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Cottrell J, Landsberger D, Breen M, Lebowitz J, Hagiwara M, Moonis G, Shapiro W, Friedmann DR, Jethanamest D, McMenomey S, Roland JT. Cochlear Apex Triangulation Utilizing Ct Measures And Middle Ear Landmarks. OTOLOGY & NEUROTOLOGY OPEN 2024; 4:e060. [PMID: 39328867 PMCID: PMC11424059 DOI: 10.1097/ono.0000000000000060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2024] [Accepted: 06/16/2024] [Indexed: 09/28/2024]
Abstract
Objective To better characterize the cochlear apex in relation to surgically relevant landmarks to guide surgeons and improve procedural success of apical electrode placement. Study Design Retrospective image analysis. Setting Tertiary referral center. Patients Cochlear implant recipients with available preoperative computed tomography (CT) imaging. Intervention None. Main Outcome Measure Cochlear dimensions and cochlear apex distance measures to surgically relevant middle ear landmarks and critical structures. Results Eighty-two temporal bone CT scans were analyzed utilizing multiplanar reformats. The average lateral width of promontory bone over the cochlear apex was 1.2 mm (standard deviation [SD], 0.3). The anteroposterior distance from the round window (avg, 4.2 mm; SD, 0.5), oval window (avg, 3.3 mm; SD, 0.3), cochleariform process (avg, 2.3; SD, 0.5), and superior-inferior distance from the cochleariform process (avg, -0.9; SD, 0.8) to the cochlear apex were measured. The relationship of the cochlear apex to critical structures was highly variable.A newly developed stapes vector was created and found to mark the posterior/superior boundary of the apex in 94% of patients. When a vector parallel to the stapes vector was drawn through the round window, it marked the anterior/inferior boundary of the cochlear apex in 89% of patients. Conclusions This study assists in characterizing cochlear apex anatomy and its relation to surrounding structures as a means of improving procedural accuracy and reducing trauma during apical cochleostomy. Understanding both distance relationships and expected boundaries of the apex could help to inform future surgical approaches.
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Affiliation(s)
- Justin Cottrell
- Department of Otolaryngology—Head and Neck Surgery, NYU Langone, New York
| | - David Landsberger
- Department of Otolaryngology—Head and Neck Surgery, NYU Langone, New York
| | - Matt Breen
- Department of Radiology, NYU Langone, New York
| | - Joseph Lebowitz
- Department of Otolaryngology—Head and Neck Surgery, NYU Langone, New York
| | | | - Gul Moonis
- Department of Radiology, NYU Langone, New York
| | - William Shapiro
- Department of Otolaryngology—Head and Neck Surgery, NYU Langone, New York
| | - David R. Friedmann
- Department of Otolaryngology—Head and Neck Surgery, NYU Langone, New York
| | - Daniel Jethanamest
- Department of Otolaryngology—Head and Neck Surgery, NYU Langone, New York
| | - Sean McMenomey
- Department of Otolaryngology—Head and Neck Surgery, NYU Langone, New York
| | - J. Thomas Roland
- Department of Otolaryngology—Head and Neck Surgery, NYU Langone, New York
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Mewes A, Dambon J, Brademann G, Hey M. Curvature analysis of CI electrode arrays: a novel approach to categorize perimodiolar positions without anatomical landmarks. Eur Arch Otorhinolaryngol 2024:10.1007/s00405-024-08917-1. [PMID: 39214908 DOI: 10.1007/s00405-024-08917-1] [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: 06/24/2024] [Accepted: 08/12/2024] [Indexed: 09/04/2024]
Abstract
PURPOSE Perimodiolar electrode arrays may be positioned regular, over-inserted or under-inserted into the cochlea depending on the cochlear size and shape. The study aimed to examine whether there are differences between these groups in the local curvature along the intracochlear array. Individual curvature variables were developed to categorize the groups and the relationship between the curvature and the angular insertion depth at the electrode tip was analyzed. METHODS The curvature along the intracochlear array was measured in the CBCT image of 85 perimodiolar electrodes of a single type. The mean curvature and the ratio of the mean curvature at contacts E14-16 to the mean curvature at E7-8 (bowing ratio) were calculated across the array, and its true positive rate (TPR) and false positive rate (FPR) were calculated to establish optimal threshold values to categorize the groups. RESULTS 68.2% of the cases were categorized as regular positioned, 22.4% had an over-insertion and 9.4% had an under-insertion. The mean curvature was significantly weaker with under-insertion (< 342°) than with normal insertion depth (≥ 342°). With an over-insertion, the bowing ratio was < 1 and otherwise > 1. Both the mean curvature and bowing ratio were found to have an optimal threshold value with high TPR (= 1.00) and low FPR (≤ 0.06) for categorizing under-insertion and over-insertion, respectively. CONCLUSION Curvature analysis is a useful tool to assess if a perimodiolar electrode array has been inserted deep enough into the cochlea. Independent of critical anatomical landmarks, over-inserted arrays and under-inserted arrays could be well categorized by using individual curvature variables. The results need to be validated using additional data sets.
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Affiliation(s)
- Alexander Mewes
- Christian-Albrecht University of Kiel, Kiel, Germany.
- Department of Otorhinolaryngology, Head and Neck Surgery, Universitätsklinikum Schleswig-Holstein (UKSH), Campus Kiel, Kiel, Germany.
| | - Jan Dambon
- Department of Otorhinolaryngology, Head and Neck Surgery, Universitätsklinikum Schleswig-Holstein (UKSH), Campus Kiel, Kiel, Germany
| | - Goetz Brademann
- Department of Otorhinolaryngology, Head and Neck Surgery, Universitätsklinikum Schleswig-Holstein (UKSH), Campus Kiel, Kiel, Germany
| | - Matthias Hey
- Department of Otorhinolaryngology, Head and Neck Surgery, Universitätsklinikum Schleswig-Holstein (UKSH), Campus Kiel, Kiel, Germany
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Vranken B, Schoovaerts M, Geerardyn A, Kerkhofs L, Devos J, Hermans R, Putzeys T, Verhaert N. Innovative computed tomography based mapping of the surgical posterior tympanotomy: An exploratory study. Heliyon 2024; 10:e36335. [PMID: 39262979 PMCID: PMC11388378 DOI: 10.1016/j.heliyon.2024.e36335] [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: 03/19/2024] [Revised: 08/12/2024] [Accepted: 08/13/2024] [Indexed: 09/13/2024] Open
Abstract
Robotic devices have recently enhanced cochlear implantation by improving precision resulting in reduced intracochlear damage during electrode insertion. This study aimed to gain first insights into the expected dimensions of the cone-like workspace from the posterior tympanotomy towards the round window membrane. This retrospective chart review analyzed ten postoperative CT scans of adult patients who were implanted with a CI in the past ten years. The dimensions of the cone-like workspace were determined using four landmarks (P1-P4). In the anteroposterior range, P1 and P2 were defined on the edge of the bony layer over the facial nerve and chorda tympani nerve, respectively. In the inferosuperior range, P3 was defined on the bony edge of the incus buttress and P4 was obtained at a distance of 0.45 mm between the facial nerve and the chorda tympani nerve. After selecting the landmarks, the calculations of the dimensions of the surgical access space were done in a standardized coordinate system and presented using descriptive statistics. The cone-like space is limited by two maximal angles, α and β. The average angle α of 19.84 (±3.55) degrees defines the angle towards the round window membrane between P1 and P2. The second average angle β of 53.56 (±10.29) degrees defines the angle towards the round window membrane between P3 and P4. Based on the angles the mean anteroposterior range of 2.25 (±0.42) mm and mean inferosuperior range of 6.73 (±2.42) mm. The distance from the posterior tympanotomy to the round window membrane was estimated at 6.05 (±0.71) mm. These findings present data on the hypothetical maximum workspace in which a future robotically steered insertion tool can be positioned for an optimal automated electrode insertion. A larger sample size is necessary before generalizing these dimensions to a population. Further research including preoperative CT scans is needed for planning robotic-steered cochlear implantation.
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Affiliation(s)
- Brecht Vranken
- Faculty of Medicine, KU Leuven, Herestraat 49, 3000 Leuven Belgium
| | - Maarten Schoovaerts
- ExpORL, Department of Neurosciences, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Alexander Geerardyn
- ExpORL, Department of Neurosciences, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Lore Kerkhofs
- ExpORL, Department of Neurosciences, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Johannes Devos
- Department of Radiology, University Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Robert Hermans
- Department of Radiology, University Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Tristan Putzeys
- ExpORL, Department of Neurosciences, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Nicolas Verhaert
- ExpORL, Department of Neurosciences, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
- Department of Otorhinolaryngology - Head & Neck Surgery, University Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium
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Siebrecht M, Briaire JJ, Verbist BM, Kalkman RK, Frijns JH. Automated segmentation of clinical CT scans of the cochlea and analysis of the cochlea's vertical profile. Heliyon 2024; 10:e35737. [PMID: 39224385 PMCID: PMC11367034 DOI: 10.1016/j.heliyon.2024.e35737] [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: 12/19/2023] [Revised: 07/17/2024] [Accepted: 08/02/2024] [Indexed: 09/04/2024] Open
Abstract
Purpose Knowledge of the cochlear anatomy in individual patients is helpful for improving electrode selection and placement during cochlear implantation, as well as in surgical planning. The aim of this study was to develop a model-free automated segmentation algorithm to obtain 3D surfaces from clinical computed tomography (CT) scans that describe an individual's cochlear anatomy and can be used to quantitatively analyze the cochlea's vertical trajectory. Methods Clinical CT scans were re-oriented and re-sliced to obtain mid-modiolar slices. Using these slices, we segmented the cross-section of the cochlea. Results 3D surfaces were obtained for the first 1.5 turns of 648 cochleae. Validation of our algorithm against the manually segmented ground truth obtained from 8 micro-CT scans showed good agreement, with 90 % area overlap and an average distance of 0.11 mm between the segmentation contours. The average cochlear duct length for the basal turn was 16.1 mm along the central path and 22.4 mm along the outer wall. The use of an intrinsic, observer-independent coordinate system and principal component analysis enabled unambiguous quantitative evaluation of the vertical trajectory of the cochlea, revealing only a weak correlation between the symmetry of the commonly used basal turn diameters (B-ratio of A and B diameters) and the profile of the vertical trajectory. Conclusion A model-free segmentation algorithm can achieve similar accuracy as previously published methods relying on statistical shapes. Quantitative analysis of the vertical trajectory can replace the categorization into rollercoaster, sloping, or intermediate vertical trajectory types.
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Affiliation(s)
- Michael Siebrecht
- Department of Otorhinolaryngology and Head & Neck Surgery, Leiden University Medical Center, PO Box 9600, 2300 RC, Leiden, the Netherlands
| | - Jeroen J. Briaire
- Department of Otorhinolaryngology and Head & Neck Surgery, Leiden University Medical Center, PO Box 9600, 2300 RC, Leiden, the Netherlands
- Leiden Institute for Brain and Cognition, PO Box 9600, 2300 RC, Leiden, the Netherlands
| | - Berit M. Verbist
- Department of Radiology, Leiden University Medical Center, PO Box 9600, 2300 RC, Leiden, the Netherlands
| | - Randy K. Kalkman
- Department of Otorhinolaryngology and Head & Neck Surgery, Leiden University Medical Center, PO Box 9600, 2300 RC, Leiden, the Netherlands
| | - Johan H.M. Frijns
- Department of Otorhinolaryngology and Head & Neck Surgery, Leiden University Medical Center, PO Box 9600, 2300 RC, Leiden, the Netherlands
- Leiden Institute for Brain and Cognition, PO Box 9600, 2300 RC, Leiden, the Netherlands
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Andonie RR, Wimmer W, Schraivogel S, Mantokoudis G, Caversaccio M, Weder S. Electrocochleography in Cochlear Implant Recipients: Correlating Maximum Response With Residual Hearing. Ear Hear 2024:00003446-990000000-00314. [PMID: 39010266 DOI: 10.1097/aud.0000000000001546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/17/2024]
Abstract
OBJECTIVES Electrocochleography (ECochG) is increasingly recognized as a biomarker for assessing inner ear function in cochlear implant patients. This study aimed to objectively determine intraoperative cochlear microphonic (CM) amplitude patterns and correlate them with residual hearing in cochlear implant recipients, addressing the limitations in current ECochG analysis that often depends on subjective visual assessment and overlook the intracochlear measurement location. DESIGN In this prospective study, we investigated intraoperative pure-tone ECochG following complete electrode insertion in 31 patients. We used our previously published objective analysis method to determine the maximum CM amplitude and the associated electrode position for each electrode array. Using computed tomography, we identified electrode placement and determined the corresponding tonotopic frequency using Greenwood's function. Based on this, we calculated the tonotopic shift, that is, the difference between the stimulation frequency and the estimated frequency of the electrode with the maximum CM amplitude. We evaluated the association between CM amplitude, tonotopic shift, and preoperative hearing thresholds using linear regression analysis. RESULTS CM amplitudes showed high variance, with values ranging from -1.479 to 4.495 dBµV. We found a statistically significant negative correlation ( ) between maximum CM amplitudes and preoperative hearing thresholds. In addition, a significant association ( ) between the tonotopic shift and preoperative hearing thresholds was observed. Tonotopic shifts of the maximum CM amplitudes occurred predominantly toward the basal direction. CONCLUSIONS The combination of objective signal analysis and the consideration of intracochlear measurement locations enhances the understanding of cochlear health and overcomes the obstacles of current ECochG analysis. We could show the link between intraoperative CM amplitudes, their spatial distributions, and preoperative hearing thresholds. Consequently, our findings enable automated analysis and bear the potential to enhance specificity of ECochG, reinforcing its role as an objective biomarker for cochlear health.
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Affiliation(s)
- Raphael R Andonie
- Hearing Research Laboratory, ARTORG Center for Biomedical Engineering Research, Bern University Hospital, University of Bern, Bern, Switzerland
- Department of Otorhinolaryngology, Head & Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Wilhelm Wimmer
- Department of Otorhinolaryngology, Head & Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Department of Otorhinolaryngology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Stephan Schraivogel
- Hearing Research Laboratory, ARTORG Center for Biomedical Engineering Research, Bern University Hospital, University of Bern, Bern, Switzerland
- Department of Otorhinolaryngology, Head & Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Georgios Mantokoudis
- Department of Otorhinolaryngology, Head & Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Marco Caversaccio
- Hearing Research Laboratory, ARTORG Center for Biomedical Engineering Research, Bern University Hospital, University of Bern, Bern, Switzerland
- Department of Otorhinolaryngology, Head & Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Stefan Weder
- Department of Otorhinolaryngology, Head & Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
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Burck I, Yel I, Martin S, Albrecht MH, Koch V, Booz C, Pinto Dos Santos D, Kaltenbach B, Ackermann H, Koivisto J, Helbig S, Stöver T, Vogl TJ, Scholtz JE. Comparison of 96-kV and 120-kV cone-beam CT for the assessment of cochlear implants. BMC Med Imaging 2024; 24:145. [PMID: 38872126 DOI: 10.1186/s12880-024-01322-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 06/04/2024] [Indexed: 06/15/2024] Open
Abstract
BACKGROUND To compare the diagnostic value of 120-kV with conventional 96-kV Cone-Beam CT (CBCT) of the temporal bone after cochlear implant (CI) surgery. METHODS This retrospective study included CBCT scans after CI surgery between 06/17 and 01/18. CBCT allowed examinations with 96-kV or 120-kV; other parameters were the same. Two radiologists independently evaluated following criteria on 5-point Likert scales: osseous spiral lamina, inner and outer cochlear wall, semi-circular canals, mastoid trabecular structure, overall image quality, metal and motion artefacts, depiction of intracochlear electrode position and visualisation of single electrode contacts. Effective radiation dose was assessed. RESULTS Seventy-five patients (females, n = 39 [52.0%], mean age, 55.8 ± 16.5 years) were scanned with 96-kV (n = 32, 42.7%) and 120-kV (n = 43, 57.3%) protocols including CI models from three vendors (vendor A n = 7; vendor B n = 43; vendor C n = 25). Overall image quality, depiction of anatomical structures, and electrode position were rated significantly better in 120-kV images compared to 96-kV (all p < = 0.018). Anatomical structures and electrode position were rated significantly better in 120-kV CBCT for CI models from vendor A and C, while 120-kV did not provide improved image quality in CI models from vendor B. Radiation doses were significantly higher for 120-kV scans compared to 96-kV (0.15 vs. 0.08 mSv, p < 0.001). CONCLUSIONS 120-kV and 96-kV CBCT provide good diagnostic images for the postoperative CI evaluation. While 120-kV showed improved depiction of temporal bone and CI electrode position compared to 96-kV in most CI models, the 120-kV protocol should be chosen wisely due to a substantially higher radiation exposure.
