Comparative assessment of 3D printed skull materials and ex vivo bone for craniosynostosis training: a finite element analysis

Craniosynostosis, a congenital premature fusion of cranial sutures, causes abnormal skull growth and potential neurodevelopmental complications. Surgical correction aims to restore cranial shape and allow normal brain growth. Three-dimensional printed patient-specific models are increasingly used for preoperative planning, surgical rehearsal, and training, particularly in complex cases. However, while anatomically accurate, these models often fail to replicate the mechanical behavior of pediatric cranial bone. This study evaluated six fused deposition modeling (FDM) materials—PLA, ASA, PET-G, Simu Bone, polypropylene (PP), and TPU—against pediatric calvarial bone specimens using three-point bending tests and finite element simulations. Native bone showed a mean Young’s modulus of 375 ± 204 MPa. Simu Bone was overly stiff (3380 ± 14 MPa), TPU too compliant (61 ± 11 MPa), and PP most closely approximated bone mechanics, though with printing challenges. Infill reduction modestly decreased stiffness. Finite element analysis indicated that replicating global elasticity alone is insufficient, as regional deformation patterns are critical for realistic simulation. These findings emphasize the need to balance mechanical fidelity and printability in 3D-printed cranial models, with PP providing the closest match for pediatric surgical training.