New Aspects of Cerebrospinal Fluid Circulation Models with Emphasis on the Stability of the Model Parameters

Since the early seventies physical and mathematical models describing the CSF circulation have been developed among which the “Marmarou” model (1973) is the most widely used. Although most models primarily describe the disturbances between formation, storage and absorption of CSF in hydrocephalus, they can also be applied to CSF circulatory disorders resulting from other causes. The model parameters provide information on the rate of CSF formation and absorption (compensatory ability) as well as on the storage capacities (elastance) of the system. The absolute values of these parameters, however, depend largely on the assumptions made in the model equations. For example, the parameters are generally assumed to be unaffected by the type and rate of volume disturbance (volume-pressure test versus infusion test), although the results of Sullivan et al. (1978) and Borgesen et al. (1979) have invalidated this assumption.