title: Cryptic Recanalization of Chronic Vertebral Artery Occlusion by Head Rotation.
abstract: BACKGROUND
  Chronic vertebral artery occlusion (VAO) can be associated with ischemic stroke, as thrombi formed under blood flow stagnation around the stump of the VAO may migrate into the brain. We report a new mechanism of chronic VAO-associated ischemic stroke and a patient with cryptic recanalization of chronic VAO by head rotation.
  
  
  METHODS
  A 74-year-old man presented with chronic right VAO and repeated ischemic embolic stroke in the posterior circulation despite antiplatelet therapy. He also manifested vertigo with 30° leftward head rotation, indicative of rotational vertebrobasilar insufficiency due to mechanical compression of the patent left vertebral artery (VA) at the C4-C5 level. Surgical decompression of the vessel via the anterior approach resulted in the disappearance of his rotational vertebrobasilar insufficiency. Adequate decompression of the VA on the left side was confirmed on postoperative computed tomography angiography scans obtained with his head rotated more to the left than on preoperative scans. Unexpected partial recanalization of his right chronic VAO was observed at the C5-C6 level. VAO was due to VA compression by osteophytes at neutral head position; it was released by head rotation. We suspected that his repeated brain infarcts were attributable to head rotation-related opening and closing of the VA lumen and these decompressed the left VA by removing the implicated osteophyte via the anterior approach.
  
  
  CONCLUSIONS
  Cryptic recanalization of chronic VAO by head rotation contributed to repeated infarcts in the posterior circulation and was resolved by surgical decompression.
authors.affiliation: Department of Neurosurgery, Tokushima University Hospital, Tokushima, Japan; Department of Neurosurgery, Faculty of Medicine, Fukuoka University, Fukuoka, Japan. Electronic address: yagi_neuro@yahoo.co.jp.
authors.forename: Kenji
authors.initials: K
authors.lastname: Yagi
authors.affiliation: Department of Neurosurgery, Kushiro Kojinkai Memorial Hospital, Kushiro, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nakagawa
authors.affiliation: Department of Neurosurgery, Tokushima University Hospital, Tokushima, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Mure
authors.affiliation: Department of Neurosurgery, Tokushima University Hospital, Tokushima, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Okita
authors.affiliation: Department of Neurosurgery, Tokushima University Hospital, Tokushima, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Nagahiro
mesh_terms: D000368:Aged; D002533:Cerebral Angiography; D000072226:Computed Tomography Angiography; D019299:Decompression, Surgical / Q000379:methods*; D006257:Head; D006801:Humans; D008297:Male; D012399:Rotation / Q000009:adverse effects*; D014057:Tomography, X-Ray Computed; D014711:Vertebral Artery / Q000000981:diagnostic imaging / Q000601:surgery; D014715:Vertebrobasilar Insufficiency / Q000000981:diagnostic imaging / Q000209:etiology* / Q000601:surgery*
keywords: Bow hunter's syndrome; Vertebral artery stump syndrome; cervical spondylosis; rotational vetebrobasilar insufficiency