The Shunt Design Trial compared two novel (and relatively expensive) shunt valves with the standard differential pressure valve. The newer valves were both designed to prevent excessive CSF drainage. There were NO differences in survival among the 3 arms of the study at 1 and 2 years, although the patterns of failure differed between the Orbis-Sigma and the other 2 arms.
[Drake JM. Randomized trial of cerebrospinal fluid shunt valve design in pediatric hydrocephalus. Neurosurgery 1998;48:294-303.]
