Evaluation of cerebrospinal fluid production in the development of communicating hydrocephalus.

Diminished absorption of cerebrospinal fluid (CSF) is the most common cause of communicating hydrocephalus. Soon after the absorptive capacity is decreased, the CSF pressure increases, producing ventricular enlargement if the process is not halted. CSF production was measured by ventriculo-cisternal perfusion during and after the production of communicating hydrocephalus, using an atraumatic animal model. Animals with chronic hydrocephalus and normal pressure had normal CSF production. CSF production tended to be lower in animals with increased pressure. When CSF absorption is compromised, decreased CSF production does not appear to be a significant compensatory mechanism.