Verification in an animal study of the appropriate settings for a novel radiofrequency generator in radiofrequency ablation therapy for residual intraductal lesions after endoscopic papillectomy (with video)

Endoscopic intraductal radiofrequency ablation (ID-RFA) can curatively treat residual intraductal lesions after endoscopic papillectomy. This study aimed to verify the tissue invasiveness of ID-RFA using a novel RF generator and to explore its appropriate settings in an animal experiment, followed by a small clinical study. Pig liver specimens were ablated using a dedicated RF catheter and two RF generators to investigate structural differences between them and the ablation effects produced under various voltage and power settings. Appropriate settings for the novel generator were sought to provide an ablation effect equivalent to that with the recommended settings for a conventional generator. The ablation effect was also observed at various ablation times in vitro. Then we performed ID-RFA in five patients. Each generator has a different structure, and no novel generator settings are identical to the recommended conventional generator settings. Obtaining adequate ablation requires both sufficient power and sufficient voltage. Based on the validation experiments, we concluded that the appropriate novel generator settings were 125 Vp and 30 W for 30 s. In the clinical study, good tumor ablation was obtained with no recurrence after a single ID-RFA treatment, although the incidence of ductal stricture was relatively high. ID-RFA for residual intraductal lesions may potentially be curative. However, excessive ablation should be avoided. To ensure safe and effective ID-RFA, a thorough understanding of the RF generator specifications is required.