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Affiliation(s)
- Iris Burck
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany.
| | - Ibrahim Yel
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany
| | - Simon Martin
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany
| | - Moritz H Albrecht
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany
| | - Vitali Koch
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany
| | - Christian Booz
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany
| | - Daniel Pinto Dos Santos
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany
| | - Benjamin Kaltenbach
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany
| | - Hanns Ackermann
- Institute of Biostatistics and Mathematical Modeling, University Hospital Frankfurt, Frankfurt, Germany
- Department of Otorhinolaryngology, University Hospital Frankfurt, Frankfurt, Germany
| | | | - Silke Helbig
- Department of Otorhinolaryngology, University Hospital Frankfurt, Frankfurt, Germany
| | - Timo Stöver
- Department of Otorhinolaryngology, University Hospital Frankfurt, Frankfurt, Germany
| | - Thomas J Vogl
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany
| | - Jan-Erik Scholtz
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany
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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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Lee JW, Andersen SAW, Hittle B, Powell KA, Al-Fartoussi H, Banks L, Brannen Z, Lahchich M, Wiet GJ. Variability in Manual Segmentation of Temporal Bone Structures in Cone Beam CT Images. Otol Neurotol 2024; 45:e137-e141. [PMID: 38361290 DOI: 10.1097/mao.0000000000004119] [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: 02/17/2024]
Abstract
PURPOSE Manual segmentation of anatomical structures is the accepted "gold standard" for labeling structures in clinical images. However, the variability in manual segmentation of temporal bone structures in CBCT images of the temporal bone has not been systematically evaluated using multiple reviewers. Therefore, we evaluated the intravariability and intervariability of manual segmentation of inner ear structures in CBCT images of the temporal bone. METHODS Preoperative CBCTs scans of the inner ear were obtained from 10 patients who had undergone cochlear implant surgery. The cochlea, facial nerve, chorda tympani, mid-modiolar (MM) axis, and round window (RW) were manually segmented by five reviewers in two separate sessions that were at least 1 month apart. Interreviewer and intrareviewer variabilities were assessed using the Dice coefficient (DICE), volume similarity, mean Hausdorff Distance metrics, and visual review. RESULTS Manual segmentation of the cochlea was the most consistent within and across reviewers with a mean DICE of 0.91 (SD = 0.02) and 0.89 (SD = 0.01) respectively, followed by the facial nerve with a mean DICE of 0.83 (SD = 0.02) and 0.80 (SD = 0.03), respectively. The chorda tympani had the greatest amount of reviewer variability due to its thin size, and the location of the centroid of the RW and the MM axis were also quite variable between and within reviewers. CONCLUSIONS We observed significant variability in manual segmentation of some of the temporal bone structures across reviewers. This variability needs to be considered when interpreting the results in studies using one manual reviewer.
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Affiliation(s)
- Julian W Lee
- Ohio State University College of Medicine, Columbus, Ohio
| | - Steven Arild Wuyts Andersen
- Copenhagen Hearing and Balance Center, Department of Otorhinolaryngology, Head and Neck Surgery and Audiology, Rigshospitalet, Copenhagen, Denmark
| | - Bradley Hittle
- Department of Biomedical Informatics, Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Kimerly A Powell
- Department of Biomedical Informatics, Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Hagar Al-Fartoussi
- Copenhagen Hearing and Balance Center, Department of Otorhinolaryngology, Head and Neck Surgery and Audiology, Rigshospitalet, Copenhagen, Denmark
| | - Laura Banks
- Ohio State University College of Medicine, Columbus, Ohio
| | | | - Mariam Lahchich
- Copenhagen Hearing and Balance Center, Department of Otorhinolaryngology, Head and Neck Surgery and Audiology, Rigshospitalet, Copenhagen, Denmark
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Geerardyn A, Zhu M, Verhaert N, Quesnel AM. Intracochlear Trauma and Local Ossification Patterns Differ Between Straight and Precurved Cochlear Implant Electrodes. Otol Neurotol 2024; 45:245-255. [PMID: 38270168 PMCID: PMC10922381 DOI: 10.1097/mao.0000000000004102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2024]
Abstract
HYPOTHESIS Trauma to the osseous spiral lamina (OSL) or spiral ligament (SL) during cochlear implant (CI) insertion segregates with electrode type and induces localized intracochlear ossification and fibrosis. BACKGROUND The goal of atraumatic CI insertion is to preserve intracochlear structures, limit reactive intracochlear tissue formation, and preserve residual hearing. Previous qualitative studies hypothesized a localized effect of trauma on intracochlear tissue formation; however, quantitative studies failed to confirm this. METHODS Insertional trauma beyond the immediate insertion site was histologically assessed in 21 human temporal bones with a CI. Three-dimensional reconstructions were generated and virtually resectioned perpendicular to the cochlear spiral at high resolution. The cochlear volume occupied by ossification or fibrosis was determined at the midpoint of the trauma and compared with regions proximal and distal to this point. RESULTS Seven cases, all implanted with precurved electrodes, showed an OSL fracture beyond the immediate insertion site. Significantly more intracochlear ossification was observed at the midpoint of the OSL fracture, compared with the -26 to -18 degrees proximal and 28 to 56 degrees distal to the center. No such pattern was observed for fibrosis. In the 12 cases with a perforation of the SL (9 straight and 3 precurved electrodes), no localized pattern of ossification or fibrosis was observed around these perforations. CONCLUSION OSL fractures were observed exclusively with precurved electrodes in this study and may serve as a nidus for localized intracochlear ossification. Perforation of the SL, in contrast, predominantly occurred with straight electrodes and was not associated with localized ossification.
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Affiliation(s)
| | - MengYu Zhu
- Otopathology Laboratory, Massachusetts Eye and Ear, Boston, Massachusetts, USA
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Geerardyn A, Zhu M, Klabbers T, Huinck W, Mylanus E, Nadol JB, Verhaert N, Quesnel AM. Human Histology after Structure Preservation Cochlear Implantation via Round Window Insertion. Laryngoscope 2024; 134:945-953. [PMID: 37493203 DOI: 10.1002/lary.30900] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 06/22/2023] [Accepted: 07/05/2023] [Indexed: 07/27/2023]
Abstract
OBJECTIVES Current surgical techniques aim to preserve intracochlear structures during cochlear implant (CI) insertion to maintain residual cochlear function. The optimal technique to minimize damage, however, is still under debate. The aim of this study is to histologically compare insertional trauma and intracochlear tissue formation in humans with a CI implanted via different insertion techniques. METHODS One recent temporal bone from a donor who underwent implantation of a full-length CI (576°) via round window (RW) insertion was compared with nine cases implanted via cochleostomy (CO) or extended round window (ERW) approach. Insertional trauma was assessed on H&E-stained histological sections. 3D reconstructions were generated and virtually re-sectioned to measure intracochlear volumes of fibrosis and neo-ossification. RESULTS The RW insertion case showed electrode translocation via the spiral ligament. 2/9 CO/ERW cases showed no insertional trauma. The total volume of the cochlea occupied by fibro-osseous tissue was 10.8% in the RW case compared with a mean of 30.6% (range 8.7%-44.8%, N = 9) in the CO/ERW cases. The difference in tissue formation in the basal 5 mm of scala tympani, however, was even more pronounced when the RW case (12.3%) was compared with the cases with a CO/ERW approach (mean of 93.8%, range 81% to 100%, N = 9). CONCLUSIONS Full-length CI insertions via the RW can be minimally traumatic at the cochlear base without inducing extensive fibro-osseous tissue formation locally. The current study further supports the hypothesis that drilling of the cochleostomy with damage to the endosteum incites a local tissue reaction. LEVEL OF EVIDENCE 4: Case-control study Laryngoscope, 134:945-953, 2024.
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Affiliation(s)
- Alexander Geerardyn
- Department of Otolaryngology-Head & Neck Surgery, Harvard Medical School, Boston, Massachusetts, U.S.A
- Otopathology Laboratory, Massachusetts Eye and Ear, Boston, Massachusetts, U.S.A
- ExpORL, Department of Neurosciences, Katholieke Universiteit Leuven, Leuven, Belgium
| | - MengYu Zhu
- Otopathology Laboratory, Massachusetts Eye and Ear, Boston, Massachusetts, U.S.A
| | - Tim Klabbers
- Department of Otorhinolaryngology, Radboudumc, Nijmegen, the Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Nijmegen, the Netherlands
| | - Wendy Huinck
- Department of Otorhinolaryngology, Radboudumc, Nijmegen, the Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Nijmegen, the Netherlands
| | - Emmanuel Mylanus
- Department of Otorhinolaryngology, Radboudumc, Nijmegen, the Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Nijmegen, the Netherlands
| | - Joseph B Nadol
- Department of Otolaryngology-Head & Neck Surgery, Harvard Medical School, Boston, Massachusetts, U.S.A
- Otopathology Laboratory, Massachusetts Eye and Ear, Boston, Massachusetts, U.S.A
| | - Nicolas Verhaert
- ExpORL, Department of Neurosciences, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Alicia M Quesnel
- Department of Otolaryngology-Head & Neck Surgery, Harvard Medical School, Boston, Massachusetts, U.S.A
- Otopathology Laboratory, Massachusetts Eye and Ear, Boston, Massachusetts, U.S.A
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11
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Fröhlich M, Schurzig D, Rau TS, Lenarz T. On the interdependence of insertion forces, insertion speed, and lubrication: Aspects to consider when testing cochlear implant electrodes. PLoS One 2024; 19:e0295121. [PMID: 38266033 PMCID: PMC10807833 DOI: 10.1371/journal.pone.0295121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 11/14/2023] [Indexed: 01/26/2024] Open
Abstract
OBJECTIVES During the insertion of cochlear implant (CI) electrode arrays, forces occur which may cause trauma and poorer hearing outcomes. Unfortunately, research groups investigating factors influencing insertion forces come to contradicting results, especially regarding insertion speed. This study was conducted to investigate the origin of these contradicting results and to determine how different testing conditions influence experimental findings. METHODS Repeated, automated insertions with three different FLEX28 CI electrode arrays (MED-EL, Innsbruck, Austria) were performed into a newly developed, anatomically correct and 3D-printed mean scala tympani phantom. The testing protocol for each electrode included variations in insertion speed (v = 0.1-2.0 mm/s) and lubrication (90%, 50%, and 10% liquid soap), resulting in 51 insertions per electrode array and a total of 153 insertions. RESULTS The test setup and protocol allowed for repeatable insertions with only minimal change in the morphology of the insertion force profiles per testing condition. Strong but varying dependencies of the maximal insertion forces and work were found regarding both lubrication and speed: work-speed dependency is constant for the 10% lubricant, negative for the 50% lubricant and positive for the 90% lubricant. CONCLUSION Our results can explain part of the contradicting results found within previous studies by translating interrelations known from lubricated rubber friction to the field of CI electrode array insertion. We show that the main driver behind measured bulk forces are most likely the generated friction forces, which are strongly dependent on insertion speed and lubrication. The employed test setup allows for conducting repeatable and comparable insertion studies, which can be recapitulated by other centers due to the detailed explanation of the test setup as well as the developed and freely available insertion phantom. This study hence represents another important step toward standardizing CI array insertion testing.
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Affiliation(s)
- Max Fröhlich
- MED-EL Medical Electronics GmbH, MED-EL Research Center, Hannover, Germany
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany
| | - Daniel Schurzig
- MED-EL Medical Electronics GmbH, MED-EL Research Center, Hannover, Germany
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany
| | - Thomas S. Rau
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany
- Cluster of Excellence EXC 2177/1 “Hearing4all”, Hannover, Germany
| | - Thomas Lenarz
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany
- Cluster of Excellence EXC 2177/1 “Hearing4all”, Hannover, Germany
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12
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Hasan Z, Key S, Lee M, Da Cruz M. Systematic Review of Intracochlear Measurements and Effect on Postoperative Auditory Outcomes after Cochlear Implant Surgery. Otol Neurotol 2024; 45:e1-e17. [PMID: 38013462 DOI: 10.1097/mao.0000000000004044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
OBJECTIVE Quality and adequacy of the electrode neuron interface (ENI) is postulated to be a determining factor in affecting auditory outcomes after cochlear implantation. This study aims to review radiological parameters affecting ENI, including angular insertion (AngI), wrapping factor (WF), scalar translocation (ScaT), and electrode-modiolar distance (EMD) and their effect on auditory outcomes. DATABASES REVIEWED PubMed, MEDLINE, Embase, Scopus, OpenGrey, and Google Scholar from inception to 01 September 2022. METHODS Inclusion criteria were (i) all humans with any cochlear implant (CI); (ii) postoperative cross-sectional imaging with electrode position factors of AngI, ScaT, EMD, and/or WF; and (iii) associated auditory outcomes. Search was restricted to English-language literature. Two independent reviewers performed title and abstract screening, data extraction, and ROBINS-I risk of bias assessment. Formal statistical analysis not performed due to data heterogeneity. PROSPERO (CRD42022359198). RESULTS Thirty-one studies (n = 2,887 patients, 3,091 electrodes) underwent qualitative synthesis. Higher AngI (n = 1921 patients) demonstrated positive correlation in 11 studies, no correlation in eight studies, and negative correlation in four studies. ScaT (n = 2,115 patients) demonstrated negative correlation in 12 studies, none in six studies, and one unclear correlation. Larger EMD (n = 240 patients) showed negative correlation in two studies, no correlation in one, and unclear correlation in one study. Smaller WF (n = 369 patients) demonstrated no correlation in three studies and positive correlation in one study. CONCLUSIONS Our study finds variable reported relationship between AngI and auditory outcomes. CI electrodes with a ScaT or larger EMD are more likely to exhibit poorer outcomes, and WF does not correlate with outcomes.
