[Subacute subdural hematoma: report of 3 cases]

Three surgical cases of subacute subdural hematomas are reported considering the pathophysiology. All patients had head traumas and complained the worsenings of the headaches 7-14 days after the head traumas. Serial computed tomography scan (CT) revealed the expansions of the subdural hematomas with the change of the density from high to mixed. The surgical findings of the hematomas showed blood clots and liquid covered with thin membranes. Morinaga et al. suggested the etiology of the subacute subdural hematoma that the influx of cerebrospinal fluid (CSF) to the hematoma cavity through the teared arachnoid. Our macroscopic findings of the hematomas which had the CSFlike liquid supported this estimation. We suggest that subacute subdural hematoma should be differed from chronic subdural hematoma because it may have the proper mechanisms of the development. Mild acute subdural hematomas should be observed carefully because they may develop to be subacute subdural hematomas between 1 and 3 weeks after the onset.