Predicting the biomechanical behavior of lumbar intervertebral Discs: A comparative finite element analysis of a novel artificial disc design

Abstract

Osseointegration along with better mimicry of natural bone behaviour addresses the long-term performance of artificial intervertebral disc prosthesis. Here the effect of a novel artificial intervertebral disc geometry on stress, deformation and strain on lumbar segments to restore movement of the spine was investigated. The process involved, using CT image data, and solid modelling, simulation-driven design and finite element (FE) analysis, hexahedral mesh sensitivity analysis, implant placements. The range of motion (ROM) was calculated using an ANSYS deformation probe. The intact lumbar spine model established was compared with two implants, replacement at segment L4-L5 level, and biomechanical results were compared using axial loads of 500 N, 800 N, 1000 N and 10Nm moment. The two lumbosacral FE models, a novel implant Titanium Conix (TIC) and another FDA approved SB Charite™ (SBC) implant were considered. Novel TIC implant geometry exhibited comparable ROM values in four physiological motions, which were comparable to as required for restoring natural motion. The result shows that the proposed TIC observed the deformation during flexion, extension, bending and twist as 3.43 mm, 3.19 mm, 3.33 mm and 3.48 mm respectively. Similarly strain of 0.01 during flexion, 0.02 during extension, 0.01 during bending and 0.02 during twist. The implants designed in this study demonstrate the suitability of titanium alloy in endplates and annulus. The FE models in the study with their biomechanical parameters can be considered before clinical implementation of any implants, pre-surgery evaluations, implant placement simulations, postsurgical response, follow-up revisions, implant customization and manufacturing.