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Affiliation(s)
| | - Seraphina Key
- Faculty of Medicine and Health, University of Sydney, Australia
| | - Michael Lee
- Department of Otolaryngology Head and Neck Surgery, Westmead Hospital, Sydney, Australia
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13
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Kaul VF, Brannan Z, Keith J, Hittle B, Riggs W, Hiss M, Varadarajan V, Zhan K, Powell K, Wiet GJ, Adunka OF. Post-operative evaluation of computed tomography imaging following cochlear implantation. Am J Otolaryngol 2024; 45:104081. [PMID: 37820391 DOI: 10.1016/j.amjoto.2023.104081] [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: 08/21/2023] [Accepted: 09/30/2023] [Indexed: 10/13/2023]
Abstract
PURPOSE This study utilized an automated segmentation algorithm to assess the cochlear implant electrode array within the cochlea and investigate its impact on audiologic outcomes as measured by post-operative speech perception scores. Furthermore, manual evaluations of electrode placement were compared to automatic segmentation methods to determine their accuracy in predicting post-operative audiologic outcomes. MATERIALS AND METHODS This retrospective chart review was conducted at a tertiary care referral center involving adult post-lingually deafened cochlear implant recipients implanted from 2015 to 2019. Patients with appropriate postoperative imaging and speech testing were included. Patients were excluded if non-English speaking, had a cognitive deficit, or a labyrinthine malformation. Automated and manual methods were used to analyze computed tomography (CT) scans and correlate the findings with post-operative speech perception scores and detection of electrode translocation. RESULTS Among the 47 patients who met inclusion criteria, 15 had electrode translocations confirmed by automatic segmentation methods. Controlling for CI usage and pre-operative AzBio scores, patients with translocation exhibited significantly lower consonant-nucleus consonant (CNC) and AzBio scores at 6-months post-implantation compared to patients with ST insertions. Moreover, the number of translocated electrode contacts was significantly associated with post-operative CNC scores. Manual evaluations of electrode location were predictive but less sensitive to electrode translocations when compared with automated 3D segmentation. CONCLUSIONS Placement of CI electrode contacts within ST without translocation into SV, leads to improved audiologic outcomes. Manual assessment of electrode placement via temporal bone CT, without 3D reconstruction, provides a less sensitive method to determine electrode placement than automated methods. LEVEL OF EVIDENCE Level 4. LAY SUMMARY This study investigated the impact of electrode placement on speech outcomes for cochlear implant recipients. Using advanced imaging techniques, the researchers compared automated and manual methods for evaluating electrode position and examined the relationship between electrode translocation and audiologic outcomes. The findings revealed that proper placement within the cochlea without translocation into inappropriate compartments inside the cochlea improves speech understanding. Manual evaluations were somewhat accurate but less sensitive in detecting translocations compared to automated methods, which offer more precise predictions of patient outcomes. These results contribute to our understanding of factors influencing cochlear implant success and highlight the importance of optimizing electrode placement for improved speech outcomes.
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Affiliation(s)
- Vivian F Kaul
- The Ohio State Wexner Medical Center, 915 Olentangy River Rd, Columbus, OH 43212, United States of America.
| | - Zachary Brannan
- The Ohio State University College of Medicine, 370 W 9th Ave, Columbus, OH 43210, United States of America
| | - Jason Keith
- Ohio State University College of Engineering, 2070 Neil Ave, Columbus, OH 43210, United States of America.
| | - Bradley Hittle
- The Ohio State University College of Medicine, 370 W 9th Ave, Columbus, OH 43210, United States of America.
| | - William Riggs
- The Ohio State Wexner Medical Center, 915 Olentangy River Rd, Columbus, OH 43212, United States of America
| | - Meghan Hiss
- The Ohio State Wexner Medical Center, 915 Olentangy River Rd, Columbus, OH 43212, United States of America.
| | - Varun Varadarajan
- Associates of Otolaryngology Colorado, 850 E Harvard Ave # 505, Denver, CO 80210, United States of America
| | - Kevin Zhan
- Northwestern Medical Group, 251 East Huron Street, Chicago, IL 60611, United States of America.
| | - Kimerly Powell
- The Ohio State Wexner Medical Center, 915 Olentangy River Rd, Columbus, OH 43212, United States of America.
| | - Gregory J Wiet
- The Ohio State Wexner Medical Center, 915 Olentangy River Rd, Columbus, OH 43212, United States of America; Nationwide Children's Hospital, 700 Children's Dr, Columbus, OH 43205, United States of America.
| | - Oliver F Adunka
- The Ohio State Wexner Medical Center, 915 Olentangy River Rd, Columbus, OH 43212, United States of America; Nationwide Children's Hospital, 700 Children's Dr, Columbus, OH 43205, United States of America.
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14
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Haumann S, Timm ME, Büchner A, Lenarz T, Salcher RB. Intracochlear Recording of Electrocochleography During and After Cochlear Implant Insertion Dependent on the Location in the Cochlea. Trends Hear 2024; 28:23312165241248973. [PMID: 38717441 PMCID: PMC11080744 DOI: 10.1177/23312165241248973] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 02/23/2024] [Accepted: 04/04/2024] [Indexed: 05/12/2024] Open
Abstract
To preserve residual hearing during cochlear implant (CI) surgery it is desirable to use intraoperative monitoring of inner ear function (cochlear monitoring). A promising method is electrocochleography (ECochG). Within this project the relations between intracochlear ECochG recordings, position of the recording contact in the cochlea with respect to anatomy and frequency and preservation of residual hearing were investigated. The aim was to better understand the changes in ECochG signals and whether these are due to the electrode position in the cochlea or to trauma generated during insertion. During and after insertion of hearing preservation electrodes, intraoperative ECochG recordings were performed using the CI electrode (MED-EL). During insertion, the recordings were performed at discrete insertion steps on electrode contact 1. After insertion as well as postoperatively the recordings were performed at different electrode contacts. The electrode location in the cochlea during insertion was estimated by mathematical models using preoperative clinical imaging, the postoperative location was measured using postoperative clinical imaging. The recordings were analyzed from six adult CI recipients. In the four patients with good residual hearing in the low frequencies the signal amplitude rose with largest amplitudes being recorded closest to the generators of the stimulation frequency, while in both cases with severe pantonal hearing losses the amplitude initially rose and then dropped. This might be due to various reasons as discussed in the following. Our results indicate that this approach can provide valuable information for the interpretation of intracochlearly recorded ECochG signals.
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Affiliation(s)
- Sabine Haumann
- Department of Otorhinolaryngology, Hannover Medical School, Hannover, Germany
- Cluster of Excellence “Hearing4All”, Hannover, Germany
| | - Max E. Timm
- Department of Otorhinolaryngology, Hannover Medical School, Hannover, Germany
- Cluster of Excellence “Hearing4All”, Hannover, Germany
| | - Andreas Büchner
- Department of Otorhinolaryngology, Hannover Medical School, Hannover, Germany
- Cluster of Excellence “Hearing4All”, Hannover, Germany
| | - Thomas Lenarz
- Department of Otorhinolaryngology, Hannover Medical School, Hannover, Germany
- Cluster of Excellence “Hearing4All”, Hannover, Germany
| | - Rolf B. Salcher
- Department of Otorhinolaryngology, Hannover Medical School, Hannover, Germany
- Cluster of Excellence “Hearing4All”, Hannover, Germany
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15
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Franke-Trieger A, Lailach S, Shetty J, Murrmann K, Zahnert T, Neudert M. Word Recognition with a Cochlear Implant in Relation to Prediction and Electrode Position. J Clin Med 2023; 13:183. [PMID: 38202190 PMCID: PMC10780042 DOI: 10.3390/jcm13010183] [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: 11/20/2023] [Revised: 12/11/2023] [Accepted: 12/21/2023] [Indexed: 01/12/2024] Open
Abstract
BACKGROUND the word recognition score (WRS) achieved with cochlear implants (CIs) varies widely. To account for this, a predictive model was developed based on patients' age and their pre-operative WRS. This retrospective study aimed to find out whether the insertion depth of the nucleus lateral-wall electrode arrays contributes to the deviation of the CI-achieved WRS from the predicted WRS. MATERIALS AND METHODS patients with a pre-operative maximum WRS > 0 or a pure-tone audiogram ≥80 dB were included. The insertion depth was determined via digital volume tomography. RESULTS fifty-three patients met the inclusion criteria. The median WRS achieved with the CI was 70%. The comparison of pre- and post-operative scores achieved with a hearing aid and a CI respectively in the aided condition showed a median improvement of 65 percentage points (pp). A total of 90% of the patients improved by at least 20 pp. The majority of patients reached or exceeded the prediction, with a median absolute error of 11 pp. No significant correlation was found between the deviation from the predicted WRS and the insertion depth. CONCLUSIONS our data support a previously published model for the prediction of the WRS after cochlear implantation. For the lateral-wall electrode arrays evaluated, the insertion depth did not influence the WRS with a CI.
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Affiliation(s)
- Annett Franke-Trieger
- Department of Otorhinolaryngology, Head and Neck Surgery, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Fetscherstraße 74, 01307 Dresden, Germany (T.Z.)
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16
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Alahmadi A, Abdelsamad Y, Dhanasingh A, Almuhawas F, Alsanosi A. Enhancing cochlear duct length estimation by incorporating second-turn parameters. Sci Rep 2023; 13:21496. [PMID: 38057331 PMCID: PMC10700305 DOI: 10.1038/s41598-023-48641-0] [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: 10/19/2022] [Accepted: 11/28/2023] [Indexed: 12/08/2023] Open
Abstract
Estimating insertion depth, cochlear duct length (CDL), and other inner ear parameters is vital to optimizing cochlear implantation outcomes. Most current formulas use only the basal turn dimensions for CDL prediction. In this study, we investigated the importance of the second turn parameters in estimating CDL. Two experienced neuro-otologists blindly used segmentation software to measure (in mm) cochlear parameters, including basal turn diameter (A), basal turn width (B), second-turn diameter (A2), second-turn width (B2), CDL, first-turn length, and second-turn length (STL). These readings were taken from 33 computed tomography (CT) images of temporal bones from anatomically normal ears. We constructed regression models using A, B, A2, and B2 values fitted to CDL, two-turn length, and five-fold cross-validation to ensure model validity. CDL, A value, and STL were longer in males than in females. The mean B2/A2 ratio was 0.91 ± 0.06. Adding A2 and B2 values improved CDL prediction accuracy to 86.11%. Therefore, we propose a new formula for more accurate CDL estimation using A, B, A2, and B2 values. In conclusion, the findings of this study revealed a notable improvement in the prediction of two-turn length (2TL), and CDL by clinically appreciable margins upon adding A2 and B2 values to the prediction formulas.
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Affiliation(s)
- Asma Alahmadi
- King Abdullah Ear Specialist Center (KAESC), King Saud University Medical City (KSUMC), College of Medicine, King Saud University, P.O. Box: 245, 11411, Riyadh, Saudi Arabia.
| | | | | | - Fida Almuhawas
- King Abdullah Ear Specialist Center (KAESC), King Saud University Medical City (KSUMC), College of Medicine, King Saud University, P.O. Box: 245, 11411, Riyadh, Saudi Arabia
| | - Abdulrahman Alsanosi
- King Abdullah Ear Specialist Center (KAESC), King Saud University Medical City (KSUMC), College of Medicine, King Saud University, P.O. Box: 245, 11411, Riyadh, Saudi Arabia
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17
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Ding L, Zhang L, Li J, Lin T. Electrode-Modiolus Distance Affects Speech Perception for Lateral Wall Electrodes. Otol Neurotol 2023; 44:e702-e709. [PMID: 37939358 DOI: 10.1097/mao.0000000000004019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2023]
Abstract
OBJECTIVES The goal of this study was to use cone-beam computed tomography to locate the electrode-modiolus distance (EMD) and correlate this with speech perception in cochlear implant (CI) recipients of the 31.5-mm lateral wall (LW) electrode arrays. STUDY DESIGN Retrospective review. PATIENTS Forty-five child CI recipients with prelingual profound sensorineural hearing loss of inserted 31.5-mm LW arrays listening with a CI-alone device. INTERVENTIONS Stepwise forward multiple linear regression was performed to control and reduce the variability in implant performance to determine whether EMD affects speech perception. MAIN OUTCOME MEASURES Electrode location (angular insertion depth [AID], EMD), together with the electrode impedance (EI), surgical approach, sex, CI age, and preimplant hearing aid usage were estimated as independent variables. The dependent variables were the Meaningful Use of Speech Scale (MUSS) and parents' evaluation of children's aural/oral performance (PEACH) assessed with the CI alone at 12 months postactivation. RESULTS EMD and CI age were predictive variables for PEACH/MUSS. A negative correlation was found between AID and EMD (r = -0.56, p < 0.01), whereas EMD had a moderately positive correlation with EI (r = 0.32, p < 0.01). CONCLUSIONS The best "location-related" predictor of postoperative speech perception was EMD with a 31.5-mm array among CI-alone users.
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Affiliation(s)
- Ling Ding
- Department of Otorhinolaryngology-Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Luguang Zhang
- Department of Medical Imaging, The Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Jing Li
- Department of Otorhinolaryngology-Head and Neck Surgery, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Tao Lin
- Department of Neurosurgery, Shandong Second Provincial General Hospital, Jinan, Shandong, 250022, China
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18
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Stebani J, Blaimer M, Zabler S, Neun T, Pelt DM, Rak K. Towards fully automated inner ear analysis with deep-learning-based joint segmentation and landmark detection framework. Sci Rep 2023; 13:19057. [PMID: 37925540 PMCID: PMC10625555 DOI: 10.1038/s41598-023-45466-9] [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: 11/30/2022] [Accepted: 10/19/2023] [Indexed: 11/06/2023] Open
Abstract
Automated analysis of the inner ear anatomy in radiological data instead of time-consuming manual assessment is a worthwhile goal that could facilitate preoperative planning and clinical research. We propose a framework encompassing joint semantic segmentation of the inner ear and anatomical landmark detection of helicotrema, oval and round window. A fully automated pipeline with a single, dual-headed volumetric 3D U-Net was implemented, trained and evaluated using manually labeled in-house datasets from cadaveric specimen ([Formula: see text]) and clinical practice ([Formula: see text]). The model robustness was further evaluated on three independent open-source datasets ([Formula: see text] scans) consisting of cadaveric specimen scans. For the in-house datasets, Dice scores of [Formula: see text], intersection-over-union scores of [Formula: see text] and average Hausdorff distances of [Formula: see text] and [Formula: see text] voxel units were achieved. The landmark localization task was performed automatically with an average localization error of [Formula: see text] voxel units. A robust, albeit reduced performance could be attained for the catalogue of three open-source datasets. Results of the ablation studies with 43 mono-parametric variations of the basal architecture and training protocol provided task-optimal parameters for both categories. Ablation studies against single-task variants of the basal architecture showed a clear performance benefit of coupling landmark localization with segmentation and a dataset-dependent performance impact on segmentation ability.
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Affiliation(s)
- Jannik Stebani
- Magnetic Resonance and X-Ray Imaging Department, Fraunhofer Institute for Integrated Circuits IIS, 97074, Würzburg, Germany.
- Universität Würzburg, Experimentelle Physik V, 97074, Würzburg, Germany.
