[Experimental study on brain damage by extracerebral compression; alteration of cerebral circulation and microvascular architectures].

Effects of extracerebral compression on cerebral circulation and microvascular architectures were investigated in 23 adult cats. Brain compression was produced by inserting 12 steel balls (5 mm in diameter) into the extradural space through a burr hole at the left temporal bone. One ball was inserted every 10 minutes. Mean arterial blood pressure (MABP), intracranial pressure (ICP) and cerebral blood flow (CBF) were measured continuously. Cerebral perfusion pressure (CPP) and cerebrovascular resistance (CVR) were then calculated. Microvascular architectures of the brain were studied by scanning electron microscopy (SEM) with cerebrovascular casting methods. CBF decreased significantly on the compressed side though CPP remained unchanged till 5 balls had been inserted. CVR increased correlatively to the numbers of balls on the compressed side while remaining unchanged during insertion of the balls on the contralateral side. In SEM study, flection and interruption of capillaries and compressed phenomenon of veins were most remarkable on the compressed side. Alterations of microvascular architectures correspond to cortical deformity in degree. These data show that increase of CVR correlating to alteration of microvascular architectures plays an important role in decrease of CBF in a compressed brain. It is thus suggested that intracranial mass lesion causing deformity of the brain must be removed in order to avoid further brain tissue damage due to microvascular lesions.