A comparison of pulsed radiofrequency and continuous radiofrequency on thermocoagulation of egg white in vitro.

BACKGROUND Clinical studies have demonstrated the efficacy of pulsed radiofrequency (PRF). PRF energy is delivered to neural structures via specifically designed, percutaneously placed needles to treat some chronic pain states. PRF was introduced as a non-destructive alternative to destructive lesioning produced by continuous radiofrequency (CRF) energy. However, there is an ongoing controversy regarding the potential tissue-destructive effects of PRF used for pain management. OBJECTIVE To evaluate the ability of PRF to coagulate egg white at various temperatures used clinically and to compare with CRF. METHODS A commercially available (TYCO-Radionics Labs) 5 cm, 22G (0.7 mm) SMK needle with 5 mm active tip was inserted into a 10 mL test tube containing raw egg white at 37 degrees C and the tip was heated up to 80 degrees C. The photographic patterns of thermocoagulation of egg white in vitro produced by continuous and pulsed radiofrequency (RF) were compared and the lowest temperature at which PRF produced thermocoagulation was determined. RESULTS Pulsed RF produced barely detectable thermocoagulation at 60 degrees C. Above 60 degrees C, the pattern of coagulation produced by PRF resembled that observed with CRF. However, the density and size of the coagulation ball appeared somewhat greater with CRF. CONCLUSION PRF coagulated egg white at temperatures above 60degrees C in a manner similar to CRF. Monitoring needle tip temperature using the thermode supplied with the needle during PRF and keeping the recorded tip temperature below 60degrees C may minimize unwanted thermal destruction of tissue.