Effect of vertebral degeneration on the instability of spine

Insufficient exploration of the dependence between diseases of degenerative bones and the range of motion (ROM) during torsion, flexion and lateral bending limits further understanding about the lumbar biomechanics and treating of the lumbar related dysfunction. The objective of this study was to determine the effect of vertebral degradation on the instability of spine 2 motion L2–L4 segments during torsion, flexion and lateral bending by the finite element method (FEM). Three different 3D FE models comprising the healthy state and the degradation of trabecular bone and cortical bone were developed. Nonlinear numerical analyses of lumbar spine stability discovered that osteoporotic degradation can lead to critical segmental ROM and intervertebral shearing values, which results in the loss of spine stability for the case of flexion loading. Instability is caused by microscopic changes in the thickness of cortical shell. This analysis of the intervertebral shearing and ROM may be further used to diagnose such translation abnormalities like hypomobility or hypermobility.