title: Nontraumatic posterior atlantooccipital dislocation associated with atlantoaxial instability.
abstract: BACKGROUND
  Nontraumatic posterior atlantooccipital dislocation has only been rarely reported. In the current study, the authors reported an extremely rare case of nontraumatic posterior atlantooccipital dislocation associated with atlantoaxial instability.
  
  
  METHODS
  A 47-year-old female was referred with a history of neck pain for 5 years. The patient had no history of trauma. The axial rotation of range of motion of the cervical spine was severely restricted. Posterior atlantooccipital dislocation with atlantoaxial instability was confirmed through conventional radiography, computed tomography and magnetic resonance imaging. We performed realignment of the dislocation and posterior occipitocervical (C0-C2) fusion. After the surgery, the patient's symptoms improved significantly and she manifested neurological improvement.
  
  
  CONCLUSIONS
  To our knowledge, this lesion has not been reported previously. Anomalies of upper cervical spine may have induced this instability.
authors: Department of Orthopaedic Surgery, The Second Affiliated Hospital to Nanchang University, Nanchang, 330006, Jiangxi, China.
authors: Tian-Long
authors: TL
authors: Wu
authors: Jing-Yu
authors: JY
authors: Jia
authors: Wei-Cai
authors: WC
authors: Chen
authors: Ding-Wen
authors: DW
authors: He
authors: Xi-Gao
authors: XG
authors: Cheng
mesh_terms: D001268:Atlanto-Axial Joint / Q000601:surgery*; D001269:Atlanto-Occipital Joint / Q000601:surgery*; D002574:Cervical Vertebrae / Q000601:surgery; D005260:Female; D006801:Humans; D004204:Joint Dislocations / Q000175:diagnosis / Q000209:etiology* / Q000601:surgery; D007593:Joint Instability / Q000150:complications* / Q000175:diagnosis / Q000601:surgery; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D016059:Range of Motion, Articular; D013123:Spinal Fusion / Q000379:methods; D014057:Tomography, X-Ray Computed