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Micuda A, Li H, Rask-Andersen H, Ladak HM, Agrawal SK. Morphologic Analysis of the Scala Tympani Using Synchrotron: Implications for Cochlear Implantation. Laryngoscope 2024; 134:2889-2897. [PMID: 38189807 DOI: 10.1002/lary.31263] [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: 09/30/2023] [Revised: 12/04/2023] [Accepted: 12/20/2023] [Indexed: 01/09/2024]
Abstract
OBJECTIVES To use synchrotron radiation phase-contrast imaging (SR-PCI) to visualize and measure the morphology of the entire cochlear scala tympani (ST) and assess cochlear implant (CI) electrode trajectories. METHODS SR-PCI images were used to obtain geometric measurements of the cochlear scalar diameter and area at 5-degree increments in 35 unimplanted and three implanted fixed human cadaveric cochleae. RESULTS The cross-sectional diameter and area of the cochlea were found to decrease from the base to the apex. This study represents a wide variability in cochlear morphology and suggests that even in the smallest cochlea, the ST can accommodate a 0.4 mm diameter electrode up to 720°. Additionally, all lateral wall array trajectories were within the anatomically accommodating insertion zone. CONCLUSION This is the first study to use SR-PCI to visualize and quantify the entire ST morphology, from the round window to the apical tip, and assess the post-operative trajectory of electrodes. These high-resolution anatomical measurements can be used to inform the angular insertion depth that can be accommodated in CI patients, accounting for anatomical variability. LEVEL OF EVIDENCE N/A. Laryngoscope, 134:2889-2897, 2024.
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Affiliation(s)
- Ashley Micuda
- Department of Medical Biophysics, Western University, London, Ontario, Canada
| | - Hao Li
- Department of Surgical Sciences, Otorhinolaryngology and Head and Neck Surgery, Uppsala University, Uppsala, Sweden
| | - Helge Rask-Andersen
- Department of Surgical Sciences, Otorhinolaryngology and Head and Neck Surgery, Uppsala University, Uppsala, Sweden
| | - Hanif M Ladak
- Department of Medical Biophysics, Western University, London, Ontario, Canada
- School of Biomedical Engineering, Western University, London, Ontario, Canada
- Department of Otolaryngology-Head and Neck Surgery, Western University, London, Ontario, Canada
- Department of Electrical and Computer Engineering, Western University, London, Ontario, Canada
| | - Sumit K Agrawal
- Department of Medical Biophysics, Western University, London, Ontario, Canada
- School of Biomedical Engineering, Western University, London, Ontario, Canada
- Department of Otolaryngology-Head and Neck Surgery, Western University, London, Ontario, Canada
- Department of Electrical and Computer Engineering, Western University, London, Ontario, Canada
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Alahmadi A, Abdelsamad Y, Thabet EM, Hafez A, Alghamdi F, Badr KM, Alghamdi S, Hagr A. Advancing Cochlear Implant Programming: X-ray Guided Anatomy-Based Fitting. Otol Neurotol 2024; 45:107-113. [PMID: 38206059 DOI: 10.1097/mao.0000000000004069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
BACKGROUND Anatomy-based fitting (ABF) is a new research area in the field of cochlear implants (CIs). Despite the reported benefits and acceptable levels of ABF among CI recipients, some limitations remain, like the postoperative computed tomography (CT) scan, which is preferred for confirming electrode array insertion. OBJECTIVE This study aimed to investigate the feasibility of using plain film radiography (X-ray) for postoperative electrode detection and for building ABF as an alternative to CT. METHODS A total of 53 ears with CI were studied. All cases had routine post-insertion X-rays in the cochlear view and additionally underwent postoperative CT. The insertion angles and center frequencies measured by two independent observers were compared for each imaging modality. The angular insertion depth and center frequencies resulting from the X-ray and CT scans were then compared. RESULTS No significant differences were observed between the X-ray- and CT-measured angles for the electrode contacts. Radiographic measurements between the two readers showed an almost perfect (≥0.8) or substantial (0.71) intraclass correlation coefficient along the electrode contacts. X-ray images showed a mean difference of 4.7 degrees from CT. The mean semitone deviation of the central frequency between the CT and X-ray images was 0.6. CONCLUSIONS X-ray imaging provides a valid and easy-to-perform alternative to CT imaging, with less radiation exposure and lower costs. The radiographs showed excellent concordance with the CT-measured angular insertion depth and consequently with the central frequency for most electrode contacts. Therefore, plain X-ray could be a viable alternative in building ABF for the CI recipients.
