title: Magnetic stimulation of the cauda equina in the spinal canal with a flat, large round coil.
abstract: Magnetic round coil stimulation over the spinal enlargement activates the spinal nerves at the neuro-foramina level. However, activation of the cauda equina in the spinal canal has never been described in the literature. This study, for which 40 healthy subjects were recruited, activated the cauda equina using a round 20-cm-diameter coil designated as a Magnetic Augmented Translumbosacral Stimulation (MATS) coil. Magnetic stimulation placing the edge of the coil over the L1 and L3 spinous processes elicited compound muscle action potentials (CMAPs) from the abductor hallucis muscle. The CMAPs were compared with those elicited through high-voltage electrical stimulation. The CMAP latencies to L1 level MATS coil stimulation were not significantly different from those evoked by electrical stimulation at the same level. The CMAP latencies to L3 level MATS coil stimulation were varied in each subject. In fact, the L1 level MATS coil stimulation is considered to activate the cauda equina at the root exit site from the conus medullaris; the L3 level MATS coil stimulation activates some mid-part of the cauda equina or the distal cauda equina by spreading current. The MATS coil facilitates evaluation of spinal nerve conduction in the cauda equina.
authors.affiliation: Department of Neurology, Division of Neuroscience. Graduate School of Medicine, University of Tokyo, Japan. hideyukimatsumoto@mail.goo.ne.jp
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Matsumoto
authors.forename: Fitri
authors.initials: F
authors.lastname: Octaviana
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Terao
authors.forename: Ritsuko
authors.initials: R
authors.lastname: Hanajima
authors.forename: Akihiro
authors.initials: A
authors.lastname: Yugeta
authors.forename: Masashi
authors.initials: M
authors.lastname: Hamada
authors.forename: Satomi
authors.initials: S
authors.lastname: Inomata-Terada
authors.forename: Setsu
authors.initials: S
authors.lastname: Nakatani-Enomoto
authors.forename: Shoji
authors.initials: S
authors.lastname: Tsuji
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Ugawa
mesh_terms: D000200:Action Potentials; D002420:Cauda Equina / Q000502:physiology* / Q000503:physiopathology; D003943:Diagnostic Techniques, Neurological / Q000295:instrumentation*; D004558:Electric Stimulation; D019054:Evoked Potentials, Motor; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000209:etiology / Q000503:physiopathology; D008159:Lumbar Vertebrae; D008228:Lymphoma, Non-Hodgkin / Q000175:diagnosis / Q000503:physiopathology; D008280:Magnetics / Q000295:instrumentation; D008297:Male; D008875:Middle Aged; D009431:Neural Conduction; D010524:Peripheral Nervous System Neoplasms / Q000175:diagnosis / Q000503:physiopathology; D011930:Reaction Time; D012016:Reference Values; D013115:Spinal Canal; D013979:Tibial Nerve / Q000502:physiology