SPINE UPDATE THE USE OF ANIMAL-MODELS TO STUDY SPINAL-FUSION

The outcome of a spinal fusion depends upon a multifactorial process. Therefore, it is difficult and impractical to study individual variabl es clinically. Animal models have been useful in studying the paramete rs that influence the spinal fusion process. Despite the knowledge gai ned from previous animal studies, there exists a large void in our bas ic understanding of this complex process. The purpose of this update i s to review the concept of animal models of spine fusion by summarizin g previous models, identifying strengths and deficiencies, reviewing t he strategy for selecting a model, and highlighting knowledge gaps sui table for future research. With recent advances in the knowledge regar ding gene-specific therapies and the availability of osteoinductive pr oteins, we have entered a new era of biologic manipulation of bone for mation. Animal data, however, are only as applicable as the model from which it is derived, acid future animal models must overcome the defi ciencies highlighted in this review. A valid animal model will prove e ssential in studing the use of growth factors for spinal fusion. The u ltimate goal is that fusion nonunions will no longer be of clinical co ncern.