Membrane neovascularization and drainage of subdural hematoma in a rat model.

Studies on the pathophysiology of subdural hematomas (SDH) have been primarily focused on the acute phase and associated cortical injury, whereas the course of hematoma absorption remains poorly understood. Using a rat model of SDH, we have specifically investigated the correlation between neovascularization of membrane and the rate of hematoma absorption. Using improved surgical techniques, we have reduced surgery-related injury and increased the rate of generating successful SDH to 71.4%. With this model, we demonstrate that hematoma absorption was slow in the first 4 days and accelerated thereafter. The absorption rate and recovery of sensorimotor deficits were closely associated with neovascularization in the neomembrane characterized by the formation of arachnoid granulation-like structures at the interface between the hematoma and encapsulating neomembrane. Our data suggest that neovascularization in the neomembrane plays a key role in hematoma absorption and neuronal recovery. Furthermore, measures to enhance neovascularization could have therapeutic potentials.