Delayed intracerebral haemorrhage after intracranial surgery

Intracerebral haemorrhage may occur several hours after intracranial surgery. The exact mechanism by which this occurs is still unclear, although prolonged brain retraction is considered to be the most responsible factor. In these delayed postoperative haematoma cases, serial angiography has never been performed. We performed angiographic evaluation in such 12 cases and, in 5 of them, surgical evacuation of the haematoma was performed because of life-threatening mass effect and the cortical veins and the surrounding cerebral tissues were examined histologically. In all cases, angiographically thrombotic difufse occlusion of the cortical vein(s) without collateral circulation was observed, and histologically there was marked damage to the intima of the vein, remarkable macrophage infiltration into the subadventitial spaces, and extensive red cell extravasation into the subarachnoid space and brain parenchyma from the maximally dilated venules and capillaries. These findings suggest that diffuse intravenous thrombosis induced by cortical vein injury and prolonged brain retraction may be important causes of unexpected delayed postoperative intracerebral haematoma in surgery using the interhemispheric or subtemporal approach.