Étude biomécanique de la stabilité du rachis cervical post-traumatique

Abstract

Spinal traumas can have devastating neurological consequences, especially when affecting the cervical segment. Emergency care procedure generally imposes the use of immobilization devices to prevent further damages. However immobilization and more precisely the ability of cervical collars to efficiently restrict unstable spine motions have recently been questioned. The research question of this project was then to understand the post-trauma effect of an injury on spinal stability and on the spinal cord. The proposed objective was then to use a finite element model to study the effect of posterior ligamentous complex (NL, ISL and LF) disruption on the creation of cervical spine instability and on strains and stress intensity. To address this objective, mechanical properties of the Spine Model for Safety and Surgery were first refined and calibrated under quasi-static flexion/extension. The impact of a PLC disruption on global and local flexion rotations as well as strains in remaining ligaments was then analyzed in a first article. Secondly, the effect of PLC disruption on strains and stress in the spinal cord was studied. A preliminary analysis of the effect of bone prominences in the vertebral canal was also proposed. The results showed that when the entire PLC is removed, a physiological flexion movement could: • potentially provoke capsular ligaments disruption and create a mechanical instability in the cervical spine. However to have a more complete overview, the instability should also be tested for lateral bending and axial rotation; • increase local stresses and strains in the spinal cord specially when bone prominences are present without creating any permanent mechanical damage. The link between stresses and strains and neurological damage should however be described in order to further analyse these results. This study shows that even when dealing with a purely ligamentous injury, immobilization is a key factor to prevent further damages. This research is part of a larger scope with the objective of increasing knowledge about post-traumatic instability in order to improve emergency care procedure.

Date	26 May 2016
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Yvan Petit (Supervisor) & Éric Wagnac (Co-supervisor)