Anterior Cerebral Artery Bypass for Complex Aneurysms: Advances in Intracranial-Intracranial Bypass Techniques
Mohamed Labib, Michael Lawton
Introduction: Previous experience with anterior cerebral artery (ACA) bypasses for complex aneurysms demonstrates how infrequent this alternative treatment strategy is implemented, and how important intracranial-intracranial (IC-IC) bypass techniques are, relative to extracranial-intracranial (EC-IC) techniques. Our experience with ACA bypass has grown and bypass construction has evolved. These technical advances and their clinical results were reviewed.
Methods 23 patients with 23 complex aneurysms requiring an ACA bypass were reviewed retrospectively. Ten patients were treated in the 16-year period between 1997 and 2013 (Period 1), and 13 patients were treated in the 5-year period between 2014 and 2018 (Period 2).
Results: There were 3 pre-communicating ACA (13%), 8 communicating ACA (ACoA, 35%), and 8 post-communicating ACA aneurysms (35%), plus 4 middle cerebral artery (MCA) aneurysms (17%). ACA in situ bypass was the most common bypass (9 patients, 39%). The classic L A3 ACA-R A3 ACA in situ bypass was performed in 5 patients, but 3 new in situ variations were performed in Period 2: L PcaA-R PcaA (n=1), L CmaA-R CmaA (n=2), and L CmaA-R A3 ACA (n=1). The sole reimplantation in Period 1 was the ipsilateral and vertical PcaA-CmaA reimplantation, whereas reimplantations in Period 2 were contralateral and horizontal (L PcaA-R PcaA and R A3 ACA-L AIFA). A1 ACA was not used as a donor for any bypasses in Period 1, but was used in 4 patients with MCA bifurcation aneurysms in Period 2 (17% of all ACA bypasses). Bypass patency was 91%, and 21 patients (91%) improved or remained unchanged neurologically (mean follow-up duration, 26 months).
Conclusions: The frequency of ACA bypass is increasing and ACA bypass technique is evolving dynamically. Despite using all 5 of the IC-IC bypasses in Period 1, 9 additional variations of ACA