Numerical modeling and evaluation of the biomechanical performance and stability of cranial implants with varying thicknesses and biomaterials

Cranioplasty is a standard neurosurgical procedure performed on patients following decompressive craniectomy. This study investigates the influence of implant thickness and material on biomechanical performance through finite element analysis. Cranial implants composed of Polyether Ether Ketone (PEEK), Polymethyl Methacrylate (PMMA), and Ti6Al4V with thicknesses in the range of 1 mm to 5 mm were systematically evaluated under three loading conditions. The findings indicate that increased implant thickness significantly reduces both deformation and von Mises stress. Implants with thicknesses of 1 mm and 2 mm exhibited the greatest deformation, potentially surpassing the material's yield strength. Maximum stress was predominantly localized at the interface between the implant fixation points and the skull, with implant thickness exerting a more pronounced effect than material type. Notably, implants with a 4 mm thickness in PEEK and PMMA demonstrated optimal mechanical performance, maintaining strain values at screw locations within the safe range of 200 to 2500 µε, thereby promoting bone formation and growth. Additionally, implant micromotion (IMM) was assessed to determine the biological durability of the implants. This analysis provides critical insights into cranial implants' biocompatibility and long-term mechanical stability.