Optimal duration of postoperative drainage following burr hole surgery for chronic subdural hematoma: A systematic review and network meta-analysis.

Background: Chronic subdural hematoma (CSDH) is a prevalent neurosurgical condition with a high recurrence rate after burr-hole surgery. The optimal duration of postoperative drainage remains controversial, with varying clinical practices worldwide.

Objective: This systematic review and network meta-analysis aimed to determine the optimal postoperative drainage duration to minimize recurrence while maintaining favorable clinical outcomes.

Methods: A comprehensive search was conducted across five databases up to January 2025, including randomized controlled trials (RCTs) and cohort studies evaluating the postoperative drainage duration in CSDH patients undergoing burr-hole surgery. The primary outcome was recurrence rate, while the secondary outcomes included mortality and functional outcomes. A random-effects network meta-analysis was performed, and the risk of bias was assessed using standardized tools.

Results: Seven studies with 1,842 patients were included, comprising three RCTs and four cohort studies. Drainage durations of 3 and 6 days significantly reduced recurrence rates compared with shorter durations (0-8 h and 17-24 h). Notably, the 6-day drainage had the highest probability (86.2%) of minimizing recurrence, followed by the 3-day drainage (13.8%). A shorter drainage duration (< 24 h) was associated with higher recurrence risks. However, no significant differences in mortality rates were observed across the drainage durations.

Conclusion: This study highlights that longer postoperative drainage durations (3-6 days) may reduce recurrence rates after burr-hole surgery for chronic subdural hematomas. However, its effect on mortality remains unclear. These findings support the importance of optimizing the drainage duration and call for further high-quality studies to guide clinical practice.