Abstract
The goal of this in vitro study was to investigate the initial mechanical state of the lumher functional spinal unit (FSU) with three types of spinal fixation devices. An experimental porcine FSU testing system was developed for the in vitro motion measurement during flexion-extension, lateral bending and axial rotation. Three groups of FSU (L1/2,3/4,5/6) with each system of Hokkaido Hook and Rod (HHR), Graf and Global were tested. These initial lumber stabilization states were compared on the basis of stiffness and mechanical characteristics during FSU motions. The dominate result of the study were that the mean stiffness in the HHR system decreased significantly when compared to those in both Graf and Global systems, and that the mean neutral zone was visibly wide.
