title: The outcome of a surgical protocol based on ischemia overprotection in large and giant aneurysms of the anterior cerebral circulation.
abstract: Aiming to define the optimal treatment of large and giant aneurysms (LGAs) in the anterior circulation, we present our surgical protocol and patient outcome. A series of 42 patients with intracavernous LGAs (n = 16), paraclinoid (C2) LGAs (n = 17), and peripheral (middle cerebral artery-MCA or anterior cerebral artery-ACA) LGAs (n = 9) were treated after bypass under motor evoked potential (MEP) monitoring. Preoperatively, three categories of ischemic tolerance during internal carotid artery (ICA) occlusion were defined on conventional angiography: optimal, suboptimal, and insufficient collaterals. Accordingly, three types of bypass: low flow (LFB), middle flow (MFB) and high flow (HFB) were applied for the cases with optimal, suboptimal, and insufficient collaterals, respectively. Outcome was evaluated by the Glasgow Outcome Scale (GOS). All patients had excellent GOS score except one, who suffered a major ischemic stroke immediately after surgery for a paraclinoid lesion. Forty-one patients were followed up for 87.1 ± 40.1 months (range 13-144 months). Intracavernous LGAs were all treated by proximal occlusion with bypass surgery. Of paraclinoid LGA patients, 15 patients had direct clipping under suction decompression and other 2 patients with recurrent aneurysms had ICA (C2) proximal clipping with HFB. MEP monitoring guided for temporary clipping time and clip repositioning, observing significant MEP changes for up to 6 min duration. Of 9 peripheral LGAs patients 7 MCA LGAs had reconstructive clipping (n = 4) or trapping (n = 3) with bypass including LFB in 3 cases, MFB in 1 and HFB in 1. Two ACA LGAs had clipping (n = 1) or trapping (n = 1) with A3-A3 bypass. The applied protocol provided excellent results in intracavernous, paraclinoid, and peripheral thrombosed LGAs of the anterior circulation.
authors.affiliation: Department of Neurosurgery, Faculty of Medicine, The University of Tokyo Graduate School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Imai
authors.affiliation: Department of Neurosurgery, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan.
authors.forename: Katsushige
authors.initials: K
authors.lastname: Watanabe
authors.affiliation: Department of Neurosurgery, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Miyagishima
authors.affiliation: Department of Neurosurgery, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan.
authors.forename: Yuhei
authors.initials: Y
authors.lastname: Yoshimoto
authors.affiliation: Department of Neurosurgery, Faculty of Medicine, The University of Tokyo Graduate School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan.
authors.forename: Taichi
authors.initials: T
authors.lastname: Kin
authors.affiliation: Department of Neurosurgery, Faculty of Medicine, The University of Tokyo Graduate School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Nakatomi
authors.affiliation: Department of Neurosurgery, Faculty of Medicine, The University of Tokyo Graduate School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan. nsaito-tky@umin.net.
authors.forename: Nobuhito
authors.initials: N
authors.lastname: Saito
mesh_terms: D000328:Adult; D000368:Aged; D020771:Anterior Cerebral Artery / Q000601:surgery*; D002545:Brain Ischemia / Q000601:surgery*; D002340:Carotid Artery Diseases / Q000601:surgery*; D002533:Cerebral Angiography / Q000379:methods; D002560:Cerebrovascular Circulation / Q000502:physiology; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000601:surgery*; D008297:Male; D008866:Microsurgery / Q000379:methods; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000601:surgery*; D019635:Neurosurgical Procedures / Q000379:methods; D013525:Surgical Instruments; D016896:Treatment Outcome
keywords: Bypass; Giant/large cerebral aneurysm; Internal carotid artery; Intracavernous aneurysm; Motor evoked potential; Perforating artery