Stress Analyses of Load Sharing on Facet and Uncovertebral Joints with Bryan, Prestige LP, and Prodisc-C Cervical Disc Prostheses

INTRODUCTION Artificial disc arthroplasty, as a promising treatment for disc degenerative diseases, has been reported to restore normal disc height, preserve segmental motion and decrease adjacent level degeneration. Despite its encouraging short term outcomes, complications related to device and surgical procedure such as subsidence, dislocation and instability due to misalignment warrant further study. Moreover, the attempts to investigate the possible influence of the device design on facet and uncovertebral joint degeneration are rare. Previously, three different artificial disc prostheses, Bryan, Prestige LP (Medtronic Spinal & Biologics, Minneapolis, MN), and ProDisc-C (Synthes, Inc., West Chester, PA) were analyzed in our group using an image based finite element method (FEM) to investigate the propensity of subsidence due to the device design. In this successive study, the load sharing at the facet and uncovertebral joints was estimated by FEM and the difference in the device designs that leads to the presented consequences was also discussed.