/2022] [Indexed: 02/01/2023] Open
Abstract
As biomolecular approaches for hearing restoration in profound sensorineural hearing loss evolve, they will be applied in conjunction with or instead of cochlear implants. An understanding of the current state-of-the-art of this technology, including its advantages, disadvantages, and its potential for delivering and interacting with biomolecular hearing restoration approaches, is helpful for designing modern hearing-restoration strategies. Cochlear implants (CI) have evolved over the last four decades to restore hearing more effectively, in more people, with diverse indications. This evolution has been driven by advances in technology, surgery, and healthcare delivery. Here, we offer a practical treatise on the state of cochlear implantation directed towards developing the next generation of inner ear therapeutics. We aim to capture and distill conversations ongoing in CI research, development, and clinical management. In this review, we discuss successes and physiological constraints of hearing with an implant, common surgical approaches and electrode arrays, new indications and outcome measures for implantation, and barriers to CI utilization. Additionally, we compare cochlear implantation with biomolecular and pharmacological approaches, consider strategies to combine these approaches, and identify unmet medical needs with cochlear implants. The strengths and weaknesses of modern implantation highlighted here can mark opportunities for continued progress or improvement in the design and delivery of the next generation of inner ear therapeutics.
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Mueller F, Hermann J, Weber S, O'Toole Bom Braga G, Topsakal V. Image-Based Planning of Minimally Traumatic Inner Ear Access for Robotic Cochlear Implantation. Front Surg 2021; 8:761217. [PMID: 34901143 PMCID: PMC8655094 DOI: 10.3389/fsurg.2021.761217] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 11/02/2021] [Indexed: 12/12/2022] Open
Abstract
Objective: During robotic cochlear implantation, an image-guided robotic system provides keyhole access to the scala tympani of the cochlea to allow insertion of the cochlear implant array. To standardize minimally traumatic robotic access to the cochlea, additional hard and soft constraints for inner ear access were proposed during trajectory planning. This extension of the planning strategy aims to provide a trajectory that preserves the anatomical and functional integrity of critical intra-cochlear structures during robotic execution and allows implantation with minimal insertion angles and risk of scala deviation. Methods: The OpenEar dataset consists of a library with eight three-dimensional models of the human temporal bone based on computed tomography and micro-slicing. Soft constraints for inner ear access planning were introduced that aim to minimize the angle of cochlear approach, minimize the risk of scala deviation and maximize the distance to critical intra-cochlear structures such as the osseous spiral lamina. For all cases, a solution space of Pareto-optimal trajectories to the round window was generated. The trajectories satisfy the hard constraints, specifically the anatomical safety margins, and optimize the aforementioned soft constraints. With user-defined priorities, a trajectory was parameterized and analyzed in a virtual surgical procedure. Results: In seven out of eight cases, a solution space was found with the trajectories safely passing through the facial recess. The solution space was Pareto-optimal with respect to the soft constraints of the inner ear access. In one case, the facial recess was too narrow to plan a trajectory that would pass the nerves at a sufficient distance with the intended drill diameter. With the soft constraints introduced, the optimal target region was determined to be in the antero-inferior region of the round window membrane. Conclusion: A trend could be identified that a position between the antero-inferior border and the center of the round window membrane appears to be a favorable target position for cochlear tunnel-based access through the facial recess. The planning concept presented and the results obtained therewith have implications for planning strategies for robotic surgical procedures to the inner ear that aim for minimally traumatic cochlear access and electrode array implantation.
