Modelling the Intervertebral Disc – A Biomechanical Challenge

Abstract

From a microscopic perspective, the intervertebral disc (IVD) as a soft biological tissue is a complex arrangement of mostly ionized water and collagen fibers embedded in a charged extracellular meshwork of protein compounds. The difficulty of describing the physiological properties of the disc on the macroscale lies in the strong interaction of all components contributing to the inhomogeneous tissue micro structure. Therefore, an appropriate macroscopic approach must account for a fiber-reinforced porous solid, which is saturated by a free movable interstitial fluid. In addition to the solid-fluid interaction, electrostatic and osmotic effects as well as the intrinsic viscoelasticity of the extracellular matrix must be considered. All these requirements are consistently realized within the well-founded framework of the Theory of Porous Media (TPM), which moreover enables efficient large strain analyses based on the finite element method (FEM). (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)