Routine placement of subdural drain after burr hole evacuation of chronic and subacute subdural hematoma: a contrarian evidence based approach

The objective of this paper was to evaluate whether available evidence supporting placement of subdural drain placement after evacuation of chronic subdural haematoma (CSDH) is applicable to a cohort of patients managed by us. In this observational cohort study, clinical follow-up was obtained in 166 patients who underwent burr hole evacuation of CSDH without placement of subdural drain followed by 3 days of bed rest. The primary outcome studied was recurrence requiring reoperation. Factors predicting recurrence were also analysed. We compared the patient characteristics and management protocols in our cohort with that in reports supporting drain placement to determine whether such evidence is relevant to our patient group. The mean age of our patients was 58 ± 17 years (range, 1 to 89 years). Sixteen of the 166 (9.6%) patients presented with symptomatic recurrence. The median time to reoperation for recurrence (15 of 16 patients) after the primary procedure was 17 days (range, 2 to 68 days). Antiplatelet and anticoagulant therapy was the only factor that was significantly associated with recurrence (p = 0.01). There were no infective or non-infective complications in our patient cohort. Our patient cohort and outcomes differed from those reporting drain placements in the following parameters: they were a decade younger, all patients received bed rest for 3 days after surgery and the recurrence rate was similar to that reported in the drained groups but significantly less than that reported in the non-drained groups. Routine placement of drain following burr hole evacuation of CSDH should only be done after careful comparison of the patient cohort under consideration and those reporting superior outcomes with drains. Evidence-based medicine supports such an approach.