title: A comparative agreement evaluation of two subaxial cervical spine injury classification systems: the AOSpine and the Allen and Ferguson schemes.
abstract: We performed an agreement study using two subaxial cervical spine classification systems: the AOSpine and the Allen and Ferguson (A&F) classifications. We sought to determine which scheme allows better agreement by different evaluators and by the same evaluator on different occasions.
  
  
  
  Complete imaging studies of 65 patients with subaxial cervical spine injuries were classified by six evaluators (three spine sub-specialists and three senior orthopaedic surgery residents) using the AOSpine subaxial cervical spine classification system and the A&F scheme. The cases were displayed in a random sequence after a 6-week interval for repeat evaluation. The Kappa coefficient (κ) was used to determine inter- and intra-observer agreement.
  
  
  
  Inter-observer: considering the main AO injury types, the agreement was substantial for the AOSpine classification [κ = 0.61 (0.57-0.64)]; using AO sub-types, the agreement was moderate [κ = 0.57 (0.54-0.60)]. For the A&F classification, the agreement [κ = 0.46 (0.42-0.49)] was significantly lower than using the AOSpine scheme. Intra-observer: the agreement was substantial considering injury types [κ = 0.68 (0.62-0.74)] and considering sub-types [κ = 0.62 (0.57-0.66)]. Using the A&F classification, the agreement was also substantial [κ = 0.66 (0.61-0.71)]. No significant differences were observed between spine surgeons and orthopaedic residents in the overall inter- and intra-observer agreement, or in the inter- and intra-observer agreement of specific type of injuries.
  
  
  
  The AOSpine classification (using the four main injury types or at the sub-types level) allows a significantly better agreement than the A&F classification. The A&F scheme does not allow reliable communication between medical professionals.
authors.affiliation: Department of Orthopaedic Surgery, School of Medicine, Pontificia Universidad Catolica de Chile, Marcoleta 352, Santiago, Chile. jurrutia@med.puc.cl.
authors.forename: Julio
authors.initials: J
authors.lastname: Urrutia
authors.affiliation: Department of Orthopaedic Surgery, School of Medicine, Pontificia Universidad Catolica de Chile, Marcoleta 352, Santiago, Chile.
authors.forename: Tomas
authors.initials: T
authors.lastname: Zamora
authors.affiliation: Department of Orthopaedic Surgery, School of Medicine, Pontificia Universidad Catolica de Chile, Marcoleta 352, Santiago, Chile.
authors.forename: Mauricio
authors.initials: M
authors.lastname: Campos
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, Marcoleta 352, 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, Marcoleta 352, 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, Marcoleta 352, Santiago, Chile.
authors.forename: Carlos
authors.initials: C
authors.lastname: Prada
mesh_terms: D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000293:injuries*; D006801:Humans; D008279:Magnetic Resonance Imaging; D019838:Neck Injuries / Q000145:classification / Q000000981:diagnostic imaging; D015588:Observer Variation; D000072161:Orthopedic Surgeons; D011859:Radiography; D015203:Reproducibility of Results; D016103:Spinal Fractures / Q000145:classification* / Q000000981:diagnostic imaging; D013124:Spinal Injuries / Q000145:classification / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed
keywords: Agreement study; Cervical spine; Spinal injury classification system; Spine fracture; Subaxial cervical spine