The use of the valvogram for the detection of shunt blockage in hydrocephalic children.

Valvography is a simple, safe, rapid, easily interpreted technique for the investigation of possible blockage of the distal end of the shunt system containing a Spitz-Holter valve. Details are presented of 64 investigations in 46 children, 30 of which demonstrated distal obstruction of the shunt system. The unreliability of some physical signs is discussed. No serious complications were encountered and the procedure has proved to be a valuable addition to the practical management of shunt-dependent children.