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Open Access research with a European policy impact...

The Strathprints institutional repository is a digital archive of University of Strathclyde's Open Access research outputs. Strathprints provides access to thousands of Open Access research papers by Strathclyde researchers, including by researchers from the European Policies Research Centre (EPRC).

EPRC is a leading institute in Europe for comparative research on public policy, with a particular focus on regional development policies. Spanning 30 European countries, EPRC research programmes have a strong emphasis on applied research and knowledge exchange, including the provision of policy advice to EU institutions and national and sub-national government authorities throughout Europe.

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The internal mechanics of the intervertebral disc under cyclic loading

Riches, P.E. and Dhillon, N. and Lotz, J. and Woods, A.W. and McNally, D.S. (2002) The internal mechanics of the intervertebral disc under cyclic loading. Journal of Biomechanics, 35 (9). pp. 1263-1271. ISSN 0021-9290

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Abstract

The mechanics of the intervertebral disc (IVD) under cyclic loading are investigated via a one-dimensional poroelastic model and experiment. The poroelastic model, based on that of Biot (J. Appl. Phys. 12 (1941) 155; J. Appl. Mech. 23 (1956) 91), includes a power-law relation between porosity and permeability, and a linear relation between the osmotic potential and solidity. The model was fitted to experimental data of the unconfined IVD undergoing 5 cyclic loads of 20 min compression by an applied stress of 1 MPa, followed by 40 min expansion. To obtain a good agreement between experiment and theory, the initial elastic deformation of the IVD, possibly associated with the bulging of the IVD into the vertebral bodies or laterally, was removed from the experimental data. Many combinations of the permeability-porosity relationship with the initial osmotic potential (πi) were investigated, and the best-fit parameters for the aggregate modulus (HA) and initial permeability (ki) were determined. The values of HA and ki were compared to literature values, and agreed well especially in the context of the adopted high-stress testing regime, and the strain related permeability in the model.