A flow-regulating device to control differential pressure in CSF shunt systems. Technical note.

A method of regulating flow rate through cerebrospinal fluid (CSF) shunts with the addition of a flow-regulating device (FRD) is reported. The FRD consists of a small-caliber (0.4 mm) Teflon tube placed in the usual connector. This device has the advantage of converting the original shunt valves to valves for higher-resistance flow without replacing the entire distal catheter. An experimental study revealed that this device reduced the CSF flow rate in the shunt by approximately 30%. The author has found it reliable in 32 patients, without causing CSF obstruction. The device is easily installed and removed.