Structural analysis of healthy and degenerated intervertebral discs using meshless methods

Intervertebral disc (IVD) degeneration is a progressive condition that modifies the geometric morphology, biomechanical behavior, and material properties of an IVD, affecting its ability to transmit and distribute loads. The aim of this work is to analyze the effects of applying different loads in different orientations both in healthy and degenerated IVDs. To perform the numerical analysis, a three-dimensional (3D) discretized model was constructed and analyzed with the radial point interpolation method (RPIM) and the finite element method (FEM). In order to simulate the IVD degeneration, the mechanical properties, height and applying loads were altered, allowing to represent six different study cases. With an elasto-static analysis, assuming small strains, the von Mises equivalent stress and principal stresses ( and ) variable fields were obtained with both RPIM and FEM. Also, for a region of interest, the equivalent strain is also addressed. The results show that distinct IVD conditions lead to distinct stress/strain distributions. Additionally, the comparison between the RPIM and FEM solutions indicate that the RPIM provides variable fields with lower magnitude. Nevertheless, both technique provide similar variable field distributions