Abstract
Background
Idiopathic normal pressure hydrocephalus (iNPH) is a potentially reversible neurocognitive disorder causing severe functional decline in the elderly. Cerebrospinal fluid (CSF) shunting aims to relieve ventricular stress and restore perfusion; however, high-quality placebo-controlled evidence has historically been limited.Methods
This PRISMA-compliant systematic review and meta-analysis (PROSPERO: CRD420261372290) evaluated adults aged 60 years or older with iNPH. We included randomized controlled trials (RCTs) comparing immediate active CSF shunting against placebo or no shunting. The primary outcome was the change in gait speed using standardized timed assessments. Data were pooled using a restricted maximum-likelihood random-effects model, supplemented by Trial Sequential Analysis (TSA) and GRADE assessment to control for random error.Results
Four RCTs comprising 224 patients were included. Shunting significantly improved the primary outcome of gait velocity (SMD 0.73, 95% CI 0.45 to 1.01; P Conclusion
Cerebrospinal fluid shunting appears to provide meaningful clinical benefit in patients with idiopathic normal pressure hydrocephalus, particularly through improvement in gait velocity and functional independence. However, the evidence suggests a more limited or uncertain effect on cognitive and urinary symptoms. Importantly, the available randomized evidence is too imprecise to rule out an increase in major complications such as surgically treated subdural hematoma; positional headaches were significantly more frequent with shunting, and the largest included trial independently reported a significant excess of subdural bleeding. These safety signals warrant careful discussion with patients considering shunt surgery. These findings support shunting as an effective therapeutic option for appropriately selected patients with iNPH, while emphasizing the need for careful patient selection, standardized outcome assessment, and further high-quality, large-scale trials with longer follow-up.