title: Conductive neuromagnetic fields in the lumbar spinal canal.
abstract: OBJECTIVE
  To measure neuromagnetic evoked fields in the lumbar spinal canal.
  
  
  METHODS
  Using a newly developed superconducting quantum interference device (SQUID) fluxmeter, neuromagnetic fields of 5 healthy male volunteers were measured at the surface of the lower back after stimulation of the tibial nerves at the ankles. For validation, we inserted a catheter-type electrode percutaneously in the lumbar epidural space in 2 of the subjects and measured cauda equina action potentials after tibial nerve stimulation.
  
  
  RESULTS
  Neuromagnetic fields propagating from the intervertebral foramina into the spinal canal were measured, and the latencies of the magnetic fields corresponded largely with those of the cauda equina action potentials.
  
  
  CONCLUSIONS
  We successfully measured ascending neuromagnetic fields originating at the nerve root and the cauda equina with high spatial resolution. Future studies will determine whether neuromagnetic field measurement of the lumbar spine can be a useful diagnostic method for the identification of the disordered site in spinal nerves.
  
  
  CONCLUSIONS
  We successfully measured neuromagnetic fields in the lumbar spinal canal, which have previously been difficult to verify. Future studies will determine whether neuromagnetic field measurement of the lumbar spine can be a useful diagnostic method for identifying disorders of spinal nerves.
authors.affiliation: Department of Frontier Surgical Therapeutics, Section of Orthopedic and Spinal Surgery, Division of Advanced Therapeutical Sciences, Graduate School of Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Senichi
authors.initials: S
authors.lastname: Ishii
authors.forename: Shigenori
authors.initials: S
authors.lastname: Kawabata
authors.forename: Shoji
authors.initials: S
authors.lastname: Tomizawa
authors.forename: Masaki
authors.initials: M
authors.lastname: Tomori
authors.forename: Kyohei
authors.initials: K
authors.lastname: Sakaki
authors.forename: Kenichi
authors.initials: K
authors.lastname: Shinomiya
authors.forename: Kensuke
authors.initials: K
authors.lastname: Sekihara
authors.forename: Tomoya
authors.initials: T
authors.lastname: Sato
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Adachi
authors.forename: Atsushi
authors.initials: A
authors.lastname: Okawa
mesh_terms: D000328:Adult; D002420:Cauda Equina / Q000502:physiology*; D004558:Electric Stimulation; D004568:Electrodiagnosis / Q000379:methods; D006801:Humans; D008159:Lumbar Vertebrae; D060526:Magnetic Fields; D008297:Male; D009431:Neural Conduction / Q000502:physiology*; D013115:Spinal Canal / Q000502:physiology*; D013979:Tibial Nerve / Q000502:physiology*