On the effect of nerve roots and denticulate ligaments on flow and transport in the spinal canal.

MRI-informed direct numerical simulations are used to quantify effects of micro-anatomical elements, namely nerve roots and denticulate ligaments, on the flow of cerebrospinal fluid (CSF) and the transport of solutes along the spinal canal. The computations utilize an anatomically correct model of the canal along with a physiologically correct flow rate. The resulting oscillatory flow is used to evaluate the time-averaged Eulerian velocity as well as the mean Lagrangian velocity. These steady velocities are used to develop and test different reduced models for solute transport that circumvent the need to track the periodic flow oscillations, thereby significantly reducing the associated computational cost.