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

Objectives The advent of hybrid electro-acoustic implants requires precise positioning of the electrode-array (EA) within the cochlea. The cochlea size, that is, the length of the cochlear scala tympani, is often indirectly estimated from distance A by Escudé’s method. This technique has been confir...

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Bibliographic Details
Published in:European archives of oto-rhino-laryngology 2019-08, Vol.276 (8), p.2135-2140
Main Authors: Vu, Thi Hau, Perazzini, Chiara, Puechmaille, Mathilde, Bachy, Aurélie, Mulliez, Aurélien, Boyer, Louis, Mom, Thierry, Gabrillargues, Jean
Format: Article
Language:English
Subjects:
Cochlea - diagnostic imaging
Cochlea - pathology
Cochlear Duct - diagnostic imaging
Cochlear Duct - pathology
Cochlear Implantation - methods
Cochlear Implants
Dimensional Measurement Accuracy
Female
Head and Neck Surgery
Hearing Loss - surgery
Humans
Male
Medicine
Medicine & Public Health
Middle Aged
Neurosurgery
Otology
Otorhinolaryngology
Prosthesis Fitting - methods
Reproducibility of Results
Tomography, X-Ray Computed - methods
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Summary:Objectives The advent of hybrid electro-acoustic implants requires precise positioning of the electrode-array (EA) within the cochlea. The cochlea size, that is, the length of the cochlear scala tympani, is often indirectly estimated from distance A by Escudé’s method. This technique has been confirmed by anatomical studies, in a bunch of cadaveric specimens, but it is not yet widely established in the field of computed tomography (CT). We compared cochlear duct length obtained by Escudé’s method to those directly acquired on CT images. Materials and methods The lengths of cochlear scala tympani were directly measured on CT scans by contouring the external cochlear wall (contouring technique-CoT). In fifteen patients implanted with a straight EA, the length of the EA and the measured length of the cochlea by the CoT were compared, to check the reliability of the CoT. Then, in 200 CT-scans, the length of the cochlear duct was measured by the CoT then compared to Escudé’s method. Results In the 200 CT-scans which served for cochlear length measurements, a significant variability between the cochleae were observed, as expected. At 360°, the correlation between the measurements of the length of the cochlear scala tympani between the two techniques differed, with a difference of 0.2 ± 0.7 mm at 360° (extreme: 2 mm; p  
ISSN:0937-4477
1434-4726
DOI:10.1007/s00405-019-05432-6