Law of PMMA flowing and distributing in the vertebra by computer modeling

    LIU Xuª²Li, LEI Wei, ZHENG Jin, LI Guoª²Jun, YU Haiª²Long

    PLA Institute of Orthopaedics, Xijing Hospital,Fourth Military Medical University, Xi¬ðan 710033, China, Department of Fluid Mechanics, School of Energy and Power Engineering, Xi¬ðan Jiaotong University, Xi¬ðan 710049, China

    ¡¾Abstract¡¿AIM: To investigate the law that PMMA (polymethylmethacrylate) flows and distributes in the vertebra so as to lay the operational theoretical foundation for the clinical work of percutaneous vertebroplasty. METHODS: Based on the structural characteristics and parameters of the healthy adult vertebra,a vertebral model of porous media was made by the computer software and the law that silicone oil with a viscosity matching that of PMMA flew and distributed in the model was calculated and analyzed by means of hydrodynamics and numeric modeling. RESULTS: The silicone oil distributed in a circleª²like shape on each plane in the vertebral model,and the largest amount was on the planes through the injection point.The volume fraction of the silicone oil decreased from the center of planes to outward on each plane. CONCLUSION: The law that PMMA flows and distributes in the vertebral model was to spread in all directions in a circleª²like shape on the planes through the injection point as a centre and it finally became a ballª²like shape as a whole. ......