- Department of Oto-Rhino-Laryngology, Plastic, Aesthetic and Reconstructive Head and Neck Surgery and the Comprehensive Hearing Center, Universitätsklinikum Würzburg, 97080, Würzburg, Germany.
| | - Martin Blaimer
- Magnetic Resonance and X-Ray Imaging Department, Fraunhofer Institute for Integrated Circuits IIS, 97074, Würzburg, Germany
| | - Simon Zabler
- Magnetic Resonance and X-Ray Imaging Department, Fraunhofer Institute for Integrated Circuits IIS, 97074, Würzburg, Germany
- Faculty of Computer Science, Deggendorf Institute of Technology, Deggendorf, Germany
| | - Tilmann Neun
- Institute for Diagnostic and Interventional Neuroradiology, Universitätsklinikum Würzburg, 97080, Würzburg, Germany
| | - Daniël M Pelt
- Leiden Institute of Advanced Computer Science (LIACS), Universiteit Leiden, Leiden, CA, 2333, The Netherlands
| | - Kristen Rak
- Department of Oto-Rhino-Laryngology, Plastic, Aesthetic and Reconstructive Head and Neck Surgery and the Comprehensive Hearing Center, Universitätsklinikum Würzburg, 97080, Würzburg, Germany
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19
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Yokoi J, Fujita T, Uehara N, Iwaki S, Kakigi A, Nibu KI. Vestibular function after simultaneous bilateral cochlear implantation in adults. Front Neurol 2023; 14:1304927. [PMID: 38020629 PMCID: PMC10657651 DOI: 10.3389/fneur.2023.1304927] [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: 09/30/2023] [Accepted: 10/24/2023] [Indexed: 12/01/2023] Open
Abstract
Introduction Binaural hearing enhances speech intelligibility, source localization, and speech comprehension in noisy environments. Although bilateral cochlear implantation (CI) offers several benefits, concerns arise regarding the risk of bilateral postoperative vestibular dysfunction with simultaneous CI. This study aimed to longitudinally evaluate changes in vestibular function in adult patients who underwent simultaneous bilateral CI using minimally invasive electrodes and surgical techniques. Methods A retrospective review was conducted on 10 patients who underwent simultaneous bilateral CI at our hospital. Vertigo symptoms and vestibular function test results were examined preoperatively, 1-6 months postoperatively, and 1 year postoperatively. Nystagmus tests, caloric reflex tests, vestibular evoked myogenic potentials (VEMP) measurements, and static stabilometry were performed as vestibular function tests. Results Although an initial transient decline in vestibular function was observed, no significant long-term decline was observed in the caloric reflex test, ocular VEMP (oVEMP), or cervical VEMP (cVEMP). Moreover, regardless of the presence or absence of abnormalities in caloric reflex, oVEMP, or cVEMP, no significant deterioration was detected in the static stabilometer test. While two patients reported preoperative dizziness, all patients were symptom-free 1 year postoperatively. Discussion The findings suggest that using current minimally invasive electrodes and surgical techniques in simultaneous bilateral CI leads to temporary vestibular function decline postoperatively. However, most patients experience a recovery in function over time, highlighting the potential safety and efficacy of the procedure. Simultaneous bilateral CI surgery is viable, depending on the patient's auditory needs and burden.
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Affiliation(s)
| | - Takeshi Fujita
- Department of Otolaryngology - Head and Neck Surgery, Kobe University Graduate School of Medicine, Kobe, Japan
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20
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Schraivogel S, Aebischer P, Wagner F, Weder S, Mantokoudis G, Caversaccio M, Wimmer W. Postoperative Impedance-Based Estimation of Cochlear Implant Electrode Insertion Depth. Ear Hear 2023; 44:1379-1388. [PMID: 37157125 PMCID: PMC10583924 DOI: 10.1097/aud.0000000000001379] [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: 01/06/2023] [Accepted: 04/01/2023] [Indexed: 05/10/2023]
Abstract
OBJECTIVES Reliable determination of cochlear implant electrode positions shows promise for clinical applications, including anatomy-based fitting of audio processors or monitoring of electrode migration during follow-up. Currently, electrode positioning is measured using radiography. The primary objective of this study is to extend and validate an impedance-based method for estimating electrode insertion depths, which could serve as a radiation-free and cost-effective alternative to radiography. The secondary objective is to evaluate the reliability of the estimation method in the postoperative follow-up over several months. DESIGN The ground truth insertion depths were measured from postoperative computed tomography scans obtained from the records of 56 cases with an identical lateral wall electrode array. For each of these cases, impedance telemetry records were retrieved starting from the day of implantation up to a maximum observation period of 60 mo. Based on these recordings, the linear and angular electrode insertion depths were estimated using a phenomenological model. The estimates obtained were compared with the ground truth values to calculate the accuracy of the model. RESULTS Analysis of the long-term recordings using a linear mixed-effects model showed that postoperative tissue resistances remained stable throughout the follow-up period, except for the two most basal electrodes, which increased significantly over time (electrode 11: ~10 Ω/year, electrode 12: ~30 Ω/year). Inferred phenomenological models from early and late impedance telemetry recordings were not different. The insertion depth of all electrodes was estimated with an absolute error of 0.9 mm ± 0.6 mm or 22° ± 18° angle (mean ± SD). CONCLUSIONS Insertion depth estimations of the model were reliable over time when comparing two postoperative computed tomography scans of the same ear. Our results confirm that the impedance-based position estimation method can be applied to postoperative impedance telemetry recordings. Future work needs to address extracochlear electrode detection to increase the performance of the method.
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Affiliation(s)
- Stephan Schraivogel
- Hearing Research Laboratory, ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
- Department of Otorhinolaryngology, Head and Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Philipp Aebischer
- Hearing Research Laboratory, ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
- Department of Otorhinolaryngology, Head and Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Franca Wagner
- Department of Diagnostic and Interventional Neuroradiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Stefan Weder
- Department of Otorhinolaryngology, Head and Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Georgios Mantokoudis
- Department of Otorhinolaryngology, 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 Otorhinolaryngology, Head and Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Wilhelm Wimmer
- Hearing Research Laboratory, ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
- Department of Otorhinolaryngology, Head and Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Technical University of Munich, Germany; TUM School of Medicine, Klinikum rechts der Isar, Department of Otorhinolaryngology
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21
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Windmeijer CAA, Biesheuvel JD, Boermans PPBM, Briaire JJ, Frijns JHM. Full-array channel discrimination in cochlear implants: validation and clinical application. Int J Audiol 2023; 62:992-1001. [PMID: 35875843 DOI: 10.1080/14992027.2022.2101028] [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: 01/31/2022] [Accepted: 07/08/2022] [Indexed: 11/05/2022]
Abstract
OBJECTIVE We sought to validate our proposed tool for estimating channel discrimination of cochlear implant (CI) users along the full electrode array and to assess associations between place-pitch discrimination and speech perception. DESIGN In two tests, participants identified one stimulus (probe) as the odd-one-out compared with two reference stimuli. Probe stimuli were evoked using dual electrode stimulation characterised by the current steering coefficient α. The first test measured psychometric functions (PFs) on pre-defined contacts, with just a noticeable difference (JNDα) as the outcome variable. The second test estimated channel discrimination on the full electrode array, yielding a discrimination score of Dα. We measured speech perception as free-field consonant-vowel-consonant phoneme recognition scores. STUDY SAMPLE We included 25 adults with at least 6 months of CI experience. RESULTS JNDα and Dα scores measured on the same contact correlated significantly (rs = 0.64, p < 0.001). Mean JNDα and speech perception scores showed significant relationships in quiet and in noise. CONCLUSIONS Dα correlated strongly with JNDα scores obtained with the PFs. For poor performers, the full-array test may underestimate JNDα. The full-array pitch discrimination test could be a helpful clinical tool, such as for fitting regions of lesser pitch discrimination ability.
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Affiliation(s)
| | | | | | - Jeroen J Briaire
- ENT Department, Leiden University Medical Centre, Leiden, The Netherlands
| | - Johan H M Frijns
- ENT Department, Leiden University Medical Centre, Leiden, The Netherlands
- Leiden Institute for Brain and Cognition, Leiden University, Leiden, The Netherlands
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22
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Mewes A, Bennett C, Dambon J, Brademann G, Hey M. Evaluation of CI electrode position from imaging: comparison of an automated technique with the established manual method. BMC Med Imaging 2023; 23:143. [PMID: 37773060 PMCID: PMC10543862 DOI: 10.1186/s12880-023-01102-6] [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: 02/13/2023] [Accepted: 09/13/2023] [Indexed: 09/30/2023] Open
Abstract
BACKGROUND A manual evaluation of the CI electrode position from CT and DVT scans may be affected by diagnostic errors due to cognitive biases. The aim of this study was to compare the CI electrode localization using an automated method (image-guided cochlear implant programming, IGCIP) with the clinically established manual method. METHODS This prospective experimental study was conducted on a dataset comprising N=50 subjects undergoing cochlear implantation with a Nucleus® CI532 or CI632 Slim Modiolar electrode. Scalar localization, electrode-to-modiolar axis distances (EMD) and angular insertion depth (aDOI) were compared between the automated IGCIP tool and the manual method. Two raters made the manual measurements, and the interrater reliability (±1.96·SD) was determined as the reference for the method comparison. The method comparison was performed using a correlation analysis and a Bland-Altman analysis. RESULTS Concerning the scalar localization, all electrodes were localized both manually and automatically in the scala tympani. The interrater differences ranged between ±0.2 mm (EMD) and ±10° (aDOI). There was a bias between the automatic and manual method in measuring both localization parameters, which on the one hand was smaller than the interrater variations. On the other hand, this bias depended on the magnitude of the EMD respectively aDOI. A post-hoc analysis revealed that the deviations between the methods were likely due to a different selection of mid-modiolar axis. CONCLUSIONS The IGCIP is a promising tool for automated processing of CT and DVT scans and has useful functionality such as being able to segment the cochlear using post-operative scans. When measuring EMD, the IGCIP tool is superior to the manual method because the smallest possible distance to the axis is determined depending on the cochlear turn, whereas the manual method selects the helicotrema as the reference point rigidly. Functionality to deal with motion artifacts and measurements of aDOI according to the consensus approach are necessary, otherwise the IGCIP is not unrestrictedly ready for clinical use.
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Affiliation(s)
- Alexander Mewes
- Department of Otorhinolaryngology, Head and Neck Surgery, Universitätsklinikum Schleswig-Holstein (UKSH), Campus Kiel, Arnold-Heller-Straße 3, 24105, Kiel, Germany.
| | | | - Jan Dambon
- Department of Otorhinolaryngology, Head and Neck Surgery, Universitätsklinikum Schleswig-Holstein (UKSH), Campus Kiel, Arnold-Heller-Straße 3, 24105, Kiel, Germany
| | - Goetz Brademann
- Department of Otorhinolaryngology, Head and Neck Surgery, Universitätsklinikum Schleswig-Holstein (UKSH), Campus Kiel, Arnold-Heller-Straße 3, 24105, Kiel, Germany
| | - Matthias Hey
- Department of Otorhinolaryngology, Head and Neck Surgery, Universitätsklinikum Schleswig-Holstein (UKSH), Campus Kiel, Arnold-Heller-Straße 3, 24105, Kiel, Germany
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23
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Fujiwara RJ, Ishiyama G, Lopez IA, Ishiyama A. Morphometric Analysis and Linear Measurements of the Scala Tympani and Implications in Cochlear Implant Electrodes. Otol Neurotol 2023; 44:e343-e349. [PMID: 36893208 PMCID: PMC10175138 DOI: 10.1097/mao.0000000000003848] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/10/2023]
Abstract
HYPOTHESIS The objective of this study was to perform detailed height and cross-sectional area measurements of the scala tympani in histologic sections of nondiseased human temporal bones and correlate them with cochlear implant electrode dimensions. BACKGROUND Previous investigations in scala tympani dimensions have used microcomputed tomography or casting modalities, which cannot be correlated directly with microanatomy visible on histologic specimens. METHODS Three-dimensional reconstructions of 10 archival human temporal bone specimens with no history of middle or inner ear disease were generated using hematoxylin and eosin histopathologic slides. At 90-degree intervals, the heights of the scala tympani at lateral wall, midscala, and perimodiolar locations were measured, along with cross-sectional area. RESULTS The vertical height of the scala tympani at its lateral wall significantly decreased from 1.28 to 0.88 mm from 0 to 180 degrees, and the perimodiolar height decreased from 1.20 to 0.85 mm. The cross-sectional area decreased from 2.29 (standard deviation, 0.60) mm 2 to 1.38 (standard deviation, 0.13) mm 2 from 0 to 180 degrees ( p = 0.001). After 360 degrees, the scala tympani shape transitioned from an ovoid to triangular shape, corresponding with a significantly decreased lateral height relative to perimodiolar height. Wide variability was observed among the cochlear implant electrode sizes relative to scala tympani measurements. CONCLUSION The present study is the first to conduct detailed measurements of heights and cross-sectional area of the scala tympani and the first to statistically characterize the change in its shape after the basal turn. These measurements have important implications in understanding locations of intracochlear trauma during insertion and electrode design.
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Affiliation(s)
- Rance J.T. Fujiwara
- David Geffen School of Medicine at UCLA, Department of Head and Neck Surgery, Los Angeles 90095
| | - Gail Ishiyama
- David Geffen School of Medicine at UCLA, Department of Neurology, Los Angeles 90095
| | - Ivan A. Lopez
- David Geffen School of Medicine at UCLA, Department of Head and Neck Surgery, Los Angeles 90095
| | - Akira Ishiyama
- David Geffen School of Medicine at UCLA, Department of Head and Neck Surgery, Los Angeles 90095
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Paouris D, Kunzo S, Goljerová I. Validation of Automatic Cochlear Measurements Using OTOPLAN ® Software. J Pers Med 2023; 13:jpm13050805. [PMID: 37240975 DOI: 10.3390/jpm13050805] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 05/02/2023] [Accepted: 05/05/2023] [Indexed: 05/28/2023] Open
Abstract
INTRODUCTION Electrode length selection based on case-related cochlear parameters is becoming a standard pre-operative step for cochlear implantation. The manual measurement of the parameters is often time-consuming and may lead to inconsistencies. Our work aimed to evaluate a novel, automatic measurement method. MATERIALS AND METHODS A retrospective evaluation of pre-operative HRCT images of 109 ears (56 patients) was conducted, using a development version of the OTOPLAN® software. Inter-rater (intraclass) reliability and execution time were assessed for manual (surgeons R1 and R2) vs. automatic (AUTO) results. The analysis included A-Value (Diameter), B-Value (Width), H-Value (Height), and CDLOC-length (Cochlear Duct Length at Organ of Corti/Basilar membrane). RESULTS The measurement time was reduced from approximately 7 min ± 2 (min) (manual) to 1 min (AUTO). Cochlear parameters in mm (mean ± SD) for R1, R2 and AUTO, respectively, were A-value: 9.00 ± 0.40, 8.98 ± 0.40 and 9.16 ± 0.36; B-value: 6.81 ± 0.34, 6.71 ± 0.35 and 6.70 ± 0.40; H-value: 3.98 ± 0.25, 3.85 ± 0.25 and 3.76 ± 0.22; and the mean CDLoc-length: 35.64 ± 1.70, 35.20 ± 1.71 and 35.47 ± 1.87. AUTO CDLOC measurements were not significantly different compared to R1 and R2 (H0: Rx CDLOC = AUTO CDLOC: p = 0.831, p = 0.242, respectively), and the calculated intraclass correlation coefficient (ICC) for CDLOC was 0.9 (95% CI: 0.85, 0.932) for R1 vs. AUTO; 0.90 (95% CI: 0.85, 0.932) for R2 vs. AUTO; and 0.893 (95% CI: 0.809, 0.935) for R1 vs. R2. CONCLUSIONS We observed excellent inter-rater reliability, a high agreement of outcomes, and reduced execution time using the AUTO method.
