Functional Bionic Design of Additively Manufactured Polyetherketoneketone Cranial Implants

Objective To address the current challenges in cranial implant development, such as the difficulty in balancing functionality and lightweight design, as well as inadequate personalization, this study proposes a functional bionic design method, which enables an integrated macro-micro structural design of polyetherketoneketone (PEKK) cranial implants with reduced cost, lightweight characteristics, and optimized biomechanical performance. Methods Three-dimensional (3D) reconstruction of the cranial implant was performed based on the patient’s computed tomography (CT) data. An integrated structure consisting of a ‘perforated outer layer, cobweb-like truss middle layer, and smooth inner layer’ was designed to simulate the three-layer structure of natural cranial bone. The core parameters of the middle-layer truss were optimized via orthogonal experiments. Fused filament fabrication (FFF) technology was employed for the 3D printing of PEKK implants, followed by surface morphology characterization, static mechanical analysis, and mechanical performance tests (including impact resistance and compression tests). Results The core parameters of the truss structure in the middle layer of the cranial implant were determined as follows: spiral line width of 3 mm, radial line width of 4 mm, and 8 radial lines. The optimized PEKK cranial implant achieved an energy absorption efficiency of over 70%, which could effectively dissipate energy under impact loading. In the static compression test, the peak load reached approximately 1250 N, and the failure displacement extended to 14 mm, demonstrating low stiffness and high ductility characteristics. This implant exhibited good compatibility with the physiological properties of the human skull. Additionally, the porous design of the outer layer reduced material consumption and manufacturing costs. Conclusions The integration of bionic design and 3D printing technology achieves the synergistic optimization of personalization, lightweight performance, and mechanical-biological properties of cranial implants, thus providing theoretical and technical support for clinical cranial repair.