Feasibility Study: Replicating Dynamic Impact Events of the Spinal Cord

Injuries related to the central nervous system (CNS) pose significant health challenges and are among the leading cause of disability worldwide. The spinal cord is an ultra-soft and complex structure that transmits motor signals from the brain to the body and, viceversa, returns sensory perceptions to the brain. The transmission of nerve signals is entrusted to highly oriented, myelinated axon bundles embedded in the white matter of the spinal cord. Dynamic events, such as traffic accidents or falls, can severely damage this “information highway”, leading to functional and neurological damage. In literature, the characterisation of spinal cord tissue subjected to dynamic tests is incomplete. In particular, it is not yet fully understood how the high strain rate affects the microstructure of the tissue. Simultaneous and combined mechanical loading, testing and subsequent imaging of regions of interest may therefore contribute to understanding the potential damage mechanisms that occur during dynamic spinal cord impacts. This work is a feasibility study with the aim of assessing the possibility of identifying axonal damage in spinal cord tissue and identifying the tools needed to do so. After a mechanical characterisation of the porcine spinal cord tissue by applying shear, tensile and compressive loads, an experimental system for the uniaxial machine is constructed to simulate physiological loading on the spinal cord tissue during dynamic impacts. However, the obtained results show that the system is not suitable for replicating a dynamic impact on the spinal cord. Therefore, in the future, it is desired to test a new system to be used with the triaxial testing machine, and, using histological analysis, it is intended to investigate whether there is a correlation between the mechanical variables (loading speed and displacement) and the potential damage to the internal structure of the spinal cord.