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Affiliation(s)
- Dimitrios Paouris
- Clinic of Pediatric Otorhinolaryngology of the Medical Faculty, National Institute of Children's Diseases, Comenius University, 83340 Bratislava, Slovakia
| | - Samuel Kunzo
- Clinic of Pediatric Otorhinolaryngology of the Medical Faculty, National Institute of Children's Diseases, Comenius University, 83340 Bratislava, Slovakia
| | - Irina Goljerová
- Clinic of Pediatric Otorhinolaryngology of the Medical Faculty, National Institute of Children's Diseases, Comenius University, 83340 Bratislava, Slovakia
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25
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Müller-Graff FT, Voelker J, Kurz A, Hagen R, Neun T, Rak K. Accuracy of radiological prediction of electrode position with otological planning software and implications of high-resolution imaging. Cochlear Implants Int 2023; 24:144-154. [PMID: 36617441 DOI: 10.1080/14670100.2022.2159128] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
OBJECTIVES In cochlear implantation, preoperative prediction of electrode position has recently gained increasing attention. Currently, planning is usually done by multislice CT (MSCT). However, flat-panel volume CT (fpVCT) and its secondary reconstructions (fpVCTSECO) allow for more precise visualization of the cochlea. Combined with a newly developed otological planning software, the position of every single contact can be effectively predicted. In this study it was investigated how accurately radiological prediction forecasts the postoperative electrode localization and whether higher image resolution is advantageous. METHODS Utilizing otological planning software (OTOPLAN®) and different clinical imaging modalities (MSCT, fpVCT and fpVCTSECO) the electrode localization [angular insertion depth (AID)] and respective contact frequencies were predicted preoperatively and examined postoperatively. Furthermore, inter-electrode-distance (IED) and inter-electrode-frequency difference (IEFD) were evaluated postoperatively. RESULTS Measurements revealed a preoperative overestimation of AID. Corresponding frequencies were also miscalculated. Determination of IED and IEFD revealed discrepancies at the transition from the basal to the middle turn and round window to the basal turn. All predictions and discrepancies were lowest when using fpVCTSECO. CONCLUSION The postoperative electrode position can be predicted quite accurately using otological planning software. However, because of several potential misjudgments, high-resolution imaging, such as offered by fpVCTSECO, should be used pre- and postoperatively.
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Affiliation(s)
- Franz-Tassilo Müller-Graff
- Department of Oto-Rhino-Laryngology, Plastic, Aesthetic and Reconstructive Head and Neck Surgery and the Comprehensive Hearing Center, University of Wuerzburg, Wuerzburg, Germany
| | - Johannes Voelker
- Department of Oto-Rhino-Laryngology, Plastic, Aesthetic and Reconstructive Head and Neck Surgery and the Comprehensive Hearing Center, University of Wuerzburg, Wuerzburg, Germany
| | - Anja Kurz
- Department of Oto-Rhino-Laryngology, Plastic, Aesthetic and Reconstructive Head and Neck Surgery and the Comprehensive Hearing Center, University of Wuerzburg, Wuerzburg, Germany
| | - Rudolf Hagen
- Department of Oto-Rhino-Laryngology, Plastic, Aesthetic and Reconstructive Head and Neck Surgery and the Comprehensive Hearing Center, University of Wuerzburg, Wuerzburg, Germany
| | - Tilmann Neun
- Institute for Diagnostic and Interventional Neuroradiology, University of Wuerzburg, Wuerzburg, Germany
| | - Kristen Rak
- Department of Oto-Rhino-Laryngology, Plastic, Aesthetic and Reconstructive Head and Neck Surgery and the Comprehensive Hearing Center, University of Wuerzburg, Wuerzburg, Germany
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Hiremath SB, Biswas A, Mndebele G, Schramm D, Ertl-Wagner BB, Blaser SI, Chakraborty S. Cochlear Implantation: Systematic Approach to Preoperative Radiologic Evaluation. Radiographics 2023; 43:e220102. [PMID: 36893052 DOI: 10.1148/rg.220102] [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: 03/10/2023]
Abstract
Sensorineural hearing loss results from abnormalities that affect the hair cells of the membranous labyrinth, inner ear malformations, and conditions affecting the auditory pathway from the cochlear nerve to the processing centers of the brain. Cochlear implantation is increasingly being performed for hearing rehabilitation owing to expanding indications and a growing number of children and adults with sensorineural hearing loss. An adequate understanding of the temporal bone anatomy and diseases that affect the inner ear is paramount for alerting the operating surgeon about variants and imaging findings that can influence the surgical technique, affect the choice of cochlear implant and electrode type, and help avoid inadvertent complications. In this article, imaging protocols for sensorineural hearing loss and the normal inner ear anatomy are reviewed, with a brief description of cochlear implant devices and surgical techniques. In addition, congenital inner ear malformations and acquired causes of sensorineural hearing loss are discussed, with a focus on imaging findings that may affect surgical planning and outcomes. The anatomic factors and variations that are associated with surgical challenges and may predispose patients to periprocedural complications also are highlighted. © RSNA, 2023 Quiz questions for this article are available through the Online Learning Center. Online supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article.
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Affiliation(s)
- Shivaprakash B Hiremath
- From the Department of Radiology, Division of Neuroradiology (S.B.H., S.C.), and Department of Otolaryngology-Head and Neck Surgery (D.S.), University of Ottawa, The Ottawa Hospital, 1053 Carling Ave, Ottawa, ON, Canada K1Y 4E9; Division of Neuroradiology, Great Ormond Street Hospital for Children, London, England (A.B.); Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto, ON, Canada (G.M., B.B.E.W., S.I.B.); and Department of Medical Imaging, University of Toronto, Toronto, ON, Canada (S.B.H., G.M., B.B.E.W., S.I.B.)
| | - Asthik Biswas
- From the Department of Radiology, Division of Neuroradiology (S.B.H., S.C.), and Department of Otolaryngology-Head and Neck Surgery (D.S.), University of Ottawa, The Ottawa Hospital, 1053 Carling Ave, Ottawa, ON, Canada K1Y 4E9; Division of Neuroradiology, Great Ormond Street Hospital for Children, London, England (A.B.); Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto, ON, Canada (G.M., B.B.E.W., S.I.B.); and Department of Medical Imaging, University of Toronto, Toronto, ON, Canada (S.B.H., G.M., B.B.E.W., S.I.B.)
| | - Gopolang Mndebele
- From the Department of Radiology, Division of Neuroradiology (S.B.H., S.C.), and Department of Otolaryngology-Head and Neck Surgery (D.S.), University of Ottawa, The Ottawa Hospital, 1053 Carling Ave, Ottawa, ON, Canada K1Y 4E9; Division of Neuroradiology, Great Ormond Street Hospital for Children, London, England (A.B.); Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto, ON, Canada (G.M., B.B.E.W., S.I.B.); and Department of Medical Imaging, University of Toronto, Toronto, ON, Canada (S.B.H., G.M., B.B.E.W., S.I.B.)
| | - David Schramm
- From the Department of Radiology, Division of Neuroradiology (S.B.H., S.C.), and Department of Otolaryngology-Head and Neck Surgery (D.S.), University of Ottawa, The Ottawa Hospital, 1053 Carling Ave, Ottawa, ON, Canada K1Y 4E9; Division of Neuroradiology, Great Ormond Street Hospital for Children, London, England (A.B.); Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto, ON, Canada (G.M., B.B.E.W., S.I.B.); and Department of Medical Imaging, University of Toronto, Toronto, ON, Canada (S.B.H., G.M., B.B.E.W., S.I.B.)
| | - Birgit B Ertl-Wagner
- From the Department of Radiology, Division of Neuroradiology (S.B.H., S.C.), and Department of Otolaryngology-Head and Neck Surgery (D.S.), University of Ottawa, The Ottawa Hospital, 1053 Carling Ave, Ottawa, ON, Canada K1Y 4E9; Division of Neuroradiology, Great Ormond Street Hospital for Children, London, England (A.B.); Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto, ON, Canada (G.M., B.B.E.W., S.I.B.); and Department of Medical Imaging, University of Toronto, Toronto, ON, Canada (S.B.H., G.M., B.B.E.W., S.I.B.)
| | - Susan I Blaser
- From the Department of Radiology, Division of Neuroradiology (S.B.H., S.C.), and Department of Otolaryngology-Head and Neck Surgery (D.S.), University of Ottawa, The Ottawa Hospital, 1053 Carling Ave, Ottawa, ON, Canada K1Y 4E9; Division of Neuroradiology, Great Ormond Street Hospital for Children, London, England (A.B.); Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto, ON, Canada (G.M., B.B.E.W., S.I.B.); and Department of Medical Imaging, University of Toronto, Toronto, ON, Canada (S.B.H., G.M., B.B.E.W., S.I.B.)
| | - Santanu Chakraborty
- From the Department of Radiology, Division of Neuroradiology (S.B.H., S.C.), and Department of Otolaryngology-Head and Neck Surgery (D.S.), University of Ottawa, The Ottawa Hospital, 1053 Carling Ave, Ottawa, ON, Canada K1Y 4E9; Division of Neuroradiology, Great Ormond Street Hospital for Children, London, England (A.B.); Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto, ON, Canada (G.M., B.B.E.W., S.I.B.); and Department of Medical Imaging, University of Toronto, Toronto, ON, Canada (S.B.H., G.M., B.B.E.W., S.I.B.)
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Starovoyt A, Shaheen E, Putzeys T, Kerckhofs G, Politis C, Wouters J, Verhaert N. Anatomically and mechanically accurate scala tympani model for electrode insertion studies. Hear Res 2023; 430:108707. [PMID: 36773540 DOI: 10.1016/j.heares.2023.108707] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 11/25/2022] [Accepted: 01/24/2023] [Indexed: 01/26/2023]
Abstract
The risk of insertion trauma in cochlear implantation is determined by the interplay between individual cochlear anatomy and electrode insertion mechanics. Whereas patient anatomy cannot be changed, new surgical techniques, devices for cochlear monitoring, drugs, and electrode array designs are continuously being developed and tested, to optimize the insertion mechanics and prevent trauma. Preclinical testing of these developments is a crucial step in feasibility testing and optimization for clinical application. Human cadaveric specimens allow for the best simulation of an intraoperative setting. However, their availability is limited and it is not possible to conduct repeated, controlled experiments on the same sample. A variety of artificial cochlear models have been developed for electrode insertion studies, but none of them were both anatomically and mechanically representative for surgical insertion into an individual cochlea. In this study, we developed anatomically representative models of the scala tympani for surgical insertion through the round window, based on microCT images of individual human cochleae. The models were produced in transparent material using commonly-available 3D printing technology at a desired scale. The anatomical and mechanical accuracy of the produced models was validated by comparison with human cadaveric cochleae. Mechanical evaluation was performed by recording insertion forces, counting the number of inserted electrodes and grading tactile feedback during manual insertion of a straight electrode by experienced cochlear implant surgeons. Our results demonstrated that the developed models were highly representative for the anatomy of the original cochleae and for the insertion mechanics in human cadaveric cochleae. The individual anatomy of the produced models had a significant impact on the insertion mechanics. The described models have a promising potential to accelerate preclinical development and testing of atraumatic insertion techniques, reducing the need for human cadaveric material. In addition, realistic models of the cochlea can be used for surgical training and preoperative planning of patient-tailored cochlear implantation surgery.
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Affiliation(s)
- Anastasiya Starovoyt
- Research Group Experimental Oto-Rhino-Laryngology, Department of Neurosciences, KU Leuven, University of Leuven, Leuven, Belgium; Leuven Brain Institute, Department of Neurosciences, KU Leuven, 3000 Leuven, Belgium
| | - Eman Shaheen
- OMFS IMPATH Research Group, Department of Imaging and Pathology, KU Leuven, University of Leuven, Leuven, Belgium; Department of Oral and Maxillofacial Surgery, UZ Leuven, University Hospitals Leuven, Leuven, Belgium
| | - Tristan Putzeys
- Research Group Experimental Oto-Rhino-Laryngology, Department of Neurosciences, KU Leuven, University of Leuven, Leuven, Belgium; Leuven Brain Institute, Department of Neurosciences, KU Leuven, 3000 Leuven, Belgium; Laboratory for Soft Matter and Biophysics, Department of Physics and Astronomy, KU Leuven, University of Leuven, Leuven, Belgium
| | - Greet Kerckhofs
- Biomechanics lab, Institute of Mechanics, Materials, and Civil Engineering, UCLouvain, Louvain-la-Neuve, Belgium; Department of Materials Engineering, KU Leuven, University of Leuven, Leuven, Belgium; IREC, Institute of Experimental and Clinical Research, UCLouvain, Woluwé-Saint-Lambert, Belgium; Prometheus, Division of Skeletal Tissue Engineering, KU Leuven, University of Leuven, Leuven, Belgium
| | - Constantinus Politis
- OMFS IMPATH Research Group, Department of Imaging and Pathology, KU Leuven, University of Leuven, Leuven, Belgium; Department of Oral and Maxillofacial Surgery, UZ Leuven, University Hospitals Leuven, Leuven, Belgium
| | - Jan Wouters
- Research Group Experimental Oto-Rhino-Laryngology, Department of Neurosciences, KU Leuven, University of Leuven, Leuven, Belgium; Leuven Brain Institute, Department of Neurosciences, KU Leuven, 3000 Leuven, Belgium
| | - Nicolas Verhaert
- Research Group Experimental Oto-Rhino-Laryngology, Department of Neurosciences, KU Leuven, University of Leuven, Leuven, Belgium; Leuven Brain Institute, Department of Neurosciences, KU Leuven, 3000 Leuven, Belgium; Department of Otorhinolaryngology, Head and Neck Surgery, UZ Leuven, University Hospitals of Leuven, Leuven, Belgium.
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28
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Schurzig D, Repp F, Timm ME, Batsoulis C, Lenarz T, Kral A. Virtual cochlear implantation for personalized rehabilitation of profound hearing loss. Hear Res 2023; 429:108687. [PMID: 36638762 DOI: 10.1016/j.heares.2022.108687] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 12/09/2022] [Accepted: 12/26/2022] [Indexed: 12/28/2022]
Abstract
In cochlear implantation, current preoperative planning procedures allow for estimating how far a specific implant will reach into the inner ear of the patient, which is important to optimize hearing preservation and speech perception outcomes. Here we report on the development of a methodology that goes beyond current planning approaches: the proposed model does not only estimate specific outcome parameters but allows for entire, three-dimensional virtual implantations of patient-specific cochlear anatomies with different types of electrode arrays. The model was trained based on imaging datasets of 186 human cochleae, which contained 171 clinical computer tomographies (CTs) of actual cochlear implant patients as well as 15 high-resolution micro-CTs of cadaver cochleae to also reconstruct the refined intracochlear structures not visible in clinical imaging. The model was validated on an independent dataset of 141 preoperative and postoperative clinical CTs of cochlear implant recipients and outperformed all currently available planning approaches, not only in terms of accuracy but also regarding the amount of information that is available prior to the actual implantation.
