Développer un modèle cinématique de mobilisation précoce pour les blessés médullaires

Abstract

Spinal cord injury is one of the most catastrophic events an individual can suffer, resulting in major loss of motor and sensory function. After such an injury, early mobilization is crucial to recover lost function, and it is essential that it is initiated as soon as possible, i.e. within 48 hours of spinal surgery. Mobilization within this critical timeframe is only practiced at Montreal's Hôpital du Sacré-Coeur, where patients benefit from passive cyclic ergometer mobilization. Current sessions focus on patient safety, vital sign monitoring and comfort during exercise. To go beyond this approach and explore the possibility of individually tailoring sessions to optimize long-term recovery, an in-depth study was undertaken. This study used OpenSim's FullBody model to estimate the biomechanics of the lower limbs of spinal cord patients. The model was adjusted to the morphological dimensions of the patients to reproduce real movements as faithfully as possible. Manual scaling proved highly effective in accurately adapting the FullBody model to a wide range of body segment sizes. In addition, the model's ability to reproduce static poses and leg movements was confirmed as highly accurate, with a mean error of less than 1.2. Of the 14 cycling sessions planned per patient, 6 required equipment including 8 reflective markers, two rigid bodies, an Optitrack marker trajectory tracking system, electromyographic sensors with electrodes and two pressure insoles. Their placement and calibration were checked for pedaling motion analysis. The study of biomechanical relationships during passive cyclic exercise in spinal cord subjects showed a correlation between joint movements and muscle stretching but failed to identify a clear link with electrical muscle stimulation or pressure forces. By analyzing the impact of crankset amplitude and pedaling speed parameters, it was found that these significantly influenced muscle stretching and joint movements, offering the possibility of controlling these biomechanical aspects by adjusting the settings of the cyclic ergometer. This parametric study also identified a significant patient effect, meaning that the morphology of spinal cord subjects should be considered when adjusting ergometer usage parameters. Customized adaptation of pedaling parameters could thus enhance stimulation of the subjects' legs, with notable differences according to patient size. Further research is needed to confirm these preliminary observations.

Date	15 Jun 2024
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Yvan Petit (Supervisor) & Jean Marc Mac-Thiong (Co-supervisor)