Effect of the Combination of Different Electrode Spacings and Power on Bipolar Radiofrequency Fat Dissolution: A Computational and Experimental Study

Background and objectives The finite element method was used, and experiments were performed to analyze the effect of different electrode spacings and power combinations on the electrical and thermal aspects of biological tissues during bipolar radiofrequency (RF) fat dissolution. Through these efforts, this study also attempted to develop a reasonable electrode spacing and power combination that can achieve fat dissolution effects, the RF energy of which will not thermally damage the tissue. Study design/materials and methods COMSOL was adopted to conduct a finite element analysis for bio-thermoelectric coupling, and a two-dimensional time-domain model of biological tissue was built. A self-developed single-channel bipolar RF device was employed to load RF energy on the ex vivo porcine abdominal tissue. The thermal characteristics of the tissue were characterized and analyzed with a thermal imager and thermocouple probes. Results Under a power of 5 W combined with the electrode spacings of 1, 2, and 3 cm, the temperature in the tissue could not reach that required for fat dissolution. Under a power of 15 W combined with the electrode spacings of 1, 2, and 3 cm, the RF energy would thermally damage part of the skin areas. Besides this, the combination of a power of 10 W and the electrode spacing of 1 cm would thermally damage the skin areas. The combination of a power of 10 W and the electrode spacing of 2 or 3 cm made part of the fat layer of the tissue satisfy the requirements of fat dissolution, and the fat dissolution area caused by the former was 118% larger than that of the latter; in the meantime, no heat damage to the skin layer was found. Conclusion Different electrode spacings and power combinations significantly affect the electrical and thermal properties of bipolar RF energy loaded on biological tissue, a reasonable electrode spacing and power combination is one of the critical factors leading to the success of bipolar RF fat dissolution. Lasers Surg. Med. © 2020 Wiley Periodicals, Inc.