[Ventricular subarachnoidal hydrocephalus of arachnoid villi origin].

In 102 infants (0.5 to 22 months), the C.T. scan performed for various neurological symptoms, was systematically reviewed with analysis of ventricular size, pericerebral space and interhemispheric fissure. In 70% of the cases, an increase of the intracranial volume of C.S.F. was noted, with a good correlation between the ventricular and pericerebral volume. The authors discuss the pathophysiological mechanism of this condition an evoke the possibility of an idiopathic disturbance of the C.S.F. reabsorption. In two cases, suffering from severe axial hypotonus, this fact was explored by four methods: continuous monitoring of intracranial pressure, intraventricular infusion test, isotopic cisternography through ventricular injection and venous phase of angiography. From these investigations showing no venous anomaly, and because of the lack of any pathological event able to induce a C.S.F. obstruction, we suggest a delay in the maturation of arachnoïd villi (normally ended at 18 months) to explain this condition.