title: Two unusual cases of multiple dural arteriovenous fistulas.
abstract: OBJECTIVE
  Two patients with dural arteriovenous fistulas involving the transverse sinus and superior sagittal sinus are described, with a focus on the unique type of venous drainage of the fistula.
  
  
  METHODS
  Both patients presented with papilledema and progressive visual disturbance. Angiography and magnetic resonance imaging showed that the fistulas involving the superior sagittal sinus had a dilated venous channel, separate from the sinus lumen, located within the wall of the sinus.
  
  
  METHODS
  Transvenous embolization of the venous channel of the fistula, proximal to its drainage into the superior sagittal sinus, resulted in closure of the fistula and restoration of the superior sagittal sinus function. The clinical symptoms were reversed; the symptoms are believed to have reflected venous hypertension in the superior sagittal sinus, resulting from the shunted flow and interfering with normal venous drainage.
  
  
  CONCLUSIONS
  This unique type of dural arteriovenous fistula may be a variant, occurring in the developmental process of the fistula. It is significant clinically because transvenous embolization can be used to close the fistula and restore sinus function.
authors.affiliation: Department of Neurosurgery, Kobe University School of Medicine, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Nakamura
authors.forename: N
authors.initials: N
authors.lastname: Tamaki
authors.forename: Y
authors.initials: Y
authors.lastname: Hara
authors.forename: T
authors.initials: T
authors.lastname: Nagashima
mesh_terms: D000368:Aged; D001164:Arteriovenous Fistula / Q000000981:diagnostic imaging / Q000628:therapy*; D002533:Cerebral Angiography; D003392:Cranial Sinuses / Q000000981:diagnostic imaging; D004388:Dura Mater / Q000098:blood supply*; D004621:Embolization, Therapeutic; D006801:Humans; D008297:Male; D008875:Middle Aged; D009460:Neurologic Examination; D016896:Treatment Outcome; D014690:Venous Pressure / Q000502:physiology