An Independent Interobserver Reliability and Intraobserver Reproducibility Evaluation of the New AOSpine Thoracolumbar Spine Injury Classification System

Study Design. Agreement study. Objective. To perform an independent interobserver and intraobserver agreement evaluation of the new AOSpine Thoracolumbar Spine Injury Classification System. Summary of Background Data. The new AOSpine Thoracolumbar Spine Injury Classification System was recently published. It showed substantial reliability and reproducibility among the surgeons who developed it; however, an independent evaluation has not been performed. Methods. Anteroposterior and lateral radiographs, and computed tomographic scans of 70 patients with acute traumatic thoracolumbar injuries were selected and classified using the morphological grading of the new AOSpine Thoracolumbar Spine Injury Classification System by 6 evaluators (3 spine surgeons and 3 orthopedic surgery residents). After a 6-week interval, the 70 cases were presented in a random sequence to the same evaluators for repeat evaluation. The Kappa coefficient (kappa) was used to determine the interobserver and intraobserver agreement. Results. The interobserver reliability was substantial when considering the fracture type (A, B, or C), with a. kappa = 0.62 (0.57-0.66). The interobserver agreement when considering the subtypes was moderate; kappa = 0.55 (0.52-0.57). The intraobserver reproducibility was also substantial, with 85.95% full intraobserver reproducibility considering the fracture type, with kappa = 0.77 (0.720.83), and was also substantial when considering subtypes with 75.71% full agreement and kappa = 0.71 (0.67-0.76). No significant differences were observed between spine surgeons and orthopedic residents in the overall interobserver reliability and intraobserver reproducibility, or in the inter-and intraobserver agreement of specific A, B, or C types of injuries. Conclusion. This classification allows adequate agreement among different observers and by the same observer on separate occasions. Future prospective studies should evaluate whether this classification improves clinical decision making.