Modeling of Cerebrospinal Fluid for Impact Biomechanics

Traumatic spinal cord injury (TSCI) are critical injuries that have dramatic consequences. However, the underlying mechanisms in term of spinal cord damage are still investigated. Finite element models of the central nervous system (CNS) have been developed but modeling the cerebrospinal fluid (CSF) is expensive in computational time. Smoothed particle hydrodynamics (SPH) is a promising method to model the CSF for TSCI scenarios. The objective of this article was to develop a hybrid finite element and SPH model of the CNS to investigate how different SPH parameters, namely the inclusion or absence of boundary conditions and the interface gap (0, 0.35 and 0.7 mm) between the CSF and meninges, could influence the simulation results and principally the spinal cord damage. A contusion at 4.5 m.s−1 was simulated on the CNS. The model showed good correspondence in terms of impactor penetration compared to the literature. The presence of CSF reduced the maximum von Mises stresses (163 to 141 kPa). The interface gap between the meninges and the CSF had an important influence on the model stability; with a gap of 0.35 mm tensile forces were present in the SPH and at 0.7 mm the energy error was too high in the simulation. Inclusion of boundary conditions had a minimal influence on the spinal cord stresses and strains. Briefly, CSF has an impact on spinal cord protection and SPH is a good option to model this fluid.