Posthemorrhagic hemispheric cysts in neonates: treatment by cystoventriculostomy.

Two premature infants developed enlarging symptomatic hemispheric cysts secondary to intraparenchymal hemorrhages. Computed tomographic scans obtained after metrizamide was injected into the cysts demonstrated that they were isolated from the ventricular system. The cysts were treated by biopsy of the common cyst-ventricular wall through a ventriculoscope. Both patients have been followed for over 1 year. Repeat scans have demonstrated resolution of the cysts, a return to midline of the ventricular system, and an increase in the volume of cerebral tissue. The original abnormal neurological signs have disappeared, and the developmental progress has been excellent.