Properties of Injectable Composite Cements and its Application in Burst Fracture of the Spine

To explore a new type of injectable composite cements similar to the natural bone in both composition and hierarchical structure, the mineralized collagen and calcium sulphate dihydrate（CSD）were incorporated into α-calcium sulphate hemihydrate (α-CSH).The mineralized collagen was synthesized biomimetically by nanohydroxyapatite/collagen. We investigated the injectability, the setting time and the biomechanics properties to find an ideal combination of them to prepare the composite cements. SEM analysis showed biphasic cements consisting of an entanglement of calcium sulfate dihydrate and calcium-deficient hydroxyapatite crystals. We prepared porcine thoracolumbar burst fracture models and made the vertebroplasty for them by the composite cements. Imaging analysis showed the composite cements distributed uniformly and solidified well. Biomechanical test showed the ability of composite cements to repair spinal burst fractures was significant.