Analysis of Different Approaches for Clinical Cochlear Coverage Evaluation After Cochlear Implantation

Schurzig, Daniel; Timm, Max; Batsoulis, Cornelia; John, Samuel; Lenarz, Thomas

doi:10.1097/mao.0000000000001904

Cited by 29 publications

(28 citation statements)

References 31 publications

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“…Therefore, clinical analyses using fpVCT SECO probably represents the true length, since assessments with micro-fpVCT and micro-CT in temporal bone specimens have shown no significant different CDL at the lateral wall values up to over 40 mm [13,24], which corresponds to a CDL OC of about 35 mm. In line with this, in other studies, shorter CDL values have been reported in clinical modalities [8,13]. Based on these and the presented findings, it should be carefully considered whether it might be better to use longer electrodes than currently assumed for covering the correct CDL OC , when measured by MSCT or other low-resolution images.…”

Section: Discussionsupporting

confidence: 84%

“…Therefore, it is necessary to have sufficient data on the cochlear anatomy preoperatively, especially on the cochlear duct length (CDL). In recent years, new imaging technologies, models and formulas have been developed to measure the CDL [5][6][7][8][9][10][11][12][13][14]. Most of these studies were based on measurements of the CDL by Escudé in 2006 [5].…”

Section: Introductionmentioning

confidence: 99%

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Implementation of secondary reconstructions of flat-panel volume computed tomography (fpVCT) and otological planning software for anatomically based cochlear implantation

Müller-Graff¹,

Ilgen²,

Schendzielorz³

et al. 2021

Eur Arch Otorhinolaryngol

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Purpose For further improvements in cochlear implantation, the measurement of the cochlear duct length (CDL) and the determination of the electrode contact position (ECP) are increasingly in the focus of clinical research. Usually, these items were investigated by multislice computed tomography (MSCT). The determination of ECP was only possible by research programs so far. Flat-panel volume computed tomography (fpVCT) and its secondary reconstructions (fpVCTSECO) allow for high spatial resolution for the visualization of the temporal bone structures. Using a newly developed surgical planning software that enables the evaluation of CDL and the determination of postoperative ECP, this study aimed to investigate the combination of fpVCT and otological planning software to improve the implementation of an anatomically based cochlear implantation. Methods Cochlear measurements were performed utilizing surgical planning software in imaging data (MSCT, fpVCT and fpVCTSECO) of patients with and without implanted electrodes. Results Measurement of the CDL by the use of an otological planning software was highly reliable using fpVCTSECO with a lower variance between the respective measurements compared to MSCT. The determination of the inter-electrode-distance (IED) between the ECP was improved in fpVCTSECO compared to MSCT. Conclusion The combination of fpVCTSECO and otological planning software permits a simplified and more reliable analysis of the cochlea in the pre- and postoperative setting. The combination of both systems will enable further progress in the development of an anatomically based cochlear implantation.

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Section: Discussionsupporting

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Implementation of secondary reconstructions of flat-panel volume computed tomography (fpVCT) and otological planning software for anatomically based cochlear implantation

Müller-Graff¹,

Ilgen²,

Schendzielorz³

et al. 2021

Eur Arch Otorhinolaryngol

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“…A landmark was finally set every 30° to 60°. 14 , 15 The whole enrolled cochlea is presented by the software in an additional window. Herein, the CDL (A to C) and the 2TL (A to B; Figure 1 , D and D ′ ) were measured in millimeters.…”

Section: Methodsmentioning

confidence: 99%

Cochlear Duct Length Measurements in Computed Tomography and Magnetic Resonance Imaging Using Newly Developed Techniques

