Lumbosacral Plexus Conduction Study by Magnetic Stimulation

ABSTRACT

OBJECTIVE: In contrast to the electrical stimulation, the magnetic stimulation of motor system is a painless and noninvasive neurophysiologic technique. We attempted to establish a clinical feasibility of lumbosacral plexus conduction study by using the magnetic stimulation. METHOD: We performed a magnetic stimulation at the L5 spinous process and obtained the compound motor action potentials(CMAP) from individual muscles of pelvic area and lower extremity. RESULTS: The onset latencies of compound muscle action potentials(CMAP) were fastest in the gluteus maximus muscle and slowest in the abductor hallucis muscle. The onset latencies of compound muscle action potentials(CMAP) showed no significant difference in both sides, however, there was a positive correlation between height and onset latency in distal leg muscles. The amplitudes of compound muscle action potentials(CMAP) were the highest in the vastus medialis and lowest in the tibialis anterior muscle. CONCLUSION: Lumbosacral plexus conduction study by magnetic stimulation was easy to obtain the compound motor action potentials(CMAP) from individual muscles and was relatively comfortable to the subjects.