Reassessing cerebrospinal fluid (CSF) hydrodynamics: a literature review presenting a novel hypothesis for CSF physiology.

The traditional model of cerebrospinal fluid (CSF) hydrodynamics is being increasingly challenged in view of recent scientific evidences. The established model presumes that CSF is primarily produced in the choroid plexuses (CP), then flows from the ventricles to the subarachnoid spaces, and is mainly reabsorbed into arachnoid villi (AV). This model is seemingly based on faulty research and misinterpretations. This literature review presents numerous evidence for a new hypothesis of CSF physiology, namely, CSF is produced and reabsorbed throughout the entire CSF-Interstitial fluid (IF) functional unit. IF and CSF are mainly formed and reabsorbed across the walls of CNS blood capillaries. CP, AV and lymphatics become minor sites for CSF hydrodynamics. The lymphatics may play a more significant role in CSF absorption when CSF-IF pressure increases. The consequences of this complete reformulation of CSF hydrodynamics may influence applications in research, publications, including osteopathic manual treatments.