Selective-Targeted Extra-Intracranial Bypass Surgery in Complex Middle Cerebral Artery Aneurysms: Correctly Identifying the Recipient Artery Using Indocyanine Green Videoangiography

BACKGROUND: Treatment of complex middle cerebral artery (MCA) aneurysms often requires vessel sacrifice or prolonged temporary occlusion with extra-to intracranial (EC-IC) bypass to preserve perfusion. A crucial surgical step is the identification of the bypass recipient artery matching the distal territory of the involved vessel. OBJECTIVE: To report about the feasibility and efficiency of an indocyanine green videoangiography (ICG-VA) assisted technique for identification of cortical recipient vessels to perform selective-targeted EC-IC bypass. METHODS: The proposed technique is based on the analysis of differences in the timing of filling of M4 vessels seen on serial ICG-VAs. A delayed fluorescence can be visualized either primarily on a baseline ICG-VA or secondarily on an ICG-VA performed during temporary occlusion of the involved MCA branch. M4 branches presenting delayed fluorescence represent suitable bypass recipient arteries. We report 7 consecutive patients treated for complex MCA aneurysms with selective-targeted EC-IC bypass. RESULTS: Application of the proposed technique permitted the correct identification of recipient arteries (cortical branches of the involved MCA segment) in all patients. The cortex distal to the occlusion filled concomitantly on ICG-VA at the end of surgery. All patients underwent successful treatment of the aneurysm, including a cortical bypass. There were no ischemic complications, and a favorable clinical outcome was achieved in all patients (modified Rankin Scale at follow-up <= modified Rankin Scale preoperative). CONCLUSION: The proposed ICG-VA-based technique enables reliable and accurate identification of the cortical recipient artery and eliminates the risk of erroneous revascularization of noninvolved territories.