Ablative Outcomes of Various Energy Modes for No-Touch and Peripheral Tumor-Puncturing Radiofrequency Ablation: An Ex Vivo Simulation Study

Abstract

Objective To compare the outcomes of radiofrequency ablation (RFA) using dual switching monopolar (DSM), switching bipolar (SB), and combined DSM + SB modes at two different interelectrode distances (25 and 20 mm) in an ex vivo study, which simulated ablation of a 2.5-cm virtual hepatic tumor. Materials and Methods A total of 132 ablation zones were created (22 ablation zones for each protocol) using three separable clustered electrodes. The performances of the DSM, SB, and combined DSM + SB ablation modes were compared by evaluating the following parameters of the RFA zones at two interelectrode distances: shape (circularity), size (diameter and volume), peritumoral ablative margins, and percentages of the white zone at the midpoint of the two electrodes (ablative margin at midpoint, AMm) and in the electrode path (ablative margin at electrode path, AMe). Results At both distances, circularity was the highest in the SB mode, followed by the DSM + SB mode, and was the lowest in the DSM mode. The circularity of the ablation zone showed a significant difference among the three energy groups ( p < 0.001 and p = 0.002 for 25-mm and 20-mm, respectively). All size measurements, AMm, and AMe were the greatest in the DSM mode, followed by the DSM + SB mode, and the lowest were with the SB mode (all statistically significant). The white zone proportion in AMm and AMe were the greatest in the SB mode, followed by the DSM + SB mode and DSM in general. Conclusion DSM and SB appear to be complementary in creating an ideal ablation zone. RFA with the SB mode can efficiently eradicate tumors and create a circular ablation zone, while DSM is required to create a sufficient ablative margin and a large ablation zone.

Laparoscopic radiofrequency ablation versus percutaneous radiofrequency ablation for subphrenic hepatocellular carcinoma

“…The maximum (Dmax) and minimum (Dmin) diameters of the ablation zone were measured from axial CT images and the longest vertical diameter (Dv) from coronal or sagittal images. The ablation volume was calculated using the formula for an ellipsoid lesion: ablation volume=π (Dmax×Dmin×Dv)/6 [ 18 ]. The ratios of the longest diameter and volume of ablation zone to those of the tumors were compared between the PRFA and LRFA groups.…”

Percutaneous radiofrequency ablation of hepatocellular carcinoma in a recent cohort at a tertiary cancer center: incidence and factors associated with major complications and unexpected hospitalization events

“…Meanwhile, with technical developments, RFA has been performed using perfusion electrodes or multiple electrodes to produce larger ablation zones [ 7 , 8 ]. In addition, no-touch RFA has recently been implemented, which offers better local tumor control by effectively producing sufficient ablative margins without puncturing the tumor through the insertion of multiple electrodes around it [ 9 , 10 ].…”