Subdural Versus Subgaleal Drain Placement After Minicraniotomy for Chronic Subdural Hematoma

BACKGROUND AND OBJECTIVES: Surgical evacuation with placement of a postoperative drain is the standard treatment for symptomatic chronic subdural hematoma (cSDH). Subdural and subgaleal drains are equally effective after burrhole craniostomy, but the optimal location of the drain after craniotomy is not clear. We sought to compare the clinical and radiological outcomes of subdural and subgaleal drain placement in patients undergoing minicraniotomy for cSDH. METHODS: A retrospective review of 137 consecutive patients undergoing minicraniotomy for cSDH at a single institution was performed. Cases were stratified by location of postoperative drain. The primary outcome was change in functional status (modified Rankin Score, mRS) at 3 months from preoperative baseline. RESULTS: Among the patient cohort, 24.6% received subgaleal drain placement. After a median follow-up of 105 days, 79.4% (27/34) in the subgaleal group and 57.3% (59/103) in the subdural group ( P = .02) had been discharged home. Worse premorbid mRS ( P = .002), subdural drain location ( P = .004), and decreased consciousness at presentation (Glasgow Coma Scale<15) ( P < .002) were independent predictors of a discharge destination other than home. At the 3-month follow-up, the subgaleal group exhibited a mean improvement of 0.77 ± 1.2 points, while the subdural group had a deterioration of 0.14 ± 0.8 points ( P < .01). Subgaleal drain location ( P < .0001), better preoperative Glasgow Coma Scale ( P = .01), and worse premorbid mRS ( P = .0003) were independent predictors of improved mRS at 3 months. Recurrence requiring repeat surgery were more common in the subdural (13.6% (14/103) than the subgaleal 2.9% (1/34) group, P = .12), although the absolute incidence rates remained low. CONCLUSION: In patients undergoing minicraniotomy for cSDH, subgaleal drains are associated with shorter hospitalization, greater chance of discharge home, and better functional outcomes than subdural drains.