Radiological Observation of Remote Intracerebral Hemorrhage following intracranial aneurysm surgery: Is it a Manefestation of Hemorrhagic Infarction?

초록

Introduction:Postoperative remote ICH is rare but reports inrelation to aneurysm surgery are not, relatively speaking. We performed this study to elucidate the possible mechanisms of this occurrence. Methods: Between May 1997 and April 1999, we observed 11 cases of remote ICH on postoperative CT following 124 aneurysm surgeries. We reviewed the radiological findings and perioperative parameters. Results: The incidence of postoperative remote ICH was 8.9%(11 of 124 surgeries). All cases developed after a pterional approach. Four cases occurred in the supratentorial area, six in the cerebellum, and one in both areas. All supratentorial ICHs(four lobar and one extrem capsular) occurred following surgery for a ruptured aneurysm(performed between the 4th and 10th day after rupture) and had a low perilesional density. Three occurred in the low-density area on preoperative CT. We observed angiographic vasospasm preoperatively in one case with lobar hemorrhage and a compromised syvian venous sytem on postoperative angiography in the case with extreme capsular hemorrhage. Cerebellar hemorrhages developed unilaterally in four cases and bilaterally in three. Two developed following surgery for an unruptured aneurysm. All of them occurred in the superior cerebellum, which drained mainly into the superior cerebellar venous system. We observed, on postoperative MRI, THe obliteration of the galenic and superior cerebellar cisterns by upward displacement of the cerebellum in two cases and on postoperative angiography, the compromised superior venous drainage system in one. Conclusion: Postoperative remote ICH seemed to be a manifestation of hemorrhagic infarction. Silent vasospasm or venous injury may be precusor of a supratentorial lesion, while obliteration of superior cerebellar venous drainage system by upward displacement of the cerebellum following excessive CSF drainage during surgery seems to be the precusor of cerebellar lesion.