Laparoscopic and computed tomography-guided percutaneous radiofrequency ablation of renal tissue: acute and chronic effects in an animal model

• Published in: Urology (Ridgewood, N.J.) N.J.), 2001-05, Vol.57 (5), p.976-980
• Main Authors: Crowley, Jim D, Shelton, Jack, Iverson, Alan J, Burton, Mark P, Dalrymple, Neal C, Bishoff, Jay T
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Catheter Ablation - adverse effects; Catheter Ablation - methods; Feasibility Studies; Hematoma - etiology; Kidney - diagnostic imaging; Kidney - pathology; Kidney - surgery; Kidney Cortex Necrosis - etiology; Kidney Cortex Necrosis - pathology; Kidney Diseases - etiology; Laparoscopy - methods; Medical sciences; Monitoring, Intraoperative - methods; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Surgery of the urinary system; Swine; Tomography, X-Ray Computed - methods
• ISSN: 0090-4295; 1527-9995
• DOI: 10.1016/S0090-4295(00)01129-8

Objectives. To evaluate the laparoscopic and percutaneous delivery of impedance-based radiofrequency ablation (RFA) of the kidney by studying the acute and chronic clinical, radiographic, and histopathologic effects in the porcine model. Methods. Eight kidneys from 4 pigs underwent laparoscopic RFA. Six kidneys from 3 additional pigs received computed tomography (CT)-guided, percutaneous RFA. CT scans were performed immediately after RFA and before harvest at 2 hours, 24 hours, 3 weeks, and 13 weeks. The gross, radiographic, and histopathologic changes were recorded for each period. Results. Grossly, the RFA lesions were sharply demarcated, measuring 3 to 5 cm. Two major complications (14%) occurred (one urinoma, one psoas muscle injury) in 14 ablations. No deaths or significant blood loss occurred as a result of RFA. Radiographically, the immediate CT scanning demonstrated small perinephric hematomas and wedge-shaped defects. Delayed CT showed nonenhancing defects up to 5 cm. Color-flow and power Doppler were unable to distinguish significant tissue changes during RFA. The histopathologic evaluation revealed marked inflammation surrounding the necrotic regions in the early lesions; chronic lesions were characterized by dense fibrosis. The tissue temperatures ranged from 62° to 118°C in the area of ablation. Conclusions. RFA is readily delivered laparoscopically or percutaneously with minimal morbidity. Impedance-based application of radiofrequency energy allows monitoring and control of ablation. Using a multi-antenna probe, areas of tissue up to 5 cm can be completely destroyed. The RFA lesion can be monitored as a nonenhancing cortical defect on CT.