Integrated Mechanical Testing and Finite Element Modelling of a Biomorphic Bioceramic Scaffold for Spinal Fusion Applications

Abstract Selecting an optimal bone graft for critical-sized defects in load-bearing regions such as the spine, long bones, and jawbone is essential to ensure structural integrity and promote bone regeneration. While fixation systems provide initial stability, the graft’s intrinsic mechanical properties determine its ability to withstand physiological loads. This study aims to experimentally characterize an innovative biomorphic bioceramic to calibrate a constitutive material model and evaluate its performance in in silico post-surgical scenarios. The ceramic scaffold underwent both static (axial and transverse compression and axial torsion) and fatigue (axial compression) mechanical testing to determine its key mechanical properties. These data were used to calibrate a material model, which was then implemented in finite element simulations of an interbody fusion procedure at the L4–L5 level to assess its mechanical performance under post-surgical loading conditions. The experimental tests highlighted an anisotropic material behavior, with the Young’s modulus in the direction of the main macroscopic porosity three-times higher the value measured in the transverse direction (4.65 vs. 1.60 GPa). The calibrated numerical model accurately reproduced the experimental results, showing negligible deviations (< 4%). Preliminary simulations indicated that the scaffold could adequately sustain post-fusion physiological loads, but further implant optimization is required to properly ensure mechanical stability. This study provided an in-depth mechanical characterization of a novel bioceramic, identifying its key mechanical properties. By integrating experimental and numerical approaches, the mechanical resistance of a bioceramic implant for lumbar interbody fusion was preliminarily assessed, paving the way for further developments in this field.