title: Management of chronic atlantoaxial rotatory fixation.
abstract: METHODS
  Retrospective case series of chronic atlantoaxial rotatory fixation (AARF) treated by a novel closed reduction method (remodeling therapy) and review of the literature.
  
  
  OBJECTIVE
  To describe clinical features of chronic AARF and the rationale of the remodeling therapy.
  
  
  BACKGROUND
  Treatment strategy for chronic recurrent AARF remains controversial. Posterior C1-C2 arthrodesis has been widely used for recurrent unstable AARFs after the closed reduction, and a variety of posterior fusion techniques have been advocated. In contrast, several investigators reported a chronic AARF case treated by a simple traction or closed reduction followed by cervical immobilization. Previously, we have found that a deformity of the superior C2 facet joint (C2 facet deformity) on three dimensional computed tomography (3D CT) reconstructions is a risk factor for recurrent subluxation. In addition, the remodeling of this C2 facet deformity by careful closed manipulation followed by halo fixation (remodeling therapy) could prevent the recurrence of subluxation.
  
  
  METHODS
  Twelve children with chronic AARF who sustained torticollis for an average of 4.4 months after the onset were referred to our clinic. The mean age at the initial visit was 7.8 years. All patients underwent the remodeling therapy as reported previously. Radiographic findings and clinical courses were retrospectively reviewed. Treatment methodology, pearls, and pitfalls of the remodeling therapy were discussed with review of the literature.
  
  
  RESULTS
  3D CT images before reduction revealed persistent atlantoaxial subluxation and the C2 facet deformity in the dislocated side in all cases. Follow-up 3D CT scans demonstrated the remodeling of the C2 facet deformity at an average of 2.4 months after successful reduction of subluxation. Neither recurrence of symptoms nor subluxation was observed at a mean follow-up of 42 months in any case. The cervical range of motion was 73.9° at the dislocated and 83.5° at the contra-dislocated side from the midline.
  
  
  CONCLUSIONS
  Chronic irreducible and recurrent unstable AARF should be initially managed by remodeling therapy using the facet deformity sign as a clinical index, if the C1 and C2 have not been osseously fused.
authors.affiliation: Department of Orthopaedic Surgery, School of Medicine, Keio University, Tokyo, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Ishii
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Toyama
authors.forename: Masaya
authors.initials: M
authors.lastname: Nakamura
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Chiba
authors.forename: Morio
authors.initials: M
authors.lastname: Matsumoto
mesh_terms: D001268:Atlanto-Axial Joint / Q000002:abnormalities / Q000000981:diagnostic imaging / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D002908:Chronic Disease; D000013:Congenital Abnormalities; D016267:External Fixators / Q000592:standards*; D006801:Humans; D007593:Joint Instability / Q000473:pathology* / Q000503:physiopathology / Q000628:therapy; D020393:Manipulation, Spinal / Q000379:methods*; D011859:Radiography; D012189:Retrospective Studies; D013123:Spinal Fusion / Q000295:instrumentation / Q000379:methods; D014103:Torticollis / Q000473:pathology / Q000503:physiopathology / Q000628:therapy; D016896:Treatment Outcome