[Ruptured giant fusiform anterior cerebral artery aneurysm treated by proximal clipping with a3-a3 bypass:case report].

Giant fusiform aneurysm of the anterior cerebral artery (ACA) involving the anterior communicating artery (AcomA) is difficult to treat, and its postoperative course is not well known. We treated a patient with subarachnoid hemorrhage (SAH) due to rupture of a giant fusiform aneurysm of the ACA involving the AcomA. Here we describe its treatment and postoperative course, and review the literature regarding ACA involving an AcomA aneurysm that was treated with bypass surgery. A 65-year-old man presented with sudden onset of headache and vomiting. Computed tomography (CT) revealed SAH due to rupture of a giant fusiform ACA involving an AcomA aneurysm. He was admitted to the local neurosurgical unit 5 days after symptom onset. After waiting for vasospasm to resolve, he was transferred to our hospital. Three-dimensional CT demonstrated giant fusiform dilatation (25mm in diameter) of the left ACA (A1-A2), and the AcomA was involved. The perforating branches around the aneurysm were not identified. We performed proximal clipping with A3-A3 bypass for protection of reversal flow to the perforating branches of the left ACA. Postoperative magnetic resonance imaging showed a small infarction in part of the left caudate nucleus and the fornix. Cerebral angiogram revealed complete obliteration of the aneurysm. The patient did not experience palsy or aphasia, but he suffered from transient disturbance of frontal lobe function. A few months later, his cognitive function had recovered, and he was able to resume his normal daily life. Although clinicians should monitor for the development of postoperative neurological symptoms, including cognitive dysfunction proximal clipping with A3-A3 bypass was an effective and reliable treatment for ruptured giant fusiform ACA involving an AcomA aneurysm.