Limited Clinical Utility of Positive Subdural Catheter Tip Cultures and the Predictive Role of Systemic Inflammatory Markers in Chronic Subdural Hematoma: A Retrospective Study in the Republic of Korea

Objective: Burr-hole trephination with closed-system drainage is the standard treatment for chronic subdural hematoma (cSDH).However, positive drainage tip cultures often create uncertainty about whether the finding represents true infection or colonization.This study reevaluated the clinical utility of these cultures and identified systemic markers associated with true central nervous system (CNS) infection.Methods: We retrospectively reviewed 542 patients who underwent burr-hole evacuation for cSDH from 2014 to 2025.Of these, 72 patients (13.3%) with positive drainage tip cultures were included in the analysis.Based on the clinical course and use of targeted antibiotics, patients were classified into the true infection group (n = 10) or the colonization group (n = 62).Results: Staphylococcus epidermidis was the most frequently isolated pathogen.Compared with the colonization group, the true infection group had a significantly higher incidence of fever ( ≥ 38.0°C; 90.0% vs. 14.5%;P < 0.001) and higher peak C-reactive protein (CRP) levels (8.5 ± 10.2 vs. 3.1 ± 3.3 mg/dL, P = 0.012).Multivariable logistic regression showed that fever was strongly associated with true CNS infection (odds ratio, 105.7; 95% confidence interval, 5.81-1,923.6;P = 0.002).Receiver operating characteristic curve analysis of peak CRP showed an area under the curve of 0.748.Conclusion: A positive drainage tip culture alone has limited clinical utility and predominantly reflects colonization rather than true infection.Fever was strongly associated with true CNS infection.Assessment of systemic inflammatory markers may help reduce unnecessary broad-spectrum antibiotic use and support antimicrobial stewardship in older neurosurgical patients.