Radiofrequency ablation of subcapsular lesions with internally cooled perfusion electrode: ex vivo study

Abstract

Purpose To compare the ex vivo efficiency of an internally cooled perfusion (ICP) electrode and an internally cooled (IC) electrode for radiofrequency ablation (RFA) of subscapular lesions. Material and methods Using 200 W generator and ICP electrode (group A, n = 10) or 15 gauge or 17 gauge IC electrode (group B, n = 10 and group C, n = 10), RFA was applied to the bovine liver for 12 min. Each electrode was inserted at a 3 cm depth into the liver block, and the proximal end of the active exposure portion of each electrode was located at a capsule of the liver block. During RFA, normal saline was pumped through the side hole of the ICP electrode into the tissue at an injection rate of 0.5 mL/min. Results The ICP electrode achieved larger capsular ablative area and ablative volume than the IC electrode: 7.29 ± 1.59 cm2 and 44.56 ± 10.08 cm3 in group A; 4.36 ± 1.29cm2 and 30.15 ± 5.97 cm3 in group B; and 3.57 ± 0.99cm2 and 24.52 ± 4.21 cm3 in group C (p < .05), respectively. Mean impedance of ICP RFA was lower than IC RFA: 41.5 ± 3.75Ω in group A; 52.4 ± 5.64Ω in group B; and 58.1 ± 10.98Ω in group C (p < .05). Conclusion RFA using the ICP electrode more efficiently created a larger capsular ablative area and ablative volume of ablation than IC RFA for subcapsular lesions. The results were obtained in an ex vivo liver model without tumor simulation inside.