Use of the proGAV shunt valve in normal-pressure hydrocephalus.

BACKGROUND: Overdrainage is a common complication associated with shunt insertion in normal-pressure hydrocephalus (NPH) patients. Using adjustable valves with antigravity devices has been shown to reduce its incidence. The optimal starting setting of an adjustable shunt valve in NPH is debatable.OBJECTIVE: To audit our single-center practice of setting adjustable valves.METHODS: We performed a retrospective review of clinical records of all NPH patients treated in our unit between 2006 and 2009 by the insertion of shunts with a proGAV valve, recording demographic and clinical data, shunt complications, and revision rates. Radiological reports of postoperative follow-up computed tomography scans of the brain were reviewed for detected subdural hematomas.RESULTS: A proGAV adjustable valve was inserted in 50 probable NPH patients between July 2006 and November 2009. Mean +/- SD age was 76 +/- 7 years. Mean follow-up was 15 months. The initial shunt setting was 6 +/- 3 cm H2O, and the final setting was 4.9 +/- 1.9 cm H2O. Nineteen patients required 24 readjustment procedures (readjustment rate, 38%; readjustment number, 0.48 times per patient). One patient (2%) developed delayed bilateral subdural hematoma after readjustment of his shunt valve setting as an outpatient.CONCLUSION: Starting with a low opening pressure setting on a proGAV adjustable shunt valve does not increase the chances of overdrainage complications and reduces the need for repeated readjustments.