[Biomechanical evaluation of five fixation techniques for the lower cervical spine].

ABSTRACT

OBJECTIVE: This study biomechanically investigated the three-dimensional motion stability of five reconstruction methods in the cervical spine, in order to provide the biomechanical basis for the clinical selection of fixation methods. METHODS: With eight adult cervical spine fresh specimens, the three-column injury was produced at C(4 - 5) level. The spinal constructs, reconstructed by various techniques including anterior titanium locking screw plate (TLSP), posterior interspinous wiring (IW), combined fixation with the TLSP and IW (TLSP + IW), Roy-Camille plate (RP), and transpedicular screw plate (TP), were tested under six loading modes-flexion, extension, right/left lateral bending, and right/left axial rotation. RESULTS: The three-dimensional motion stability of either TLSP or IW was less than that of intact cervical spine. The TLSP + IW and RP provided increased stability compared with the intact spine. The stabilizing capabilities of transpedicular screw plate fixation was the best in all loading modes. CONCLUSIONS: In three-column instability of cervical spine injury, exclusive use of the anterior plate or the posterior interspinous wiring was not supported by the results. The stabilizing capabilities provided by combined anterior and posterior instrumentation and posterior plate were good. The three-column fixation for the cervical spine using transpedicular screw plate fixation offers increased stability significantly over that of other conventional cervical fixation systems.