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Affiliation(s)
- Daniel Schurzig
- Institute of AudioNeuroTechnology & Department of Experimental Otology, ENT Department, Hannover Medical School, Hannover, Germany; MED-EL Research Center, Hannover, Germany.
| | | | - Max E Timm
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany
| | | | - Thomas Lenarz
- Institute of AudioNeuroTechnology & Department of Experimental Otology, ENT Department, Hannover Medical School, Hannover, Germany; Department of Otolaryngology, Hannover Medical School, Hannover, Germany
| | - Andrej Kral
- Institute of AudioNeuroTechnology & Department of Experimental Otology, ENT Department, Hannover Medical School, Hannover, Germany; Department of Otolaryngology, Hannover Medical School, Hannover, Germany; Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
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Development and In-Silico and Ex-Vivo Validation of a Software for a Semi-Automated Segmentation of the Round Window Niche to Design a Patient Specific Implant to Treat Inner Ear Disorders. J Imaging 2023; 9:jimaging9020051. [PMID: 36826970 PMCID: PMC9965310 DOI: 10.3390/jimaging9020051] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 02/02/2023] [Accepted: 02/16/2023] [Indexed: 02/22/2023] Open
Abstract
The aim of this study was to develop and validate a semi-automated segmentation approach that identifies the round window niche (RWN) and round window membrane (RWM) for use in the development of patient individualized round window niche implants (RNI) to treat inner ear disorders. Twenty cone beam computed tomography (CBCT) datasets of unilateral temporal bones of patients were included in the study. Defined anatomical landmarks such as the RWM were used to develop a customized 3D Slicer™ plugin for semi-automated segmentation of the RWN. Two otolaryngologists (User 1 and User 2) segmented the datasets manually and semi-automatically using the developed software. Both methods were compared in-silico regarding the resulting RWM area and RWN volume. Finally, the developed software was validated ex-vivo in N = 3 body donor implantation tests with additively manufactured RNI. The independently segmented temporal bones of the different Users showed a strong consistency in the volume of the RWN and the area of the RWM. The volume of the semi-automated RWN segmentations were 48 ± 11% smaller on average than the manual segmentations and the area of the RWM of the semi-automated segmentations was 21 ± 17% smaller on average than the manual segmentation. All additively manufactured implants, based on the semi-automated segmentation method could be implanted successfully in a pressure-tight fit into the RWN. The implants based on the manual segmentations failed to fit into the RWN and this suggests that the larger manual segmentations were over-segmentations. This study presents a semi-automated approach for segmenting the RWN and RWM in temporal bone CBCT scans that is efficient, fast, accurate, and not dependent on trained users. In addition, the manual segmentation, often positioned as the gold-standard, actually failed to pass the implantation validation.
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Ishiyama P, Ishiyama G, Lopez IA, Ishiyama A. Archival Human Temporal Bone: Anatomical and Histopathological Studies of Cochlear Implantation. J Pers Med 2023; 13:352. [PMID: 36836587 PMCID: PMC9959196 DOI: 10.3390/jpm13020352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/12/2023] [Accepted: 02/14/2023] [Indexed: 02/22/2023] Open
Abstract
Since being FDA approved in 1984, cochlear implantation has been used successfully to restore hearing in those with severe to profound hearing loss with broader applications including single-sided deafness, the use of hybrid electroacoustic stimulation, and implantation at all extremes of age. Cochlear implants have undergone multiple changes in the design aimed at improving the processing technology, while simultaneously minimizing the surgical trauma and foreign body reaction. The following review examines the human temporal bone studies regarding the anatomy of the human cochlea and how the anatomy relates to cochlear implant design, the factors related to complications after implantation, and the predictors of new tissue formation and osteoneogenesis. Histopathological studies are reviewed which aim to understand the potential implications of the effects of new tissue formation and inflammation following implantation.
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Affiliation(s)
- Paul Ishiyama
- Department of Head and Neck Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Gail Ishiyama
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Ivan A. Lopez
- Department of Head and Neck Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Akira Ishiyama
- Department of Head and Neck Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, 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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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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Claussen AD, Shibata SB, Kaufmann CR, Henslee A, Hansen MR. Comparative Analysis of Robotics-Assisted and Manual Insertions of Cochlear Implant Electrode Arrays. Otol Neurotol 2022; 43:1155-1161. [PMID: 36201552 PMCID: PMC10962863 DOI: 10.1097/mao.0000000000003707] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
HYPOTHESIS Robotics-assisted cochlear implant (CI) insertions will result in reduced intracochlear trauma when compared with manual, across multiple users. BACKGROUND Whether intracochlear trauma and translocations are two factors that may contribute to significant variability in CI outcomes remains to be seen. To address this issue, we have developed a robotics-assisted insertion system designed to aid the surgeon in inserting electrode arrays with consistent speeds and reduced variability. This study evaluated the effect of robotics-assisted insertions on the intracochlear trauma as compared with manual insertions in cadaveric cochleae in a simulated operative environment. METHODS Twelve neurotologists performed bilateral electrode insertions into cochleae of full cadaveric heads using both the robotics-assisted system and manual hand insertion. Lateral wall electrodes from three different manufacturers (n = 24) were used and randomized between surgeons. Insertion angle of the electrode and trauma scoring were evaluated using high-resolution three-dimensional x-ray microscopy and compared between robotics-assisted and manual insertions. RESULTS Three-dimensional x-ray microscopy provided excellent resolution to characterize the in situ trauma and insertion angle. Robotics-assisted insertions significantly decreased insertional intracochlear trauma as measured by reduced trauma scores compared with manual insertions (average: 1.3 versus 2.2, device versus manual, respectively; p < 0.05). There was no significant difference between insertion angles observed for manual and robotics-assisted techniques (311 ± 131° versus 307 ± 96°, device versus manual, respectively). CONCLUSIONS Robotics-assisted insertion systems enable standardized electrode insertions across individual surgeons and experience levels. Clinical trials are necessary to investigate whether insertion techniques that reduce insertional variability and the likelihood of intracochlear trauma also improve CI auditory outcomes.
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Affiliation(s)
| | - Seiji B Shibata
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa
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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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The effect of the surgical approach and cochlear implant electrode on the structural integrity of the cochlea in human temporal bones. Sci Rep 2022; 12:17068. [PMID: 36224234 PMCID: PMC9556579 DOI: 10.1038/s41598-022-21399-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 09/27/2022] [Indexed: 12/30/2022] Open
Abstract
Cochlear implants (CI) restore hearing of severely hearing-impaired patients. Although this auditory prosthesis is widely considered to be very successful, structural cochlear trauma during cochlear implantation is an important problem, reductions of which could help to improve hearing outcomes and to broaden selection criteria. The surgical approach in cochlear implantation, i.e. round window (RW) or cochleostomy (CO), and type of electrode-array, perimodiolar (PM) or lateral wall (LW), are variables that might influence the probability of severe trauma. We investigated the effect of these two variables on scalar translocation (STL), a specific type of severe trauma. Thirty-two fresh frozen human cadaveric ears were evenly distributed over four groups receiving either RW or CO approach, and either LW or PM array. Conventional radiological multiplanar reconstruction (MPR) was compared with a reconstruction method that uncoils the spiral shape of the cochlea (UCR). Histological analysis showed that RW with PM array had STL rate of 87% (7/8), CO approach with LW array 75% (6/8), RW approach with LW array 50% (4/8) and CO approach with PM array 29% (2/7). STL assessment using UCR showed a higher inter-observer and histological agreement (91 and 94% respectively), than that using MPR (69 and 74% respectively). In particular, LW array positions were difficult to assess with MPR. In conclusion, the interaction between surgical approach and type of array should be preoperatively considered in cochlear implant surgery. UCR technique is advised for radiological assessment of CI positions, and in general it might be useful for pathologies involving the inner ear or other complex shaped bony tubular structures.
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Mntungwa N, Human-Baron R, Hanekom T. Morphology of the internal auditory canal: Deriving parameters from computer tomography scans. An observational STROBE-MR study. EAR, NOSE & THROAT JOURNAL 2022:1455613221116196. [PMID: 35968806 DOI: 10.1177/01455613221116196] [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: 12/22/2023] Open
Abstract
OBJECTIVES The objective of this study is to identify and define landmarks to adequately describe the internal auditory canal for inclusion in three-dimensional computational models of the cochlea and its surrounding structures. PARTICIPANTS Computer tomography scans of live human cochleae were collected in the retrospective period. Descriptive and comparative statistics were used to describe the data obtained from the scans. RESULTS The mean anterior-posterior (AP) diameter at the base of the basal turn, the diameter of the AP at the midpoint of the IAC, and the anterior and posterior length of the internal acoustic canal were measured. 57.14% of the internal acoustic canals observed presented with a cylindrical, 40.48% was funnel-shaped and 2.38 % were bud-shaped. A statistically significant differences were found between the diameters of male and female internal acoustic meatus. CONCLUSIONS This paper serves as a reference that provides a set of references for the description of the internal acoustic canal for inclusion in three-dimensional computational reconstruction of the cochlea and surrounding structures.
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Affiliation(s)
- Nandipha Mntungwa
- Department of Anatomy, Faculty of Health Sciences, School of Medicine, University of Pretoria, Pretoria, South Africa
| | - Rene Human-Baron
- Department of Anatomy, Faculty of Health Sciences, School of Medicine, University of Pretoria, Pretoria, South Africa
| | - Tania Hanekom
- Department of Electric, Electronic and Computer Engineering, Faculty of Engineering, Built Environment and Information Technology, University of Pretoria, Pretoria, South Africa
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Wimmer W, Soldati FO, Weder S, Vischer M, Mantokoudis G, Caversaccio M, Anschuetz L. Cochlear base length as predictor for angular insertion depth in incomplete partition type 2 malformations. Int J Pediatr Otorhinolaryngol 2022; 159:111204. [PMID: 35696773 DOI: 10.1016/j.ijporl.2022.111204] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 05/26/2022] [Accepted: 06/05/2022] [Indexed: 11/17/2022]
Abstract
INTRODUCTION The preoperative determination of suitable electrode array lengths for cochlear implantation in inner ear malformations is a matter of debate. The choice is usually based on individual experience and the use of intraoperative probe electrodes. The purpose of this case series was to evaluate the applicability and precision of an angular insertion depth (AID) prediction method, based on a single measurement of the cochlear base length (CBL). METHODS We retrospectively measured the CBL in preoperative computed tomography (CT) images in 10 ears (8 patients) with incomplete partition type 2 malformation. With the known electrode length (linear insertion depth, LID) the AID at full insertion was retrospectively predicted for each ear with a heuristic equation derived from non-malformed cochleae. Using the intra- or post-implantation cone beam CT images, the actual AID was assessed and compared. The deviations of the predicted from the actual insertion angles were quantified (clinical prediction error) to assess the precision of this single-measure estimation. RESULTS Electrode arrays with 15 mm (n = 3), 19 mm (n = 2), 24 mm (n = 3), and 26 mm (n = 2) length were implanted. Postoperative AIDs ranged from 211° to 625°. Clinical AID prediction errors from -64° to 62° were observed with a mean of 0° (SD of 44°). In two ears with partial insertion of the electrode, the predicted AID was overestimated. The probe electrode was intraoperatively used in 9/10 cases. CONCLUSION The analyzed method provides good predictions of the AID based on LID and CBL. It does not account for incomplete insertions, which lead to an overestimation of the AID. The probe electrode is useful and well established in clinical practice. The investigated method could be used for patient-specific electrode length selection in future patients.
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Affiliation(s)
- Wilhelm Wimmer
- Hearing Research Laboratory, ARTORG Center for Biomedical Engineering Research, University of Bern, Switzerland; Department of Otorhinolaryngology, Head & Neck Surgery, Inselspital, Bern University Hospital, University of Bern, 3008, Bern, Switzerland.
| | - Fabio O Soldati
- Department of Otorhinolaryngology, Head & Neck Surgery, Inselspital, Bern University Hospital, University of Bern, 3008, Bern, Switzerland
| | - Stefan Weder
- Hearing Research Laboratory, ARTORG Center for Biomedical Engineering Research, University of Bern, Switzerland; Department of Otorhinolaryngology, Head & Neck Surgery, Inselspital, Bern University Hospital, University of Bern, 3008, Bern, Switzerland
| | - Mattheus Vischer
- Department of Otorhinolaryngology, Head & Neck Surgery, Inselspital, Bern University Hospital, University of Bern, 3008, Bern, Switzerland
| | - Georgios Mantokoudis
- Hearing Research Laboratory, ARTORG Center for Biomedical Engineering Research, University of Bern, Switzerland; Department of Otorhinolaryngology, Head & Neck Surgery, Inselspital, Bern University Hospital, University of Bern, 3008, Bern, Switzerland
| | - Marco Caversaccio
- Hearing Research Laboratory, ARTORG Center for Biomedical Engineering Research, University of Bern, Switzerland; Department of Otorhinolaryngology, Head & Neck Surgery, Inselspital, Bern University Hospital, University of Bern, 3008, Bern, Switzerland
| | - Lukas Anschuetz
- Hearing Research Laboratory, ARTORG Center for Biomedical Engineering Research, University of Bern, Switzerland; Department of Otorhinolaryngology, Head & Neck Surgery, Inselspital, Bern University Hospital, University of Bern, 3008, Bern, Switzerland
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Computed-Tomography Estimates of Interaural Mismatch in Insertion Depth and Scalar Location in Bilateral Cochlear-Implant Users. Otol Neurotol 2022; 43:666-675. [PMID: 35761459 DOI: 10.1097/mao.0000000000003538] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
HYPOTHESIS Bilateral cochlear-implant (BI-CI) users will have a range of interaural insertion-depth mismatch because of different array placement or characteristics. Mismatch will be larger for electrodes located near the apex or outside scala tympani, or for arrays that are a mix of precurved and straight types. BACKGROUND Brainstem superior olivary-complex neurons are exquisitely sensitive to interaural-difference cues for sound localization. Because these neurons rely on interaurally place-of-stimulation-matched inputs, interaural insertion-depth or scalar-location differences for BI-CI users could cause interaural place-of-stimulation mismatch that impairs binaural abilities. METHODS Insertion depths and scalar locations were calculated from temporal-bone computed-tomography scans for 107 BI-CI users (27 Advanced Bionics, 62 Cochlear, 18 MED-EL). RESULTS Median interaural insertion-depth mismatch was 23.4 degrees or 1.3 mm. Mismatch in the estimated clinically relevant range expected to impair binaural processing (>75 degrees or 3 mm) occurred for 13 to 19% of electrode pairs overall, and for at least three electrode pairs for 23 to 37% of subjects. There was a significant three-way interaction between insertion depth, scalar location, and array type. Interaural insertion-depth mismatch was largest for apical electrodes, for electrode pairs in two different scala, and for arrays that were both-precurved. CONCLUSION Average BI-CI interaural insertion-depth mismatch was small; however, large interaural insertion-depth mismatch-with the potential to degrade spatial hearing-occurred frequently enough to warrant attention. For new BICI users, improved surgical techniques to avoid interaural insertion-depth and scalar mismatch are recommended. For existing BI-CI users with interaural insertion-depth mismatch, interaural alignment of clinical frequency tables might reduce negative spatial-hearing consequences.
