Shunt Function Test Using Radioisotope and ICP Monitoring

ABSTRACT

OBJECTIVE: Authors report the usefulness and limitation of shunt function test. METHODS: Of 457 who underwent shunt placement from 1993 to 2001, 33 patients with suspected shunt malfunction underwent the shunt function test using radioisotope and intracranial pressure(ICP) monitoring to evaluate shunt patency and to determine the site of obstruction. We analyzed retrospectively results of 36 shunt function test with operative finding in shunt revision. RESULTS: Of 36 results, 21 cases(58.3%) had patent shunt on the shunt function test and one of those underwent shunt revision regardless of the result. Five cases(13.8%) had proximal malfunction on test and three cases of those had obstruction in the shunt revision. Ten cases(27.2%) had distal malfunction on test and eight cases of those had obstruction. The sensitivity of shunt function test was 91.6%, the specificity 90.9%, and the accuracy 81.6%. CONCLUSION: The shunt function test using radioisotope and ICP monitoring is a reliable method to evaluate shunt patency. However, interpretation of the result should be based on the clinical and radiological findings of the patient, particularly in case of partial obstruction and functional malfunction due to valve system.