Percutaneous radiofrequency ablation therapy using a clustered electrode in the animal liver

Background/Aims: The aim of the present study was to examine the safety and effectiveness of percutaneous radiofrequency ablation therapy using a needle with cluster radiofrequency electrodes in an animal model. Methodology: A total of 10 radiofrequency applications were performed in the normal liver of 5 domestic pigs with real-time ultrasonography until roll-off occurred two times. Aspartate aminotransferase, alanine aminotransferase, lactic dehydrogenase, and total bilirubin were evaluated before the procedure and 1 h, 24 h, and 7 days following percutaneous radiofrequency ablation therapy. The animals were euthanized 1 or 2 weeks after percutaneous radiofrequency ablation therapy, and the livers were removed for gross and histopathologic analysis for coagulation necrosis. Results: There were no complications in any of the experimental animals. Aspartate aminotransferase, alanine aminotransferase, and lactic dehydrogenase levels peaked 24 h following percutaneous radiofrequency ablation therapy, and decreased with time thereafter. Total bilirubin was not elevated in any of the animals at any time. Macroscopic examination revealed that the area of coagulated necrosis was 28x21mm when using a 2.0-cm needle, and 41x35mm when using a 3.5-cm needle. Coagulation necrosis did not occur near large vessels. Microscopic examination of the fixed tissue revealed that coagulation necrosis occurred in preserving lobular structure. Conclusions: Percutaneous radiofrequency ablation therapy using a clustered electrode is a safe and effective treatment for liver tumor. Incomplete coagulation necrosis, however, can occur when percutaneous radiofrequency ablation therapy is performed for tumors located near large vessels.