The biomechanical evaluation of spinal implant provides useful information for implant installation, on the mechanical behavior of the entire column-implant construct and for numerical models validation. Still, experimental results are directly related to the boundary conditions, and some authors have attempted to standardize these tests to ensure uniform assessment procedures. For this project, a test bench has previously been designed according to the above mentioned standards. However, its repeatability still needs to be evaluated. Superelastic cables have first been used for sternum closure and for greater trochanter reattachment but their potential for sub-laminar fixation of the spine remains to be studied.
The main objective of this study is the validation, with the designed test bench, of a sublaminar fixation system using superelastic cables for posterior instrumentation of the spine. To do this, the specific objectives of this study are:
1. Validate an experimental testing device simulating the loads transmitted to the spine in anatomical movements by studying its test-retest reliability;
2. Experimentally compare the biomechanics ability of a fixing system of sublaminar cables (Atlas cables (Medtronic Sofamor Danek, Memphis, TN) and superelastic cables) to maintain the initial stabilization after the application of loads.
To meet the first objective, repeatability tests were performed on the testing device. Thus, moment control tests were conducted twice on cadaveric porcine spine segments. To meet the second objective, a hybrid protocol was performed on porcine spine specimens to compare sublaminar fixations using Atlas cables and superelastic cables.
The results show that the testing device offers a reliable and repeatable test method for performing in vitro tests with instrumented vertebral segments. The results provide a good base to approach different in vitro testing’s on spine specimen. The superelastic cables seem to be a stiffer stabilization for lower installation force and limit adjacent intradiscal pressure.
| Date | 17 Jan 2013 |
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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), Vladimir Brailovski (Co-supervisor) & Jean Marc Mac-Thiong (Co-supervisor) |
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Tremblay, J. (Author),
Petit (Supervisor),
Brailovski (Co-supervisor) & Mac-Thiong (Co-supervisor),
17 Jan 2013Student thesis: Master's thesis › Master in Engineering: Engineering