Radiofrequency coagulation of renal parenchyma: Comparison of effects of energy generators on treatment efficacy

Purpose: We compared experimental renal lesions created with temperature-based or impedance-based radiofrequency (RF) generators using normal renal parenchyma in an animal model with protocols recommended by the manufacturer. Materials and Methods: Bilateral renal mobilization was completed in seven farm pigs in preparation for RF ablation, and the tines of each RF probe were expanded to a 2-cm diameter. Pigs were sacrificed immediately (N = 3) or at 24 hours (N = 4) after treatment. Lesions were examined grossly and microscopically after hematoxylin and eosin (H&E) and nicotinamide adenine dinucleotide (NADH) staining. Results: Gross lesions were firm and white with a hemorrhagic border, regardless of RF generator. Staining with H&E revealed preservation of renal architecture but loss of distinct cytoplasmic features with both RF systems. Staining for NADH showed no viable cells within the lesions produced by either RF system. Immediately and after a 24-hour survival, the mean sizes of the treatment lesions were 1.6 × 1.8 × 1.3 cm and 2.0 × 1.6 × 1.9 cm, respectively, for the temperature-based RF generator and 2.7 × 2.4 × 2.5 cm and 2.2 × 2.1 × 1.8 cm, respectively, for the impedance-based RF generator. Conclusion: Use of a specific RF energy generator with recommended treatment protocols does not appear to affect coagulation of normal renal parenchyma in the porcine model.