Physical examination of patients with cerebrospinal fluid shunts: is there useful information in pumping the shunt?

To assess the value of the information derived from pumping the shunt valve in hydrocephalic patients with cerebrospinal fluid shunts, the findings on examination of 200 consecutive patients were recorded prospectively. The status of each shunt was determined on the basis of all available clinical data, and the results of the shunt pumping test were compared to the final status of each shunt for various subsets of the study group. In the most clinically pertinent subsets, the sensitivity of the shunt pumping test in the detection of shunt obstruction was 18% to 20%, and the predictive value of a negative shunt pumping test, indicating shunt patency, was only 65% to 81%. For the hydrocephalic patient with symptoms of shunt malfunction, definitive imaging studies must not be deferred because of reassuring findings on examination of the shunt valve.