Cognitive decline and dementia outcomes among patients with obstructive hydrocephalus undergoing endoscopic third ventriculostomy versus shunting: A national retrospective analysis.

INTRODUCTION: Hydrocephalus is associated with cognitive morbidity that can improve after cerebrospinal fluid (CSF)-diversion however, there remains a paucity of data comparing these outcomes following endoscopic third ventriculostomy (ETV) versus CSF-diverting shunt. METHODS: This is a retrospective analysis of the 2016-2025 TriNetX database. Patients > 12 years old with newly diagnosed obstructive hydrocephalus undergoing primary ETV or shunting were identified. The primary outcome was cognitive decline or dementia at 5 years post-procedure and evaluated using 1:1 propensity score matching (PSM). Outcomes are reported using Cox proportional hazard models to estimate Hazard ratios (HR) with 95% confidence interval (CI). Significance was determined using log-rank tests. RESULTS: PSM yielded 1194 well balanced pairs. At 5 years post index procedure, ETV was associated with a significantly reduced incidence of cognitive decline or dementia (24.4% v. 29.3%, absolute risk reduction 4.9%, p = 0.001, HR 0.77; 95% CI:0.66-0.90) compared to patients who received a shunt. The number needed to treat with ETV to avoid cognitive decline or dementia was 20.4. ETV patients also experienced significantly reduced incidence of fatigue (HR 0.81; 95%CI:0.67-0.97, p = 0.023), subsequent CSF-diverting procedure (HR 0.59; 95%CI:0.52-0.68, p < 0.001), intracranial infection (HR 0.61; 95%CI:0.45-0.81, p = 0.001), and intracranial hypotension (HR 0.69; 95%CI: 0.52-0.92, p = 0.01). CONCLUSION: Among propensity score-matched patients with obstructive hydrocephalus, ETV is associated with significantly reduced risk of cognitive decline or dementia compared to those undergoing primary CSF-diverting shunt. Prospective study is needed to compare cognitive outcomes following ETV versus CSF-diverting shunt.