Taeger¹,

Müller-Graff²,

Ilgen³

et al. 2021

OTO Open

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Objective Growing interest in measuring the cochlear duct length (CDL) has emerged, since it can influence the selection of cochlear implant electrodes. Currently the measurements are performed with ionized radiation imaging. Only a few studies have explored CDL measurements in magnetic resonance imaging (MRI). Therefore, the presented study aims to fill this gap by estimating CDL in MRI and comparing it with multislice computed tomography (CT). Study Design Retrospective data analyses of 42 cochleae. Setting Tertiary care medical center. Methods Diameter (A value) and width (B value) of the cochlea were measured in HOROS software. The CDL and the 2-turn length were determined by the elliptic circular approximation (ECA). In addition, the CDL, the 2-turn length, and the angular length were determined via HOROS software by the multiplanar reconstruction (MPR) method. Results CDL values were significantly shorter in MRI by MPR ( d = 1.38 mm, P < .001) but not by ECA. Similar 2-turn length measurements were significantly lower in MRI by MPR ( d = 1.67 mm) and ECA ( d = 1.19 mm, both P < .001). In contrast, angular length was significantly higher in MRI ( d = 26.79°, P < .001). When the values were set in relation to the frequencies of the cochlea, no clinically relevant differences were estimated (58 Hz at 28-mm CDL). Conclusion In the presented study, CDL was investigated in CT and MRI by using different approaches. Since no clinically relevant differences were found, diagnostics with radiation may be omitted prior to cochlear implantation; thus, a concept of radiation-free cochlear implantation could be established.

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“…The method of CBCT imaging and analysis and the dataset have been described in detail previously [36][37][38] ; here we reuse these data. In brief, a total of 95 patients (51 female, 44 male) with cochlear implants were included in the analysis.…”

Section: Cbct Measurements ("Clinical Ct")mentioning

confidence: 99%

“…These clinical scans are part of the clinical routine at the Hannover Medical School to preoperatively evaluate the condition of the cochlea and postoperatively confirm correct intracochlear array placement. All segmentations of the cochlear modiolar wall in preoperative CBCT data were performed with the software tool OsiriXMD (version 2.5.1 64bit, Pixmeo SARL, Switzerland) according to previous studies [37][38][39][40] .…”

Section: Cbct Measurements ("Clinical Ct")mentioning

confidence: 99%

Variations in Microanatomy of the Human Modiolus: Implications for Cochlear Implants

Pietsch

Schurzig

Salcher

et al. 2021

Preprint

Self Cite

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Human cochlear anatomy is highly variable. The phenomenon has been first described qualitatively, followed by a quantitative variability assessment with detailed anatomical models of the human cochlea. However, all previous work focused on lateral cochlear wall. Few information is available on the variability of the modiolar wall. Modiolar variability, likely determined by variability in the spiral ganglion, provides key information on when during ontogenesis the individual cochlear morphology is established: before and/or after neuronal structures are formed. In the present study we analyzed 108 corrosion casts, 95 clinical cone beam computer tomographies 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 has a common cause, very likely established already during the time when the spiral ganglion is formed. Proximity of other neuronal and vascular structures, defining the remaining variability in scalar spaces, are determined later in ontogenesis, when the scalae are formed. The present data further allows implications for perimodiolar cochlear implants and their tip fold-overs. In particular, 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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Analysis of Different Approaches for Clinical Cochlear Coverage Evaluation After Cochlear Implantation

Abstract: Insertion angle measurements are well suited for cochlear coverage determination, especially regarding retrospective analyses. Prospective studies independent of anatomical irregularities should be performed with the newly proposed approaches.

Cited by 29 publications

References 31 publications

Implementation of secondary reconstructions of flat-panel volume computed tomography (fpVCT) and otological planning software for anatomically based cochlear implantation

Implementation of secondary reconstructions of flat-panel volume computed tomography (fpVCT) and otological planning software for anatomically based cochlear implantation

Cochlear Duct Length Measurements in Computed Tomography and Magnetic Resonance Imaging Using Newly Developed Techniques

Variations in Microanatomy of the Human Modiolus: Implications for Cochlear Implants

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