Outcomes of subdural versus subperiosteal drain after burr-hole evacuation of chronic subdural hematoma: a multicenter cohort study

Abstract Background Although use of a postoperative drain following burr-hole evacuation of chronic subdural hematoma (CSDH) is known to improve surgical outcomes, the superiority of subdural over subperiosteal drains has not been firmly established. Evidence comparing these two drain types is largely restricted to single-center series with limited numbers. Using a multicenter cohort study, we aimed to demonstrate non-inferiority of subperiosteal drains vis-a-vis subdural drains following burr-hole evacuation of CSDH. Materials and methods We performed a retrospective analysis of all consecutive CSDH patients aged 21 years and above who had undergone burr-hole craniostomy across three tertiary hospitals from January 2011 to October 2017. Primary outcome measures included CSDH recurrence and modified Rankin Scale (mRS) at 6 months. Outcomes of patients in the subdural versus subperiosteal drain groups were analyzed and confounders were adjusted for using multivariate logistic regression. Results Of the 570 cases analyzed, 329 (57.7%) received a subdural drain and 241 (42.3%) received a subperiosteal drain. There was no significant difference between the two drain groups in CSDH recurrence (13.1% in the subdural group versus 11.2% in the subperiosteal group, p=0.502) or 6-month mRS score (27.2% with mRS 4-6 in the subdural group versus 20.4% in the subperiosteal group, p=0.188). Independent predictors of CSDH recurrence identified on multivariate analysis included premorbid mRS 0-3 (p=0.021), separated CSDH type on preoperative computed tomography scan (p=0.002) and postoperative pneumocephalus of at least 15mm (p=0.005). Conclusion Outcomes of subdural and subperiosteal drains following burr-hole craniostomy for CSDH are largely equivalent based on our findings.