Simulating the influence of proteoglicans changes in intervertebral disc mechanical behaviour

Abstract

Around 80% of world population will suffer of low back pain (LBP). Such condition is often related with intervertebral disc (IVD) degeneration (DD). In DD, the proteoglycan (PG) loss is highly important since it compromises IVD response under compressive loads. DD has been studied using numerical models. Most of them address how mechanical loads affect nutrition and cells. Yet, no model has studied how extracellular matrix (ECM) changes affect disc mechanical response. Hence, the aim of this thesis is to study how PG changes can affect IVD mechanical behaviour. A novel 3D mechanotransport model of the L4-L5 IVD is used, incorporating a novel approach for fixed charged density (FCD) that considers nutrition-dependent PG dynamics. Simulations under physiological loads are performed for both non-degenerated and degenerated tissue conditions. FCD decrease, related to PG loss, significant impacts intradiscal pressure (IDP) but has minimal effect on disc height. This study shed light into the intricate relationship between ECM changes, disc degeneration and mechanical response, providing foundation for future research.