Optimiser la mobilisation précoce des blessés médullaires

Abstract

Spinal cord injuries are ones of the most catastrophic event human can face, leading to a loss of motor and sensitive functions. Following a spinal cord injury, mobilization is a decisive phase in the recovery of lost functions. This mobilization has to reproduce natural walking and be initiated within 48h after spinal surgery, to maximize the patient’s chances of walking again. Currently, only Sacré Coeur hospital initiates mobilization of spinal injured patients in this time interval, with a cyclic ergometer. However, the circular trajectory reproduced by this ergometer displays, initially, few similarities with the kinematics of natural walking, this movement being the main function we want to reproduce. Moreover, the ways of setting this ergometer and installing the patients are still poorly understood. The main objective of this research was to optimize early mobilization for spinal cord injured patients. First, a new ergometer aiming to reproduce natural walking in a hospital bed, was numerically designed with CATIA software. A linear motion was chosen. Then, a digital tool simulating lower limbs dynamics in the ergometer was built, using MATLAB software. Reliability of the digital tools was tested by comparing its results with experimental data from 10 subjects using a cyclic ergometer. Our results suggested a good reliability for lower limb kinematics with a CORA > 0.65, but limited reliability for reaction forces (p<0,5) compared to experimental data. Then, we conducted an experimental design, to study the effects of configuration parameters and determine the optimal configuration for the linear and cyclic ergometer. The maximum knee extension angle was found to be the most influential parameter, contributing over 50% to variations in hip and knee dynamics. The position of the foot on pedals contributes to 18% of the variations of the maximum reaction force and the height at which the movement is performed, contributes over 30% to variations in hip extension. Cadence had no effects on kinematics but contributed to an 8% variation in maximum reaction force. Finally, we compared the linear and cyclic ergometer under optimal conditions and found that the linear ergometer had a hip flexion/extension pattern identical to walking (r=0,97) and a greater number of morphological adjustments than the cyclic ergometer. Although, the linear ergometer showed less hip extension (6,4°) and more reaction force (2,7%) but these differences were not significant according to the established evaluation scale. In conclusion, our research proposes a new device that appears to be advantageous for early mobilization of spinal cord injured patients and a digital tool that provides better understanding of mobilization performance in a hospital bed. This project has thus advanced knowledge on the mobilization strategies to be adopted in a hospital bed.

Date	8 May 2023
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Yvan Petit (Supervisor) & Jean Marc Mac-Thiong (Co-supervisor)