Experimental vertebroplasty using osteoconductive granular material

Study Design. Osteoporotic human cadaveric thoracic vertebral bodies and ve rtebral bodies from mature Sheep were used as model systems to assess coral resorption and new bone formation after injection of coral granules. Objective. To evaluate the use of natural coral exoskeleton, an osteoconduc tive material, for the filling of vertebral bodies. Summary of Background Data. Percutaneous injection of polymethylmetacrylate (PMMA) is often proposed for prophylactically stabilizing osteoporotic ver tebral bodies at risk for fracture or augmentation of vertebral bodies that have already fractured. Recently, the possibility of using osteoconductive materials in granular formulation was assessed in pilot studies. Methods. As a first step, the possibility of injecting coral granules percu taneously within osteoporotic human cadaveric thoracic vertebral bodies was assessed. As a second step, cavities were drilled into vertebral bodies of 10 mature ewes and were either left empty (control group) or filled with c oral alone (CC) or coral supplemented with fibrin sealant (CC+FS). Quantita tive evaluation of coral resorption and new bone formation was made 2 month s and 4 months after implantation. Results. The distribution of coral granules injected into human cadaveric t horacic vertebral bodies was homogenous as assayed radiographically. In the experimental animal model, osteogenesis was increased in cavities filled w ith coral in comparison with cavities left empty at both 2 months and 4 mon ths (P < 0.005 and P < 0.02, respectively). Surprisingly, supplementation o f coral with a fibrin sealant had no positive influence on osteogenesis (P < 0.0008 at 2 months; P < 0.002 at 4 months). In addition, it led to an inc rease in coral resorption by as soon as 2 months < 0.0008). Conclusion. These results demonstrate the osteoconductivity of coral in gra nular form for vertebral filling. Interestingly, interconnectivity between adjacent bone trabeculae and newly formed bone was restored; however, its m echanical significance remains to be determined. Further investigations are needed to evaluate the efficacy of coral in osteopenic animals and in reli eving pain.