title: Anterior paraclinoid aneurysms.
abstract: OBJECTIVE
  The characteristics of a previously unclassified paraclinoid aneurysm arising from the anterolateral (dorsal) wall of the proximal internal carotid artery were retrospectively analyzed in seven patients (five women and two men) who were treated surgically for an aneurysm in this unusual location.
  
  
  METHODS
  One patient presented with subarachnoid hemorrhage (SAH) caused by rupture of this aneurysm. The lesions were found incidentally (five cases) or during investigation of SAH due to another aneurysm (one case). There was a female predominance in this series; all female patients harbored multiple aneurysms. All patients underwent surgery. Removal of the anterior clinoid process was necessary because the proximal neck of the aneurysm was closely adjacent to the dural ring.
  
  
  CONCLUSIONS
  This special group of aneurysms is very rare, is located exclusively in the intradural space, and carries the risk of SAH. The results of surgical treatment for this aneurysm are quite satisfactory.
authors.affiliation: Department of Neurosurgery, Akita University School of Medicine, Japan. kinouchi@nsg.med.akita-u.ac.jp
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kinouchi
authors.forename: Kazuo
authors.initials: K
authors.lastname: Mizoi
authors.forename: Yoshihide
authors.initials: Y
authors.lastname: Nagamine
authors.forename: Noritaka
authors.initials: N
authors.lastname: Yanagida
authors.forename: Shigeki
authors.initials: S
authors.lastname: Mikawa
authors.forename: Akira
authors.initials: A
authors.lastname: Suzuki
authors.forename: Toshio
authors.initials: T
authors.lastname: Sasajima
authors.forename: Takashi
authors.initials: T
authors.lastname: Yoshimoto
mesh_terms: D000368:Aged; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery*; D002533:Cerebral Angiography; D002560:Cerebrovascular Circulation / Q000502:physiology; D003399:Craniotomy; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013100:Sphenoid Bone / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery*