Radiofrequency ablation of the kidney: Acute and chronic histology in porcine model

Objectives, To our knowledge, the chronic histopathologic effects of radiof requency ablation (RFA) of renal parenchyma have not been extensively docum ented. In this study, we report the light and electron microscopic features of renal RFA in acute and chronic porcine models. Methods, Eleven animals underwent renal RFA of the lower pole kidney bilate rally. RFA was performed laparoscopically in 6 acute animals and percutaneo usly in 5 chronic animals. Acute animals were killed immediately following surgery. One chronic animal each was killed on postoperative day 3, 7, 14, 30, and 90. Histopathologic evaluation of all renal tissue specimens was ca rried out with light and electron microscopy. Results, Acutely, the renal radiolesion appeared as a yellowish white, well -circumscribed, necrotic area on gross examination, with evidence of extens ive coagulative necrosis and marked inflammation on microscopic examination . From day 1 through 90, light and electron microscopy revealed evidence of progressive, irreversible cell death and necrosis with diminishing inflamm atory response in the glomeruli, tubules, and renal interstitium. RFA lesio ns underwent gradual spontaneous resorption of the necrotic area with ultim ate autoamputation. Conclusions. RFA results in necrosis of the ablated renal parenchyma. UROLO GY 56: 872-875, 2000. (C) 2000, Elsevier Science Inc.