Treatment for Dissecting Aneurysm of Posterior Fossa

Abstract

Nine cases of cerebral ischemia and 10 cases of subarachnoid hemorrhage attributed to dissecting aneurysm in the posterior fossa are analyzed for their clinical courses to choose therapeutic modality. Patients with ischemic symptoms had neither clinical deterioration nor reccurence, and most of their outcomes were excellent or good. Angiographic findings of all cases tended to improve 3 months after onset. Considering the high risk of ischemic symptoms associated with occlusion of the parent artery resulting from surgical treatment for dissecting aneurysm, the best initial treatment for dissecting aneurysm of the ischemic type seems to be conservative therapy, including amelioration of circulation, control of blood pressure and serial observation by cerebral angiography.
All 10 patients developing subarachnoid hemorrhage had episodes of unconsciousness before admission. The neurological grades of 6 patients were worst and their vital signs were very unstable. Rebleeding occurred within 24 hours of the onset in the 6 patients. Their outcome was extremely poor except for one who had been treated surgically. He had an excellent outcome in spite of having the worst grade on admission. Therefore, early surgery should be performed in patients with dissecting aneurysm developing subarachnoid hemorrhage.