Reliability of the evaluation of posterior ligamentous complex injury in thoracolumbar spine trauma with the use of computed tomography scan

The AOSpine thoracolumbar (TL) spine injury classification system is based mainly on computed tomography (CT). The main purpose of this study was to evaluate the reliability of CT scan in the diagnosis of posterior ligamentous complex (PLC) injury in thoracolumbar spine trauma (TLST). We performed a cross-sectional study of 43 patients with TLST. CT scans were evaluated independently by three spine surgeons on two separate occasions, 2 months apart. The reliability of PLC injury parameters was assessed by the Kappa coefficient (kappa) and the average percentage of these parameters was established. Injuries were classified according to the AOSpine classification as type A (compression), B (anterior and/or posterior tension band injuries) or C (dislocation) injury and the reliability of the classification was calculated. On average, PLC injury was identified in 91.4 % of type B or C injuries. Tension band injury and dislocation were found in 90.5 % of type B and 93.2 % of type C injuries. The intraobserver reliability for the PLC injury parameters ranged from 0.518 to 1.000, except for increased interspinous distance (IID). Interobserver reliability ranged from 0.303 to 0.688. When the patients were evaluated as a whole, dislocation showed the highest kappa (0.656 and 0.688). When type A or B injuries were assessed, the highest kappa were found for IID (0.533 and 0.511) and tension band injury (0.486 and 0.452). The kappa for AOSpine classification was 0.526 and 0.645 in both assessments. In this study, the use of CT scan as the only diagnostic tool could identify PLC injury in most cases and demonstrated satisfactory reliability. Dislocation could satisfactorily diagnose type C injury, while IID was the best parameter to differentiate between type A and B injuries.