The isolated lateral ventricle. Experience at the Hospital for Sick Children

Isolation of the lateral ventricle has long been known to occur following ventriculitis. However, in recent years, functional isolation of the lateral ventricle has been seen with increasing frequency. Since 1979, eight patients without evidence of infection have required treatment for an isolated lateral ventricle following insertion of a contralateral ventriculoperitoneal shunt at the Hospital for Sick Children, Toronto, Ontario, Canada. Two of these patients developed their hydrocephalus after intraventricular hemorrhage, and in six patients the hydrocephalus was associated with myelodysplasia. We specifically excluded patients in whom isolation of the lateral ventricle was secondary to ventriculitis. We feel that the isolated lateral ventricle following ventriculoperitoneal shunting may be due to a dynamic situation where overdrainage of the shunted ventricle leads to a functional obliteration of the foramen of Monro and subsequent enlargement of the contralateral lateral ventricle.