Biomechanical response simulation of tetrahedral mass-spring model of intervertebral disc in a spine segment with haptic interface

This study presents a new, three-dimensional tetrahedral mass-spring model of an intervertebral disc within a L2-L3 spine unit. The tetrahedral mesh of the disc model is generated using ABAQUS software. The nodes are interconnected by linear elastic springs aligned with edges of the tetrahedra. In each tetrahedron, radial springs are added between barycenter and each vertex to preserve the volume of the disc under complex loading. Torsional springs are attached at each node to support the disc in resisting torsion. The haptic interface integrated with this model will help users to perceive and explore the mechanical properties of the disc such as stiffness and compliance through force feedback. Simulation results show that the volume of the disc model is maintained during continuous deformation. Biomechanical properties of the intervertebral disc behave differently with various assigned materials. The present tetrahedral mass-spring model can be run using a real-time haptically integrated graphical environment and may be useful for assessing medical conditions in the spine or the biomechanical behavior of new designs for artificial intervertebral discs.