title: Anterior spinal artery as a collateral channel in cases of bilateral vertebral arterial steno-occlusive diseases.
abstract: OBJECTIVE
  We report 6 cases of retrograde flow through the anterior spinal artery (ASA) from cervical vertebral artery (VA) to intracranial distal VA because the perfusion from bilateral vertebral arteries was tenuous. Its hemodynamic and clinical implications are discussed.
  
  
  METHODS
  In association with bilateral steno-occlusive disease of vertebral arteries, 6 cases of retrograde flow through ASA were reviewed in terms of clinical and angiographic characteristics. All 6 patients presented with stroke in the posterior fossa and underwent conventional angiography as part of diagnostic evaluation and/or therapeutic intervention.
  
  
  RESULTS
  On the angiography, 2 patients showed bilateral VA occlusion, and the other 4 patients showed VA occlusion on 1 side and severe stenosis in the other VA. Distal perfusion by ASA was prominent in 2, and not prominent in 4. Reversal or disappearance of the retrograde flow through ASA was observed after successful recanalization of the occluded VA in 4 patients. In 1 patient, increased perfusion through ASA was observed because the stenosed VA was completely occluded.
  
  
  CONCLUSIONS
  When the vertebral arteries were occluded bilaterally or when a single VA was occluded and the other carried a severe stenosis and, as a result, the basilar arterial blood supply was tenuous, retrograde flow through ASA could be observed. This is a potentially important source of collateral supply to the posterior fossa neural contents. The degree and extent of perfusion via this collateral channel varied depending on presence of other collateral routes and patency of the vertebrobasilar junction.
authors.affiliation: Department of Neurosurgery, Konkuk University Hospital, Seoul, Korea.
authors.forename: H-S
authors.initials: HS
authors.lastname: Kang
authors.forename: M H
authors.initials: MH
authors.lastname: Han
authors.forename: S H
authors.initials: SH
authors.lastname: Kim
authors.forename: O-K
authors.initials: OK
authors.lastname: Kwon
authors.forename: H G
authors.initials: HG
authors.lastname: Roh
authors.forename: Y C
authors.initials: YC
authors.lastname: Koh
authors.forename: Y C
authors.initials: YC
authors.lastname: Ko
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography; D001933:Brain Stem / Q000098:blood supply; D002533:Cerebral Angiography; D002560:Cerebrovascular Circulation; D003097:Collateral Circulation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D013116:Spinal Cord / Q000098:blood supply*; D014711:Vertebral Artery / Q000000981:diagnostic imaging / Q000503:physiopathology; D014715:Vertebrobasilar Insufficiency / Q000000981:diagnostic imaging* / Q000503:physiopathology*