Complication of an acute subdural hemotoma located between dura and outer membrane space after burr-hole drainage for chronic subdural hemorrhage

SummaryChronic subdural hematoma (SDH) is a common clinical entity in neurosurgery. Craniostomy, including twist-drill holes or burr holes with or without drainage, is the treatment of choice for SDH. Despite convincing results from this surgical procedure, unexpected complications may still develop such as acute epidural hematoma, acute SDH, intracerebral hemorrhage (ICH), tension pneumocephalus, and empyema. We present a rare complication of an acute SDH located between the dura and the outer membrane instead of within the previous hematoma cavity (i.e., between the outer and the inner membrane), which occurred after chronic SDH burr-hole evacuation with closed-system drainage. This complication resulted from misplacement of the drainage catheter and superimposed coagulopathy. In conclusion, precisely inserting the drainage catheter in the chronic SDH space and reversing coagulopathy before and after the surgical procedure are necessary to prevent such complications.