Subgaleal/subperiosteal versus subdural drainage for chronic subdural hematoma: a systematic review and meta-analysis

Chronic subdural hematomas (cSDH) are increasingly prevalent, particularly among the elderly, and often require surgical intervention as the standard treatment. The placement of drains following surgical evacuation of cSDH is widely recognized as an effective strategy to reduce recurrence rates and improve clinical outcomes. However, the optimal location for drain placement remains a topic of debate. This study aims to comparatively evaluate the efficacy and safety of subgaleal/subperiosteal drainage (SGPD) and subdural drainage (SDD) techniques in patients with cSDH. This study followed PRISMA guidelines and the Cochrane Handbook. Systematic searches were conducted in PubMed, Embase, Scopus, and Web of Science. Comparative studies of SGPD and SDD in patients undergoing surgical treatment for cSDH were included. The primary outcome was the recurrence rate. Secondary outcomes included favorable clinical outcomes (mRS 0-3), mortality, and complications such as infections, intracerebral hemorrhages, pneumocephalus, and seizures. The risk of bias was assessed using the Cochrane RoB 2 and ROBINS-I tools, and statistical analyses employed fixed or random-effects models based on heterogeneity, utilizing RStudio software. A total of 21 studies involving 6,430 patients were included. SGPD was associated with a significant reduction in recurrence rates compared to SDD (RR = 0.87; 95% CI [0.76; 0.99]; p = 0.0317; I² = 2,9%). No significant differences were observed in secondary outcomes, including mortality (RR = 0.86; 95% CI [0.72; 1.03]; p = 0.0995; I² = 0.0%), favorable clinical outcomes (RR = 1.00; 95% CI [0.97; 1.03]; p = 0.9495; I² = 0.0%), infectious complications (RR = 0.88; 95% CI [0.57; 1.34]; p = 0.5470; I² = 0.0%), seizures (RR = 0.81; 95% CI [0.51; 1.28]; p = 0.1774; I² = 26.2%), pneumocephalus (RR = 0.94; 95% CI [0.71; 1.25]; p = 0.6819; I² = 1.7%), and intracerebral hemorrhage (RR = 0.60; 95% CI [0.32; 1.10]; p = 0.0982; I² = 0.0%). The present meta-analysis suggests that SGPD is more effective in reducing the recurrence rate compared to SDD in the surgical treatment of cSDH. However, no statistically significant differences were observed in the other evaluated outcomes. Future studies, particularly multicenter clinical trials, are needed to confirm these findings. Clinical trial number Not applicable.