The failure of ventricles to enlarge after acute shunt malfunction in long-term shunt-dependent patients is generally attributed to the presence of periventricular rigidity resulting from gliosis. The aim of this study was to test the hypothesis that periventricular rigidity is present in these patients.
Fifteen pediatric patients who presented with acute shunt malfunction were studied; slit ventricles were detected in all of these patients. Pressure measurements were recorded simultaneously in both the ventricle and the brain parenchyma during shunt revision and then repeated after bolus infusion of fluid into the ventricle.
The mean intraventricular pressure (IVP) at presentation was 24.1 mm Hg (standard deviation 10 mm Hg). The mean baseline IVP after drainage of cerebrospinal fluid but prior to the infusion was 7.5 ± 4.3 mm Hg. There was no significant difference in the increase in the IVP and the intraparenchymal pressure (IPP) after bolus infusion into the ventricle (3.6 ± 2.4 mm Hg and 3.3 ± 2.1 mm Hg, respectively; p = 0.39). The mean pressure volume index was 24.1 ml (standard error of the mean 4.6 ml).
The profile of the changes in IVP and IPP indicates that the periventricular wall does not restrict ventricular enlargement following shunt malfunction in long-term shunt-dependent patients.