Synthetic biomaterials for spinal fusion.

Calcium hydroxylapatite (HAP), tricalcium phosphate (TCP), and Bioglass (BG) were implanted in the spines of dogs to determine their potential in augmenting and enhancing spinal fusion. HAP and TCP showed continuous bone to biomaterial interfaces of varying degrees. Trabecular bone surrounded and incorporated the particulate hydroxylapatite. Tricalcium phosphate ceramic showed little evidence of resorption. The glass particulate, BG, showed a thin, fibrous encapsulation with some adjacent bony trabeculae. Decortication and autogenous bone enhanced incorporation. This multivariant initial study showed that trends found for the biomaterials implanted independently were similar to those used in combination. No adverse tissue reactions were noted for the combination of materials.