Pressure-induced end-plate fracture in the porcine spine: Is the annulus fibrosus susceptible to damage?

Abstract

PURPOSE: To determine if the mechanical properties of the annulus fibrosus (AF) are altered following end-plate fracture. Vertebral fractures, particularly those in the growth plate, are relatively common among adolescents. What is unclear is whether or not these fractures are also associated with concomitant damage to the intervertebral disc (IVD), in particular the AF. METHODS: The current study employed a high-rate IVD pressurization model to create growth plate fractures in the porcine cervical spine. Posterior AF mechanical properties and laminate adhesion strength were quantified in fractured spines and compared to samples obtained from non-pressurized, un-fractured spines. RESULTS: AF laminate adhesion strength was 31% lower in the fractured spines compared to the un-fractured spines. CONCLUSION: This decrease in laminate adhesion strength suggests that growth plate fracture damage is not isolated to the vertebra and results in microdamage to the interlamellar matrix of the AF. This may increase in the risk of progressive delamination of the AF, which is associated with IVD herniation. These slides can be retrieved under Electronic Supplementary Material.