Experimental hydrocephalus: cerebrospinal fluid dynamics and ventricular distensibility during early stages.

Adult craniectomized cats, rendered hydrocephalic by intracisternal kaolin injection, were repeatedly studied as to parameters pertaining to cerebrospinal fluid (CSF) dynamics and ventricular size. Intraventricular pressure was up to 8-fold of normal (mean 17.1 cm H2O) initially after induction of hydrocephalus and then went gradually down after 1 month. Ventricular volumes attained their maximum volume of approximately 4.5 ml at the very earliest study. The absorptive reserve (excess of absorption over formation rate of CSF) increased with time, thereby theoretically enabling the 'arrest' of the hydrocephalic process. Ventricular distensibility also increased with time, thus even the low ventricular pressure maintains the larger ventricular volume.