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Affiliation(s)
- Fabian Mueller
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
| | - Jan Hermann
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
| | - Stefan Weber
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
| | | | - Vedat Topsakal
- Department of Otorhinolaryngology, Head and Neck Surgery, Vrije Universiteit Brussel, Brussels, Belgium.,Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital UZ Brussel, Vrije Universiteit Brussel, Brussels, Belgium
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Elzayat S, Elfarargy HH, Soltan I, Abdel-Kareem MA, Barbara M, Fayed A, Baki F. Morphological classification of crista fenestra of round window corridor during pediatric cochlear implantation. Int J Pediatr Otorhinolaryngol 2021; 148:110816. [PMID: 34198228 DOI: 10.1016/j.ijporl.2021.110816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/19/2021] [Accepted: 06/24/2021] [Indexed: 10/21/2022]
Abstract
OBJECTIVES This study aimed to document the observation of the Crista Fenestra's morphological types (CF) of the round window and to detect its impact during cochlear implant operation. STUDY DESIGN A prospective descriptive cohort study. SETTINGS We conducted this study at tertiary referral institutions in Egypt. PATIENTS This study included 140 children who underwent cochlear implantation. INTERVENTION We observed the CF's morphological type during the operation according to (Baki-Elzayat) novel classification of CF anatomy, and the need for drilling in each CI operation. MAIN OUTCOME MEASURES CF has two main types. Type A, in which CF was present at the same level of round window membrane and attached to it. Type B, in which CF was medial to the Round window membrane. RESULTS Type (A) CF was detected in 125 cases (89.28%), while 25 cases (10.71%) showed type (B) CF. Drilling was needed in 10 cases (7.14%), including CF types A.3 and B2. Drilling was not needed in 130 cases (92.85%), including CF type A.1, A.2, and B.1. There was a statistically significant difference in the need for drilling (P-value <0.001). CONCLUSIONS According to this prospective study, CF had complicated anatomy. Baki-Elzayat classified the CF into two main types. In type A, CF was at the same level of RWM and attached to it. In type B, CF was medial to RWM. We recommended drilling for partial removal of massive CF types (A.3 and B.2) for atraumatic safe insertion of the electrode without deflection. This classification can offer an easy language system for CI surgeons to describe and register CF during their operations and in the surgical files.
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Affiliation(s)
- Saad Elzayat
- Otolaryngology, Otolaryngology Department, Kafrelsheikh University, Egypt
| | - Hitham H Elfarargy
- Otolaryngology, Otolaryngology Department, Kafrelsheikh University, Egypt.
| | - Islam Soltan
- Otolaryngology, Otolaryngology Department, Kafrelsheikh University, Egypt
| | | | - Maurizio Barbara
- Otolaryngology, Otolaryngology Department, Sapienza University of Rome, Italy
| | - Ashraf Fayed
- Otolaryngology, Otolaryngology Department, El-Glaa Military Hospital, Egypt
| | - Fathi Baki
- Otolaryngology, Otolaryngology Department, Alexandria University, Egypt
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Pawley DC, Goncalves S, Bas E, Dikici E, Deo SK, Daunert S, Telischi F. Dexamethasone (DXM)‐Coated Poly(lactic‐
co
‐glycolic acid) (PLGA) Microneedles as an Improved Drug Delivery System for Intracochlear Biodegradable Devices. ADVANCED THERAPEUTICS 2021. [DOI: 10.1002/adtp.202100155] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Devon C. Pawley
- Department of Biochemistry and Molecular Biology University of Miami Miller School of Medicine Miami FL 33136 USA
- Dr. JT Macdonald Foundation Biomedical Nanotechnology Institute of the University of Miami Miami FL 33136 USA
| | - Stefania Goncalves
- University of Miami Ear Institute Department of Otolaryngology University of Miami Miller School of Medicine Miami FL 33136 USA
| | - Esperanza Bas
- University of Miami Ear Institute Department of Otolaryngology University of Miami Miller School of Medicine Miami FL 33136 USA
| | - Emre Dikici
- Department of Biochemistry and Molecular Biology University of Miami Miller School of Medicine Miami FL 33136 USA
- Dr. JT Macdonald Foundation Biomedical Nanotechnology Institute of the University of Miami Miami FL 33136 USA
| | - Sapna K. Deo
- Department of Biochemistry and Molecular Biology University of Miami Miller School of Medicine Miami FL 33136 USA
- Dr. JT Macdonald Foundation Biomedical Nanotechnology Institute of the University of Miami Miami FL 33136 USA
| | - Sylvia Daunert
- Department of Biochemistry and Molecular Biology University of Miami Miller School of Medicine Miami FL 33136 USA
- Dr. JT Macdonald Foundation Biomedical Nanotechnology Institute of the University of Miami Miami FL 33136 USA
- University of Miami Clinical and Translational Science Institute University of Miami Miller School of Medicine Miami FL 33136 USA
| | - Fred Telischi
- University of Miami Ear Institute Department of Otolaryngology University of Miami Miller School of Medicine Miami FL 33136 USA
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A Review on Recent Advancement on Age-Related Hearing Loss: The Applications of Nanotechnology, Drug Pharmacology, and Biotechnology. Pharmaceutics 2021; 13:pharmaceutics13071041. [PMID: 34371732 PMCID: PMC8309044 DOI: 10.3390/pharmaceutics13071041] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 07/01/2021] [Accepted: 07/01/2021] [Indexed: 11/30/2022] Open
Abstract
Aging is considered a contributing factor to many diseases such as cardiovascular disease, Alzheimer’s disease, and hearing loss. Age-related hearing loss, also termed presbycusis, is one of the most common sensory impairments worldwide, affecting one in five people over 50 years of age, and this prevalence is growing annually. Associations have emerged between presbycusis and detrimental health outcomes, including social isolation and mental health. It remains largely untreatable apart from hearing aids, and with no globally established prevention strategies in the clinical setting. Hence, this review aims to explore the pathophysiology of presbycusis and potential therapies, based on a recent advancement in bile acid-based bio-nanotechnologies. A comprehensive online search was carried out using the following keywords: presbycusis, drugs, hearing loss, bile acids, nanotechnology, and more than 150 publications were considered directly relevant. Evidence of the multifaceted oxidative stress and chronic inflammation involvement in cellular damage and apoptosis that is associated with a loss of hair cells, damaged and inflamed stria vascularis, and neuronal signalling loss and apoptosis continues to emerge. New robust and effective therapies require drug delivery deeper into the various layers of the cochlea. Bile acid-based nanotechnology has gained wide interest in its permeation-enhancing ability and potential for numerous applications in treating presbycusis.
