Time to and Possible Risk Factors for Recurrence after Burr-hole Drainage of Chronic Subdural Hematoma: A Subanalysis of the cSDH-Drain Randomized Controlled Trial

OBJECTIVE: The randomized controlled Chronic Subdural Hematoma (cSDH)-Drain-Trial showed comparable recurrence rates after placing a subperiosteal drain (SPD) or a subdural drain (SDD) for surgically drained cSDH, although SDD was associated with higher rates of infection and iatrogenic brain injury. This subanalysis examines the time to recurrence and possible risk factors for recurrence after burr-hole drainage of cSDH and placement of a SPD compared with a SDD. METHODS: We included 220 patients from the preceding cSDH-Drain-Trial. Time to recurrence was compared within the 2 groups using a univariate Cox proportional hazards model. Apart from intraoperative brain expansion (iBE), defined by residual hematoma-cavity on computer tomography 24 hours after surgery, other possible pre-, intra- and postoperative risk factors for recurrence were assessed through univariate and multivariate analysis. RESULTS: Median time to recurrence was 22.5 days (interquartile range: 9.25-52 days, range: 0-81) showing no difference between the 2 groups. Less iBE (P = 0.019), lower Glasgow Outcome Scale score at discharge (P = 0.007), and lower Glasgow Coma Scale score at 24 hours (P = 0.037) were strongly associated with recurrence on univariate analysis. After multivariate logistic analysis, less iBE (odds ratio: 1.10, 95% CI: 1.01; 1.21; P = 0.03) remained the only significant risk factor associated with recurrence. When comparing the risk factors within the 2 groups, less iBE and lower Glasgow Outcome Scale score at release were associated with recurrence only in the SDD group. CONCLUSIONS: The inserted drain type after burr-hole drainage of cSDH does not seem to influence time to recurrence. SPD may be warranted in routine clinical practice, independent of individual patient, surgical, or hematoma characteristics.