Shunt tube problems due to placement of valves on the chest wall--three case reports.

Programmable valves are often used for ventriculoperitoneal (VP) shunts with the shunt valve positioned on the chest wall. Three cases of shunt problems occurred due to placement of the valve on the chest wall. A 43-year-old male was treated with a VP shunt, and suffered shunt malfunction due to dislocation of the ventricular tube. A 21-year-old male was treated with a VP shunt, and suffered shunt malfunction due to disconnection of the shunt tube. A 4-day-old female neonate was treated with a VP shunt, and suffered migration of the shunt valve. The shunt system has two anchor sites on the head and chest wall, with the neck between the two anchor sites. High tension is sometimes caused in the shunt tube between the two points due to movement of the neck or growth, and may induce such dislocation and disconnection of the shunt tube. We recommend a longer shunt tube in such cases.