Moving-shot versus fixed electrode techniques for radiofrequency ablation: comparison in an ex-vivo bovine liver tissue model.

Abstract

OBJECTIVE: To compare the ablation characteristics of the moving-shot technique

(MST) and the fixed electrode technique (FET) for radiofrequency (RF) ablation in

an ex-vivo bovine liver tissue model. MATERIALS AND METHODS: We performed RF

ablation using FET in 110 bovine liver blocks using 11 different ablation times

ranging from 5 seconds to 5 minutes (10 blocks per each time duration). Ten

bovine liver blocks at each ablation time of 1- or 2-minute, were ablated with

MST, which treated conceptual ablation units by moving the electrode tip. We

evaluated the ablation volume obtained with FET across ablation time lengths. The

results of FET and MST performed with the same ablation time lengths, i.e., 1-

and 2-minute ablation time were also compared. RESULTS: The ablation volume

achieved with FET gradually increased with increasing ablation time; however, the

pair-wise statistical comparison between 2 neighboring ablation time lengths was

not significant after 30 seconds. MST with either 1- or 2-minute ablation time

achieved larger ablation volumes (1.1 +/- 0.2 mL vs. 2.7 +/- 0.3 mL, p < 0.001;

and 1.4 +/- 0.2 mL vs. 5.6 +/- 0.4 mL, p < 0.001, respectively), longer true RF

times (46.7 +/- 4.6 seconds vs. 60 seconds, p < 0.001; and 64.8 +/- 4.6 seconds

vs. 120 seconds, p < 0.001, respectively), fewer numbers of RF cut-offs (1.6 +/-

0.5 vs. 0, p < 0.001; and 5.5 +/- 0.5 vs. 0, p < 0.001, respectively), and

greater energy deposition (2050.16 +/- 209.2 J vs. 2677.76 +/- 83.68 J, p <

0.001; and 2970.64 +/- 376.56 J vs. 5564.72 +/- 5439.2 J, p < 0.001,

respectively), than FET. CONCLUSION: The MST can achieve a larger ablation volume

by preventing RF cut-off, compared with the FET in an ex-vivo bovine liver model.