Quantification of cerebrospinal fluid shunt flow rates. Assessment of the programmable pressure valve

Shunt placement diverting cerebrospinal fluid (CSF) has been the treatment of choice for hydrocephalus for the past several decades. However, the procedure often requires revisions owing to excessive drainage, low CSF flow rates, or infections within the system. With regard to valve pressure, selection of an appropriate valve for a specific patient prior to surgery is not always a simple task. Further, an optimal valve selected at the time of implantation may no longer be appropriate given changing pathophysiological conditions as time passes. It is thus desirable to provide a single valve in which the pressure may be modified when necessary without revision. A programmable pressure valve (designed by Sophysa of France) comes in one model which accommodates different pressure settings obviating revision when pressure changes are needed. Pressure changes can be achieved externally by means of a special magnet which allows precise adjustments in valve pressure to be made through the scalp. The authors introduce the mechanism and describe the cases treated using this valve.