BackgroundThis retrospective study from a single center aimed to compare patient outcomes following burr hole craniotomy (BHC) and hematoma drainage within 48 hours and between 48 hours and 5 days in 208 patients with unilateral chronic subdural hematoma (CSDH).Material/MethodsPatients were divided into 2 groups according to the duration of drainage: early (1 or 2 days, n=100) and late (3–5 days, n=108) drain removal. We compared the clinical outcomes, recurrence rate, time to recurrence, and complications between the groups. Quantitative analysis of computed tomography parameters at various time points (postoperative, day of drain removal, and postoperative day 7) was also performed to compare radiologic outcomes.ResultsClinical outcomes and recurrence rate were similar in both groups. We found no significant differences in radiologic outcomes of both groups through all chronologies, although the total drainage volume was significantly greater in the late removal group (P<0.001). The incidence of surgical complications was significantly higher in the late drain removal group (8% vs 22.2%, P=0.007). Specifically, contralateral subdural effusion (CSE) tended to occur more frequently in the late removal group (2% vs 8.3%, P=0.038).ConclusionsFollowing BHC and hematoma drainage for unilateral CSDH, maintaining the subdural drain for more than 48 hours did not improve patient outcomes or reduce the recurrence of hematoma, but increased the surgical complications, including CSE.