Thi Hau Vu1,2, Chiara Perazzini2, Mathilde Puechmaille3,4, Aurélie Bachy3, Aurélien Mulliez5, Louis Boyer2,6, Thierry Mom7,8, Jean Gabrillargues2. 1. Department of Radiology, Hôpital Bach Mai, Université de Médecine de Ha Noi, 78 Giai Phong, Dong Da, Ha Noi, Viet Nam. 2. Department of Radiology, CHU Gabriel Montpied, Université Clermont Auvergne, 58 Rue Montalembert, 63000, Clermont-Ferrand, France. 3. Department of Otolaryngology Head and Neck Surgery, CHU Gabriel Montpied, Université Clermont Auvergne, 58 Rue Montalembert, 63000, Clermont-Ferrand, France. 4. Unité Mixte de Recherche de l'Institut National des Sciences et de la Recherche en Médecine (UMR-INSERM, 1107), Laboratory of Neurosensory Biophysics, Université Clermont Auvergne, 63000, Clermont-Ferrand, France. 5. Délégation à la Recherche Clinique et aux Innovations, CHU Gabriel Montpied, Université Clermont Auvergne, 58 Rue Montalembert, 63000, Clermont-Ferrand, France. 6. Cardiovascular Interventional Therapy and Imaging (CaVITI Team), Therapy Guided By Imaging Institute (TGI-Institut Pascal), Unité Mixte de Recherche 6602 du Centre National de la Recherche Scientifique (UMR-CNRS), Université Clermont Auvergne, UCA/CNRS/SIGMA, Campus Universitaire des Cézeaux, 4 Avenue Blaise Pascal, Clermont-Ferrand, France. 7. Department of Otolaryngology Head and Neck Surgery, CHU Gabriel Montpied, Université Clermont Auvergne, 58 Rue Montalembert, 63000, Clermont-Ferrand, France. tmom@chu-clermontferrand.fr. 8. Unité Mixte de Recherche de l'Institut National des Sciences et de la Recherche en Médecine (UMR-INSERM, 1107), Laboratory of Neurosensory Biophysics, Université Clermont Auvergne, 63000, Clermont-Ferrand, France. tmom@chu-clermontferrand.fr.
Abstract
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 < 0.001) and 2.2 ± 1.2 mm at 540° (extreme: 5.6 mm; p < 0.001). CONCLUSION: The CoT can predict with accuracy the length of EA-insertion depth, more precisely than estimation methods such as Escudé's.
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 < 0.001) and 2.2 ± 1.2 mm at 540° (extreme: 5.6 mm; p < 0.001). CONCLUSION: The CoT can predict with accuracy the length of EA-insertion depth, more precisely than estimation methods such as Escudé's.
Authors: Ohad Hilly; Leah Smith; Euna Hwang; David Shipp; Sean Symons; Julian M Nedzelski; Joseph M Chen; Vincent Y W Lin Journal: Ann Otol Rhinol Laryngol Date: 2016-07-21 Impact factor: 1.547
Authors: Franz-Tassilo Müller-Graff; Lukas Ilgen; Philipp Schendzielorz; Johannes Voelker; Johannes Taeger; Anja Kurz; Rudolf Hagen; Tilmann Neun; Kristen Rak Journal: Eur Arch Otorhinolaryngol Date: 2021-06-08 Impact factor: 3.236