材料和孔隙率对可降解支架内骨形成的影响

目的研究可降解支架植入人体后的骨修复,不同材料和孔隙率对支架内骨形成的影响。方法根据骨折愈合自然反应机理,运用有限元方法,结合支架几何结构,搭建以材料降解曲线和骨重建控制方程为基础的计算耦合模型。通过这一平台,选择5种材料、4种孔隙率的支架代表性体积元进行计算模拟分析,并通过骨密度和支架最大应力反映这一动态过程。结果材料弹性模量对支架内骨组织生长的影响较大,材料弹性模量越小,骨形成量越大,但会对支架的力学性能造成较大影响。较高孔隙率的支架刚度小,能够更好地促进骨组织形成,但同时也会破坏支架的力学稳定性。结论根据不同年龄、性别和部位骨组织的性能需求,为可降解多孔骨支架的材料和孔隙率选择、结构设计以及临床应用提供个性化参考和计算依据。

The Effect of Materials and Porosity on Bone Formation of Degradable Scaffolds

Objective To study the effect of different materials and porosities on bone formation in the scaffold after implantation of the degradable bone scaffold into human body. Methods According to natural reaction mechanism of fracture healing, the finite element method was used, combined with geometry of the scaffold, to establish a computationally coupled model based on material degradation curve and bone reconstruction control equation. Through this platform, representative volume elements of the scaffold with five kinds of materials and four types of porosities were selected for calculation and analysis, and dynamic process was reflected by bone mineral density (BMD) and maximum stress of the scaffold. Results The elastic modulus of the materials had a greater influence on growth of bone tissues in the scaffold. The smaller elastic modulus of the materials would lead to the greater amount of bone formation, but it would also have a greater impact on mechanical properties of the scaffold. The scaffold with higher porosity had lower rigidity, which could better promote formation of bone tissues, meanwhile it would also destroy mechanical stability of the scaffold. Conclusions According to performance requirements for different age, gender and location of bone tissues, personalized reference and calculation basis for selection of materials and porosity, structural design and clinical application of degradable porous bone scaffolds can be provided.