Reevaluation on Resolving Subdural Hematoma

Spontaneous resolution of the encapsulated chronic subdural hematoma has been observed not rarely in clinical practise. The authors had investigated eight such cases in detail in 1967, and the tentative criteria for the resolving hematoma had been proposed. Further eight cases were presented in this paper which accounted to seven percent of 121 cases of chronic subdural hematoma encountered between 1968 and 1978. Two cases of bilateral hematomas, two cases of apoplectic type and two cases of biconvex hematomas on CAG were included in the eight. These observations meant that the resolving subdural hematoma was not a different clinical entity from conventional chronic ones. The resolving hematoma appeared as preservation of low density area or area of decreasing density from mixed to low in successive CT scans in a course of resolution. It was proposed that in case of the resolving type increased fibrinolytic activity of the hematoma capsule and of the fluid became prematurely diminished due to unknown initiation and that spontaneous resolution took place without surgery. The previous criteria were commented based on discussion on the natural history of chronic subdural hematoma, outline of which was graphically illustrated.