Partial Laparoscopic Nephrectomy Using Monopolar Saline-Coupled Radiofrequency Device: Animal Model and Tissue Effect Characterization

Abstract

The optimal surgical tool for laparoscopic partial nephrectomy (LPN) would permit resection of lesions that penetrate relatively deeply and achieve hemostasis while allowing accurate viewing of the margins of the lesion, identification of the collecting system, control of both arteries and veins, and sealing of the collecting system. We hypothesized that the TissueLink Floating Ball (TissueLink, Inc.) might provide a simple, "pure" method of LPN. Ten adult female pigs (30-50 kg) underwent LPN of the left kidney with the TissueLink operating at 70 to 80 W as the sole means of hemostasis. Operative time, estimated blood loss (EBL), and specimen weight and characteristics, were recorded. On postoperative day 7, an intravenous urogram was carried out, and an open partial nephrectomy and surface treatment were performed on the other side with the TissueLink and intraparenchymal temperature monitoring. All LPNs were performed without complications with an average operating time of 148 minutes and a mean estimated blood loss of 49 mL. The urograms performed at postoperative day 7 demonstrated prompt excretion and no evidence of urinary extravasation or hydronephrosis. At harvest, all eight kidneys in which the collecting system had been entered showed evidence of localized urine leak. No evidence of retroperitoneal hematoma was noted, and all renal arteries and veins were patent and with good flow. The resected edge showed a gross 2 to 3 mm of flat, whitish discoloration and a well-demarcated edge. During the open partial nephrectomy, significant temperature variations were noted according to the distance from the point of application of the TissueLink. Pathologic examination of the acute specimens demonstrated altered cytoplasmic and nuclear staining in tubules extending approximately 6 to 8 mm from the treated surface. In contrast, the kidney that had been left in situ after LPN demonstrated overt cortical necrosis (coagulated necrosis), bordered by cortical scarring with apparent dystrophic calcifications at the resection edge from the previous partial nephrectomy. Tubular atrophy was obvious, with interstitial fibrosis and interstitial inflammation. A well-demarcated zone of several millimeters of tissue was evident on gross examination. The saline-cooled monopolar radiofrequency dissector (TissueLink) is a valuable adjunct for LPN. The device provided excellent hemostatic control with resection of as much as 40% of the renal parenchyma. Our initial observations of the device in the laboratory and in clinical use led us to develop a successful technique for its use for deep parenchymal resection, which is described in detail.