Étude des fractures vertébrales traumatiques sur un modèle porcin

Abstract

Vertebral burst fracture is a severe trauma with major consequences for the patient and their relatives. The optimal intervention is often complex to define and subject to many debates in the medical community. The number of experimental models has multiplied recently in order to better understand this fracture. Alas, current models are limited as the evaluation of two fundamentals aspects of this fracture cannot be studied together: the biomechanics and neurological functions. This project is the cornerstone toward the creation of a living experimental model with an unstable vertebral fracture with associated to neurologic deficits. The objective of this thesis is to study the vertebral fracture and to develop a method to create in situ unstable vertebral fractures on whole mature minipigs. Three sub-objectives have been established in order to: study the vertebral fracture mechanisms leading to the desired fracture, study the biomechanics of the fractured spine segment and conceive the apparatus capable of creating a vertebral fracture in situ. The loading parameters leading to the creation of vertebral unstable burst fracture with a significant canal encroachment have been identified with the completion of the first objective. A scientific paper has been published in the September 2011 issue of the Journal of Biomechanical Engineering to expose the results obtained (Chapter 3). We have demonstrated that the dynamic loading of a spinal segment without flexion are conditions easing the creation of the desired fracture. These loading characteristics have been used in the conception of the in situ method. The second objective aimed to assess the influence of physiological loadings on the spinal canal encroachment of fractured specimens. The conclusion of this study has resulted in the publication of a paper in the Journal of Spinal Disorders and Techniques (Chapter 4) in February 2012. We have noted that the application of physiological loads may increase the spinal canal encroachment. This knowledge is important especially since the intervertebral loads are higher in the quadruped’s spine than the human’s spine. We may expect the spinal canal encroachment measured on live specimens to be greater than the encroachment measured on cadaveric specimens. The conception of an apparatus capable of creating vertebral fractures in situ on whole minipigs has been instigated based on the knowledge acquired in the previous steps. The developed apparatus and the first results have been exposed in a paper submitted to The Spine Journal (Chapter 5) in April 2012. Comminuted unstable fractures with significant canal encroachment have been produced in situ on whole specimens. The method conceived did not cause any additional fracture to the adjacent structures. The method and apparatus developed is without precedent. This method produces vertebral fractures of great interest for the scientific community and localises the trauma to the spine alone. With some modifications, a living experimental model with an unstable vertebral burst fracture and potential neurologic deficits could be created. This model could be used in the context of exploratory and preclinical studies.

Date	5 Jul 2012
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Yvan Petit (Supervisor) & Stefan Parent (Co-supervisor)