Surgical flow modification of the anterior cerebral artery-anterior communicating artery complex in the management of giant aneurysms of internal carotid artery bifurcation: An alternative for a difficult clip reconstruction

BACKGROUND Internal carotid artery bifurcation (ICAb) aneurysms account for about 2-15% of all intracranial aneurysms. In giant and complex cases, treatment may be difficult and dangerous, once some aneurysms have wide neck and anterior cerebral artery (ACA) and middle cerebral artery (MCA) may arise from the aneurysm itself. Clip reconstruction may be difficult in such cases. Whenever possible, the occlusion of ACA transform the bifurcation in a single artery reconstruction (ICA to MCA), much easier than a bifurcation reconstruction. METHODS In patients with giant and complex ICAb aneurysms, we propose routine preoperative angiography with anatomical evaluation of anterior communicating artery (ACoA) patency during cervical common carotid compression with concomitant contralateral carotid artery injection. This allowed visualization of the expected reversal of flow in the A1 segment-ACoA complex. When test is positive, we can perform ipsilateral ACA (A1 segment) clip occlusion and flow modification of the ACA-ACoA complex transforming a three vessel (ICA, ACA, and MCA) reconstruction into a two vessel (ICA and MCA) reconstruction. RESULTS Two patients were treated, with 100% of occlusion and good outcome. CONCLUSIONS Surgical treatment of giant and complex ICAb may be achieved with acceptable morbidity.