Management of hydrocephalus in infants by using shunts with adjustable valves.

Object: Previous reports suggest that the use of adjustable differential-pressure valves may improve shunt performance. The absence of a flow- or siphon-controlled mechanism, however, is a concern. The goal of this prospective study was to assess the efficacy of valve adjustments in preventing slitlike ventricles in children < 6 months old after the first shunt insertion.

Methods: A total of 15 infants < 6 months of age who were undergoing initial shunt placement were included. Imaging was performed preoperatively, at 14 days postoperatively, and every 4 weeks thereafter. Ventricle size was assessed using ultrasonography and MR imaging or cerebral CT scanning at 1 and 2 years postoperatively. Clinical follow-up duration was 24 months for all patients. Valve settings were changed by 50 mm H(2)O if ventricle size decreased by 30% compared to preoperative size.

Results: The valve pressure setting was increased to 200 mm H(2)O in 11 children within the follow-up time, whereas ventricle size decreased from 0.6 +/- 0.08 to 0.39 +/- 0.09 (frontal/occipital horn ratio, mean +/- standard deviation). There was neither clinical nor radiological evidence of underdrainage.

Conclusions: The adjustable differential-pressure valve used in this study was not effective in preventing slitlike ventricles in the majority of patients. Despite the small number of patients, this study provides a rationale for examining whether new shunt designs (gravitational shunt valves) are superior to conventional shunt systems in managing challenging hydrocephalus problems.