[Somatosensory evoked potentials in patients with low back pain with special reference to intervertebral disc herniations].

To evaluate the diagnostic value of somatosensory evoked potentials (SEPs), produced by stimulation of the common peroneal nerve of the lumbar intervertebral disc herniation, 43 patients were examined. In addition, recordings of SEPs in patients with spondylolysis and spinal canal stenosis, and in healthy subjects, were also made for the purpose of comparison. In general, there was strong correlation between the latency of P 30 and N 40 in normal persons. However, there was no correlation between P30 and N40 in patients with intervertebral disc herniation of L4-5, indicating an abnormal phenomenon. A significant delay in latency was observed only in the spinal canal stenosis group. Therefore this method is valuable as a routine test in order to diagnose L5 radiculopathy.