Biomechanics of fusion and stabilization.

STUDY DESIGN: Literature review.

OBJECTIVES: To assess the state of the art in the biomechanics of fusions, fusion materials, and the use of instrumentation by critically reviewing the literature as modified by group discussion.

SUMMARY OF BACKGROUND DATA: A considerable body of knowledge addresses these issues based on in vitro biomechanical testing and mathematical models. Much biomechanical information is available regarding the biomechanical behavior of the graft material, the fusion, and the instrumentation. Biomechanical testing and finite element analyses remain to be done on semirigid devices, interbody spacers, and artificial discs.

METHODS: The literature was reviewed to analyze papers written on the following topics: graft material, in vitro tests of instrumentation, device evaluation using artificial spine models, in vivo human studies, animal models, finite element studies, effects of rigidity, and bone adaptive remodeling.

RESULTS: One hundred forty-one modern articles were reviewed and their data analyzed. Much important insight has come from biomechanical studies.

CONCLUSIONS: Fusions are largely successful. Biomechanical data is complete except for some of the latest devices.