The diagnostic value of measurement of cochlear length and height in temporal bone CT multiplanar reconstruction of inner ear malformation

Liu, Yikang; Qi, Cheng-Lin; Tang, Jie; Jiang, Muliang; Du, Long; Li, Zhenhua; Tan, Sheng; Tang, Anzhou

doi:10.1080/00016489.2016.1221132

Cited by 27 publications

(48 citation statements)

References 18 publications

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“…A comparison of the results of the left and right sides revealed that the difference between the two sides was not statistically significant. Also, compared with the results, obtained from a HRCT image, reported by Liu et al (2016) the results of this study were slightly larger. Nevertheless, the measurement results in the 3D models used in this study were closer to the true value, and are consistent with the results reported by Shin et al (2013).…”

Section: Variation In the Size And Orientation Of The Human Cochleacontrasting

confidence: 65%

Anatomical Variations of the Human Cochlea Determined from Micro‐CT and High‐Resolution CT Imaging and Reconstruction

Tang

et al. 2018

The Anatomical Record

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Understanding the anatomical variations in the human cochlea is important for cochlear implants. This study examined these variations using a reconstructed fusion model of the skull and temporal bone. The three-dimensional (3D) digital model of the temporal bone was reconstructed from multiple axial micro-computed tomography (CT) scans of temporal bone and high resolution CT of the skull from 15 cadavers. A skull model was reconstructed and merged with the reconstructed temporal bone. The 3D relationship between the cochlea and the skull's mid-sagittal plane was analyzed. The α and β angles of the cochlear autogenous rotation and bottom position, respectively, further subdivided the cochlear spatial orientation. The relationship between the base of the cochlea and the round window was evaluated with the Φ angle. Cochlear size was measured and the relationship was statistically analyzed. Cochlear implant electrode arrays were observed in five cases of right-temporal bone specimens. The α, β, and Φ angles were 46.01 ± 9.65, 56.79 ± 3.58, and 44.41 ± 7.23, respectively. The α angle varied greatly and was negatively correlated to the Φ angle (correlation coefficient = -0.211, P < 0.05). Among the five specimens, the α and Φ angle of the 2R and 4R cochlear specimens was lower and higher than the mean value, respectively. These measurements revealed variations in the size and position of the cochlea. Some of these variations may require surgical adjustments for insertion of electrodes with cochlear implants and present a greater challenge for implantation of cochlear electrode implantation. These data also provide a better understanding of variations in human cochlear anatomy. Anat Rec, 301:1086-1095, 2018. © 2017 Wiley Periodicals, Inc.

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Section: Variation In the Size And Orientation Of The Human Cochleacontrasting

confidence: 65%

Anatomical Variations of the Human Cochlea Determined from Micro‐CT and High‐Resolution CT Imaging and Reconstruction

Tang

et al. 2018

The Anatomical Record

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“…Furthermore, dysplasia and other syndromes exist which have an effect on cochlear geometry, especially regarding the length, shape and number of turns (e.g. Mondini dysplasia) [ 28 ].…”

Section: Introductionmentioning

confidence: 99%

Patient specific selection of lateral wall cochlear implant electrodes based on anatomical indication ranges

et al. 2018

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ObjectivesThe aim of this study was to identify anatomical indication ranges for different lateral wall cochlear implant electrodes to support surgeons in the preoperative preparation.Methods272 patients who were implanted with a FLEX20, FLEX24, FLEX28, or a custom-made device (CMD) were included in this study. The cochlear duct length (CDL) and basal cochlear diameter (length A) were measured within preoperative imaging data. The parameter A was then employed to additionally compute CDL estimates using literature approaches. Moreover, the inserted electrode length (IEL) and insertion angle (IA) were measured in postoperative CT data. By combining the preoperative measurements with the IA data, the covered cochlea length (CCL) and relative cochlear coverage (CC) were determined for each cochlea.ResultsThe measurements of the CDL show comparable results to previous studies. While CDL measurements and estimations cover similar ranges overall, severe deviations occur in individual cases. The electrode specific IEL and CCL are fairly consistent and increase with longer electrodes, but relatively wide ranges of electrode specific CC values were found due to the additional dependence on the respective CDL. Using the correlation of IEL and CCL across electrode arrays, CDL ranges for selected arrays were developed (FLEX24: 31.3–34.4, FLEX28: 36.2–40.1, FLEXSoft: 40.6–44.9).ConclusionsOur analysis shows that electrode specific CC varies due to the CDL variation. Preoperative measurement of the CDL allows for an individualized implant length selection yielding optimized stimulation and a reduced risk of intraoperative trauma. The CDL, as derived from preoperative CT imaging studies, can help the implant surgeon select the appropriate electrode array to maximize the patient’s outcomes.

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“…Majority agrees that measuring the basal turn diameter which is also called as “A” value of the cochlea (Fig. 1A) from the pre-operative CT image of the cochlea, is relevant in estimating the full length of the cochlear duct length 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21. Escude et al 4 and Erixon et al 5 have proposed mathematical equations that involve “A” value as the input in estimating the CDL (LW) position, whereas the equations proposed by Alexiades et al 8 and Koch et al 22 estimates the CDL (OC) position.…”

Section: Methodsmentioning

confidence: 87%

Cochlear duct length along the outer wall vs organ of corti: Which one is relevant for the electrode array length selection and frequency mapping using Greenwood function?

Dhanasingh

2019

World j. otorhinolaryngol.-head neck surg.

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Cochlear duct length (CDL) measurement or estimation is a hot topic for various research groups in the cochlear implant (CI) field as of today. Getting the CDL along the outer wall (LW) and organ of corti (OC) is possible but considering the clinical application especially in the selection of the electrode array length and applying Greenwood's frequency function, we need to have a clear understanding on the CDL in general and as well on the Greenwood's frequency function. It is very clear from the histology images of the cochlea with straight electrode inside, that the electrode locates itself right under the basilar membrane. Also the Greenwood's frequency function involves a variable that corresponds to the CDL at the basilar membrane/organ of corti level. This brings us to conclude that the CDL at the OC is relevant for the selection of electrode array length and in applying Greenwood's frequency function. The ratio between CDL (LW) and CDL (OC) is 0.9 which is a very important number that needs to be remembered when converting CDL (LW) to CDL (OC).

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The diagnostic value of measurement of cochlear length and height in temporal bone CT multiplanar reconstruction of inner ear malformation

Cited by 27 publications

References 18 publications

Anatomical Variations of the Human Cochlea Determined from Micro‐CT and High‐Resolution CT Imaging and Reconstruction

Anatomical Variations of the Human Cochlea Determined from Micro‐CT and High‐Resolution CT Imaging and Reconstruction

Patient specific selection of lateral wall cochlear implant electrodes based on anatomical indication ranges

Cochlear duct length along the outer wall vs organ of corti: Which one is relevant for the electrode array length selection and frequency mapping using Greenwood function?

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