Endovascular treatments for posterior cerebral artery aneurysms and vascular insufficiency of fetal-type circulation after parent artery occlusion

We present a retrospective analysis of endovascular treatments for posterior cerebral artery (PCA) aneurysms and discuss the susceptibility of a fetal-type PCA to vascular insufficiency after parent artery occlusion. Among 1207 aneurysms treated with endovascular therapy between March 1997 and March 2013 in our institution, 10 patients (0.8%) presented PCA aneurysms. The principal strategy was to employ selective coil embolization for the aneurysm. However, in certain cases of fusiform or dissecting aneurysms, we performed parent artery occlusion with coils. Clinical and radiological data were collected from hospital charts and evaluated retrospectively. The mean age was 52.7±15.6years (range, 12-65years). Five patients (50%) were admitted with a subarachnoid hemorrhage, and one patient presented with slowly developing paralysis. The remaining four patients were diagnosed incidentally. Five patients underwent selective coil embolization, and five patients underwent parent artery occlusion. All endovascular therapies were successfully performed. However, two patients in the parent artery occlusion group suffered cerebral infarction, and both patients exhibited a fetal-type PCA. The remaining three patients in the parent artery occlusion group exhibited an adult-type PCA and did not suffer a cerebral infarction. Endovascular treatment with either selective coil embolization or parent artery occlusion is safe and effective as the long as the anatomical type of the PCA is considered. Patients with a fetal-type PCA may develop vascular insufficiency upon parent artery occlusion. Neurosurgeons should attempt to preserve the parent artery using a flow-diverting stent or stent-assisted technique for a fetal-type PCA aneurysm.