• Helical axis of motion of the cervical spine
• Geriatric spinal cord injury
• Madymo modeling of a rear impact
• Destructive cervical spine compression testing
• Finite element modeling of spinal cord compression

Current Research Projects

Finite element modeling of spinal cord compression

Material properties of the spinal cord are not well understood. The properties of the spinal cord are known to change quickly after death; therefore measurements are made in live (in vivo) animal subjects, which are technically challenging. While some studies have examined the spinal cord's response to axial stretching, there is a paucity of published data for the in vivo spinal cord under transverse compression. The objective of this study was to develop a technique combining static indentation tests of in vivo ovine spinal cords in conjunction with finite element (FE) analysis in order to determine the spinal cord's effective stiffness (Young's modulus) under transverse compression. This project is in support of the development a biofidelic surrogate spinal cord for use in cadaveric impact studies to advance the understanding of injurious spinal cord deformations.

In this study, transverse compression tests were performed on surrogate cords of known stiffness. Force vs. displacement data were obtained. A three dimensional finite element model (ANSYS) was created and used to calculate the force required to produce the indentation. These parameters, were then used to determine the stiffness (Elastic Modulus) of the cord.

While this static indentation method presented is limited to small strains it has widely been used in conjunction with FE analysis to determine the material properties of soft tissues. Further model development and non linear constitutive relations are in progress to accommodate larger strains, in the range of those seen during spinal cord injuries.

This project is in collaboration with the Injury Biomechanics Laboratory, Departments of Mechanical Engineering and Orthopaedics (Tim S. Nelson, B.A.Sc., Shannon Reed, M.A.Sc., Rebecca Rankine) at the University of British Columbia. Synaptic acknowledges financial support for this work from the Natural Sciences and Engineering Research Council of Canada and the British Columbia Neurotrauma fund.