Bypass surgery for complex middle cerebral artery aneurysms: an algorithmic approach to revascularization.
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.
Department of Neurosurgery and.|Skull Base and Cerebrovascular Laboratory, University of California, San Francisco, California.
Ali
A
Tayebi Meybodi
Department of Neurosurgery and.
Wendy
W
Huang
Department of Neurosurgery and.|Skull Base and Cerebrovascular Laboratory, University of California, San Francisco, California.
Arnau
A
Benet
Skull Base and Cerebrovascular Laboratory, University of California, San Francisco, California.
Olivia
O
Kola
Department of Neurosurgery and.|Skull Base and Cerebrovascular Laboratory, University of California, San Francisco, California.
Michael T
MT
Lawton
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D002548:Cerebral Revascularization / Q000379:methods*; D002648:Child; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000145:classification / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D055815:Young Adult
ACA = anterior cerebral artery; ATA = anterior temporal artery; CCA = common carotid artery; EC = extracranial; ECA = external carotid artery; IC = intracranial; ICA = internal carotid artery; LSA = lenticulostriate artery; MCA = middle cerebral artery; RAG = radial artery graft; SAH = sub-arachnoid hemorrhage; STA = superficial temporal artery; SVG = saphenous vein graft; complex aneurysm; extracranial–intracranial bypass; giant aneurysm; intracranial–intracranial bypass; mRS = modified Rankin Scale; orbitozygomatic craniotomy; pterional craniotomy; vascular disorders