Biomechanical Analysis of a Novel Equine Cervical Stabilization Technique

Introduction: Cervical vertebral malformation is a common cause of neurologic deficits. The authors have developed a novel cervical stabilization technique utilizing pedicle screws and rod construct with interbody device (PSR). To further validate this novel technique and understand its true biomechanical properties, we aimed to evaluate nondestructive range of motion kinematics. We hypothesize that the PSR technique will result in reduced ROM and compliance.

Materials and Methods: Nondestructive range of motion (ROM) and compliance kinematics in the equine cervical spine after single-level stabilization was performed using a custom-built testing system to apply pure moments in flexion, lateral bending, and axial loads.

Results: The PSR technique had decreased compliance at the adjacent level for the flexion axis. The PSR technique ROM for the treated level in the axial axis had increased compliance and ROM. The pedicle screw construct without an interbody device (R) technique had decreased ROM and compliance for the flexion axis at the treated level. The R technique had increased ROM and compliance at the adjacent level for flexion and lateral movement when compared with PSR and control.

Discussion/Conclusion: The PSR technique had increased the ROM and compliance for treated level in the flexion axis. It is likely that the interbody cage offers a higher point of leverage responsible for the increase in extension at the ventral aspect of the spine, which translates into the increased flexion–extension movement. The PSR technique does not result in significant stability of the adjacent FSU, which may decrease risk of the domino effect or degeneration.

Acknowledgement: Young Investigators Award at Colorado State University.