Experimental production of subdural hematomas

Abstract

✓ Experimental evidence is offered to refute the hypothesis that cerebrospinal fluid alters blood coagulation or clots to favor the formation of chronic subdural hematomas. Rather, the envelopment of preformed blood clots in membranes containing neovascular sinusoidal channels and their subsequent regression from the subdural space are seen as a normal biological process analogous to that occurring elsewhere in the body. The presence of fibrin and its contact with the dura have been found to be essential precursors to membrane formation. Histological evidence of bleeding into both blood and fibrin subdural clots is presented, and theoretical considerations are discussed to explain possible mechanisms of enlargement and chronicity of subdural hematomas as well as repeated failures to obtain an experimental small animal model.