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3D-reconstructions of Bast's Valve and Membranous Labyrinth: Insights for Vestibular Implantation and Meniere's Disease. Otol Neurotol 2021; 42:e1652-e1660. [PMID: 34172664 DOI: 10.1097/mao.0000000000003239] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
HYPOTHESIS/BACKGROUND Bast's valve is a poorly understood inner ear structure located at the junction between pars superior and inferior in the membranous labyrinth. Anatomically precise three-dimensional reconstructions (3D-reconstructions) of Bast's valve can help illuminate the morphology of the valve, and point toward its role in normal physiology and pathological states such as endolymphatic hydrops. This is of particular relevance to the development of a vestibular implant, a device intended to rehabilitate deficits in the vestibular system. METHODS Six postmortem human temporal bones from healthy donors were scanned using a micro-computed tomography (microCT) scanner. The microCT data allowed 3D-reconstructions of the membranous labyrinth, with a particular focus on Bast's valve, vestibule, and cochlear duct. RESULTS The microCT images of Bast's valve showed a rigid lip containing a core of soft tissue, opposing the thin membranous wall of the utricle. The maximum recorded length and width of the rigid lip were 440.4 μm and 88 μm, respectively. The 3D-reconstructions illustrated the slit-like opening of Bast's valve into the utricle, the twisting course of the basal turn of the cochlear duct, and the spatial orientation of utricle and saccule with respect to the stapes footplate. CONCLUSIONS The present study provided a novel anatomical perspective on the microscopic structure of Bast's valve. The interplay between endolymphatic hydrops and Bast's valve is an ongoing area of research, but defining this anatomy in 3D will play a key role in furthering our understanding of the disease process. Implications for vestibular implantation are explored through the various 3D-reconstructions.
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Abstract
OBJECTIVE To study the surgical results, intracochlear position of the electrode array (EA) and auditory performance of the LISTENT LCI-20PI cochlear implant device, and daily use status at 3 years. STUDY DESIGN A retrospective study. SETTING A single-tertiary referral center. PATIENTS Between January and December 2016, 20 patients underwent cochlear implantation using the LISTENT LCI-20PI (lateral wall EA). INTERVENTION Cochlear implantation. MAIN OUTCOME MEASURES Measurement of cochlear size, extent of posterior tympanotomy, and insertion depth. Scalar position of the EA evaluated by 3D reconstruction. Auditory outcomes 1 year after implantation and daily use status at 3 years. RESULTS EAs were completely inserted in all cases with an insertion depth of 288 ± 36.8 degrees. One year later, the average sentence recognition score (SRS) was 90 ± 21.7%. EA scalar location was analyzed in 18 patients. Thirteen EAs (72.2%) were fully inserted into the scala tympani (ST) and 5 (27.8%) had shifted from the ST to the scala vestibuli (SV). There was no statistically significant difference in cochlear size, extent of posterior tympanotomy, or insertion depth between these two groups. EAs inserted by cochleostomy had a higher chance of scalar shift than those inserted via the round window (60% vs 15.4%, p = 0.099). SRS at 1 year with full ST insertion was significantly better than in those with scalar shift (99 ± 1.3% vs 83 ± 16.5%, p = 0.002). Three years after implantation, 92% of patients were daily users and 46% were telephone users. CONCLUSIONS The LISTENT LCI-20PI provided accredited hearing rehabilitation with a short insertion depth. Full insertion into the ST was associated with better cochlear implantation outcomes.
