[Stability analysis of various forms of fusion of the lumbar vertebrae using a computer simulation model]

To analyze mechanical properties of a lumbar functional unit a mathematical simulation model was developed. Using this model in different lumbar fusions immediate postoperative and secondary stability was analysed. Stability of different interbody and posterior fusions was compared looking at different techniques of operation an instrumentation. The calculation showed best results in the combination of posterolateral fusion with interspinal distraction or transpedicular screw instrumentation. These showed well-balanced load carrying properties primarily and high secondary stability.