Reliability and Reproducibility Analysis of the AOSpine Thoracolumbar Spine Injury Classification System in Korea

Study Design: Retrospective study. Objectives: The aim of the current study was to perform an independent interobserver and intraobserver agreement study of the AOSpine Thoracolumbar Spine Injury Classification System, including surgeons with different levels of expertise in spinal trauma. Summary of Literature Review: The new AOSpine Thoracolumbar Spine Injury Classification System is widely used at most trauma centers worldwide. This classification has shown substantial interobserver reliability and intraobserver reproducibility when it was evaluated by its authors, the world leaders in spinal trauma; however, there is a lack of evidence for its reproducibility among surgeons with different levels of expertise. Materials and Methods: Plain radiographs and computed tomographic scans of 166 acute traumatic thoracolumbar injury cases were reviewed and classified using the morphological grading of the new AOSpine Thoracolumbar Spine Injury Classification System twice by four evaluators (two spine surgeons and two senior orthopedic surgery residents) 1 month apart. Results: The interobserver reliability was substantial for all cases (κ =0.71; 95% CI, 0.70-0.72). The kappa coefficients for each fracture morphology type were 0.73 (95% CI, 0.72-0.74) for type A injuries, 0.68 (95% CI, 0.45-0.91) for type B injuries, and 0.76 (95% CI, 0.71-0.81) for type C injuries. The intraobserver reproducibility was also substantial for all cases (κ =0.84; 95% CI, 0.80-0.87). No significant differences were observed in the overall interobserver reliability and intraobserver reproducibility depending on the surgeons’ experience. Conclusions: The new AOSpine Thoracolumbar Spine Injury Classification System was demonstrated to have adequate interobserver reliability and intraobserver reproducibility in Korea, regardless of the surgeons’ experience.