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Affiliation(s)
- Asma Alahmadi
- King Abdullah Ear Specialist Center (KAESC), College of Medicine, King Saud University Medical City (KSUMC), King Saud University, Riyadh, Saudi Arabia
| | | | | | - Ahmed Hafez
- Electrophysiology Department, MED-EL GmbH, Riyadh, Saudi Arabia
| | | | | | | | - Abdulrahman Hagr
- King Abdullah Ear Specialist Center (KAESC), College of Medicine, King Saud University Medical City (KSUMC), King Saud University, Riyadh, Saudi Arabia
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Dillon MT, Helpard L, Brown KD, Selleck AM, Richter ME, Rooth MA, Thompson NJ, Dedmon MM, Ladak HM, Agrawal S. Influence of the Frequency-to-Place Function on Recognition with Place-Based Cochlear Implant Maps. Laryngoscope 2023; 133:3540-3547. [PMID: 37078508 DOI: 10.1002/lary.30710] [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: 10/21/2022] [Revised: 04/07/2023] [Accepted: 04/11/2023] [Indexed: 04/21/2023]
Abstract
OBJECTIVE Comparison of acute speech recognition for cochlear implant (CI) alone and electric-acoustic stimulation (EAS) users listening with default maps or place-based maps using either a spiral ganglion (SG) or a new Synchrotron Radiation-Artificial Intelligence (SR-AI) frequency-to-place function. METHODS Thirteen adult CI-alone or EAS users completed a task of speech recognition at initial device activation with maps that differed in the electric filter frequency assignments. The three map conditions were: (1) maps with the default filter settings (default map), (2) place-based maps with filters aligned to cochlear SG tonotopicity using the SG function (SG place-based map), and (3) place-based maps with filters aligned to cochlear Organ of Corti (OC) tonotopicity using the SR-AI function (SR-AI place-based map). Speech recognition was evaluated using a vowel recognition task. Performance was scored as the percent correct for formant 1 recognition due to the rationale that the maps would deviate the most in the estimated cochlear place frequency for low frequencies. RESULTS On average, participants had better performance with the OC SR-AI place-based map as compared to the SG place-based map and the default map. A larger performance benefit was observed for EAS users than for CI-alone users. CONCLUSION These pilot data suggest that EAS and CI-alone users may experience better performance with a patient-centered mapping approach that accounts for the variability in cochlear morphology (OC SR-AI frequency-to-place function) in the individualization of the electric filter frequencies (place-based mapping procedure). LEVEL OF EVIDENCE 3 Laryngoscope, 133:3540-3547, 2023.
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Affiliation(s)
- Margaret T Dillon
- Department of Otolaryngology/Head & Neck Surgery, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Luke Helpard
- School of Biomedical Engineering, Western University, London, Ontario, Canada
| | - Kevin D Brown
- Department of Otolaryngology/Head & Neck Surgery, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - A Morgan Selleck
- Department of Otolaryngology/Head & Neck Surgery, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Margaret E Richter
- Department of Otolaryngology/Head & Neck Surgery, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Meredith A Rooth
- Department of Otolaryngology/Head & Neck Surgery, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Nicholas J Thompson
- Department of Otolaryngology/Head & Neck Surgery, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Matthew M Dedmon
- Department of Otolaryngology/Head & Neck Surgery, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Hanif M Ladak
- School of Biomedical Engineering, Western University, London, Ontario, Canada
- Department of Electrical and Computer Engineering, Western University, London, Ontario, Canada
- Department of Medical Biophysics, Western University, London, Ontario, Canada
- Department of Otolaryngology - Head & Neck Surgery, Western University, London, Ontario, Canada
| | - Sumit Agrawal
- Department of Otolaryngology - Head & Neck Surgery, Western University, London, Ontario, Canada
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Gatto A, Tofanelli M, Costariol L, Rizzo S, Borsetto D, Gardenal N, Uderzo F, Boscolo-Rizzo P, Tirelli G. Otological Planning Software-OTOPLAN: A Narrative Literature Review. Audiol Res 2023; 13:791-801. [PMID: 37887851 PMCID: PMC10603892 DOI: 10.3390/audiolres13050070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 10/10/2023] [Accepted: 10/16/2023] [Indexed: 10/28/2023] Open
Abstract
The cochlear implant (CI) is a widely accepted option in patients with severe to profound hearing loss receiving limited benefit from traditional hearing aids. CI surgery uses a default setting for frequency allocation aiming to reproduce tonotopicity, thus mimicking the normal cochlea. One emerging instrument that may substantially help the surgeon before, during, and after the surgery is a surgical planning software product developed in collaboration by CASCINATION AG (Bern, Switzerland) and MED-EL (Innsbruck Austria). The aim of this narrative review is to present an overview of the main features of this otological planning software, called OTOPLAN®. The literature was searched on the PubMed and Web of Science databases. The search terms used were "OTOPLAN", "cochlear planning software" "three-dimensional imaging", "3D segmentation", and "cochlear implant" combined into different queries. This strategy yielded 52 publications, and a total of 31 studies were included. The review of the literature revealed that OTOPLAN is a useful tool for otologists and audiologists as it improves preoperative surgical planning both in adults and in children, guides the intraoperative procedure and allows postoperative evaluation of the CI.
