Data for: Evaluation of patient-specific cranial implant design using finite elemental analysis

This study aims to assess the load-bearing capacity of three patient-specific cranial implants. Although various studies exist that have analysed the mechanical behaviour of cranial implants, little attention is given to the design evaluation of a ceramic-titanium (CeTi) implant. The CeTi implant consists of a solid part in the centre of the implant and a scaffold at the border, both made of the Ti6Al4V-alloy. In the scaffold structure, HydroSet® is injected and sculpted. In order to better understand the mechanical behaviour of the CeTi implant, both tangential and axial screws are compared with a PEEK implant. Six computational models are developed in Abaqus/CAE. For each patient-specific implant, a global as well as a local model is constructed. The global models are subjected to two static loading conditions representing an impact load and the intracranial pressure. Nodal boundary conditions are imposed on the local models which represent the two aforementioned loading conditions. The global models are used to evaluate the location and magnitude of maximum Von Mises stress and displacement, whereas the local models offer the possibility to evaluate the Max Principal Stress in more detail. Hence, this work offers a broad view of the biomechanical properties of the cranial implants as different stress criteria are evaluated. Interaction properties are assigned between the cranial implant and neurocranium in order to mimic the biofidelic situation. Linear elastic and isotropic material properties are implemented for the various models. The results of the different analyses show that the PEEK cranial implant offers a less good brain and neurocranial protection due to its high flexibility and local peak stresses at the bone-screw interface. The CeTi implants are able to evenly distribute the stresses along the interface and thus reduce the risk for neurocranial fracture. The scaffold structure at the border of the implant reduces stress shielding and enhances bone ingrowth. Moreover, brain injuries are less likely to occur as the CeTi implant has a small deflection. The design evaluation presented in this work can further be used for design optimization purposes.

本研究旨在评估三款个性化颅骨植入物（patient-specific cranial implants）的承载能力。尽管已有诸多研究分析了颅骨植入物的力学行为，但针对陶瓷-钛（ceramic-titanium, CeTi）植入物的设计评价却鲜有涉及。该CeTi植入物由植入物中心的实心结构与边缘的支架结构构成，二者均采用Ti6Al4V合金制备；支架结构内会注入并成型HydroSet®材料。为更深入理解CeTi植入物的力学行为，本研究将切向螺钉与轴向螺钉分别与聚醚醚酮（PEEK）植入物进行对比。研究在Abaqus/CAE中构建了六组计算模型：针对每一款个性化植入物，分别搭建全局模型与局部模型。全局模型施加两种静态加载工况，分别模拟冲击载荷与颅内压；局部模型则施加对应上述两种工况的节点边界条件。全局模型用于评估最大冯·米塞斯应力（Von Mises stress）与位移的位置及幅值，而局部模型则可更细致地分析最大主应力（Max Principal Stress）。因此，本研究通过评估多种应力准则，全面展现了颅骨植入物的生物力学特性。为模拟生物逼真的实际工况，本研究为颅骨植入物与神经颅骨之间赋予了交互属性；各模型均采用线弹性各向同性材料属性。不同分析的结果表明，PEEK颅骨植入物因柔韧性较强，且在骨-螺钉界面处存在局部峰值应力，对脑部与神经颅骨的防护性能欠佳。而CeTi植入物可将应力沿界面均匀分布，从而降低神经颅骨骨折的风险。植入物边缘的支架结构可减少应力遮挡效应，并促进骨长入。此外，由于CeTi植入物的变形量较小，脑部损伤的发生概率更低。本研究提出的设计评价方法，可进一步用于颅骨植入物的设计优化工作。