Bypass surgery for complex middle cerebral artery aneurysms: an algorithmic approach to revascularization

• Published in: Journal of neurosurgery Vol. 127; no. 3; p. 463
• Main Authors: Tayebi Meybodi, Ali, Huang, Wendy, Benet, Arnau, Kola, Olivia, Lawton, Michael T
• Format: Journal Article
• Language: English
• Published: United States 01.09.2017
• Subjects: ACA = anterior cerebral artery; pterional craniotomy; orbitozygomatic craniotomy; MCA = middle cerebral artery; ICA = internal carotid artery; LSA = lenticulostriate artery; SAH = sub-arachnoid hemorrhage; vascular disorders; ECA = external carotid artery; SVG = saphenous vein graft; STA = superficial temporal artery; ATA = anterior temporal artery; RAG = radial artery graft; CCA = common carotid artery; IC = intracranial; EC = extracranial; complex aneurysm; mRS = modified Rankin Scale; giant aneurysm; extracranial–intracranial bypass; intracranial–intracranial bypass
• DOI: 10.3171/2016.7.jns16772

OBJECT Management of complex aneurysms of the middle cerebral artery (MCA) can be challenging. Lesions not amenable to endovascular techniques or direct clipping might require a bypass procedure with aneurysm obliteration. Various bypass techniques are available, but an algorithmic approach to classifying these lesions and determining the optimal bypass strategy has not been developed. The objective of this study was to propose a comprehensive and flexible algorithm based on MCA aneurysm location for selecting the best of multiple bypass options. METHODS Aneurysms of the MCA that required bypass as part of treatment were identified from a large prospectively maintained database of vascular neurosurgeries. According to its location relative to the bifurcation, each aneurysm was classified as a prebifurcation, bifurcation, or postbifurcation aneurysm. RESULTS Between 1998 and 2015, 30 patients were treated for 30 complex MCA aneurysms in 8 (27%) prebifurcation, 5 (17%) bifurcation, and 17 (56%) postbifurcation locations. Bypasses included 8 superficial temporal artery-MCA bypasses, 4 high-flow extracranial-to-intracranial (EC-IC) bypasses, 13 IC-IC bypasses (6 reanastomoses, 3 reimplantations, 3 interpositional grafts, and 1 in situ bypass), and 5 combination bypasses. The bypass strategy for prebifurcation aneurysms was determined by the involvement of lenticulostriate arteries, whereas the bypass strategy for bifurcation aneurysms was determined by rupture status. The location of the MCA aneurysm in the candelabra (Sylvian, insular, or opercular) determined the bypass strategy for postbifurcation aneurysms. No deaths that resulted from surgery were found, bypass patency was 90%, and the condition of 90% of the patients was improved or unchanged at the most recent follow-up. CONCLUSIONS The bypass strategy used for an MCA aneurysm depends on the aneurysm location, lenticulostriate anatomy, and rupture status. A uniform bypass strategy for all MCA aneurysms does not exist, but the algorithm proposed here might guide selection of the optimal EC-IC or IC-IC bypass technique.