Hydrostatic Force in Regulation of CSF Volume

Abstract

The cerebrospinal fluid (CSF) volume is regulated by a balance between CSF formation and absorption. It is generally believed that the increase of hydrostatic pressure enhances absorption of CSF across arachnoid villi into venous blood without affecting CSF formation in brain ventricles. We have recently demonstrated by ventricular perfusion that in isolated brain ventricles augmentation of intracranial pressure (ICP) decreases CSF formation [4]. These data may also suggest that CSF formation and absorption occur in the whole CSF system and that CSF volume is dependent on hydrostatic pressure of CSF. Since only about one fifth of CSF volume is contained inside the brain ventricles, the aim of this study was to investigate by ventriculocisternal perfusion the influence of ICP on the total CSF volume. For calculation of CSF formation (Vf) and absorption (Va) the perfusion of CSF spaces was used as a generally accepted method, with the assumption that the indicator substance in the perfusate does not diffuse into the central nervous system (CNS).