title: Outflow occlusion with A3-A3 anastomosis for a doughnut-shaped partially thrombosed giant A2 aneurysm.
abstract: BACKGROUND
  A doughnut-shaped aneurysm, which is defined as a round-shaped aneurysm composed of an intraluminar thrombus and marginal parent artery, is an extremely uncommon subtype of partially thrombosed giant aneurysms. Surgical treatment of this characteristic aneurysm is technically challenging.
  
  
  METHODS
  We report a rare case of a 79-year-old man with a symptomatic doughnut-shaped giant aneurysm at the A2 portion, which was successfully treated by outflow occlusion with an A3-A3 side-to-side anastomosis. Postoperative angiograms demonstrated no filling of the doughnut-shaped aneurysm and perfusion in the distal right anterior cerebral artery territory via the anastomosis. Follow-up magnetic resonance imaging 1 year after the surgery demonstrated significant diminution of the aneurysm.
  
  
  CONCLUSIONS
  Outflow occlusion with distal revascularization could be an effective surgical option for such a unique aneurysm. To the best of our knowledge, this is the first report of outflow occlusion as a therapy for doughnut-shaped aneurysms.
authors.affiliation: Department of Neurosurgery, St. Marianna University School of Medicine, Kanagawa, Japan.
authors.forename: Hidemichi
authors.initials: H
authors.lastname: Ito
authors.affiliation: Department of Neurosurgery, St. Marianna University School of Medicine, Kanagawa, Japan.
authors.forename: Ryotaro
authors.initials: R
authors.lastname: Miyano
authors.affiliation: Department of Neurosurgery, St. Marianna University School of Medicine, Kanagawa, Japan.
authors.forename: Taigen
authors.initials: T
authors.lastname: Sase
authors.affiliation: Department of Neurosurgery, St. Marianna University School of Medicine, Kanagawa, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Wakui
authors.affiliation: Department of Neurosurgery, St. Marianna University School of Medicine, Kanagawa, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Matsumori
authors.affiliation: Department of Neurosurgery, St. Marianna University School of Medicine, Kanagawa, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Takasuna
authors.affiliation: Department of Neurosurgery, St. Marianna University School of Medicine, Kanagawa, Japan.
authors.forename: Kotaro
authors.initials: K
authors.lastname: Oshio
authors.affiliation: Department of Neurosurgery, St. Marianna University School of Medicine, Kanagawa, Japan.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Tanaka
keywords: Anterior cerebral artery; bypass surgery; giant aneurysm; outflow occlusion; partially thrombosed aneurysm