Moiduddin Khaja
Princess Fatima Alnijiris's Research Chair for Advanced Manufacturing Technology (FARCAMT Chair), Advanced Manufacturing Institute, King Saud University, Riyadh, Saudi Arabia.
Proc Inst Mech Eng H. 2018 Feb;232(2):185-199. doi: 10.1177/0954411917751558. Epub 2018 Jan 13.
The traditional methods of metallic bone implants are often dense and suffer from adverse reactions, biomechanical mismatch and lack of adequate space for new bone tissue to grow into the implant. The objective of this study is to evaluate the customized porous cranial implant with mechanical properties closer to that of bone and to improve the aesthetic outcome in cranial surgery with precision fitting for a better quality of life. Two custom cranial implants (bulk and porous) are digitally designed based on the Digital Imaging and Communications in Medicine files and fabricated using additive manufacturing. Initially, the defective skull model and the implant were fabricated using fused deposition modeling for the purpose of dimensional validation. Subsequently, the implant was fabricated using titanium alloy (Ti6Al4V extra low interstitial) by electron beam melting technology. The electron beam melting-produced body diagonal node structure incorporated in cranial implant was evaluated based on its mechanical strength and structural characterization. The results show that the electron beam melting-produced porous cranial implants provide the necessary framework for the bone cells to grow into the pores and mimic the architecture and mechanical properties closer to the region of implantation. Scanning electron microscope and micro-computed tomography scanning confirm that the produced porous implants have a highly regular pattern of porous structure with a fully interconnected network channel without any internal defect and voids. The physical properties of the titanium porous structure, containing the compressive strength of 61.5 MPa and modulus of elasticity being 1.20 GPa, represent a promising means of reducing stiffness and stress-shielding effect on the surrounding bone. This study reveals that the use of porous structure in cranial reconstruction satisfies the need of lighter implants with an adequate mechanical strength and structural characteristics, thus restoring better functionality and aesthetic outcomes for the patients.
传统的金属骨植入物方法通常较为致密，存在不良反应、生物力学不匹配以及缺乏足够空间供新骨组织长入植入物等问题。本研究的目的是评估定制的多孔颅骨植入物，其力学性能更接近骨骼，并通过精确适配改善颅骨手术的美学效果，以提高生活质量。基于医学数字成像和通信文件对两个定制颅骨植入物（整体式和多孔式）进行数字化设计，并使用增材制造技术制造。最初，使用熔融沉积建模制造有缺陷的颅骨模型和植入物，以进行尺寸验证。随后，通过电子束熔化技术使用钛合金（Ti6Al4V超低间隙）制造植入物。基于其机械强度和结构特征对融入颅骨植入物的电子束熔化产生的体对角线节点结构进行评估。结果表明，电子束熔化产生的多孔颅骨植入物为骨细胞长入孔隙提供了必要框架，并模仿了更接近植入区域的结构和力学性能。扫描电子显微镜和微计算机断层扫描证实，所生产的多孔植入物具有高度规则的多孔结构模式，具有完全相互连接的网络通道，没有任何内部缺陷和空隙。钛多孔结构的物理性能，包括抗压强度为61.5MPa和弹性模量为1.20GPa，是一种有前途的降低对周围骨骼的刚度和应力屏蔽效应的方法。本研究表明，在颅骨重建中使用多孔结构满足了对具有足够机械强度和结构特征的更轻植入物的需求，从而为患者恢复更好的功能和美学效果。