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Surgical considerations during cochlear implantation: the utility of temporal bone computed tomography. The Journal of Laryngology & Otology 2021; 135:134-141. [PMID: 33536091 DOI: 10.1017/s0022215121000232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVE This paper describes the construction of portals for electrode placement during cochlear implantation and emphasises the utility of pre-operative temporal bone three-dimensional computed tomography. METHODS Temporal bone three-dimensional computed tomography was used to plan portal creation for electrode insertion. RESULTS Pre-operative temporal bone three-dimensional computed tomography can be used to determine the orientation of temporal bone structures, which is important for mastoidectomy, posterior tympanotomy and cochleostomy, and when using the round window approach. CONCLUSION It is essential to create appropriate portals (from the mastoid cortex to the cochlea) in a step-by-step manner, to ensure the safe insertion of electrodes into the scala tympani. Pre-operative three-dimensional temporal bone computed tomography is invaluable in this respect.
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Characterization of the Sheep Round Window Membrane. J Assoc Res Otolaryngol 2020; 22:1-17. [PMID: 33258054 DOI: 10.1007/s10162-020-00778-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 10/19/2020] [Indexed: 12/21/2022] Open
Abstract
Intratympanic injection is a clinically used approach to locally deliver therapeutic molecules to the inner ear. Drug diffusion, at least in part, is presumed to occur through the round window membrane (RWM), one of the two openings to the inner ear. Previous studies in human temporal bones have identified a three-layered structure of the RWM with a thickness of 70-100 μm. This is considerably thicker than the RWM in rodents, which are mostly used to model RWM permeability and assess drug uptake. The sheep has been suggested as a large animal model for inner ear research given the similarities in structure and frequency range for hearing. Here, we report the structure of the sheep RWM. The RWM is anchored within the round window niche (average vertical diameter of 2.1 ± 0.3 mm and horizontal diameter of 2.3 ± 0.4 mm) and has a curvature that leans towards the scala tympani. The centre of the RWM is the thinnest (55-71 μm), with increasing thickness towards the edges (< 171 μm), where the RWM forms tight attachments to the surrounding bony niche. The layered RWM structure, including an outer epithelial layer, middle connective tissue and inner epithelial layer, was identified with cellular features such as wavy fibre bundles, melanocytes and blood vessels. An attached "meshwork structure" which extends over the cochlear aqueduct was seen, as in humans. The striking anatomical similarities between sheep and human RWM suggest that sheep may be evaluated as a more appropriate system to predict RWM permeability and drug delivery in humans than rodent models.
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Stuermer K, Winter T, Nachtsheim L, Klussmann JP, Luers JC. Round window accessibility during cochlear implantation. Eur Arch Otorhinolaryngol 2020; 278:363-370. [PMID: 32506146 DOI: 10.1007/s00405-020-06095-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Accepted: 05/26/2020] [Indexed: 12/20/2022]
Abstract
OBJECTIVE To assess data regarding round window (RW) visibility and surgical approaches in cochlear implant cases, and to describe and analyze surgical steps relevant for the RW approach in cochlear implantation. STUDY DESIGN Prospective clinical study. METHODS A questionnaire was completed by surgeons after each of altogether 110 cochlear implantations. Round window membrane (RWM) visibility was graded according to the St Thomas Hospital (STH) classification. RESULTS Performing different surgical steps during the preparation of the RW niche, the RWM could be fully exposed (STH Type I) in 87%. A RW approach could be used for electrode insertion in 89% of the adult and 78% of the pediatric cases. The distribution of RW types differed significantly between adults and children. Drilling of the superior bony lip was the surgical step most frequently needed in adult as well as pediatric cases to obtain optimal RW exposure. CONCLUSION In children, optimized surgical exposure of the RW niche resulted in only 52% full RWM visibility; whereas in adults, this could be achieved in 87%. The facial nerve (FN) had to be exposed at the level of the posterior tympanotomy in more than 70% of pediatric cases with full RWM visibility; while in adult cases with 100% visibility, such specific exposure was necessary in only 33%. Thus, surgical preparation of the RW niche seems to be more demanding in children than in adults.
