Anterior Cerebral Artery Bypass for Complex Aneurysms: Advances in Intracranial-Intracranial Bypass Techniques

Abstract

Background: Anterior cerebral artery (ACA) bypasses for complex aneurysms are infrequently performed, yet previous experience demonstrates the importance of intracranial-intracranial bypasses. Here we describe technical advances in intracranial-intracranial bypass techniques and their clinical results. Methods: Twenty-three patients with complex aneurysms requiring ACA bypasses were retrospectively studied. Ten patients were treated in period 1 (1997–2013) and 13 in period 2 (2014–2018). Results: There were 3 precommunicating, 8 communicating, and 8 postcommunicating ACA aneurysms, plus 4 middle cerebral artery aneurysms. ACA in situ bypass was the most commonly performed (9 patients; 39%). The classic left A3 ACA–right A3 ACA in situ bypass was performed in 5 patients, but 3 new in situ variations emerged in period 2: left pericallosal artery (PcaA)–right PcaA (n = 1), left callosomarginal artery (CmaA)–right CmaA (n = 2), and left CmaA–right 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 (left PcaA–right PcaA and right A3 ACA–left anterior internal frontal artery). The A1 ACA was used as a donor only in period 2 in 4 patients with middle cerebral artery bifurcation aneurysms. Bypass patency was 91%, and 21 patients (91%) improved or remained at neurologic baseline (mean [standard deviation] follow-up duration, 26 [8.2] months). Conclusions: ACA bypass techniques continue to evolve with the addition of several variations. These variations push bypass techniques beyond the standard constructs and add important alternatives to our bypass arsenal.