Pressure-controlled Active CSF Irrigation Versus Non-Pressure-controlled Management Following Aneurysmal Subarachnoid Hemorrhage: a Systematic Review and Comparative Meta-Analysis of DCI and Safety Outcomes

Delayed cerebral infarction (DCI) is a major cause of poor outcome after aneurysmal subarachnoid hemorrhage (aSAH) and is closely associated with intracranial blood burden. Pressure-controlled cerebrospinal fluid (CSF) irrigation techniques have been developed to actively accelerate blood clearance; however, their overall clinical effectiveness and safety profile have not been comprehensively evaluated in a comparative framework. Accordingly, we performed a systematic synthesis of the available evidence focusing on both clinical efficacy and treatment-related safety outcomes. A systematic review and meta-analysis were conducted in accordance with PRISMA guidelines to evaluate both safety and efficacy. PubMed/MEDLINE, Embase, and Scopus were searched from inception through October 15, 2025. Studies comparing pressure-controlled active CSF irrigation techniques (including stereotactic ventriculocisternostomy, cisterno-ventricular catheter systems, ventriculo-lumbar irrigation, and lumbo-lumbar irrigation) with non-pressure-controlled management were included. The primary radiographic outcome was delayed cerebral infarction. Secondary outcomes captured both additional efficacy endpoints and safety, including symptomatic vasospasm, in-hospital mortality, functional outcome, and procedure-related complications. Arm-specific outcome prevalences were pooled descriptively using random-effects models, while comparative treatment effects were synthesized as odds ratios from direct within-study comparisons between pressure-controlled and non-pressure-controlled management. Risk of bias was assessed using ROBINS-I and RoB 2. Nine studies comprising 2,033 patients were included; most evidence was observational and at serious risk of confounding. In direct within-study comparative meta-analyses, pressure-controlled irrigation was associated with lower odds of delayed cerebral infarction (OR 0.36, 95