CT-scan contouring technique allows for direct and reliable measurements of the cochlear duct length: implication in cochlear implantation with straight electrode-arrays

Vu, Thi Hau; Perazzini, Chiara; Puechmaille, M.; Bachy, Aurélie; Mulliez, Aurélien; Boyer, L.; Mom, T.; Gabrillargues, Jean

doi:10.1007/s00405-019-05432-6

Cited by 12 publications

(8 citation statements)

References 32 publications

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“…In this systematic review, the data were obtained from 56 studies 2–5,11,12,14–17,19,20,22–26,28–30,32–37,39–45,53–74 . However, there were 65 different subgroups.…”

Section: Resultsmentioning

confidence: 99%

Comprehensive Analysis of Factors Affecting Cochlear Size: A Systematic Review and Meta‐analysis

et al. 2021

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Objectives To determine the cochlea's average size in humans and evaluate the relationships between certain covariates and cochlear size. Methods A systematic search on articles on cochlear size and published in English was conducted using Cochrane, PubMed, Web of Science, and Scopus databases up to September 15, 2020. Data were pooled using random‐effects with three models. The effect of demographic, clinical, and measurement‐related parameters was specifically analyzed. Meta‐regression and subgroup analyses were conducted. The overall effect estimation was made for outcomes. Results The meta‐analysis included 4,708 cochleae from 56 studies. The overall length of the organ of Corti was 32.94 mm (95% confidence interval [CI]: 32.51–33.38). The first and second models revealed that age, gender, country, continent, measurement method (direct, indirect), measured structure (“A” value, cochlear lateral wall), origin (in vivo, in vitro), and type (histology specimens, plastic casts, imaging) of the cochlear material did not affect the cochlear size. However, study populations (general population, patients with a cochlear implant, and patients with congenital sensorineural hearing loss [CSNHL]) were found to affect the outcomes. Compared to the other populations, patients with CSNHL had shorter cochleae. Therefore, we developed a third model and found that the general population and patients with cochlear implants did not differ in cochlear size. Conclusion This meta‐analysis investigated the factors that could affect the cochlear size and found that patients with CSNHL had significantly shorter cochleae, whereas other covariates had no significant effect. Laryngoscope, 132:188–197, 2022

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“…In this systematic review, the data were obtained from 56 studies 2–5,11,12,14–17,19,20,22–26,28–30,32–37,39–45,53–74 . However, there were 65 different subgroups.…”

Section: Resultsmentioning

confidence: 99%

Comprehensive Analysis of Factors Affecting Cochlear Size: A Systematic Review and Meta‐analysis

et al. 2021

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“…HLL denotes helicotrema linear length; HAL denotes helicotrema angular length cochlear apex was excluded from the analysis. Direct length measurement techniques, such as those proposed by Vu et al [24], require the user to identify the exact end-point of the BM to use Greenwood's equation. This is generally not achievable due to the lack of visualization of soft-tissue membranes in the apex.…”

Section: Discussionmentioning

confidence: 99%

Characterization of the human helicotrema: implications for cochlear duct length and frequency mapping

Helpard

Rask‐Andersen

et al. 2020

J of Otolaryngol - Head & Neck Surg

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Background: Despite significant anatomical variation amongst patients, cochlear implant frequency-mapping has traditionally followed a patient-independent approach. Basilar membrane (BM) length is required for patient-specific frequency-mapping, however cochlear duct length (CDL) measurements generally extend to the apical tip of the entire cochlea or have no clearly defined end-point. By characterizing the length between the end of the BM and the apical tip of the entire cochlea (helicotrema length), current CDL models can be corrected to obtain the appropriate BM length. Synchrotron radiation phase-contrast imaging has made this analysis possible due to the soft-tissue contrast through the entire cochlear apex. Methods: Helicotrema linear length and helicotrema angular length measurements were performed on synchrotron radiation phase-contrast imaging data of 14 cadaveric human cochleae. On a subset of six samples, the CDL to the apical tip of the entire cochlea (CDL TIP) and the BM length (CDL BM) were determined. Regression analysis was performed to assess the relationship between CDL TIP and CDL BM. Results: The mean helicotrema linear length and helicotrema angular length values were 1.6 ± 0.9 mm and 67.8 ± 37.9 degrees, respectively. Regression analysis revealed the following relationship between CDL TIP and CDL BM : CDL BM = 0.88(CDL TIP) + 3.71 (R 2 = 0.995). Conclusion: This is the first known study to characterize the length of the helicotrema in the context of CDL measurements. It was determined that the distance between the end of the BM and the tip of the entire cochlea is clinically consequential. A relationship was determined that can predict the BM length of an individual patient based on their respective CDL measured to the apical tip of the cochlea.

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“…Vu et al (2019) contoured the lateral wall of the cochlea directly on computed tomography (CT) images using the contouring technique (CoT) method, and like other previous studies this method estimated the length of the lateral wall (Vu et al 2019). In the present work, we compared the EA length estimated by this method to the actual length, and we found an apparent gap between the measurements.…”

Section: Introductionmentioning

confidence: 99%

An Accurate and Individualized Preoperative Estimation Method for the Linear Insertion Depth of Cochlear Implant Electrode Arrays Based on Computed Tomography

Jia

Song

et al. 2023

Ear &Amp; Hearing

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Objectives: Cochlear implantation or auditory brainstem implantation is currently the only accepted method for improving severe or profound sensorineural hearing loss. The length of the electrodes implanted during cochlear implantation is closely related to the degree of hearing improvement of hearing after the surgery. We aimed to explore new methods to accurately estimate the electrode array (EA) linear insertion depth based on computed tomography (CT) images prior surgery, which could help surgeons select the appropriate EA length for each patient. Design: Previous studies estimated the linear insertion depth by measuring the length of the lateral wall of the cochlea rather than the electrode’s path in the cochlea duct. Here, we determined the actual position of the EA on the CT image after cochlear surgery in order to predict the path of the EA, and the length of the predicted EA path was measured by the contouring technique (CoT) to estimate the linear insertion depth of the EA. Because CoT can only measure the length of the estimated EA path on a two-dimensional plane, we further modified the measurement by weighting the height of the cochlea and the length of the EA tail (the length of the last stimulating electrode to the end, which cannot be displayed on the CT image), which we termed the modified CoT + height + tail (MCHT) measurement. Results: Based on our established method, MCHT could reduce the error to the submillimeter range (0.67 ± 0.37 mm) when estimating the linear insertion depth of various kinds of EAs compared with the actual implant length. The correlation coefficient between the linear insertion depth as predicted by MCHT and the actual was 0.958. The linear insertion depth estimated by this method was more accurate than that estimated using the classical CoT technique (R = 0.442) and using the modified Escudé’s method (R = 0.585). Conclusions: MCHT is a method based on CT images that can accurately predict the linear insertion depth of cochlear implants preoperatively. This is the first report that we are aware of a method for predicting linear insertion depth before cochlear implantation with only submillimeter errors and that is tailored to different types of EAs.

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CT-scan contouring technique allows for direct and reliable measurements of the cochlear duct length: implication in cochlear implantation with straight electrode-arrays

Cited by 12 publications

References 32 publications

Comprehensive Analysis of Factors Affecting Cochlear Size: A Systematic Review and Meta‐analysis

Comprehensive Analysis of Factors Affecting Cochlear Size: A Systematic Review and Meta‐analysis

Characterization of the human helicotrema: implications for cochlear duct length and frequency mapping

An Accurate and Individualized Preoperative Estimation Method for the Linear Insertion Depth of Cochlear Implant Electrode Arrays Based on Computed Tomography

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