Increasing Ablation Area Using the Arfa Ablation System: An Experimental Study in the Bovine Liver
Toru Ishikawa1, Hiroshi Hirosawa2, Yuzo Tanabe2
1Department of Gastroenterology, Saiseikai Niigata Hospital, Niigata, Japan; toruishi@ngt.saiseikai.or.jp.
Background/Aim:
Expanding the ablation area remains a critical challenge in the treatment of hepatocellular carcinoma. Herein, we investigated the utility of various radiofrequency ablation (RFA) protocols for increasing ablation areas, using the bovine liver as a model.
Materials And Methods:
A bovine liver (7.2 kg) placed in a stainless-steel tray was subjected to RFA using an arfa 17-G electrode. The starting and increment wattages were varied in the linear mode. RFA was stopped after one break. The size of the discolored area, indicating thermally coagulated tissue, was measured along both the vertical and horizontal axes. The ablated area and total heat generated were calculated.
Results:
RFA conducted using a 30-mm needle yielded sufficient ablation areas along both the transverse and longitudinal diameters when using a low-power start at 20 W with a 5 W/min linear increase protocol. Similarly, using a 20-mm needle, a low-power start at 20 W with a 5 W/min linear increase protocol also yielded sufficient ablation areas. Although the ablation time was prolonged in both cases, the output wattage at the breakpoint and average wattage were low.
Conclusion:
Ablation using the arfa linear mode method (i.e., starting at a low power and gradually increasing the output) can achieve a larger ablation area than standard RFA. However, this method presents the challenge of prolonged ablation time. Regardless, this approach has the potential to be a more effective procedure for yielding extensive ablation areas in clinical practice. Given the low final output levels, this finding indicates its potential utility as a minimally invasive treatment. Future clinical practices should consider strategies to address prolonged ablation times.
