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. 2022 Dec;22(12):2042-2049.
doi: 10.1016/j.spinee.2022.08.005. Epub 2022 Aug 12.

AO Spine upper cervical injury classification system: a description and reliability study

Alexander R Vaccaro  1 , Mark J Lambrechts  2 , Brian A Karamian  1 , Jose A Canseco  1 , Cumhur Oner  3 , Emiliano Vialle  4 , Shanmuganathan Rajasekaran  5 , Marcel R Dvorak  6 , Lorin M Benneker  7 , Frank Kandziora  8 , Mohammad El-Sharkawi  9 , Jin Wee Tee  10 , Richard Bransford  11 , Andrei F Joaquim  12 , Sander P J Muijs  3 , Martin Holas  13 , Masahiko Takahata  14 , Waeel O Hamouda  15 , Rishi M Kanna  5 , Klaus Schnake  16 , Christopher K Kepler  1 , Gregory D Schroeder  1
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Free article

AO Spine upper cervical injury classification system: a description and reliability study

Alexander R Vaccaro et al. Spine J. 2022 Dec.
Free article

Abstract

Background context: Prior upper cervical spine injury classification systems have focused on injuries to the craniocervical junction (CCJ), atlas, and dens independently. However, no previous system has classified upper cervical spine injuries using a comprehensive system incorporating all injuries from the occiput to the C2-3 joint.

Purpose: To (1) determine the accuracy of experts at correctly classifying upper cervical spine injuries based on the recently proposed AO Spine Upper Cervical Injury Classification System (2) to determine their interobserver reliability and (3) identify the intraobserver reproducibility of the experts.

Study design/setting: International Multi-Center Survey.

Patient sample: A survey of international spine surgeons on 29 unique upper cervical spine injuries.

Outcome measures: Classification accuracy, interobserver reliability, intraobserver reproducibility.

Methods: Thirteen international AO Spine Knowledge Forum Trauma members participated in two live webinar-based classifications of 29 upper cervical spine injuries presented in random order, four weeks apart. Percent agreement with the gold-standard and kappa coefficients (ƙ) were calculated to determine the interobserver reliability and intraobserver reproducibility.

Results: Raters demonstrated 80.8% and 82.7% accuracy with identification of the injury classification (combined location and type) on the first and second assessment, respectively. Injury classification intraobserver reproducibility was excellent (mean, [range] ƙ=0.82 [0.58-1.00]). Excellent interobserver reliability was found for injury location (ƙ = 0.922 and ƙ=0.912) on both assessments, while injury type was substantial (ƙ=0.689 and 0.699) on both assessments. This correlated to a substantial overall interobserver reliability (ƙ=0.729 and 0.732).

Conclusions: Early phase validation demonstrated classification of upper cervical spine injuries using the AO Spine Upper Cervical Injury Classification System to be accurate, reliable, and reproducible. Greater than 80% accuracy was detected for injury classification. The intraobserver reproducibility was excellent, while the interobserver reliability was substantial.

Keywords: AO Spine; Atlas; Cervical spine; Craniovertebral junction; Dens; Occipital condyle; Reliability.

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Conflict of interest statement

Declarations of competing interests The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. This study was organized and funded by AO Spine through the AO Spine Knowledge Forum Trauma, a focused group of international Trauma experts. AO Spine is a clinical division of the AO Foundation, which is an independent medically-guided not-for-profit organization. Study support was provided directly through the AO Spine Research Department.

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