Journal of biomechanics
-
Journal of biomechanics · Sep 2016
Region and strain-dependent diffusivities of glucose and lactate in healthy human cartilage endplate.
The cartilage endplate (CEP) is implicated as the main pathway of nutrient supply to the healthy human intervertebral disc (IVD). In this study, the diffusivities of nutrient/metabolite solutes in healthy CEP were assessed, and further correlated with tissue biochemical composition and structure. The CEPs from non-degenerated human IVD were divided into four regions: central, lateral, anterior, and posterior. ⋯ The solute diffusivities were significantly correlated with the tissue porosities (glucose: p<0.0001, r=0.581; lactate: p<0.0001, r=0.534). Histological and SEM studies further revealed that the collagen fibers in healthy CEP are more compacted than those in the nucleus pulposus (NP) and annulus fibrosus (AF) and show no clear orientation. Compared to human AF and NP, much smaller solute diffusivities in human CEP suggested that it acts as a gateway for solute diffusion through the disc, maintaining the balance of nutritional environment in healthy human disc under mechanical loading and preventing the progression of disc degeneration.
-
Journal of biomechanics · Sep 2016
Effects of inter-individual lumbar spine geometry variation on load-sharing: Geometrically personalized Finite Element study.
There is a large, at times contradictory, body of research relating spinal curvature to Low Back Pain (LBP). Mechanical load is considered as important factor in LBP etiology. Geometry of the spinal structures and sagittal curvature of the lumbar spine govern its mechanical behavior. ⋯ However, resistance of the facet joints to extension was more important in the Norm- and Hyper-L spines which reduced the disc compression. The spinal curvature strongly influenced the magnitude and location of load on the spinal components and also altered the kinematics and load-sharing particularly in extension. Consideration of the subject-specific geometry and sagittal curvature should be an integral part of mechanical analysis of the lumbar spine.