Chuah Hun Guan, Abd Rahim Inzarulfaisham, Yusof Mohd Imran
School of Mechanical Engineering, Universiti Sains Malaysia, Engineering Campus, 14300, Nibong Tebal, Pulau Pinang, Malaysia.
Comput Methods Biomech Biomed Engin. 2010 Jun;13(3):319-26. doi: 10.1080/10255840903208189.
The stress shielding effect is an event in which the replacement implant limits the load transferred to bone and the ineffective stress in the vertebrae causes bony growth to cease. In the present study, a 3D finite element L4-L5 model was developed and subjected to a 1200 N compression preload. Five groups of muscle forces were applied on L4 under flexion-extension, lateral bending and axial rotation. Topology optimisation was employed for reducing the stress shielding effect by removing the ineffective material from the design domain. The optimised design was designed with polyaryletheretherketone (PEEK) titanium and cortical materials to encounter the shielding response. The stress responses show that the new design increased the stress magnitude by at least 17.10, 18.11 and 18.43% in 4 Nm of flexion-extension, lateral bending and axial rotation, respectively. In conclusion, the material factor did not significantly alter the stress magnitude, but volume was the key factor in reducing the stress shielding effect.
应力屏蔽效应是指替代植入物限制传递至骨骼的载荷，且椎骨中的无效应力导致骨生长停止的一种现象。在本研究中，建立了一个L4-L5三维有限元模型，并对其施加1200 N的压缩预载荷。在屈伸、侧弯和轴向旋转状态下，对L4施加了五组肌肉力。采用拓扑优化方法，通过从设计域中去除无效材料来降低应力屏蔽效应。优化设计采用聚芳醚醚酮（PEEK）、钛和皮质材料，以应对屏蔽反应。应力响应表明，在4 Nm的屈伸、侧弯和轴向旋转状态下，新设计分别使应力大小至少增加了17.10%、18.11%和18.43%。总之，材料因素并未显著改变应力大小，但体积是降低应力屏蔽效应的关键因素。
