Control of the Mechanical Properties of the Synthetic Anterior Longitudinal Ligament and its Effect on the Mechanical Analogue Lumbar Spine Model

Abstract

The development and validation of an anatomically correct mechanical analogue spine model would serve as a valuable tool in helping researchers and implant designers understand and alleviate low back pain. Advanced composite ligaments were designed to mimic the tensile mechanical properties of human spinal ligaments. By changing the composite properties, the stiffness and deformation at toe were controlled in a repeatable manner. Five analogue spine models, with three different Anterior Longitudinal Ligament (ALL) stiffness configurations, were tested in bending and compression using displacement control in a MTS load frame. The bending stiffness and kinematic ranges of motion of the spines were compared for each ALL stiffness configuration. The ALL stiffness had a significant effect on the stiffness and peak moment in extension of the overall spine model. The study demonstrated that a change in the synthetic ligament properties successfully controls the biomechanics of the analogue spine model and the model effectively mimics the human cadaveric biomechanical response.