Ablation of renal tumors in a rabbit model with interstitial saline- augmented radiofrequency energy: Preliminary report of a new technology

Thomas J. Polascik, Ulrike Hamper, Benjamin R. Lee, Yutian Dai, John Hilton, Carolyn A. Magee, Julie K. Crone, Matthew J. Shue, Meg Ferrell, Victoria Trapanotto, Alan W. Partin

Research output: Contribution to journalArticle

Abstract

Objectives. To evaluate the efficacy of interstitial saline radiofrequency energy for reproducibly ablating nonmalignant (control) and malignant (the VX-2 tumor) renal tissue in a rabbit model, and to determine the ability of conventional gray-scale and power sonography to image the tumor and ablative process in real time before, during, and after treatment. Methods. The VX-2 tumor was implanted beneath the renal capsule in 18 rabbit kidneys. Twelve days after implantation, 50 W of 500-kHz radiofrequency energy was delivered into the surgically externalized renal tumor and contralateral control kidney for 30 or 45-second treatment intervals using an interstitial saline-augmented radiofrequency probe (the virtual electrode). Localization of the tumor and response to treatment were imaged with gray- scale and power Doppler ultrasonography. The effect of radiofrequency and extent of the destructive process on benign and malignant renal tissue were evaluated histologically. Results. Mean tumor size was 1.3 x 0.7 cm. Both 30 and 45-second treatment intervals provided marked tissue/tumor ablation. Gross anatomic and histologic analysis showed time-dependent ablated lesions averaging 1.4 ± 0.3 x 1.0 ± 0.3 cm (30-second treatment) and 1.8 ± 0.4 x 1.5 ± 0.3 cm (45-second treatment), with clear demarcation of the surrounding parenchyma. Conventional gray-scale sonography allowed visualization of the ablative process, and power Doppler ultrasound demonstrated changes in the vascular pattern of the tumor both before and after ablation. No immediate treatment-related complications were observed. Conclusions. These preliminary studies in a rabbit model demonstrate the feasibility of using the interstitial saline-augmented electrode to ablate small renal tumors and the ability to simultaneously visualize the ablative process using real-time ultrasonography. This technology may have the potential to treat small renal tumors in a minimally invasive manner in the clinical setting.

Original languageEnglish (US)
Pages (from-to)465-470
Number of pages6
JournalUrology
Volume53
Issue number3
DOIs
StatePublished - Mar 1999

ASJC Scopus subject areas

  • Urology

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