The spinal mechanical properties obtained in vivo from the flexibility tests are essential for surgical planning of scoliosis. In spite of the fact that these tests are commonly used in scoliosis clinics, they are not recommended for brace treatment since they require additional important X-ray irradiation doses. The flexibility indices obtained can also be integrated in treatment simulators, whether it is surgical or brace, in order to customize their mechanical behavior. This project aims to develop and validate a non-irradiating method to assess adolescent idiopathic scoliosis’s (AIS) curve flexibility.
A harness was specially designed to suspend 37 patients by the axillae and to provide visibility to radiopaque markers placed over the spinous processes of the thoracic and lumbar vertebrae. Two acquisitions were taken for each patient, one in the standing position and the other suspended, for both low dose radiographs (Rx-Cent) and 3D optical system (Op-M) methods.
The mean scoliotic curve reduction for Op-M [3,4 ± 3,2°] is significantly different than Rx- Cent [9,5 ± 5,2°] (p<0,0005, difference in medians: 7,2°). Nevertheless, the mean flexibility index estimation for Op-M [3,5 ± 7,6 °/Nm] is not significantly different than the one achieved by Rx-Cent [1,9 ± 1,1 °/Nm] (p = 0,9543).
The suspension test shows very good reproducibility (ICC=0,777) which supports its use in the planning of surgical or conservative treatment for AIS. There are significant différences between the reductions of the optical and radiographic methods. These may be caused by several factors: (1) positioning errors for external markers; (2) movement of the skin relative to the spinal anatomic landmark; (3) differences between the spinal curves obtained from the centroids and from the spinous processes. Therefore, further research on these sources of discrepancies should be carried out on this study in order to support the replacement of radiographic spinal flexibility measurements by the optical method proposed.
The use of suspension tests in both conservative and surgical treatments presents great potential to improve the planning of AIS orthopaedic treatment.
| Date | 22 Oct 2014 |
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| Original language | French |
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| Awarding Institution | - École de technologie supérieure
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| Supervisor | Yvan Petit (Supervisor), Delphine Périé-Curnier (Co-supervisor) & Stefan Parent (Co-supervisor) |
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Moulin, D. (Author),
Petit (Supervisor), Périé-Curnier (Co-supervisor) & Parent (Co-supervisor),
22 Oct 2014Student thesis: Master's thesis › Master in Engineering: Engineering