An evaluation of electrocoagulation and thermal diffusion following radiofrequency microneedling using an in vivo porcine skin model

BACKGROUND: Few studies exist that examined the role of radiofrequency microneedling (RFMN) in skin electrocoagulation. This research utilized a porcine model to understand bipolar dermal delivery from an RFMN device. AIMS: The objective of this study was to elucidate and compare the dermal thermal effects of a RFMN device producing 1 and 2 MHz signal amplitudes, with respective voltage and current gradients, utilizing noninsulated and insulated needles by examining the histologic effects on porcine skin. METHODS: Two separate animal studies were conducted to evaluate the electrocoagulation and thermal diffusion effects using the RFMN device. The electrocoagulation effects were assessed histologically using hematoxylin and eosin (H&E) staining, and heating effects were assessed through thermal imaging. RESULTS: Histology results of the thermal injury induced by insulated needles demonstrated that 2 MHz resulted in a narrow and concentrated coagulation zone as compared to 1 MHz. Further, the 1 MHz insulated needle resulted in ovular shaped tissue coagulation as compared to 2 MHz tissue coagulation that was columnar. Finally, full thermal diffusion occurs seconds after the set RF conduction time. CONCLUSION: The findings showed that 1 MHz insulated needle produces larger coagulations with an increase in power level, the 1 MHz noninsulated array was comparable to the 2 MHz insulated array with similar histologic features, and heat dissipates seconds after the set conduction time.