Sensitivity of various material properties to the intervertebral disc biomechanics

This study aims to conduct a parameter sensitivity analysis to identify the most influential material properties governing intervertebral disc creep behavior. The 12 key material properties include water contents (${\varphi }^w$), fixed charge densities ($c^f$), and mechanical properties (μ, λ, k₁)) across the nucleus pulposus, annulus fibrosus, and cartilaginous endplate. Finite element simulations of creep tests were validated against experimental bounds. Of 600 simulations, 58 fell within experimental bounds (R² > 0.8). Water content was the most influential parameter across all creep response variables, followed by fiber reinforcement and fixed charge density. Our findings are important for understanding disc biomechanics.