title: Bilateral ethmoidal dural arteriovenous fistulae: a previously unreported entity: case report.
abstract: OBJECTIVE
  Ethmoidal dural arteriovenous fistulas (AVFs) are rare intracranial lesions associated with a high risk of intracranial hemorrhage. Reported hemorrhage rates have ranged from 62 to 91%, and an aggressive clinical course is more likely than a benign clinical course. We describe the first case of a patient with bilateral ethmoidal dural AVFs.
  
  
  METHODS
  A 50-year-old man presented with posterior fossa subarachnoid hemorrhage and cerebellar intraparenchymal hemorrhage. Angiography revealed a tentorial AVF and a complex anterior ethmoidal dural AVF.
  
  
  METHODS
  The tentorial AVF was treated with preoperative embolization and surgical obliteration. On follow-up angiography, the ethmoidal dural AVF was not considered amenable to embolization. A right modified orbitozygomatic approach was performed and the right-sided fistula was interrupted. Intraoperative angiography revealed obliteration of the right-sided fistula, but a persistent fistula on the left. Further surgical exploration revealed this contralateral anterior ethmoidal dural AVF, which was clip ligated. No residual fistula was noted on intraoperative angiography.
  
  
  CONCLUSIONS
  Anterior ethmoidal dural AVFs may occur bilaterally. Given their complex angiographic appearance, their presence bilaterally may not be readily apparent on preoperative angiography. Intraoperative angiography is crucial to identify a contralateral fistula and to verify that ligation has been curative.
authors.affiliation: Division of Neurological Surgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA.
authors.forename: Vivek R
authors.initials: VR
authors.lastname: Deshmukh
authors.forename: Steve
authors.initials: S
authors.lastname: Chang
authors.forename: Felipe C
authors.initials: FC
authors.lastname: Albuquerque
authors.forename: Cameron G
authors.initials: CG
authors.lastname: McDougall
authors.forename: Robert F
authors.initials: RF
authors.lastname: Spetzler
mesh_terms: D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging / Q000601:surgery; D002533:Cerebral Angiography; D035262:Cranial Fossa, Anterior / Q000098:blood supply / Q000601:surgery*; D004388:Dura Mater / Q000098:blood supply / Q000601:surgery*; D004621:Embolization, Therapeutic; D005004:Ethmoid Bone / Q000098:blood supply / Q000601:surgery*; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000150:complications / Q000601:surgery* / Q000628:therapy; D007430:Intraoperative Care; D008026:Ligation; D008297:Male; D008875:Middle Aged; D009880:Ophthalmic Artery / Q000002:abnormalities / Q000601:surgery; D013345:Subarachnoid Hemorrhage / Q000209:etiology / Q000628:therapy