A one-dimensional theoretical prediction of the effect of reduced end-plate permeability on the mechanics of the intervertebral disc

The permeability of the cartilage end-plate (CEP) may play an important role in intervertebral disc (IVD) degeneration by controlling the convective and diffusive transport of metabolites into the nucleus pulposus. A one-dimensional poroelastic model was used to predict the effect of a CEP of lower permeability than the disc tissue on the convective transfer into and out of the IVD. With decreasing CEP permeability, associated with degeneration, the model predicted that the change in disc height with time became more linear; the disc could not rehydrate as quickly; and internal fluid movement was slowed. This study has shown that CEP permeability will only markedly have an effect on fluid movement, and hence convective nutrition, if the permeability of the CEP is reduced to less than that of the disc tissue.