Unilateral Fenestrated A1 Segment of Anterior Cerebral Artery Multiple Aneurysms: Case Reports and Literature Review

Single-lane clipping technique for a ruptured aneurysm of A1 fenestration of the anterior cerebral artery: a case report and literature review

Fenestration of the A1 segment of the anterior cerebral artery is a rare vascular anomaly with a high risk of saccular aneurysm at the proximal end of the A1 fenestration. These aneurysms have a high risk of rupture. However, conventional surgical clipping can be technically challenging due to the anatomical characteristics. We report a case of A1 fenestration with a ruptured aneurysm wherein we successfully achieved complete obliteration of the aneurysm with a new "single-lane" clipping technique. A 64-year-old woman presented with a ruptured saccular A1 aneurysm at the proximal end of an A1 fenestration, resulting in subarachnoid hemorrhage. Microsurgical clipping was attempted; however, adequate exposure of the aneurysm could not be achieved. The recurrent artery of Heubner originated near the distal end of the lateral limb of the A1 fenestration. The lateral limb of the A1 fenestration had no perforating arteries, according to surgical examination. Thus, the aneurysm neck and lateral limb were concurrently obliterated using a nonfenestrated clip, preserving the medial limb of the A1 fenestration. The antegrade flow of the recurrent artery of Heubner was detected using the retrograde flow of the distal part of the lateral limb of the A1 fenestration during intraoperative indocyanine green video angiography. The postoperative course was uneventful without any evidence of ischemic stroke. For A1 aneurysms arising from the proximal end of the A1 fenestration, this technique may be a useful treatment option. Before using this technique, careful surgical exploration should be performed to assess the A1 perforating arteries.

Endovascular treatment for aneurysms at the A1 segment of the anterior cerebral artery: current difficulties and solutions

Aneurysms located at the A1 segment of the anterior cerebral artery are considered rare and unique entities. Endovascular treatment (EVT) is effective in preventing aneurysmal bleeding. However, EVT for A1 aneurysms is difficult due to their distinctive configurations. A current review of EVT for A1 aneurysms is lacking. Therefore, we focused on the available literature on this specific issue. To more clearly expound this entity, we also provided some illustrative cases. The A1 segment can be equally divided into the proximal, middle, and distal segments. Proximal aneurysms are most common and difficult to treat via EVT. The A1 segment has a complex anatomy and many important branches. Due to the small size, predominant posterior direction, and sharp upturn of the microcatheter from the parent artery, microcatheter positioning and support is difficult for A1 aneurysms. EVT for A1 aneurysms mainly includes reconstructive and deconstructive strategies. The complications of EVT for A1 aneurysms include aneurysmal perforation, thromboembolic events, and coil protrusion related to stent-assisted embolization. A1 aneurysms represent rare and difficult vascular lesions. EVT is quite challenging for A1 aneurysms due to their distinctive configurations. The outcomes are acceptable.

Endovascular Management of Complex Fenestration-Associated Aneurysms: A Single-Institution Retrospective Study and Review of Existing Techniques

BACKGROUND

Aneurysms associated with fenestrations of intracranial arteries are exceptionally rare findings. Management strategies for these aneurysms are not well-defined, especially regarding endovascular treatment. We sought to investigate the strategies and feasibility of endovascular treatment approaches for various fenestration-associated intracranial aneurysms.

METHODS

We performed a retrospective chart review of 2000 aneurysms treated endovascularly, identifying 8 aneurysms located at arterial fenestrations. The technical details and procedural outcomes were reviewed to identify common management approaches, technical nuances, and treatment outcomes.

RESULTS

There were 3 (37.5%) aneurysms associated with fenestrations of the basilar artery or vertebrobasilar junction. All 3 were successfully treated with a previously undescribed coil-assisted flow-diversion technique, resulting in complete obliteration. Three (37.5%) aneurysms were associated with fenestrations of the anterior communicating artery. Of those, 2 were successfully treated with stent-assisted coil embolization and 1 with coil embolization alone. One (12.5%) aneurysm was associated with a fenestration of the paraclinoid internal carotid artery and 1 (12.5%) aneurysm found was at the takeoff of the posterior inferior cerebellar artery at a fenestration of the vertebral artery. Both were successfully treated with coil-assisted flow diversion. There were no permanent procedural complications. Major considerations for endovascular management of these aneurysms were the dominance of fenestration trunks, aneurysms arising from the fenestration apex or a fenestration limb, amenability to flow diversion, and anticipation of vascular remodeling.

CONCLUSIONS

Fenestration-associated aneurysms are very rare. We have identified common factors to help guide decision-making for endovascular approaches and demonstrate successful aneurysm treatment using these methods.