Classification of unstable spinal gunshot wounds: interim results of the 2nd phase of the study

Background . Gunshot wounds are the most common type of spinal cord and spinal cord injury in battlefields. In some cases, spinal cord injury leads to instability in the spinal motion segment. A protocol for scoring tactical classification of unstable gunshot wounds of the thoracolumbar spine was developed. Aim . To analyze the interexpert agreement in assessing the “significance” of a fracture of a specific anatomical structure and deciding on the influence of this injury on the necessity to perform stabilizing intervention. Materials and methods . An evaluation of 30 anonymized clinical and radiological cases by 15 surgeons was performed. Each surgeon completed 30 questionnaires based on the computed tomography images. A kappa (к) coefficient was used to determine the degree of agreement between surgeons in the points of view on the stability and contribution to destabilization of each anatomic structure. Results . A good level of inter-expert agreement was demonstrated in surgeons' detection of posterior osseous-ligamentous complex injury (к = 0.854), assessment of its significance (к = 0.56), detection of transverse processes fracture (к = 0.664), arch joints (к = 0.521), arch root (к = 0.717) and its significance (к = 0.4), and vertebral body (к = 0.655). All surgeons found that fracture of two arch roots resulted in absolute fracture instability. A good level of agreement was also demonstrated in the overall assessment of the fracture: unstable fracture, к = 0.41; stable fracture, к = 0.55; the level of agreement on the applicability of the McCormack classification was 0.406. Conclusion . High level of inter-expert concordance on the fact of injury of the structures proposed in the questionnaire was obtained which demonstrates accuracy of identification of skeletal elements affecting development of instability. Preliminary evaluation of the results does not allow to make judgement on certain concordance in assessment of significance of injuries of these structures. Critical impact of bilateral fractures of the articular processes or pedicles of the vertebral arch requiring stabilizing intervention was established. The aim of further studies is final analysis of inter-expert and intra-expert concordance. Based on the analysis of the experts' answers, classification of primary spinal instability in thoracic and lumbar gunshot wounds will be developed. Additionally, evaluation of clinical situations by expert surgeons with subsequent statistical analysis will be performed to improve reliability and reproducibility of the new classification system.