Abstract: Objective To investigate the changes of morphology of injured nerve after pulsed radiofrequency (PRF) and radiofrequency thermocoagulation (RFTC) on rats. Methods 55 male Wistar rats were selected, in which 5 were allocated to control group (group C) and the other 50 were randomly divided into group PRF (n=25) and group RFTC (n=25). The specimens were analyzed both with light microscopy and electron microscopy at immediate, and 1, 7, 14 and 28 d after operation. Results In group PRF, the nerve function of rats maintained after operation. The edema among nerve fibers was found under light microscope, while myelin lamellar structure disorder and myelin balls shaped, and compensatory hyperplasia of ultrastructure under electron microscopic level. Those effects were more pronounced 1 d after operation. In group RFTC, the nerve function of rats disappeared and autophagy behaviors happened, meanwhile Waller's degeneration and nerve regeneration appeared under both light microscopy and electron microscopy. Conclusion PRF and RFTC can produce destruction of nerve, but PRF was minor and recoverable.

Key words: pulsed radiofrequency, radiofrequency thermocoagulation, morphology, plexus nerve