Prediction of posterior ligamentous complex injury in thoracolumbar fractures using non-MRI imaging techniques.

Abstract

We aimed to formulate a radiological index based on plain radiographs and computer tomography (CT) to reliably detect posterior ligamentous complex (PLC) injury without need for MRI. Sixty out of 148 consecutive thoracolumbar fractures with doubtful PLC were assessed with MRI, CT and radiographs. PLC injury was assessed with the following radiological parameters: superior-inferior end plate angle (SIEA), vertebral body height (BH), local kyphosis (LK), inter-spinous distance (ISD) and inter-pedicular distance (IPD) and correlated with MRI findings of PLC injury. Statistical analysis was performed to identify the predictive values for the parameters to identify PLC damage. MRI identified PLC injury in 25/60 cases. The ISD and LK were found to be significant predictors of PLC injury. On radiographs the mean LK with PLC damage was 25.86° compared to 21.02° with an intact PLC (p = 0.006). The ISD difference was 6.70mm in cases with PLC damage compared to 2.86mm with an intact PLC (p = 0.011). In CT images, the mean LK with PLC damage was 22.96° compared to 18.44° with an intact PLC ( p = 0.019). The ISD difference was 3.10mm with PLC damage compared to 1.62mm without PLC damage (p = 0.005). On plain radiographs the presence of LK greater than 20 °(CI 64-95) and ISD difference greater than 2mm (CI 70-97) can predict PLC injury. These guidelines may be utilised in the emergency room especially when the associated cost, availability and time delay in performing MRI are a concern.