title: An Independent Inter- and Intraobserver Agreement Evaluation of the AOSpine Subaxial Cervical Spine Injury Classification System.
abstract: METHODS
  An agreement study.
  
  
  OBJECTIVE
  The aim of this study was to perform an independent interobserver and intraobserver agreement assessment of the AOSpine subaxial cervical spine injury classification system.
  
  
  BACKGROUND
  The AOSpine subaxial cervical spine injury classification system was recently described. It showed substantial inter- and intraobserver agreement in the study describing it; however, an independent evaluation has not been performed.
  
  
  METHODS
  Anteroposterior and lateral radiographs, computed tomography scans, and magnetic resonance imaging of 65 patients with acute traumatic subaxial cervical spine injuries were selected and classified using the morphologic grading of the subaxial cervical spine injury classification system by 6 evaluators (3 spine surgeons and 3 orthopedic surgery residents). After a 6-week interval, the 65 cases were presented to the same evaluators in a random sequence for repeat evaluation. The kappa coefficient (κ) was used to determine the inter- and intraobserver agreement.
  
  
  RESULTS
  The interobserver agreement was substantial when considering the fracture main types (A, B, C, or F), with κ = 0.61 (0.57-0.64), but moderate when considering the subtypes: κ = 0.57 (0.54-0.60). The intraobserver agreement was substantial considering the fracture types, with κ = 0.68 (0.62-0.74) and considering subtypes, κ = 0.62 (0.57-0.66). No significant differences were observed between spine surgeons and orthopedic residents in the overall inter- and intraobserver agreement, or in the inter- and intraobserver agreement of specific A, B, C, or F type of injuries.
  
  
  CONCLUSIONS
  This classification allows adequate agreement among different observers and by the same observer on separate occasions. Future prospective studies should determine whether this classification allows surgeons to decide the best treatment for patients with subaxial cervical spine injuries.
  
  
  METHODS
  3.
authors.affiliation: Department of Orthopaedic Surgery, School of Medicine, Pontificia Universidad Catolica de Chile, Santiago, Chile.
authors.forename: Julio
authors.initials: J
authors.lastname: Urrutia
authors.affiliation: Department of Orthopaedic Surgery, School of Medicine, Pontificia Universidad Catolica de Chile, Santiago, Chile.
authors.forename: Tomas
authors.initials: T
authors.lastname: Zamora
authors.affiliation: Department of Orthopaedic Surgery, Clinica Alemana de Santiago, Santiago, Chile.
authors.forename: Ratko
authors.initials: R
authors.lastname: Yurac
authors.affiliation: Department of Orthopaedic Surgery, School of Medicine, Pontificia Universidad Catolica de Chile, Santiago, Chile.
authors.forename: Mauricio
authors.initials: M
authors.lastname: Campos
authors.affiliation: Department of Orthopaedic Surgery, School of Medicine, Pontificia Universidad Catolica de Chile, Santiago, Chile.
authors.forename: Joaquin
authors.initials: J
authors.lastname: Palma
authors.affiliation: Department of Orthopaedic Surgery, School of Medicine, Pontificia Universidad Catolica de Chile, Santiago, Chile.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Mobarec
authors.affiliation: Department of Orthopaedic Surgery, School of Medicine, Pontificia Universidad Catolica de Chile, Santiago, Chile.
authors.forename: Carlos
authors.initials: C
authors.lastname: Prada
mesh_terms: D000328:Adult; D002574:Cervical Vertebrae / Q000293:injuries*; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000293:injuries*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D015588:Observer Variation; D011446:Prospective Studies; D015203:Reproducibility of Results; D013124:Spinal Injuries / Q000175:diagnosis*; D013904:Thoracic Vertebrae / Q000293:injuries*; D014057:Tomography, X-Ray Computed / Q000379:methods