Department of Mechanical Engineering, National Institute of Technology Warangal, Warangal, Telangana, 506004, India.
Department of Metallurgical & Material Engineering, National Institute of Technology Warangal, Warangal, Telangana, 506004, India.
Med Biol Eng Comput. 2017 Nov;55(11):2053-2065. doi: 10.1007/s11517-017-1649-3. Epub 2017 May 5.
This computational study explores a unique modelling approach of the cranial implant, homogenous scaffold algorithm and meshless method, respectively. This meshless method is employed to review the implant underneath intracranial pressure (ICP) conditions with a standard ICP range of 7 mm of Hg to 15 mm of Hg. The algorithm is used to introduce uniform porosity within the implant enabling the implant behaviour with respect to ICP conditions. However, increase in the porosity leads to variation in deformation and equivalent stress, respectively. The meshless approach provides a valuable insight in order to know the effect of total deformation and equivalent stress (von Mises stress) and replaces the standard meshing strategies. The patient CT data (computed tomography) is processed in MIMICS software to get the mesh model. An entirely unique modelling approach is developed to model the cranial implant with the assistance of the Rhinoceros software. This modelling methodology is the easiest one and addressing both the symmetrical and asymmetrical defects. The implant is embedded in a unit cell-based porous structure with the help of an algorithm, and this algorithm is simple to manage the consistency in porosity and pore size of the scaffold. Totally six types of implants are modelled with variation in porosity and replicate the original cranial bone. Among six implants, Type 2 (porosity 82.62%) and Type 5 (porosity 45.73%) implants are analysed with the meshless approach under ICP. The total deformation and equivalent stress (von Mises stress) of porous implants are compared with the solid implant under same ICP conditions. Consequently, distinctive materials are used for structural analysis such as titanium alloy (Ti6Al4V) and polyether-ether-ketone (PEEK), respectively. The deformation and equivalent stress (von Mises stress) results are obtained through the structural analysis. It was observed from the results that the titanium-based solid implant is the best implant in all aspects, while considering weight and osseointegration PEEK-based Type 5 implant is the best one. A novel free-form closed curve network (FCN) technique is successfully developed to model a cranial implant for symmetrical and asymmetrical defects. The porous implant is adequately modelled through the unit cell algorithm and analysed through meshless approach. The implementation of 3D printed component will allow physicians to gain knowledge and successfully plan the preoperative surgery.
本计算研究分别探索了颅骨植入物的独特建模方法、均匀骨架算法和无网格方法。采用无网格方法研究颅内压 (ICP) 条件下植入物的行为，ICP 标准范围为 7mmHg 至 15mmHg。该算法用于在植入物内引入均匀的孔隙率，从而使植入物能够适应 ICP 条件。然而，孔隙率的增加会导致变形和等效应力的变化。无网格方法提供了有价值的见解，以便了解总变形和等效应力（von Mises 应力）的影响，并取代标准的网格策略。通过 MIMICS 软件处理患者的 CT 数据（计算机断层扫描）以获得网格模型。借助 Rhinoceros 软件开发了一种全新的建模方法来模拟颅骨植入物。这种建模方法最简单，可解决对称和非对称缺陷。在算法的帮助下，将植入物嵌入基于单元的多孔结构中，该算法易于管理支架的孔隙率和孔径一致性。总共对六种具有不同孔隙率的植入物进行建模，以复制原始颅骨。在这六种植入物中，在 ICP 下使用无网格方法分析了 Type 2（孔隙率 82.62%）和 Type 5（孔隙率 45.73%）植入物。多孔植入物的总变形和等效应力（von Mises 应力）与相同 ICP 条件下的实心植入物进行比较。因此，分别使用不同的材料进行结构分析，例如钛合金 (Ti6Al4V) 和聚醚醚酮 (PEEK)。通过结构分析获得变形和等效应力（von Mises 应力）结果。结果表明，在所有方面，考虑到重量和骨整合，基于钛的实心植入物是最好的植入物，而基于 PEEK 的 Type 5 植入物是最好的。成功开发了一种新颖的自由形式封闭曲线网络 (FCN) 技术，用于模拟对称和非对称缺陷的颅骨植入物。通过单元算法充分模拟多孔植入物，并通过无网格方法进行分析。3D 打印组件的实现将使医生能够获得知识并成功规划术前手术。