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Mewes A, Burg S, Brademann G, Dambon JA, Hey M. Quality-assured training in the evaluation of cochlear implant electrode position: a prospective experimental study. BMC MEDICAL EDUCATION 2022; 22:386. [PMID: 35596162 PMCID: PMC9121556 DOI: 10.1186/s12909-022-03464-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 05/13/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND The objective of this study was to demonstrate the utility of an approach in training predoctoral medical students, to enable them to measure electrode-to-modiolus distances (EMDs) and insertion-depth angles (aDOIs) in cochlear implant (CI) imaging at the performance level of a single senior rater. METHODS This prospective experimental study was conducted on a clinical training dataset comprising patients undergoing cochlear implantation with a Nucleus® CI532 Slim Modiolar electrode (N = 20) or a CI512 Contour Advance electrode (N = 10). To assess the learning curves of a single medical student in measuring EMD and aDOI, interrater differences (senior-student) were compared with the intrarater differences of a single senior rater (test-retest). The interrater and intrarater range were both calculated as the distance between the 0.1th and 99.9th percentiles. A "deliberate practice" training approach was used to teach knowledge and skills, while correctives were applied to minimize faulty data-gathering and data synthesis. RESULTS Intrarater differences of the senior rater ranged from - 0.5 to 0.5 mm for EMD and - 14° to 16° for aDOI (respective medians: 0 mm and 0°). Use of the training approach led to interrater differences that matched this after the 4th (EMD) and 3rd (aDOI) feedback/measurement series had been provided to the student. CONCLUSIONS The training approach enabled the student to evaluate the CI electrode position at the performance level of a senior rater. This finding may offer a basis for ongoing clinical quality assurance for the assessment of CI electrode position.
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Affiliation(s)
- Alexander Mewes
- Universitätsklinikum Schleswig-Holstein (UKSH), Campus Kiel, Department of Otorhinolaryngology, Head and Neck Surgery, Kiel, Germany.
| | - Sebastian Burg
- Christian-Albrechts-Universität (CAU) zu Kiel, Faculty of Medicine, Kiel, Germany
| | - Goetz Brademann
- Universitätsklinikum Schleswig-Holstein (UKSH), Campus Kiel, Department of Otorhinolaryngology, Head and Neck Surgery, Kiel, Germany
| | - Jan Andreas Dambon
- Universitätsklinikum Schleswig-Holstein (UKSH), Campus Kiel, Department of Otorhinolaryngology, Head and Neck Surgery, Kiel, Germany
| | - Matthias Hey
- Universitätsklinikum Schleswig-Holstein (UKSH), Campus Kiel, Department of Otorhinolaryngology, Head and Neck Surgery, Kiel, Germany
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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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Buechner A, Bardt M, Haumann S, Geissler G, Salcher R, Lenarz T. Clinical experiences with intraoperative electrocochleography in cochlear implant recipients and its potential to reduce insertion trauma and improve postoperative hearing preservation. PLoS One 2022; 17:e0266077. [PMID: 35452461 PMCID: PMC9032378 DOI: 10.1371/journal.pone.0266077] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 03/14/2022] [Indexed: 11/18/2022] Open
Abstract
Access to low-frequency acoustic information in cochlear implant patients leads to better speech understanding in noise. Electrocochleography (ECochG) can provide real-time feedback about the health of the cochlea during the insertion process with the potential to reduce insertion trauma. We describe our experiences of using this technique. Data from 47 adult subjects with measurable residual hearing and an Advanced Bionics (Valencia, CA) SlimJ (46) or MidScala (1) electrode array were analyzed. ECochGs were recorded intraoperatively via the implant. The surgeon adjusted the course of the electrode insertion based on drops in the ECochG. The final array position was assessed using postoperative imaging and pure tone thresholds were measured before and after surgery. Three different patterns of ECochG response amplitude were observed: Growth, Fluctuating and Total Loss. Subjects in the growth group showed the smallest postoperative hearing loss. However, the group with fluctuating amplitudes showed no meaningful correlation between the ECochG responses and the postoperative hearing loss, indicating that amplitude alone is insufficient for detecting damage. Considering the phase of the signal additionally to the amplitude and reclassifying the data by both the phase and amplitude of the response into three groups Type I–Type III produced statistically significant correlations between postoperative hearing loss and the grouping based on amplitude and phase respectively. We showed significantly better hearing preservation for Type I (no drop in amplitude) and Type II (drop with a concurrent phase shift), while Type III (drop without concurrent phase shift) had more surgery induced hearing loss. ECochG potentials measured through the implant could provide valuable feedback during the electrode insertion. Both the amplitude and phase of the ECochG response are important to consider. More data needs to be evaluated to better understand the impact of the different signal components to design an automated system to alert the surgeon ahead of damaging the cochlea.
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Affiliation(s)
- Andreas Buechner
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany
- * E-mail:
| | - Michael Bardt
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany
| | - Sabine Haumann
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany
| | - Gunnar Geissler
- European Research Center, Advanced Bionics GmbH, Hannover, Germany
| | - Rolf Salcher
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany
| | - Thomas Lenarz
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany
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van der Jagt AMA, Briaire JJ, Boehringer S, Verbist BM, Frijns JHM. Prolonged Insertion Time Reduces Translocation Rate of a Precurved Electrode Array in Cochlear Implantation. Otol Neurotol 2022; 43:e427-e434. [PMID: 35213473 DOI: 10.1097/mao.0000000000003499] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
HYPOTHESIS Insertion speed during cochlear implantation determines the risk of cochlear trauma. By slowing down insertion speed tactile feedback is improved. This is highly conducive to control the course of the electrode array along the cochlear contour and prevent translocation from the scala tympani to the scala vestibuli. BACKGROUND Limiting insertion trauma is a dedicated goal in cochlear implantation to maintain the most favorable situation for electrical stimulation of the remaining stimulable neural components of the cochlea. Surgical technique is one of the potential influencers on translocation behavior of the electrode array. METHODS The intrascalar position of 226 patients, all implanted with a precurved electrode array, aiming a mid-scalar position, was evaluated. One group (n = 113) represented implantation with an insertion time less than 25 seconds (fast insertion) and the other group (n = 113) was implanted in 25 or more seconds (slow insertion). A logistic regression analysis studied the effect of insertion speed on insertion trauma, controlled for surgical approach, cochlear size, and angular insertion depth. Furthermore, the effect of translocation on speech performance was evaluated using a linear mixed model. RESULTS The translocation rate within the fast and slow insertion groups were respectively 27 and 10%. A logistic regression analysis showed that the odds of dislocation increases by 2.527 times with a fast insertion, controlled for surgical approach, cochlear size, and angular insertion depth (95% CI = 1.135, 5.625). We failed to find a difference in speech recognition between patients with and without translocated electrode arrays. CONCLUSION Slowing down insertion speed till 25 seconds or longer reduces the incidence of translocation.
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Affiliation(s)
| | | | | | - Berit M Verbist
- Department of Radiology
- Department of Radiology, Radboud University Medical Center Nijmegen, Nijmegen
| | - Johan H M Frijns
- Department of Otorhinolaryngology
- Leiden Institute for Brain and Cognition, Leiden University Medical Center, Leiden, the Netherlands
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Zhang L, Chen B, Kong Y, Liau N, Wei X, Shi Y, Chen J, Yang M, Dhanasingh A, Li Y. Analysis of Long-Term Cochlear Implantation Outcomes and Correlation With Imaging Characteristics in Patients With Common Cavity Deformity. Front Neurosci 2022; 16:857855. [PMID: 35401101 PMCID: PMC8983960 DOI: 10.3389/fnins.2022.857855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 02/14/2022] [Indexed: 11/22/2022] Open
Abstract
Object To investigate the long-term development of auditory and speech in patients with common cavity deformity (CCD) after cochlear implantation (CI) and its relationship to imaging characteristics. Methods Twenty-three CCD patients and 59 age- and sex-matched CI children with normal inner ear structure were recruited. The auditory and speech development of these two groups were evaluated at 0, 1, 3, 6, 12, and 18 months after CI activation using four parent reports questionnaires [Categories of Auditory Performance (CAP), Speech Intelligibility Rating (SIR), Meaningful Auditory Integration Scale/Infant-Toddler Meaningful Auditory Integration Scale (MAIS/ITMAIS), and Meaningful Use of Speech Scale (MUSS)]. Computed tomography-based 3-dimensional reconstruction of the surgical side of 18 CCD children was performed, the volume and surface area were calculated. Correlation analysis was performed on the imaging performance and post-operative outcomes. Results The percentages of MAIS/IT-MAIS scores and CAP scores at different evaluation time points are significantly different (p < 0.05). When comparing SIR results across time points, significant growth was observed in most of the comparisons. In addition, significant differences (p < 0.05) are observed among the percentages of MUSS scores at different time points except the comparison between 0 and 1 month after CI activation. Patients in the CCD group had poorer auditory and speech performances at different stages after CI compared with those in the control group. According to the reconstruction of CCD patients, the volume ranged from 12.21 to 291.96 mm3; the surface area ranged from 27.81 to 284.7 mm2. When the lumen surface area was <190.45 mm2 or the volume was <157.91 mm3, the survival time for CCD children to achieve a CAP score of 4 after CI was significantly shorter. Conclusion Cochlear implantation are less effective in CCD patients than in patients with normal inner ear structures, but they can still achieve significant improvement post-operatively. The morphology and size of the inner ear vary in CCD patients, which reflects the degree of inner ear development influences the outcome after CI surgery.
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Affiliation(s)
- Lifang Zhang
- Department of Otolaryngology, Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Key Laboratory of Otolaryngology, Head and Neck Surgery, Ministry of Education, Capital Medical University, Beijing, China
| | - Biao Chen
- Department of Otolaryngology, Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Key Laboratory of Otolaryngology, Head and Neck Surgery, Ministry of Education, Capital Medical University, Beijing, China
| | - Ying Kong
- Key Laboratory of Otolaryngology, Head and Neck Surgery, Ministry of Education, Capital Medical University, Beijing, China
- Beijing Institute of Otolaryngology, Ministry of Education, Capital Medical University, Beijing, China
| | - Natalia Liau
- Department of Otolaryngology, Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Key Laboratory of Otolaryngology, Head and Neck Surgery, Ministry of Education, Capital Medical University, Beijing, China
| | - Xingmei Wei
- Department of Otolaryngology, Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Key Laboratory of Otolaryngology, Head and Neck Surgery, Ministry of Education, Capital Medical University, Beijing, China
| | - Ying Shi
- Department of Otolaryngology, Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Key Laboratory of Otolaryngology, Head and Neck Surgery, Ministry of Education, Capital Medical University, Beijing, China
| | - Jingyuan Chen
- Department of Otolaryngology, Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Key Laboratory of Otolaryngology, Head and Neck Surgery, Ministry of Education, Capital Medical University, Beijing, China
| | - Mengge Yang
- Department of Otolaryngology, Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Key Laboratory of Otolaryngology, Head and Neck Surgery, Ministry of Education, Capital Medical University, Beijing, China
| | | | - Yongxin Li
- Department of Otolaryngology, Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Key Laboratory of Otolaryngology, Head and Neck Surgery, Ministry of Education, Capital Medical University, Beijing, China
- *Correspondence: Yongxin Li,
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Variations in microanatomy of the human modiolus require individualized cochlear implantation. Sci Rep 2022; 12:5047. [PMID: 35322066 PMCID: PMC8943032 DOI: 10.1038/s41598-022-08731-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 03/10/2022] [Indexed: 11/09/2022] Open
Abstract
Cochlear variability is of key importance for the clinical use of cochlear implants, the most successful neuroprosthetic device that is surgically placed into the cochlear scala tympani. Despite extensive literature on human cochlear variability, few information is available on the variability of the modiolar wall. In the present study, we analyzed 108 corrosion casts, 95 clinical cone beam computer tomographies (CTs) and 15 µCTs of human cochleae and observed modiolar variability of similar and larger extent than the lateral wall variability. Lateral wall measures correlated with modiolar wall measures significantly. ~ 49% of the variability had a common cause. Based on these data we developed a model of the modiolar wall variations and related the model to the design of cochlear implants aimed for perimodiolar locations. The data demonstrate that both the insertion limits relevant for lateral wall damage (approximate range of 4–9 mm) as well as the dimensions required for optimal perimodiolar placement of the electrode (the point of release from the straightener; approximate range of 2–5mm) are highly interindividually variable. The data demonstrate that tip fold-overs of preformed implants likely result from the morphology of the modiolus (with radius changing from base to apex), and that optimal cochlear implantation of perimodiolar arrays cannot be guaranteed without an individualized surgical technique.
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Visualization of Different Types of Cochlear Implants in Postoperative Cone-Beam CT Imaging. Acad Radiol 2022; 29 Suppl 3:S88-S97. [PMID: 33840600 DOI: 10.1016/j.acra.2021.02.025] [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: 11/07/2020] [Revised: 02/11/2021] [Accepted: 02/23/2021] [Indexed: 11/20/2022]
Abstract
RATIONALE AND OBJECTIVES To evaluate cone-beam computed-tomography (CBCT) images of the temporal bone for radiological delineation, metal artifacts, and accuracy for localization of six different electrode arrays after cochlear device implantation. MATERIALS AND METHODS This retrospective study included 116 patients who underwent CBCT (120kV, 7.1mA) within 24 hours after cochlear device implantation. Exclusion criteria were anatomical abnormalities, and electrode misinsertion. Six different CI electrodes were implanted: Advanced Bionics HiFocus Mid-Scala, Cochlear Contour Advance, Cochlear Slim-Straight, Cochlear Slim-Modiolar, MED-EL Flex 24 and MED-EL Flex 28. Two radiologists rated independently presence of metal artifacts, overall image quality, as well as dedicated visualization of the osseous spiral lamina, inner and outer cochlear wall, single electrode contacts, and electrode position using 5-point-Likert scales. Inter-rater agreement was calculated by using Cohen's kappa and intraclass correlation. RESULTS Of 116 patients, 94 (81.0%; 56.1 ± 16.9 years; age range, 13-86 years; 49 [52.1%] females) were included in the study. Overall image quality was rated good for all electrode models without significant differences (p = 0.061). Depiction of electrode contacts was rated significantly better for Advanced Bionics HiFocus Mid-Scala, Cochlear Slim-Straight, and MED-EL Flex 24 and 28 compared to Cochlear Contour Advance and Slim-Modiolar (p < 0.001). Depiction of the osseous spiral lamina (p = 0.20), inner (p = 0.42) and outer cochlear wall (p = 0.35), metal artifacts (p = 0.18), and electrode position (p = 0.31) did not show significant differences between electrode models. Inter-rater agreement varied from substantial to almost perfect (0.70-0.93). CONCLUSION CBCT provides excellent visualization of all evaluated CI electrode types, in particular electrode arrays with greater spacing between contacts and contact size allow improved radiologic evaluation.
