Value of magnetic stimulation in the non-invasive diagnosis of St radiculopathy / 中华物理医学与康复杂志

ABSTRACT

Objective To explore the value of a new electrodiagnostic approach for evaluating motor nerve root function in patients with S1 radiculopathy. Methods Thirty healthy subjects and 30 patients with clinical mani-festations of unilateral S1 radiculopathy were recruited. Bilateral compound muscle action potentials evoked by magnetic stimulation of the first sacral nerve root were recorded from the soleus of all the subjects. F wave and M responses to electrical stimulation of the bilateral tibial nerves at the popliteal fossa were also recorded. The peripheral motor conduction time (PMCT) and the motor root conduction time (MRCT) were calculated and compared between the two groups. In addition, needle electromyographic examination (NEE) was performed on the affected side to detect any possible EMG abnormalities. Results The norm established with the normal subjects was 3.45±0.39 ms for the MRCT, and 0.28±0.15 ms for the inter-side difference in the MRCT. In the 30 patients, the mean MRCT and PMCT values on the affected side were prolonged. Of the 23 patients who received NEE, 6 had EMG abnormalities. The agreement between the NEE and MRCT diagnoses was 82.6%. Conclusion MRCT can be used reliably for non-invasive estimation of motor nerve root function and to help diagnose the S1 radiculopathy.