Surgical safety criteria for burr hole surgery with urokinase in patients with acute subdural hematoma: Retrospective comparison between burr hole surgery and craniotomy

BACKGROUND: Acute subdural hematoma (ASDH) is a common disease and craniotomy is the first choice for removing hematoma. However, patients for whom craniotomy or general anesthesia is contraindicated are increasing due to population aging. In our department, we perform burr hole surgery under local anesthesia with urokinase administration for such patients. We compared the patient background and outcomes between burr hole surgery and craniotomy to investigate the surgical safety criteria for burr hole surgery. METHODS: We reviewed 24 patients who underwent burr hole surgery and 33 patients who underwent craniotomy between January 2010 and April 2020 retrospectively. RESULTS: The median age of the burr hole surgery group was older (P = 0.01) and they had multiple pre-existing conditions. Compared with the craniotomy group, neurological deficits and CT findings were minor in the burr hole surgery group, whereas the maximum hematoma thickness was not significantly different. The hematoma was excreted after a total of 54,000 IU of urokinase was administered for a median of 3 days. The Glasgow Coma Scale score improved in all patients in the burr hole surgery group and there were no deaths. Age, especially over 65 y.o., (OR 1.16, 95% CI 1.04–1.30) and the absence of basal cistern disappearance (OR 0.04, 95% CI 0.004–0.39) were significant factors. CONCLUSION: Burr hole surgery was performed safely in all patients based on the age, especially older than 65 y.o., and the absence of basal cistern disappearance. ASDH in the elderly is increasing and less invasive burr hole surgery with urokinase is suitable for the super-aging society.