Can MRI Findings Help to Predict Neurological Recovery in Paraplegics With Thoracolumbar Fracture?

OBJECTIVE To evaluate the usefulness of various magnetic resonance imaging (MRI) findings in the prognosis of neurological recovery in paraplegics with thoracolumbar fracture using association analysis with clinical outcomes and electrodiagnostic features. METHODS This retrospective study involved 30 patients treated for paraplegia following thoracolumbar fracture. On axial and sagittal T2-weighted MRI scans, nerve root sedimentation sign, root aggregation sign, and signal intensity changes in the conus medullaris were independently assessed by two raters. A positive sedimentation sign was defined as the absence of nerve root sedimentation. The root aggregation sign was defined as the presence of root aggregation in at least one axial MRI scan. Clinical outcomes including the American Spinal Injury Association impairment scale, ambulatory capacity, and electrodiagnostic features were used for association analysis. RESULTS Inter-rater reliability of the nerve root sedimentation sign and the root aggregation sign were κ=0.67 (p=0.001) and κ=0.78 (p<0.001), respectively. A positive sedimentation sign was significantly associated with recovery of ambulatory capacity after a rehabilitation program (χ(2)=4.854, p=0.028). The presence of the root aggregation sign was associated with reduced compound muscle action potential amplitude of common peroneal and tibial nerves in nerve conduction studies (χ(2)=5.026, p=0.025). CONCLUSION A positive sedimentation sign was significantly associated with recovery of ambulatory capacity and not indicative of persistent paralysis. The root aggregation sign suggested the existence of significant cauda equina injuries.