Biomechanical Behaviors in Three Types of Spinal Cord Injury Mechanisms

Abstract

Clinically, spinal cord injuries (SCIs) are radiographically evaluated and diagnosed from plain radiographs, computed tomography (CT), and magnetic resonance imaging. However, it is difficult to conclude that radiographic evaluation of SCI can directly explain the fundamental mechanism of spinal cord damage. The von-Mises stress and maximum principal strain are directly associated with neurological damage in the spinal cord from a biomechanical viewpoint. In this study, the von-Mises stress and maximum principal strain in the spinal cord as well as the cord cross-sectional area (CSA) were analyzed under various magnitudes for contusion, dislocation, and distraction SCI mechanisms, using a finite-element (FE) model of the cervical spine with spinal cord including white matter, gray matter, dura mater with nerve roots, and cerebrospinal fluid (CSF). A regression analysis was performed to find correlation between peak von-Mises stress/peak maximum principal strain at the cross section of the highest reduction in CSA and corresponding reduction in CSA of the cord. Dislocation and contusion showed greater peak stress and strain values in the cord than distraction. The substantial increases in von-Mises stress as well as CSA reduction similar to or more than 30% were produced at a 60% contusion and a 60% dislocation, while the maximum principal strain was gradually increased as injury severity elevated. In addition, the CSA reduction had a strong correlation with peak von-Mises stress/peak maximum principal strain for the three injury mechanisms, which might be fundamental information in elucidating the relationship between radiographic and mechanical parameters related to SCI.

Effect of experimental, morphological and mechanical factors on the murine spinal cord subjected to transverse contusion: A finite element study

“…This shows that regardless of the assumptions made on the WM and GM material properties, it is possible to simulate the global mechanical behavior of the spinal cord. The three sets were chosen in view of the available data and have all been used in spinal cord FE model investigating injury mechanisms [12,13,18,[32][33][34]. This study demonstrated the strong impact of the choice of material properties on the local mechanical behavior throughout the spinal cord.…”

Stress effects of the cerebrospinal pulsatile flow on the spinal cord by a 3D fluid-structure modeling

“…The maximum Von Mises value (3.8 kPa) are respectively 5, 33 and 86 times less than the ones in a contusion, a distraction and a dislocation at the C4/ C5 functional unit (Khuyagbaatar et al 2016).…”

Increased stress and strain on the spinal cord due to ossification of the posterior longitudinal ligament in the cervical spine under flexion after laminectomy

“…There were some limitations in this study. The model used in this study was developed based on our previously validated FE model of the spinal cord 20,27 and indirectly validated by comparing the stresses and strain value in the spinal cord with those in previous computational studies. 25 Only one segmental type of OPLL at C5 was investigated, despite there being multiple factors related to clinical outcomes such as the OPLL, segmental mobility, and cervical lordosis.…”

“…Influence of flexion motion on the spinal cord was investigated, 16 and the hyperextension injury of the cervical spinal cord was analyzed in simple cases. 17 Moreover, the stress and strain distributions in the spinal cord were simulated during various column injury patterns, [18][19][20] ossified ligaments, [21][22][23][24] and contusion injuries. 14,[25][26][27][28] In our previous study, an FE model of the cervical spine with the spinal cord, including white matter, gray matter, dura mater with nerve roots, denticulate ligaments, and cerebrospinal fluid (CSF), was developed and investigated the effect of surgical extents in three different decompression methods on changes in stress, strain, and posterior shift of the spinal cord for cervical OPLL.…”