1. 2006;9;135-137A Comparison of Pulsed Radiofrequency and Continuous Radiofrequency on Thermocoagulation of Egg White in Vitro
   A Technique Report
   James E. Heavner, DVM, PhD, Mark V. Boswell, MD, PhD, and Gabor B. Racz, MD.

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° C and the tip was heated up to 80° 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° C. Above 60°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 60° 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 60° C may minimize unwanted thermal destruction of tissue.

Key words: Pulsed radiofrequency (PRF), continuous radiofrequency (CRF), chronic pain, heat lesion, coagulation