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Affiliation(s)
- Annalisa Gatto
- Department of Medical, Surgical and Health Sciences, Section of Otolaryngology, University of Trieste, 34149 Trieste, Italy; (A.G.); (N.G.); (G.T.)
| | - Margherita Tofanelli
- Department of Medical, Surgical and Health Sciences, Section of Otolaryngology, University of Trieste, 34149 Trieste, Italy; (A.G.); (N.G.); (G.T.)
| | - Ludovica Costariol
- Department of Medical, Surgical and Health Sciences, Section of Otolaryngology, University of Trieste, 34149 Trieste, Italy; (A.G.); (N.G.); (G.T.)
| | - Serena Rizzo
- Department of Medical, Surgical and Health Sciences, Section of Otolaryngology, University of Trieste, 34149 Trieste, Italy; (A.G.); (N.G.); (G.T.)
| | - Daniele Borsetto
- Department of ENT, Addenbrookes Hospital, Cambridge University Hospitals NHS Foundation Trust, Cambridge CB2 0QQ, UK
| | - Nicoletta Gardenal
- Department of Medical, Surgical and Health Sciences, Section of Otolaryngology, University of Trieste, 34149 Trieste, Italy; (A.G.); (N.G.); (G.T.)
| | - Francesco Uderzo
- Department of Medical, Surgical and Health Sciences, Section of Otolaryngology, University of Trieste, 34149 Trieste, Italy; (A.G.); (N.G.); (G.T.)
| | - Paolo Boscolo-Rizzo
- Department of Medical, Surgical and Health Sciences, Section of Otolaryngology, University of Trieste, 34149 Trieste, Italy; (A.G.); (N.G.); (G.T.)
| | - Giancarlo Tirelli
- Department of Medical, Surgical and Health Sciences, Section of Otolaryngology, University of Trieste, 34149 Trieste, Italy; (A.G.); (N.G.); (G.T.)
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Curtis DP, Baumann AN, Jeyakumar A. Variation in cochlear size: A systematic review. Int J Pediatr Otorhinolaryngol 2023; 171:111659. [PMID: 37459768 DOI: 10.1016/j.ijporl.2023.111659] [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: 03/15/2023] [Revised: 06/22/2023] [Accepted: 07/09/2023] [Indexed: 07/26/2023]
Abstract
BACKGROUND Advancements in imaging and implantation technology have invited reexamination of the classic teaching that the human cochlea maintains uniform size across demographics. Yet, studies yield conflicting results and relatively few broad systematic reviews have examined cochlear size variation. PURPOSE The purpose of this study is to quantify cochlear variability across eight different measurement categories and suggest normative values and ranges for each with consideration of disease state and gender where possible. METHODS A systematic search was conducted up to October 1, 2022, using the search terms "Cochlea/anatomy and histology"[Mesh]) AND 'size'" with filters "Humans" and "English" across three databases (PubMed, CINAHL, Medline). Further inclusion criteria involved reporting of numerical measurements in any of the eight included categories. RESULTS Of the 625 articles manually reviewed for relevance by title and abstract, 91 were selected for full-text review and 33 met all eligibility criteria. 5,791 cochleae were included and weighted means and ranges were calculated: "A" value (defined as the distance from the round window, through the modiolus, to the oppsite lateral wall) = 9.23 mm (8.43-10.4 mm, n = 2559); cochlear duct length (CDL) = 33.04 mm (range 28.2-36.4 mm, n = 2252); cochlear height = 5.14 mm (2.8-6.9 mm, n = 2098); the basal turn lumen diameter = 2.09 mm (1.7-2.2 mm, n = 617); "B" value (defined as perpendicular to "A" value and in the same plane) = 6.52 mm (5.73-6.9 mm, n = 908); width of the basal turn = 6.4 mm (6.22-6.86 mm, n = 356); height of the basal turn = 1.96 mm (1.77-2.56 mm, n = 204); length of the basal turn 21.87 mm (21.03-22.5 mm, n = 384). CONCLUSION A notable size range exists across the eight different cochlear parameters considered and we provide normative values for each measurement. Females tend to have smaller CDL and "A" value than males and the sensorineural hearing loss patients had smaller CDL and "A" value but larger cochlear height than the general population.
