title: Electrophysiologic evaluation of lumbosacral single nerve roots using compound muscle action potentials.
abstract: Transcutaneous electrical stimulation applied to the vertebral column produces compound muscle action potentials (CMAPs) from the leg muscles. Using this method, we evaluated the efferent pathways of the lumbosacral nerve roots. The subjects were 26 healthy volunteers and 31 patients with lumbar disc herniation (LDH). CMAP recordings were obtained from the bilateral vastus medialis, tibialis anterior, extensor digitorum brevis, and abductor hallucis muscles using low-output-impedance stimulation. In normal subjects, the CMAP latency increased linearly with the distance between the stimulating electrode and the recording electrode, with little difference in latency between the left and the right sides in each subject. The CMAP amplitude was significantly lower in the patients with LDH, and the latency was also prolonged when the stimulating electrode was placed above the lesion. This technique may thus be a useful noninvasive method for assessing lumbosacral nerve root function in patients with LDH.
authors.affiliation: Department of Orthopaedic Surgery, Kyoto Perfectual University of Medicine, Kyoto, Japan. togura@koto.kpu-m.ac.jp
authors.forename: Taku
authors.initials: T
authors.lastname: Ogura
authors.forename: Hideto
authors.initials: H
authors.lastname: Shikata
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Hase
authors.forename: Masaki
authors.initials: M
authors.lastname: Mori
authors.forename: Taturo
authors.initials: T
authors.lastname: Hayashida
authors.forename: Toru
authors.initials: T
authors.lastname: Osawa
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Mikami
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Kubo
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D004525:Efferent Pathways / Q000502:physiology / Q000503:physiopathology; D004558:Electric Stimulation / Q000379:methods; D004566:Electrodes / Q000592:standards; D004568:Electrodiagnosis / Q000379:methods*; D004594:Electrophysiology / Q000379:methods*; D005260:Female; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000175:diagnosis* / Q000503:physiopathology; D008161:Lumbosacral Region; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology; D018482:Muscle, Skeletal / Q000294:innervation; D009431:Neural Conduction / Q000502:physiology*; D011237:Predictive Value of Tests; D011930:Reaction Time / Q000502:physiology; D012016:Reference Values; D013126:Spinal Nerve Roots / Q000502:physiology* / Q000503:physiopathology