Surgical Techniques for Unclippable Fusiform A2-Anterior Cerebral Artery Aneurysms and Description of a Frontopolar-to-A2 Bypass

BACKGROUND: Fusiform aneurysms involving the A2 or distal A1-A2 segment of the anterior cerebral artery are uncommon and difficult to manage surgically with simple coiling or clipping. METHODS: We illustrate four technical strategies to achieve complete obliteration of such complex aneurysms based on individual clinical conditions and imaging characteristics. Such treatments included combined open and endovascular techniques. RESULTS: The techniques described include simultaneous clipping and wrap reinforcement of the aneurysm (clip-wrapping), flow reversal with A3-to-A3 bypass, trapping with A3-to-A3 bypass, and the use of an ipsilateral frontopolar-to-contralateral A2 bypass after resection of the aneurysm. CONCLUSIONS: These techniques may involve endovascular and surgical options in an attempt to obtain the best overall outcome. Bypasses in the interhemispheric fissure, while difficult, are important, even necessary, adjuncts to treatment of these complex lesions.