Kinetic and Biomechanical Testing of Two-Level Cervical Disc Replacement Available to Purchase

Cervical disc replacement has become an increasingly common practice in Europe and several disc designs are currently being evaluated via clinical trial for regulatory approval in the United States. The majority of these procedures have been performed at one level in the absence of adjacent level fusion. However, recent conference proceedings have reported on multi-level implantations of these devices. Numerous literature accounts have reported on the in vitro kinetics and kinematics of these devices that have generally shown motion equivalence to the intact spine when implanted at one level. The current study seeks to build upon this previous work by investigating the kinetics associated with two-level disc replacement. In addition, we investigated the implications of a minimally invasive two-level salvage procedure that would involve direct plating over an implanted disc prosthesis while maintaining the disc replacement at an adjacent level.