Remote Cerebellar Hemorrhage after Supratentorial Aneurysmal Clipping. A Retrospective Study

We report 5 cases of remote cerebellar hemorrhage (RCH), which occurs rarely after supratentorial aneurysmal clipping. Among 501 consecutive cases, who were operated on for their supratentorial cerebral aneurysms (unruptured 174 cases; ruptured 327 cases) in our facility between 2002 and 2007, 5 (unruptured 4; ruptured 1) were found to have RCH. RCH was not found on the first CT scan taken within an hour after surgery but was detected between 4 hours and 8 days after surgery. Postoperative epidural drainage in RCH cases amounted to more than 200 ml per 4 hours. While several risk factors for this hemorrhage have been reported, hemorrhage along the cerebellar folia and delayed occurrence suggested that the disturbed cerebellar venous drainage caused by excessive CSF drainage during the perioperative period was the cause of this hemorrhage. While the pathogenesis of RCH has not fully been elucidated, excessive CSF drainage should be avoided during supratentorial aneurysm surgery.