[Intraaneurysmal embolization and parent artery trapping to treat a giant partial thrombosed vertebral artery aneurysm after surgical proximal clipping].

We encountered a case with a giant partially-thrombosed vertebral artery aneurysm successfully treated by endovascular trapping following a surgical parent artery clipping two years previously. The patient complained only of headache on her admission. Initial CT showed no subarachnoid hemorrhage, and MRI of the left anterior aspect of the pons showed flow void and hematoma. The angiogram showed fusiform dilatation of the left vertebral artery just proximal to the vertebral union. At first, the patient was treated by surgical proximal clipping of the left vertebral artery, under a diagnosis of arterial dissection. Her symptom improved and the angiogram showed a slight retrograde aneurysmal filling after the operation. Two years later, she complained of dysphasia, right hemiparesis, and hemidysesthesia caused by the compression of the brain stem. On MRI study, a partially-thrombosed giant aneurysm was detected in the left anterior aspect of the brain stem. The retrograde filling did not change remarkably on the angiogram. We performed the GDC embolization of the left distal vertebral artery and non-thrombosed residual neck with an assisting balloon positioned through the right vertebral artery to the basilar artery. After the embolization, the patient's neurological deficits caused by the compression of the brain stem disappeared. MRI study showed the mass volume reducing gradually over a two-years follow-up period. Treatment for a partially-thrombosed giant vertebral artery aneurysm is difficult and controversial. It is necessary to shut off the blood flow into the aneurysm completely, so we consider that endovascular trapping with intraaneurysmal embolization is the most effective procedure.