Minimizing Diaphragmatic injury during radio-frequency ablation: Efficacy of subphrenic peritoneal saline injection in a porcine model

PURPOSE: To investigate if a targeted subphrenic peritoneal infusion of normal saline to separate liver from diaphragm before radio-frequency (RF) ablation could minimize or eliminate diaphragmatic injury. MATERIALS AND METHODS: With a 2-cm-diameter, eight-prong RF needle electrode, 3 7 hepatic dome RF lesions were created in 10 pigs. Seventeen lesions were created before (nonsaline group) and 20 lesions after (postsaline group) intraperitoneal infusion of approximately 500 mL of normal saline. Ten nonsaline lesions were created deep (centered 1-2 cm from the liver surface) and seven superficially (centered within 1 cm of the capsule). All 20 postsaline lesions were created superficially. Helical enhanced computed tomography was performed 24-48 hours after ablation. The pigs were killed immediately, and the diaphragm was visually inspected and sectioned. Diaphragmatic injury was graded as 0, no injury; 1, injury up to one-third thickness; 2, injury to two-thirds thickness; 3, full-thickness injury. Representative grade 3 injuries and all partial injuries underwent gross and histologic analysis. RESULTS: All 10 deep nonsaline RF lesions caused grade 0 injury. All seven superficial nonsaline lesions caused grade 3 injury. Of the 20 superficial postsaline lesions, 13 (65%) caused grade 0 injury; four (20%), grade 1; and three (15%), grade 3. The postsaline group caused significantly less diaphragmatic injury (P < .05). CONCLUSION: Intraperitoneal saline infusion may reduce the frequency and severity of diaphragmatic injury when adjacent liver is treated with RF ablation. (C) RSNA, 2002.