Percutaneous Radiofrequency Lung Ablation Combined with Transbronchial Saline Injection: An Experimental Study in Swine

To evaluate the efficacy of radiofrequency lung ablation with transbronchial saline injection. The bilateral lungs of eight living swine were used. A 13-gauge bone biopsy needle was inserted percutaneously into the lung, and 1 ml of muscle paste was injected to create a tumor mimic. In total, 21 nodules were ablated. In the saline injection group (group A), radiofrequency ablation (RFA) was performed for 11 nodules after transbronchial saline injection under balloon occlusion with a 2-cm active single internally cooled electrode. In the control group (group B), conventional RFA was performed for 10 nodules as a control. The infused saline liquid showed a wedge-shaped and homogeneous distribution surrounding a tumor mimic. All 21 RFAs were successfully completed. The total ablation time was significantly longer (13.4 ± 2.8 min vs. 8.9 ± 3.5 min; P = 0.0061) and the tissue impedance was significantly lower in group A compared with group B (73.1 ± 8.8 Ω vs. 100.6 ± 16.6 Ω; P = 0.0002). The temperature of the ablated area was not significantly different (69.4 ± 9.1°C vs. 66.0 ± 7.9°C; P = 0.4038). There was no significant difference of tumor mimic volume (769 ± 343 mm3 vs. 625 ± 191 mm3; P = 0.2783). The volume of the coagulated area was significantly larger in group A than in group B (3886 ± 1247 mm3 vs. 2375 ± 1395 mm3; P = 0.0221). Percutaneous radiofrequency lung ablation combined with transbronchial saline injection can create an extended area of ablation.