In-vitro characterization of the motion of the cerebrospinal fluid in the spinal canal

The work studies the motion of the cerebrospinal fluid (CSF) in the spinal canal (SAS), driven by intracranial pressure fluctuations with angular frequency ω. These fluctuations induces a displacement of the CSF of tidal volume very small compared with the total volume in the SAS (△V/V ∼ ε << 1). To that aim, in-vitro experiments of the dispersion of a solute have been conducted in a simplified facility to characterize the effects of the canal geometry and the Womersley number (α). The experimental results show that the flow configuration changes as α varies. Thus, the flow moves upwards along the narrowest sections of the canal for small values of α, while it starts moving downwards as α increases. Furthermore, it is also reported the formation of recirculating cells when the eccentricity varies along the canal. These experimental results are in good agreement with previous analytical and numerical predictions.