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Andersen SAW, Keith JP, Hittle B, Riggs WJ, Adunka O, Wiet GJ, Powell KA. Automated Calculation of Cochlear Implant Electrode Insertion Parameters in Clinical Cone-Beam CT. Otol Neurotol 2022; 43:199-205. [PMID: 34789695 DOI: 10.1097/mao.0000000000003432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
HYPOTHESIS Automated processing of postoperative clinical cone-beam CT (CBCT) of cochlear implant (CI) patients can be used to accurately determine electrode contacts and integrated with an atlas-based mapping of cochlear microstructures to calculate modiolar distance, angular insertion distance, and scalar location of electrode contacts. BACKGROUND Hearing outcomes after CI surgery are dependent on electrode placement. CBCT is increasingly used for in-office temporal bone imaging and might be routinely used for pre- and post-surgical evaluation. METHODS Thirty-six matched pairs of pre- and postimplant CBCT scans were obtained. These were registered with an atlas to model cochlear microstructures in each dataset. Electrode contact center points were automatically determined using thresholding and electrode insertion parameters were calculated. Automated localization and calculation were compared with manual segmentation of contact center points as well as manufacturer specifications. RESULTS Automated electrode contact detection aligned with manufacturer specifications of spacing and our algorithms worked for both distantly- and closely spaced arrays. The average difference between the manual and the automated selection was 0.15 mm, corresponding to a 1.875 voxel difference in each plane at the scan resolution. For each case, we determined modiolar distance, angular insertion depth, and scalar location. These calculations also resulted in similar insertion values using manual and automated contact points as well as aligning with electrode properties. CONCLUSION Automated processing of implanted high-resolution CBCT images can provide the clinician with key information on electrode placement. This is one step toward routine use of clinical CBCT after CI surgery to inform and guide postoperative treatment.
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Affiliation(s)
- Steven Arild Wuyts Andersen
- Department of Otolaryngology, Nationwide Children's Hospital, Columbus, Ohio
- Department of Otolaryngology-Head and Neck Surgery, The Ohio State University, Columbus, Ohio
- Department of Otorhinolaryngology-Head & Neck Surgery, Rigshospitalet, Copenhagen, Denmark
| | - Jason P Keith
- Department of Biomedical Informatics, The Ohio State University, Columbus, Ohio
| | - Brad Hittle
- Department of Biomedical Informatics, The Ohio State University, Columbus, Ohio
| | - William J Riggs
- Department of Otolaryngology-Head and Neck Surgery, The Ohio State University, Columbus, Ohio
| | - Oliver Adunka
- Department of Otolaryngology, Nationwide Children's Hospital, Columbus, Ohio
- Department of Otolaryngology-Head and Neck Surgery, The Ohio State University, Columbus, Ohio
| | - Gregory J Wiet
- Department of Otolaryngology, Nationwide Children's Hospital, Columbus, Ohio
- Department of Otolaryngology-Head and Neck Surgery, The Ohio State University, Columbus, Ohio
| | - Kimerly A Powell
- Department of Biomedical Informatics, The Ohio State University, Columbus, Ohio
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Canfarotta MW, Dillon MT, Brown KD, Pillsbury HC, Dedmon MM, O'Connell BP. Insertion Depth and Cochlear Implant Speech Recognition Outcomes: A Comparative Study of 28- and 31.5-mm Lateral Wall Arrays. Otol Neurotol 2022; 43:183-189. [PMID: 34772886 PMCID: PMC8752482 DOI: 10.1097/mao.0000000000003416] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVES 1) To compare speech recognition outcomes between cochlear implant (CI) recipients of 28- and 31.5-mm lateral wall electrode arrays, and 2) to characterize the relationship between angular insertion depth (AID) and speech recognition. STUDY DESIGN Retrospective review. SETTING Tertiary academic referral center. PATIENTS Seventy-five adult CI recipients of fully inserted 28-mm (n = 28) or 31.5-mm (n = 47) lateral wall arrays listening with a CI-alone device. INTERVENTIONS Cochlear implantation with postoperative computed tomography. MAIN OUTCOME MEASURES Consonant-nucleus-consonant (CNC) word recognition assessed with the CI-alone at 12 months postactivation. RESULTS The mean AID of the most apical electrode contact for the 31.5-mm array recipients was significantly deeper than the 28-mm array recipients (628° vs 571°, p < 0.001). Following 12 months of listening experience, mean CNC word scores were significantly better for recipients of 31.5-mm arrays compared with those implanted with 28-mm arrays (59.5% vs 48.3%, p = 0.004; Cohen's d = 0.70; 95% CI [0.22, 1.18]). There was a significant positive correlation between AID and CNC word scores (r = 0.372, p = 0.001), with a plateau in performance observed around 600°. CONCLUSIONS Cochlear implant recipients implanted with a 31.5-mm array experienced better speech recognition than those with a 28-mm array at 12 months postactivation. Deeper insertion of a lateral wall array appears to confer speech recognition benefit up to ∼600°, with a plateau in performance observed thereafter. These data provide preliminary evidence of the insertion depth necessary to optimize speech recognition outcomes for lateral wall electrode arrays among CI-alone users.
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Affiliation(s)
- Michael W Canfarotta
- Department of Otolaryngology/Head and Neck Surgery, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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Högerle C, Englhard A, Simon F, Grüninger I, Mlynski R, Hempel JM, Müller J. Cochlear Implant Electrode Tip Fold-Over: Our Experience With Long and Flexible Electrode. Otol Neurotol 2022; 43:64-71. [PMID: 34619728 DOI: 10.1097/mao.0000000000003362] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE The aim of this study was to retrospectively investigate if there is any incidence of electrode tip fold-over with 31.5 mm long and flexible lateral wall electrodes implanted in two high-volume Cochlear Implant (CI) centers in Germany. In addition, a detailed literature review was performed to capture all the peer-reviewed publications reporting on tip fold-over with CI electrodes from different CI brands for comparison. METHODS Post-operative X-ray images of FLEX SOFT electrode from MED-EL in Stenver's view were retrospectively investigated for the presence of electrode tip fold-over from 378 consecutive cases in two high-volume CI centers in Germany. All patients were implanted between 2010 and 2018 by three individual experienced CI surgeons using round window and extended round window approach for CI electrode insertion. A literature review was performed following a thorough PubMed (https://www.ncbi.nlm.nih.gov/pubmed/) search using the keywords "cochlear implant electrode tip fold-over" or "cochlear implant electrode tip roll-over" to capture articles that were published until December 2020 in English language only. Articles selection was based on electrode-related issues investigated only in-patient cases applying imaging modality. Those studies investigated tip fold-over in cadaveric temporal bones and cases with inner-ear malformation excluded. RESULTS No single case of tip fold-over was clinically detected from the retrospective investigation of post-operative X-ray images from 378 consecutive cases. The electrode angular insertion depth as measured applying the cochlear coordinate system, varied from a minimum of 560° to a maximum of 720°. The literature review on the tip fold-over issue resulted in 24 peer-reviewed published articles in total. Tip fold-over with pre-curved modiolar-hugging electrodes was reported in 85 cases out of 1,606 implantations making an incidence rate of 5.3%. With the straight lateral wall electrodes, the tip fold-over was reported in four cases out of 398 implantations making an incidence rate of 1%, not including the number of implantations reported in the current study. Otherwise it would be 0.5%. CONCLUSION Electrode tip fold-over with 31.5 mm long flexible lateral wall electrodes is highly exceptional and this can be generalized to any of the straight lateral wall electrodes from any CI brand. The literature review on tip fold-over revealed an incidence rate of 5.3% with pre-curved or modiolar-hugging electrodes and 1% with straight lateral wall electrodes from CI brands. Including this series of 0% tip fold-over, the incidence rate of electrode tip fold-over with LW electrode type would be 0.5%.
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Affiliation(s)
- Catalina Högerle
- Department of Otorhinolaryngology, Head and Neck Surgery, Ludwig Maximilians University, Munich
| | - Anna Englhard
- Department of Otorhinolaryngology, Head and Neck Surgery, Ludwig Maximilians University, Munich
| | - Florian Simon
- Department of Otorhinolaryngology, Head and Neck Surgery, Ludwig Maximilians University, Munich
| | - Ivo Grüninger
- Department of Otorhinolaryngology, Head and Neck Surgery, Ludwig Maximilians University, Munich
| | - Robert Mlynski
- Department of Otorhinolaryngology, Head and Neck Surgery "Otto Körner," Rostock University Medical Center, Rostock, Germany
| | - John-Martin Hempel
- Department of Otorhinolaryngology, Head and Neck Surgery, Ludwig Maximilians University, Munich
| | - Joachim Müller
- Department of Otorhinolaryngology, Head and Neck Surgery, Ludwig Maximilians University, Munich
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Kalkman RK, Briaire JJ, Dekker DMT, Frijns JHM. The relation between polarity sensitivity and neural degeneration in a computational model of cochlear implant stimulation. Hear Res 2021; 415:108413. [PMID: 34952734 DOI: 10.1016/j.heares.2021.108413] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 11/19/2021] [Accepted: 12/06/2021] [Indexed: 12/22/2022]
Abstract
The main aim of this computational modelling study was to test the validity of the hypothesis that sensitivity to the polarity of cochlear implant stimulation can be interpreted as a measure of neural health. For this purpose, the effects of stimulus polarity on neural excitation patterns were investigated in a volume conduction model of the implanted human cochlea, which was coupled with a deterministic active nerve fibre model based on characteristics of human auditory neurons. The nerve fibres were modelled in three stages of neural degeneration: intact, with shortened peripheral terminal nodes and with complete loss of the peripheral processes. The model simulated neural responses to monophasic, biphasic, triphasic and pseudomonophasic pulses of both polarities. Polarity sensitivity was quantified as the so-called polarity effect (PE), which is defined as the dB difference between cathodic and anodic thresholds. Results showed that anodic pulses mostly excited the auditory neurons in their central axons, while cathodic stimuli generally excited neurons in their peripheral processes or near their cell bodies. As a consequence, cathodic thresholds were more affected by neural degeneration than anodic thresholds. Neural degeneration did not have a consistent effect on the modelled PE values, though there were notable effects of electrode contact insertion angle and distance from the modiolus. Furthermore, determining PE values using charge-balanced multiphasic pulses as approximations of monophasic stimuli produced different results than those obtained with true monophasic pulses, at a degree that depended on the specific pulse shape; in general, pulses with lower secondary phase amplitudes showed polarity sensitivities closer to those obtained with true monophasic pulses. The main conclusion of this study is that polarity sensitivity is not a reliable indicator of neural health; neural degeneration affects simulated polarity sensitivity, but its effect is not consistently related to the degree of degeneration. Polarity sensitivity is not simply a product of the state of the neurons, but also depends on spatial factors.
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Affiliation(s)
- Randy K Kalkman
- ENT-department, Leiden University Medical Centre, PO box 9600, 2300, RC, Leiden, the Netherlands
| | - Jeroen J Briaire
- ENT-department, Leiden University Medical Centre, PO box 9600, 2300, RC, Leiden, the Netherlands; Leiden Institute for Brain and Cognition, PO box 9600, 2300, RC, Leiden, the Netherlands
| | - David M T Dekker
- ENT-department, Leiden University Medical Centre, PO box 9600, 2300, RC, Leiden, the Netherlands
| | - Johan H M Frijns
- ENT-department, Leiden University Medical Centre, PO box 9600, 2300, RC, Leiden, the Netherlands; Leiden Institute for Brain and Cognition, PO box 9600, 2300, RC, Leiden, the Netherlands
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Bernstein JGW, Jensen KK, Stakhovskaya OA, Noble JH, Hoa M, Kim HJ, Shih R, Kolberg E, Cleary M, Goupell MJ. Interaural Place-of-Stimulation Mismatch Estimates Using CT Scans and Binaural Perception, But Not Pitch, Are Consistent in Cochlear-Implant Users. J Neurosci 2021; 41:10161-10178. [PMID: 34725189 PMCID: PMC8660045 DOI: 10.1523/jneurosci.0359-21.2021] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 08/23/2021] [Accepted: 10/01/2021] [Indexed: 11/21/2022] Open
Abstract
Bilateral cochlear implants (BI-CIs) or a CI for single-sided deafness (SSD-CI; one normally functioning acoustic ear) can partially restore spatial-hearing abilities, including sound localization and speech understanding in noise. For these populations, however, interaural place-of-stimulation mismatch can occur and thus diminish binaural sensitivity that relies on interaurally frequency-matched neurons. This study examined whether plasticity-reorganization of central neural pathways over time-can compensate for peripheral interaural place mismatch. We hypothesized differential plasticity across two systems: none for binaural processing but adaptation for pitch perception toward frequencies delivered by the specific electrodes. Interaural place mismatch was evaluated in 19 BI-CI and 23 SSD-CI human subjects (both sexes) using binaural processing (interaural-time-difference discrimination with simultaneous bilateral stimulation), pitch perception (pitch ranking for single electrodes or acoustic tones with sequential bilateral stimulation), and physical electrode-location estimates from computed-tomography (CT) scans. On average, CT scans revealed relatively little BI-CI interaural place mismatch (26° insertion-angle mismatch) but a relatively large SSD-CI mismatch, particularly at low frequencies (166° for an electrode tuned to 300 Hz, decreasing to 14° at 7000 Hz). For BI-CI subjects, the three metrics were in agreement because there was little mismatch. For SSD-CI subjects, binaural and CT measurements were in agreement, suggesting little binaural-system plasticity induced by mismatch. The pitch measurements disagreed with binaural and CT measurements, suggesting place-pitch plasticity or a procedural bias. These results suggest that reducing interaural place mismatch and potentially improving binaural processing by reprogramming the CI frequency allocation would be better done using CT-scan than pitch information.SIGNIFICANCE STATEMENT Electrode-array placement for cochlear implants (bionic prostheses that partially restore hearing) does not explicitly align neural representations of frequency information. The resulting interaural place-of-stimulation mismatch can diminish spatial-hearing abilities. In this study, adults with two cochlear implants showed reasonable interaural alignment, whereas those with one cochlear implant but normal hearing in the other ear often showed mismatch. In cases of mismatch, binaural sensitivity was best when the same cochlear locations were stimulated in both ears, suggesting that binaural brainstem pathways do not experience plasticity to compensate for mismatch. In contrast, interaurally pitch-matched electrodes deviated from cochlear-location estimates and did not optimize binaural sensitivity. Clinical correction of interaural place mismatch using binaural or computed-tomography (but not pitch) information may improve spatial-hearing benefits.
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Affiliation(s)
- Joshua G W Bernstein
- National Military Audiology and Speech Pathology Center, Walter Reed National Military Medical Center, Bethesda, Maryland 20889
| | - Kenneth K Jensen
- National Military Audiology and Speech Pathology Center, Walter Reed National Military Medical Center, Bethesda, Maryland 20889
| | - Olga A Stakhovskaya
- Department of Hearing and Speech Sciences, University of Maryland, College Park, Maryland 20742
| | - Jack H Noble
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, Tennessee 37232
| | - Michael Hoa
- Department of Otolaryngology Head and Neck Surgery, Georgetown University Medical Center, Washington, DC 20057
| | - H Jeffery Kim
- Department of Otolaryngology Head and Neck Surgery, Georgetown University Medical Center, Washington, DC 20057
| | - Robert Shih
- Department of Radiology, Walter Reed National Military Medical Center, Bethesda, Maryland 20889
| | - Elizabeth Kolberg
- Department of Hearing and Speech Sciences, University of Maryland, College Park, Maryland 20742
| | - Miranda Cleary
- Department of Hearing and Speech Sciences, University of Maryland, College Park, Maryland 20742
| | - Matthew J Goupell
- Department of Hearing and Speech Sciences, University of Maryland, College Park, Maryland 20742
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