Basic biomechanics of spinal cord injury — How injuries happen in people and how animal models have informed our understanding

Abstract The wide variability, or heterogeneity, in human spinal cord injuryis due partially to biomechanicalfactors. This review summarizes our current knowledge surrounding the patterns of human spinal column injury and the biomechanicalfactors affecting injury. The biomechanicsof human spinal injury is studied most frequently with human cadaveric models and the features of the two most common injury patterns, burst fractureand fracture dislocation, are outlined. The biology of spinal cord injuryis typically studied with animal models and the effects of the most relevant biomechanicalfactors - injury mechanism, injury velocity, and residual compression, are described. Tissue damage patterns and behavioural outcomes following dislocation or distraction injury mechanisms differ from the more commonly used contusion mechanism. The velocity of injury affects spinal cord damage, principally in the white matter. Ongoing, or residual compression after the initial impact does affect spinal cord damage, but few models exist that replicate the clinical scenario. Future research should focus on the effects of these biomechanicalfactors in different preclinical animal models as recent data suggests that treatment outcomes may vary between models.