Magnetic lumbosacral motor root stimulation with a flat, large round coil.
OBJECTIVE
The aim of this paper is to develop a reliable method for supramaximal magnetic spinal motor root stimulation (MRS) for lower limb muscles using a specially devised coil.


METHODS
For this study, 42 healthy subjects were recruited. A 20-cm diameter coil designated as a Magnetic Augmented Translumbosacral Stimulation (MATS) coil was used. Compound muscle action potentials (CMAPs) were recorded from the abductor hallucis muscle. Their CMAPs were compared with those obtained by MRS using a conventional round or double coil and with those obtained using high-voltage electrical stimulation.


RESULTS
The MATS coil evoked CMAPs to supramaximal stimulation in 80 of 84 muscles, although round and double coils elicited supramaximal CMAPs in only 15 and 18 of 84 muscles, respectively. The CMAP size to the MATS coil stimulation was the same as that to high-voltage electrical motor root stimulation.


CONCLUSIONS
MATS coil achieved supramaximal stimulation of the lumbosacral spinal nerves.


CONCLUSIONS
The CMAPs to supramaximal stimulation are necessary for measurement of the amplitude and area for the detection of conduction blocks. The MATS coil stimulation of lumbosacral motor roots is a reliable method for measuring the CMAP size from lower limb muscles in spinal motor root stimulation.
Matsumoto
Hideyuki
H
Department of Neurology, Division of Neuroscience, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan. hideyukimatsumoto@mail.goo.ne.jp
Octaviana
Fitri
F
Hanajima
Ritsuko
R
Terao
Yasuo
Y
Yugeta
Akihiro
A
Hamada
Masashi
M
Inomata-Terada
Satomi
S
Nakatani-Enomoto
Setsu
S
Tsuji
Shoji
S
Ugawa
Yoshikazu
Y
D000200:Action Potentials / Q000502:physiology; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001703:Biophysics; D004558:Electric Stimulation / Q000295:instrumentation* / Q000379:methods*; D004576:Electromyography / Q000379:methods; D005260:Female; D006801:Humans; D008161:Lumbosacral Region; D008280:Magnetics / Q000295:instrumentation* / Q000379:methods*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000294:innervation; D012680:Sensitivity and Specificity; D013116:Spinal Cord / Q000502:physiology; D013126:Spinal Nerve Roots / Q000502:physiology*; D055815:Young Adult