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Affiliation(s)
| | | | - Anita Jeyakumar
- Department of Otolaryngology, Mercy Bon Secours, Youngstown, OH, 44512, USA
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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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Müller-Graff FT, Rak K. [Cochlear Implantation: Evaluation of Cochlear Duct Length (CDL)]. Laryngorhinootologie 2022; 101:428-441. [PMID: 35500581 DOI: 10.1055/a-1742-5254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Personalized care in the context of cochlear implantation is becoming increasingly important. Choosing the right electrode could improve speech understanding. The measurement of the cochlear length plays an important role: preoperatively, in order to select a suitable electrode length; postoperatively, on the one hand to check the correct electrode position, on the other hand to enable anatomically based fitting of the electrode contacts. Of the various possible localizations of the CDL measurements within the cochlear turns, the one on the organ of Corti (CDLOC) is the most frequently used and clinically most important. In the CDL measurement, a direct and indirect evaluation can be distinguished. There is also the possibility of reconstructing and measuring the CDL in 3D and calculating it mathematically, e.g. using spiral equations. In this context, measurements based on radiological imaging are gaining increasing importance. Therefore, if there is the possibility of performing higher-resolution imaging, this should be strived preoperatively in order to enable the most precise possible procedure and thus a good outcome. Otological planning software can help to create an interface between new findings regarding CDL measurement and higher-resolution imaging for an individualized cochlear implantation.
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Affiliation(s)
- Franz-Tassilo Müller-Graff
- Klinik und Poliklinik für Hals-, Nasen- und Ohrenkrankheiten, plastische und ästhetische Operationen, Universitätsklinikum Würzburg, Würzburg
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Neves CA, Tran ED, Cooperman SP, Blevins NH. Fully Automated Measurement of Cochlear Duct Length From Clinical Temporal Bone Computed Tomography. Laryngoscope 2021; 132:449-458. [PMID: 34536238 DOI: 10.1002/lary.29869] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 08/24/2021] [Accepted: 08/31/2021] [Indexed: 11/06/2022]
Abstract
OBJECTIVES/HYPOTHESIS To present and validate a novel fully automated method to measure cochlear dimensions, including cochlear duct length (CDL). STUDY DESIGN Cross-sectional study. METHODS The computational method combined 1) a deep learning (DL) algorithm to segment the cochlea and otic capsule and 2) geometric analysis to measure anti-modiolar distances from the round window to the apex. The algorithm was trained using 165 manually segmented clinical computed tomography (CT). A Testing group of 159 CTs were then measured for cochlear diameter and width (A- and B-values) and CDL using the automated system and compared against manual measurements. The results were also compared with existing approaches and historical data. In addition, pre- and post-implantation scans from 27 cochlear implant recipients were studied to compare predicted versus actual array insertion depth. RESULTS Measurements were successfully obtained in 98.1% of scans. The mean CDL to 900° was 35.52 mm (SD, 2.06; range, [30.91-40.50]), the mean A-value was 8.88 mm (0.47; [7.67-10.49]), and mean B-value was 6.38 mm (0.42; [5.16-7.38]). The R2 fit of the automated to manual measurements was 0.87 for A-value, 0.70 for B-value, and 0.71 for CDL. For anti-modiolar arrays, the distance between the imaged and predicted array tip location was 0.57 mm (1.25; [0.13-5.28]). CONCLUSION Our method provides a fully automated means of cochlear analysis from clinical CTs. The distribution of CDL, dimensions, and cochlear quadrant lengths is similar to those from historical data. This approach requires no radiographic experience and is free from user-related variation. LEVEL OF EVIDENCE 3 Laryngoscope, 2021.
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Affiliation(s)
- Caio A Neves
- Faculty of Medicine, University of Brasilia, Brasilia, Brazil
| | - Emma D Tran
- Department of Otolaryngology-Head & Neck Surgery, Stanford University School of Medicine, Stanford, California, U.S.A
| | - Shayna P Cooperman
- Department of Otolaryngology-Head & Neck Surgery, Stanford University School of Medicine, Stanford, California, U.S.A
| | - Nikolas H Blevins
- Department of Otolaryngology-Head & Neck Surgery, Stanford University School of Medicine, Stanford, California, U.S.A
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