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Affiliation(s)
- Konrad Stuermer
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical Faculty, University of Cologne, 50937, Cologne, Germany
| | - Tanja Winter
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical Faculty, University of Cologne, 50937, Cologne, Germany
| | - Lisa Nachtsheim
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical Faculty, University of Cologne, 50937, Cologne, Germany.
| | - Jens Peter Klussmann
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical Faculty, University of Cologne, 50937, Cologne, Germany
| | - Jan Christoffer Luers
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical Faculty, University of Cologne, 50937, Cologne, Germany
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Rutel IB, Stoner J, Kota P, Dormer K, Alleman A. Orientation of the round window membrane: A normative study of inner ear anatomical orientation using 2D projections of 3D volumes. Anat Rec (Hoboken) 2019; 303:2847-2856. [PMID: 31815368 DOI: 10.1002/ar.24327] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 10/18/2019] [Accepted: 10/28/2019] [Indexed: 12/12/2022]
Abstract
INTRODUCTION Orientation of the Round Window Membrane (RWM) is an important metric to establish if utilized as a potential access for targeted delivery of magnetically guided nanomedicines to the inner ear. Orientation with respect to an internal reference frame (such as the planes defined by the semicircular-canals [SCC]) may provide an internally consistent basis if the basis is orthogonal and consistent (from patient to patient). MATERIALS AND METHODS Utilizing a micro computed tomography (CT), 20 temporal bones are scanned for anatomical information. The scanned data sets are loaded into an imaging program to provide volumetric reconstruction and segmentation. Volumetric models of the anatomical relationships between the inner ear SCC and the RWM are utilized to get normative projection angle information and are statistically analyzed. RESULTS Micro-CT shows low to moderate reliability for reproducibility, intraobserver, and interobserver measurements; in addition, it provides mean values (±SD) for the various measured angles. The combined mean angular values for surface orientation of the RWM, with respect to the SCC basis (quasi-orthogonal spherical coordinate system), was 57.0° ± 20.9°as measured from the line defining the posterior SCC plane in the direction of the line defining the superior SCC plane. An angle of 65.2° ± 19.1° was measured for an angle away from the line defining the horizontal SCC plane.
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Affiliation(s)
- Isaac B Rutel
- Department of Radiological Sciences, University of Oklahoma Health Sciences Center (OUHSC), Oklahoma City, Oklahoma
| | - Julie Stoner
- Department of Biostatistics and Epidemiology, University of Oklahoma Health Sciences Center (OUHSC), Oklahoma City, Oklahoma
| | - Pravina Kota
- Department of Biostatistics and Epidemiology, University of Oklahoma Health Sciences Center (OUHSC), Oklahoma City, Oklahoma
| | - Kenneth Dormer
- Department of Community and Global Health, Campbell University, Jerry M. Wallace School of Osteopathic Medicine, Lillington, North Carolina
| | - Anthony Alleman
- Department of Radiological Sciences, University of Oklahoma Health Sciences Center (OUHSC), Oklahoma City, Oklahoma
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Burd C, Pai I, Connor S. Imaging anatomy of the retrotympanum: variants and their surgical implications. Br J Radiol 2019; 93:20190677. [PMID: 31593485 DOI: 10.1259/bjr.20190677] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The retrotympanic anatomy is complex and variable but has received little attention in the radiological literature. With advances in CT technology and the application of cone beam CT to temporal bone imaging, there is now a detailed depiction of the retrotympanic bony structures.With the increasing use of endoscopes in middle ear surgery, it is important for the radiologist to appreciate the nomenclature of the retrotympanic compartments in order to aid communication with the surgeon. For instance, in the context of cholesteatoma, clear imaging descriptions of retrotympanic variability and pathological involvement are valuable in pre-operative planning.The endoscopic anatomy has recently been described and the variants classified. The retrotympanum is divided into medial and lateral compartments with multiple described potential sinuses separated by bony crests.This pictorial review will describe the complex anatomy and variants of the retrotympanum. We will describe optimum reformatting techniques to demonstrate the structures of the retrotympanum and illustrate the associated anatomical landmarks and variants with CT. The implications of anatomical variants with regards to otologic surgery will be discussed.
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Affiliation(s)
- Christian Burd
- Department of Radiology Guy's and St Thomas' NHS Foundation Trust, London
| | - Irumee Pai
- King's College Hospital NHS Foundation Trust, London
| | - Stephen Connor
- Department of Radiology Guy's and St Thomas' NHS Foundation Trust, London.,School of Biomedical Engineering & Imaging Sciences Clinical Academic Group, King's College London, King's Health Partners, Guy's Hospital, London.,Department of Otolaryngology, Guy's and St. Thomas' Hospital NHS Foundation Trust, London
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