Abstract
A single venous shunt obstructing the aqueductus of Sylvius was treated by interventriculostomy. A passage for CSF was obtained between the third and fourth ventricles. The catheter which was left in the aqueduct collapsed the malformation, possibly preventing a future haemorrhage. A Simple rubber catheter in the aqueduct of Sylvius has been well tolerated by the patient for 15 years.