RESUMO
BACKGROUND:Lumbar spine MRI and electrophysiological test are reliable methods for evaluating nerve root injury caused by lumbar disc herniation. OBJECTIVE:To analyze the correlation between the MRI-based grading system and the latency and frequency of F wave as wel as latency and amplitude of H-reflex in patients with lumbar disc herniation. METHODS:MRI imaging of the lumbar spine was performed with a 3.0-T imager and a dedicated TCL coil to classify lumbar disc herniation and nerve root compression. F wave and H reflex were detected on the patient bilateral tibial nerves using Oxford myoelectricity evoked potential instrument. RESULTS AND CONCLUSION:Spearman correlation analysis showed that the MRI-based grading of patients with lumbar disc herniation had a negative correlation with F wave frequency (r=-0.594 0, P<0.000 1), and a positive correlation with F wave latency (r=0.825 6, P<0.000 1) and H-reflex latency (r=0.875 0, P<0.000 1), but no correlation with H-reflex amplitude (R=0.117 4, P=0.257 3). With MRI grading increased, F wave frequency was decreased, and F wave and H-reflex latency were prolonged gradual y, indicating aggravating nerve root compression.