Prediction of MRI findings including disc injury and posterior ligamentous complex injury in neurologically intact thoracolumbar burst fractures by the parameters of vertebral body damage on CT scan.

ABSTRACT

OBJECTIVE: To formulate radiological indexes based on CT for further MRI examination to detect posterior ligamentous complex injury (PLC) or disc injury in thoracolumbar burst fractures without neurological deficit in the emergent setting. MATERIALS AND METHODS: Patients with a single thoracolumbar burst fracture and no neurological deficit were included into this study. Radiological indexes on CT included canal compromise (CC), anterior and posterior vertebral height ratio (PVH and AVH ratio), local kyphosis (LK) and regional kyphosis (RK). PLC and disc injury were assessed on MRI. Statistical analysis was performed to identify the predictive power for radiological indexes for any MRI findings either or both disc and PLC injury. RESULTS: Eighty-four patients were included in this study. According to MRI, patients with no PLC and disc injury were allocated into MRI finding negative group, others were defined as positive group. There was no significant difference in AVH ratio, PVH ratio and RK between these two groups. The CC and LK were significant higher in positive group than that in negative group (p < 0.001).The areas under receiver operating characteristic curve were 0.826 and 0.893 for CC and LK respectively and without significant difference. The best thresholds for CC and LK were 0.19 (sensitivity 69.4%; specificity 87.5%) and 14.00° (sensitivity 83.3%; specificity 83.3%), respectively. CONCLUSION: The presence of CC > 0.19 and/or LK > 14.00° on CT scan can predict MRI findings including PLC and disc injury. These thresholds may be the guideline for MRI examination in patients with neurologically intact thoracolumbar burst fracture in the emergent condition.