Development of a Finite Element Lumbar Segment Model for Simulation of Coupled Loading Conditions Validated With In Vitro Experimental Studies

The traditional approach for evaluating the biomechanics of the spine, both experimentally and computationally, is through a series of planar loading scenarios that are reduced to sagittal (flexion/extension), frontal (lateral bending), and transverse (axial) planes of movement [1]. However, coupled movements occur through daily living activities that place further demands on a spinal device beyond simple planar movements. The objective of this study was to investigate the in vitro biomechanics of the L4-L5 lumbar motion segment unit (MSU) under the coupled loading conditions, and to use the experimental data to validate a high-fidelity non-parametric finite element (FE) model of the L4-L5 lumbar MSU.