Effect of impact velocity and ligament mechanical properties on lumbar spine injuries in posterior-anterior impact loading conditions: a finite element study

摘要

Traumatic events may lead to lumbar spine injuries ranging from low severity bony fracture to complex fracture dislocation. Injury pathomechanisms as well as the influence of loading rate and ligament mechanical properties were not yet fully elucidated. The objective was to quantify the influence of impact velocity and ligament properties variability on the lumbar spine response in traumatic flexion-shear conditions. An L1-L3 finite element spinal segment was submitted to a posterior-anterior impact at three velocities (2.7, 5, or 10m/s) and for 27 sets of ligament properties. Spinal injury pathomechanism varied according to the impact velocities: initial osseous compression in the anterior column for low and medium velocities versus distraction in the posterior column for high velocity. Impact at 2.7 and 5m/s lead to higher extent of bony injury, i.e., volume of ruptured bone, compared to the impact at 10m/s (1140, 1094, and 718mm(3) respectively), lower L2 anterior displacement (2.09, 5.36, and 7.72mm respectively), and lower facet fracture occurrence. Ligament properties had no effect on bony injury initiation but influenced the presence of facet fracture. These results improve the understanding of lumbar injury pathomechanisms and provide additional knowledge of lumbar injury load thresholds that could be used for injury prevention.