Journal of biomechanics
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Journal of biomechanics · Apr 2016
Fluid-flow dependent response of intervertebral discs under cyclic loading: On the role of specimen preparation and preconditioning.
In vivo during the day, intervertebral discs are loaded mainly in compression causing fluid and height losses that are subsequently fully recovered overnight due to fluid inflow under smaller compression. However, in vitro, fluid flow through the endplates, in particular fluid imbibition, is hampered possibly by blood clots formed post mortem. Despite earlier in vitro studies, it remains yet unclear if and how fluid flow conditions in vitro could properly emulate those in vivo. ⋯ Results highlight the significant role of disc preload magnitude in disc height recovery during low loading periods. Attention should hence be given in future studies to the proper selection of preload magnitude and duration as well as the animal models used if in vivo response is intended to be replicated. Findings also indicate that flushing the endplates or injection of bone cement respectively neither facilitates nor impedes fluid flow into or out of the disc to a noticeable degree in this bovine disc model.