Clinical equipoise in idiopathic normal pressure hydrocephalus: a survey of physicians on the need for randomized controlled trials assessing the efficacy of cerebrospinal fluid diversion.

BACKGROUND

Idiopathic normal pressure hydrocephalus (iNPH) is a syndrome that may be reversible by diversion of cerebrospinal fluid (CSF). It is increasingly recognized, and accordingly rates of CSF diversion are increasing despite the absence of level I evidence of efficacy, non-neglible rate of complications and an unclear natural history.

METHODS

A total of 349 neurosurgeons, neurologists, geriatricians and neuropsychiatrists rated the perceived efficacy of CSF diversion, the duration of effect of CSF diversion, and the risk-benefit ratio of CSF diversion in iNPH. These physicians then rated the need for a randomized controlled trial (RCT) of CSF diversion in iNPH. Participants detailed their desired selection criteria and supportive testing for a RCT, and their preferred control group.

RESULTS

Physicians believe that there is uncertain efficacy of CSF diversion in iNPH, as well as the expected duration of this benefit and the risk-benefit ratio for patients. The greatest degree of uncertainty related to the long-term benefit of surgery. Accordingly, over 75% desire a RCT to determine the efficacy of CSF diversion in iNPH. Only 2.7% of participants believe a RCT of CSF diversion in iNPH is unethical. Patients without a shunt and a programmable valve in the 'off' setting were the preferred control groups.

CONCLUSION

A RCT of CSF diversion in iNPH is absent from the literature. The majority (>75%) of physicians involved in the diagnosis and treatment of iNPH believe a RCT is required to determine the efficacy, duration of efficacy and risk-benefit ratio of CSF diversion in iNPH.