title: Doppler ultrasonography and computed tomography angiography demonstrate positional occlusion of vertebral artery associated with one-sided destruction of the atlantoaxial lateral mass caused by rheumatoid arthritis: a case report.
abstract: METHODS
  Case report of a patient with rheumatoid arthritis (RA) and a positional occlusion of the left vertebral artery (VA).
  
  
  OBJECTIVE
  To describe the utility of Doppler ultrasonography and computed tomography (CT) angiography for the diagnosis of positional VA occlusion.
  
  
  BACKGROUND
  In previous reports of positional VA occlusion in RA, angiography has been used for the diagnosis. However, it is difficult to demonstrate the three-dimensional relationship between the arteries and the bone structure with angiography.
  
  
  METHODS
  An 83-year-old man with a 20-year history of RA complained of severe vertigo when he leaned his head in the left-anterior direction. CT angiography in the neutral position revealed that the left VA was pinched between the posterior rim of the transverse foramen of C1 and the transverse process of C2. Doppler ultrasonography demonstrated positional VA occlusion and a severe reduction in blood flow at the position that most readily induces vertigo. Because the space between the transverse foramens of left C1 and C2 was reduced with the destruction of the left C1/C2 lateral masses, slight rotation, and anterior shift of C1 led to the occlusion of the VA.
  
  
  RESULTS
  After posterior O-C2 fusion at the reduced position, the VA occlusion and vertigo disappeared.
  
  
  CONCLUSIONS
  Doppler ultrasonography and CT angiography allow valuable measurements in the diagnosis of positional VA occlusion. The one-sided destruction of the C1/C2 lateral masses might be a causal factor for VA occlusion in RA. This is the first report of a new pathomechanism underlying positional VA occlusion demonstrated with three-dimensional CT angiography.
authors.affiliation: Department of Orthopaedic Surgery, Kyoto University Graduate School of Medicine, Shogoin, Sakyo, Kyoto, Japan. yositomi@kuhp.kyoto-u.ac.jp
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Yoshitomi
authors.forename: Masashi
authors.initials: M
authors.lastname: Neo
authors.forename: Hiromu
authors.initials: H
authors.lastname: Ito
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Takemoto
authors.forename: Yuki
authors.initials: Y
authors.lastname: Masaki
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakamura
mesh_terms: D000369:Aged, 80 and over; D001172:Arthritis, Rheumatoid / Q000150:complications*; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging* / Q000601:surgery; D006801:Humans; D007085:Ilium / Q000637:transplantation; D008297:Male; D011237:Predictive Value of Tests; D013123:Spinal Fusion; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D018608:Ultrasonography, Doppler; D014715:Vertebrobasilar Insufficiency / Q000000981:diagnostic imaging* / Q000209:etiology; D014717:Vertigo / Q000209:etiology