Cerebrospinal fluid dynamics: disturbances and diagnostics.

The pathophysiology of hydrocephalus can be modelled and described in terms of altered biomechanical parameters. Shunting is aimed to correct the patient's cerebrospinal fluid dynamics, compensating for inadequate cerebrospinal fluid re-absorption or insufficient volume buffering reserve. Computerized infusion studies implement intracranial pressure and arterial pressure signal processing and model analysis to allow the estimation of cerebrospinal dynamics variables such as cerebrospinal fluid outflow resistance, brain compliance and pressure-volume index, estimated sagittal sinus pressure, cerebrospinal fluid formation rate, compensatory reserve and cerebral vasoreactivity. Infusion studies can assist in the prognostication of normal pressure hydrocephalus and in the diagnosis of idiopathic intracranial hypertension. The technique is also helpful in the assessment of shunt malfunction, including posture-related over-drainage and shunt obstruction.