The Effect of Radiofrequency Current and Heat on Peripheral Nerve Action Potential in the Cat

Abstract

T HE use of radiofrequency (rf) current to produce cord lesions in percutaneous cordotomy 1~ prompted this study. The purpose was to see if the diameter of nerve fibers determined their sensitivity to rf current. Such differential sensitivity of nerve fibers to other forms of energy and manipulat ion is documented. Compression, 4,~'~'~~ cold/' '7 and anodal polarization ~1 all block the large A fibers first. By contrast, high voltage alternating current ~ and local anesthetics ';,s,', depress C fibers before the A group. Evidence indicates that peripheral nerve fibers maintain their size ranges in post-synaptic spinal cord projections? Thus, it is probable that any demonstrable relationship between fiber size and sensitivity to rf current in peripheral nerve would hold true for spinal cord. Since the effect of rf current is due to the heat that is generated, 1 the effect of graded hyper themia was also examined.