Imaging of neural conduction block by neuromagnetic recording.
OBJECTIVE
For the clinical application of neuromagnetic recordings in neural conduction block, the patterns of magnetic fields in the region should be clarified. Using an experimental in vitro model, the spatiotemporal course of the neuromagnetic fields at the site of complete conduction block was examined. Additionally, the magnetic compound action fields (CAFs) and electric compound action potentials (CAPs) were compared and correlated.


METHODS
In a chamber containing Ringer's solution, 10 isolated sciatic nerves of rabbits were electrically stimulated. Both evoked CAPs and CAFs were measured before and after the ligation of the nerve. The sequential positions of the current dipoles and the location of the conduction block were estimated by the least-squares search.


RESULTS
The magnetic contour maps of the CAFs showed a characteristic quadrupolar pattern propagating along the nerve. The peak of the leading magnetic field ceased and disappeared at the position of the nerve ligation, while the trailing magnetic field became attenuated before reaching that position. The positions of the conduction blocks were localized by magnetic recordings within a difference of 2mm.


CONCLUSIONS
The neuromagnetic recordings could visualize the change of the magnetic fields at the site of the complete conduction block and closely localize that position.


CONCLUSIONS
The neural conduction block was visualized and localized by neuromagnetic recordings.
Fukuoka
Yuko
Y
Section of Orthopedic Spinal Surgery, Department of Frontier Surgical Therapeutics, Division of Advanced Therapeutical Sciences, Graduate School of Tokyo Medical and Dental University, Tokyo, Japan. fukuoka.orth@tmd.ac.jp
Komori
Hiromichi
H
Kawabata
Shigenori
S
Ohkubo
Harunobu
H
Shinomiya
Kenichi
K
Terasaki
Omi
O
D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D004574:Electromagnetic Fields; D066298:In Vitro Techniques; D009407:Nerve Block / Q000295:instrumentation / Q000379:methods*; D009431:Neural Conduction / Q000502:physiology*; D011817:Rabbits; D012584:Sciatic Nerve / Q000502:physiology