Finite element analysis of a biomimetic artificial cervical intervertebral disc model constructed with 3D lamellar scaffold-strengthened hydrogel

Background: Artificial intervertebral discs (AIDs) aim to restore spinal kinematics, but few replicate the natural disc's essential viscoelasticity for shock absorption and stress distribution. The internal mechanics of such biomimetic designs also lack thorough finite element analysis (FEA). Therefore, this study aimed to develop a mechanically biomimetic AID model using a 3D lamellar scaffold-strengthened hydrogel and evaluate its biomechanical performance through integrated experimental testing and FEA. Methods: The biomimetic AID model was evaluated through in vitro tests (axial compression, compression shear, axial torsion) and corresponding FEA. Results: Mechanical tests demonstrated a compressive stress–strain curve with a J-shaped profile, with a linear modulus of 10 MPa. The AID exhibited a compression-shear stiffness of 90 N·mm - 1 and axial torsion stiffness of 0.23 N·m·degree - 1 , with creep behavior comparable to a natural disc. FEA revealed that coherent load transfer through both the interconnections within the lamellar scaffold and the scaffold-hydrogel interface, and the entire AID showed a stress profilometry analogous to natural intervertebral disc. Conclusion: In conclusion, we developed an annulus-nucleus structure biomimetic AID that successfully emulates the viscoelastic and mechanical properties of a natural intervertebral disc, presenting a promising prototype for clinical application.