Incidence, risk factors, and microbial spectrum of external ventricular drain-related infections among adult neurocritical care patients: A systematic review and meta-analysis.

External ventricular drains (EVDs) monitor and manage increased intracranial pressure (ICP) in neurosurgical patients. EVD-related infection (ERI) is a serious complication linked to significant morbidity and mortality. This review aims to determine the overall incidence of ERI, identify key risk factors, compare the effectiveness of different EVD types, and analyze causative organisms. A comprehensive literature search was performed on public databases (PubMed/MEDLINE, Cochrane Library, and Google Scholar) from inception to 15 July 2025. The Newcastle-Ottawa Scale (NOS) tool and Cochrane tool (RoB-2) were used to assess the quality of included studies. A random-effects model was applied for all meta-analyses. The overall incidence of ERI was 8.6% (95% CI 7.2-10.3, I 2 = 93%). The pooled incidence was 4.3% in AI EVDs, compared with 9.4% in plain EVDs and 10.5% in SI EVDs. In subgroup analysis, the overall incidence of ERI in studies conducted in the US was notably lower than that in the non-US countries (4.1% vs 10.4%). In comparison to plain catheters, the use of AI EVDs was associated with significant reduced risk of ERI occurrence (OR = 0.43, 95% CI 0.28-0.67, I 2 = 16%, p < 0.01), but there was no significant difference between AI EVDs over SI catheters (OR = 0.44, 95% CI 0.15-1.29, I 2 = 5%, p = 0.13). In sensitivity analysis, compared to plain EVDs, SI EVDs were associated with a significantly reduced risk of ERI (OR = 0.58, 95% CI 0.38-0.88, I 2 = 0%, p = 0.01). Placement of more than 1 EVD, CSF leakage, and extended catheter duration were significant risk factors for ERI. Our results revealed that ERI was associated with longer duration of EVD, hospital, and ICU length of stay. The majority of infections were due to Gram-positive bacteria (65%). The Staphylococcus (49.8%), followed by Acinetobacter (7.6%), and Klebsiella (7%) species, and at lower classifications, CoNS (58%) were the most common causative organisms. Our findings suggest that AI EVDs are associated with a lower risk of ERI compared with plain EVDs. In contrast, SI EVDs did not show a statistically significant reduction in ERI risk compared with plain EVDs in the primary analysis, although a significant reduction was observed in sensitivity analysis after excluding small studies. Further multicenter randomized controlled trials are necessary to validate these conclusions.