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.