title: Surgery for carotid dural ring aneurysms.
abstract: BACKGROUND
  Carotid aneurysms of the paraclinoid segment are usually located in the intradural space, but can infrequently straddle the intra- and extradural space.
  
  
  METHODS
  We present 2 cases of unruptured carotid dural ring aneurysms with an aneurysmal sac that straddled the distal dural ring. Each paraclinoid aneurysm projected superiorly from the anterior surface of the internal carotid artery with a relatively flattened dome and central indentation on angiography. The aneurysmal domes were circumscribed by the distal dural ring and straddled the intra- and extradural space. After broad opening of the distal dural ring, aneurysms were successfully obliterated by clip application in parallel with the internal carotid artery.
  
  
  CONCLUSIONS
  These cases underscore the significance of an aneurysmal dome indentation on angiographic images as a reflection of aneurysmal circumscription by the distal dural ring. Aneurysms that straddle the intra- and extradural space may require broad opening of the distal dural ring for adequate control and clipping.
authors.affiliation: Department of Neurosurgery, Gifu University School of Medicine, Tsukasamachi, Gifu, Japan.
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Kaku
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Yoshimura
authors.forename: Noboru
authors.initials: N
authors.lastname: Sakai
mesh_terms: D000368:Aged; D002340:Carotid Artery Diseases / Q000150:complications / Q000000981:diagnostic imaging / Q000601:surgery*; D002533:Cerebral Angiography; D004388:Dura Mater / Q000601:surgery*; D006801:Humans; D002532:Intracranial Aneurysm / Q000150:complications / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods