A case of skin burn during radiofrequency ablation by an exposed point from which the insulating coating around the ablation needle had peeled away -Analysis of tissue impedance waveform-

Abstract

The patient was male and was in his 50s. He underwent radiofrequency ablation (RFA) for two hepatocellular carcinomas (HCC). Until 12 minutes after the beginning of the procedure, tissue impedance (IMP) did not increase and there was no bubble-appearance on the ultrasound. After that, a third-degree skin burn occurred around the needle-insertion point. We checked the needle that was removed from the patient. There was an exposed point from which the insulating coating around the ablation needle had peeled away. This point was in contact with the skin during the procedure and this was obviously the cause of the skin burn. Monitoring of tissue IMP was performed during ablation, and it showed an abnormal pattern. At 6 minutes after beginning of the procedure, the IMP decreased suddenly and it plateaued out. In conclusion, monitoring of the IMP wave is useful to detect damage of the insulating coating and to prevent skin burn during RFA.