Evaluation of the reliability and validity of the newer AOSpine subaxial cervical injury classification (C-3 to C-7)

Abstract

<jats:sec> <jats:title>OBJECTIVE</jats:title> <jats:p>The authors evaluated a new classification for subaxial cervical spine trauma (SCST) recently proposed by the AOSpine group based on morphological criteria obtained using CT imaging.</jats:p></jats:sec> <jats:sec> <jats:title>METHODS</jats:title> <jats:p>Patients with SCST treated at the authors’ institution according to the Subaxial Cervical Spine Injury Classification system were included. Five different blinded researchers classified patients’ injuries according to the new AOSpine system using CT imaging at 2 different times (4-week interval between each assessment). Reliability was assessed using the kappa index (κ), while validity was inferred by comparing the classification obtained with the treatment performed.</jats:p></jats:sec> <jats:sec> <jats:title>RESULTS</jats:title> <jats:p>Fifty-one patients were included: 31 underwent surgical treatment, and 20 were managed nonsurgically. Intraobserver agreement for subgroups ranged from 0.61 to 0.93, and interobserver agreement was 0.51 (first assessment) and 0.6 (second assessment). Intraobserver agreement for groups ranged from 0.66 to 0.95, and interobserver agreement was 0.52 (first assessment) and 0.63 (second assessment). The kappa index in all evaluations was 0.67 for Type A, 0.08 for Type B, and 0.68 for Type C injuries, and for the facet modifier it was 0.33 (F1), 0.4 (F2), 0.56 (F3), and 0.75 (F4). Complete agreement for all components was attained in 25 cases (49%) (19 Type A and 6 Type C), and for subgroups it was attained in 22 cases (43.1%) (16 Type A0 and 6 Type C). Type A0 injuries were treated conservatively or surgically according to their neurological status and ligamentous status. Type C injuries were treated surgically in almost all cases, except one.</jats:p></jats:sec> <jats:sec> <jats:title>CONCLUSIONS</jats:title> <jats:p>While the general reliability of the newer AOSpine system for SCST was acceptable for group classification, significant limitations were identified for subgroups. Type B injuries were rarely diagnosed, and only mild (Type A0) and extreme severe (Type C) injuries had a high rate of interobserver agreement. Facet modifiers and intermediate injury patterns require better descriptions to improve their low agreement in cases of SCST.</jats:p></jats:sec>

External Multicenter Study of Reliability and Reproducibility for Lower Cervical Spine Injuries Classification Systems—Part 1: A Comparison of Morphological Schemes

“…During the second assessment, the expert group demonstrated significantly higher values than those using the A-F, Harris, and Argenson classification systems, a finding in accordance with data reported in current literature. 5,9,11 The main disadvantages of the AOS scale as reported by the raters included (1) a challenging identification of F1 and F2 fractures, (2) common confusion between A2 and A4 types in vertically split vertebral injuries, and (3) a frequent absence of facet-joint trauma classification in addition to the major injury. The intraobserver kappa was found to be higher for the AOS scale than for the Argenson system in our study and reached a moderate level.…”

Predictors of Neurological Outcome Following Subaxial Cervical Spine Trauma

“…The two most popular classification systems for cervical spine injury are the AOspine classification and SLIC systems [1,[4][5]. These systems provide a means to classify injuries into diagnostic categories based on injury pattern (AOspine) and also allow for guidance regarding operative versus non-operative management (SLIC).…”

“…While several classification systems exist, subaxial spine injuries are broadly defined as fractures, dislocations, or ligamentous disruption of the C3 to C7 vertebral levels. Many of these injuries can lead to cervical spine instability and SCI [4][5].…”

“…Due to the complex structure of the cervical spine, cervical spine trauma can produce heterogeneous patterns of injury. Classifications systems such as the subaxial cervical injury classification (SLIC) and the AOSpine subaxial cervical injury classification systems have been developed to aid in diagnosis and treatment [1,[4][5]. The SLIC system provides a score that guides surgical versus non-surgical treatment, while the AOSpine classification system provides a diagnostic tool to standardize descriptions of injury patterns [4][5].…”

Subaxial cervical spine trauma

“…Overall, they concluded that this classification system is reliable and reproducible [25]. On the contrary, however, a study by Silva et al found B type injuries and classification of facet injuries to be unreliable with low intraobserver and interobserver reliabilities [26]. Overall, this classification system may prove more reliable to reproducible than the SLIC; however, there may be difficulty with agreement across intermediate fractures and those affecting the facet.…”