METHODS: This was a biomechanical finite element model analysis. FE analysis of the spine was conducted with posterior instrumentation under multidirectional loading conditions in order to evaluate the kinematics of the instrumented lumbar spine, as well as stresses in the posterior spinal instrumentation. We analyzed the following: 1) the range of motion of the T9-L3 region; and 2) the von Mises stress nephograms of the pedicle screws, rods, vertebrae, endplates, and intervertebral discs of 2 fixation FE models.
RESULTS: Long-segment stabilization was found to be beneficial in terms of reducing total stress on the spine. However, it is possible to reduce the stress on the system by incorporating the spinal fracture into the stabilization system. Therefore, short-segment stabilization is sufficient to create a safe and robust stabilization system and to maintain neighboring intact vertebrae.
CONCLUSIONS: Short-segment posterior fixation is sufficient to stabilize fractures at the TL junction, where the spinal fracture is included in the stabilization system.