Variations in the Size and Shape of Human Cochlear Malformation Types

Dhanasingh, Anandhan

doi:10.1002/ar.24136

Cited by 18 publications

(18 citation statements)

References 14 publications

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“…malformations, lumen obstruction or narrowing) or its size influences the choice of the array 7 . Inner ear has a complex 3D anatomy and is surrounded by critical structures like facial nerve and blood vessels, with only few visible landmarks during surgery 8 – 10 . Moreover, its anatomy is subject to great inter individual variability justifying even more the use of preoperative CT-scan 10 – 12 .…”

Section: Introductionmentioning

confidence: 99%

Automatic segmentation of inner ear on CT-scan using auto-context convolutional neural network

Hussain

Lalande

Girum

et al. 2021

Sci Rep

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Temporal bone CT-scan is a prerequisite in most surgical procedures concerning the ear such as cochlear implants. The 3D vision of inner ear structures is crucial for diagnostic and surgical preplanning purposes. Since clinical CT-scans are acquired at relatively low resolutions, improved performance can be achieved by registering patient-specific CT images to a high-resolution inner ear model built from accurate 3D segmentations based on micro-CT of human temporal bone specimens. This paper presents a framework based on convolutional neural network for human inner ear segmentation from micro-CT images which can be used to build such a model from an extensive database. The proposed approach employs an auto-context based cascaded 2D U-net architecture with 3D connected component refinement to segment the cochlear scalae, semicircular canals, and the vestibule. The system was formulated on a data set composed of 17 micro-CT from public Hear-EU dataset. A Dice coefficient of 0.90 and Hausdorff distance of 0.74 mm were obtained. The system yielded precise and fast automatic inner-ear segmentations.

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Section: Introductionmentioning

confidence: 99%

Automatic segmentation of inner ear on CT-scan using auto-context convolutional neural network

Hussain

Lalande

Girum

et al. 2021

Sci Rep

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“… 1 While every surgeon aims at atraumatic (zero degree of trauma) electrode array placement inside the cochlea, 100% atraumatic electrode placement is still not guaranteed in every CI surgeries due to the varying degree of cochlear size, shape, anatomy and with the electrode designs from various CI brands differing in its insertion method resulting in some degree of intra-cochlear trauma. 2 , 3 , 4 With recent reports having confirmed the importance of atraumatic electrode placement to the patient's post-operative hearing with CI, 5 , 6 , 7 the pressure is now on CI surgeons and as well on implant designers.…”

Section: Introductionmentioning

confidence: 99%

The rationale for FLEX (cochlear implant) electrode with varying array lengths

Dhanasingh

2021

World j. otorhinolaryngol.-head neck surg.

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With cochlear implantation (CI) being the standard of care for profoundly deaf cases, more and more patients with low frequency residual hearing are currently being treated with CI. In view of preserving the residual hearing, the ultimate aim of both the surgeons and the CI companies is to achieve zero-degree of electrode insertion trauma. Variations in the size and shape of cochlea, cross-sectional dimensions of ST, electrode insertion techniques with and without metal stylet rod and the experience level of the operating surgeons, all play a role in the electrode array related insertion trauma. An effective electrode design must include flexible array to accommodate the cochlear shape variation, electrode with variety of array lengths to support the concept of cochlear size specific electrode array and finally smaller cross-sectional dimensions of electrode array in matching the cross-sectional dimensions of ST. As per published reports, FLEX electrode array design offers minimal degree of electrode insertion trauma along with the possibility of patient specific electrode array length matching their cochlear size. Looking at the cross-sectional dimensions of FLEX electrode array along with its volume, it appear to be highly safe to the cochlea by not taking too much volume inside the ST. To offer additional support, otological pre-planning software tool like OTOPLAN is now clinically available in measuring the cochlear size in finding the best electrode array match along with the possibilities of anatomy based post-operative speech processor fitting.

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“…Three-dimensional (3D) segmentation of the complete inner-ear was performed using 3D slicer as described previously by Dhanasingh et al 7 , 11 .…”

Section: Methodsmentioning

confidence: 99%

“…While the A-value has been recognized as a reliable measurement for CDL estimation for cochlear implantation, it does not account for variability in the curvature of the second turn of the cochlea. Furthermore, the A-value can only be applied to inner ears with a normal anatomy 7 , because malformed cochlea generally do not possess two and a half turns like the normal cochlea; the cochlear duct is typically shorter 8 .…”

Section: Introductionmentioning

confidence: 99%

“…This is of importance because up to 20% of the population with a sensorineural hearing loss have some degree of inner ear malformation 9 , with enlarged vestibular aqueduct (EVA), incomplete partition (IP) types I, II and III, cochlear hypoplasia (CH), common cavity (CC), and cochlear aplasia (CA) being the most common 7 , 10 . Therefore, applying the A-value measurement and CDL estimation under circumstances where the cochleae have a malformation of any kind be ill advised.…”

Section: Introductionmentioning

confidence: 99%

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A novel cochlear measurement that predicts inner-ear malformation

Khurayzi

Almuhawas

Alsanosi

et al. 2021

Sci Rep

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The A-value used in cochlear duct length (CDL) estimation does not take malformed cochleae into consideration. The objective was to determine the A-value reported in the literature, to assess the accuracy of the A-value measurement and to evaluate a novel cochlear measurement in distinguishing malformed cochlea. High resolution Computer Tomography images in the oblique coronal plane/cochlear view of 74 human temporal bones were analyzed. The A-value and novel C-value measurement were evaluated as predictors of inner ear malformation type. The proximity of the facial nerve to the basal turn was evaluated subjectively. 26 publications report on the A-value; but they do not distinguish normal vs. malformed cochleae. The A-values of the normal cochleae compared to the cochleae with cochlear hypoplasia, incomplete partition (IP) type I, -type II, and -type III were significantly different. The A-value does not predict the C-value. The C-values of the normal cochleae compared to the cochleae with IP type I and IP type III were significantly different. The proximity of the facial nerve to the basal turn did not relate to the type of malformation. The A-value is different in normal vs. malformed cochleae. The novel C-value could be used to predict malformed anatomy, although it does not distinguish all malformation types.

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Variations in the Size and Shape of Human Cochlear Malformation Types

Cited by 18 publications

References 14 publications

Automatic segmentation of inner ear on CT-scan using auto-context convolutional neural network

Automatic segmentation of inner ear on CT-scan using auto-context convolutional neural network

The rationale for FLEX (cochlear implant) electrode with varying array lengths

A novel cochlear measurement that predicts inner-ear malformation

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