The etiology of AIS is still the subject of discussions even if several hypotheses have been put forward concerning the role that certain malformations of the vestibular system and the semicircular canals (SCC) could play in equilibration. The objective of this study is to propose a semi-automatic method for the analysis of the inner ear in order to extract geometrical features allowing comparison of vestibular system in AIS and asymptomatic patients.
The vestibular organ of 27 AIS patients and 11 controls was examined using CBCT imaging. 3D reconstructions of their inner ears were obtained using a semi-automatic approach. Based on a literature review, geometrical features were chosen. Those features were extracted from all patients. Among others, angles between SCC best-fit planes, geodesic tunnel loops, crosssectional perimeters of SCC and nonplanarity of the SCC were computed. Parameters were also extracted from common crus, the common canal between the posterior and anterior SCC. Also, orientation and position of the SCC within the anatomical planes were analyzed.
Results indicate that the mean angles between the posterior canal plane and the lateral plane for the AIS group (91,60 ± 4,16°) is significantly superior (p = 0,0196) than the control group, which was 88,93 ± 4,94°. In addition, the global shape of the lateral canal is different for scoliosis and control patients. A segment of the lateral SCC at the opposite side of the ampulla is dilated for some AIS patients. Some scoliosis subjects even have a double ampulla at that place. Finally, the lateral SCC for the AIS patient has a more parallel orientation within the Frankfurt plane than the control patients.
Our results show that the metrics obtained from our approach were relevent for assessing the morphology of inner ear. This robust method can therefore be a valuable tool for clinical studies and quickly applied to a large cohort of AIS and controls subjects. Functional implications of the anomalies found in this research have still to be determined. It would be plausible to believe that those morphological anomalies caused postural and balance disorders who are reported in AIS.
| Date | 7 Oct 2020 |
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| Original language | French |
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| Awarding Institution | - École de technologie supérieure
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| Supervisor | Jacques A. de Guise (Supervisor) & Matthieu Schmittbuhl (Co-supervisor) |
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Lavallée, A.-P. (Author),
De Guise, J. (Supervisor) & Schmittbuhl, M. (Co-supervisor),
7 Oct 2020Student thesis: Master's thesis › Master in Engineering: Engineering