Abstract
Abstract
Objectives
A damaged vertebral body can exhibit accelerated ‘creep’ under constant load, leading to progressive vertebral deformity. However, the risk of this happening is not easy to predict in clinical practice. The present cadaveric study aimed to identify morphometric measurements in a damaged vertebral body that can predict a susceptibility to accelerated creep.
Methods
Mechanical testing of 28 human spinal motion segments (three vertebrae and intervening soft tissues) showed how the rate of creep of a damaged vertebral body increases with increasing “damage intensity” in its trabecular bone. Damage intensity was calculated from vertebral body residual strain following initial compressive overload. The calculations used additional data from 27 small samples of vertebral trabecular bone, which examined the relationship between trabecular bone damage intensity and residual strain.
Results
Calculations from trabecular bone samples showed a strong non-linear relationship between residual strain and trabecular bone damage intensity (R2 = 0.78, P < 0.001). In damaged vertebral bodies, damage intensity as calculated from residual strain was then related to vertebral creep rate (R2 = 0.39, P = 0.001). This procedure enabled accelerated vertebral body creep to be predicted from morphological changes (residual strains) in the damaged vertebral body.
Conclusion
These findings suggest that morphometric measurements obtained from fractured vertebrae can be used to quantify vertebral damage intensity and hence to predict progressive vertebral deformity.