Title: Cauda equina action potentials and nerve root action potentials in lumbar disorders.
Abstract: Electrophysiological evaluation of the cauda equina or nerve roots has been recently applied in diagnosis of lumbar disorders.The monopolar catheter electrode was inserted into the epidural space at the levels of L3-4, L4-5, and L5-S. The recordings were made on stimulating the tibial and the peroneal nerves at the bilateral popliteal fossae.The cauda equina action potentials (CEAP) were recorded in 42 cases with various kinds of lumbar disorders, including lumbar disc herniation, lumbar canal stenosis, chronic low back pain and the control was taken in case with cervical or thoracic spine without lumbar problem.The nerve action potentials (NRAP) was recorded intraoperatively at the nerve roots by monopolar catheter electode in 10 cases with either lumbar disc hernation or lumbar canal stenosis.In eight cases of eleven of disc herniation. the voltage decreased more than 30% at the affected level. In six of seven roots in disc herniation, NRAPs demonstrated polyphasic.The results suggests that CEAP and NRAP are useful for diagnosis of the affected nerve roots, and that further research will be necessary to obtain more accurate evaluation more.