Introduction: Chronic subdural hematoma (CSDH) is a common type of intracranial hemorrhage that often recurs after surgical intervention. Research has indicated a potential role for eosinophils in the persistent inflammation and neovascularization associated with CSDH, which may influence recurrence rates. However, the relationship between preoperative eosinophil counts and the likelihood of postoperative recurrence remains unclear. This meta-analysis aimed to clarify this association by examining the link between preoperative eosinophil levels and the recurrence of CSDH following surgery.
Methods: In adherence to PRISMA guidelines, PubMed, Embase, and Cochrane databases were comprehensively searched for studies reporting the association between preoperative elevation of peripheral blood eosinophils and the postoperative risk of CSDH recurrence in patients undergoing surgery for CSDH. Meta-analysis was performed using a random-effects model, and heterogeneity was assessed with I² statistics.
Results: Three studies met the inclusion criteria, totaling 829 patients and 857 cerebral hemispheres evaluated. Among these, 23.2% of hemispheres had high eosinophil counts, and 76.8% had low counts, with cut-offs between 100 and 150/µL. No significant difference in recurrence odds was observed in the general population (MD –90.81; 95% CI [-241.25, 59.64]; p=0.24; I²=97%) or between high eosinophil compared to low eosinophil groups (OR 0.24; 95% CI [0.02, 2.55]; p=0.24; I²=92%). Sensitivity analyses with removal of each individual study confirmed these findings, with persistently high heterogeneity (I² > 50%).
Conclusion : This meta-analysis found no significant association between preoperative eosinophilia and the risk of postoperative recurrence in CSDH. Elevated eosinophil levels did not correlate with recurrence rates, suggesting that eosinophil count is not an independent predictor for CSDH recurrence. Further studies are needed for definite conclusions.
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