Water jet assisted laparoscopic partial nephrectomy without hilar clamping in the calf model

Purpose: Hemostasis represents a primary challenge during laparoscopic partial nephrectomy (LPN). We typically clamp the renal artery/vein en bloc and perform LPN expeditiously under warm ischemia conditions. We evaluated Helix Hydro-jet® assisted LPN without renal hilar vascular control in the survival calf model. Materials and Methods: Staged bilateral LPN using the Hydro-jet® was performed without renal hilar vessel control in 10 survival calves (20 kidneys). Parenchymal hydrodissection was performed with a high velocity, ultracoherent saline stream at 450 psi through a small nozzle with integrated suction at the tip. The denuded intrarenal parenchymal blood vessels were precisely coagulated with a BIClamp® bipolar instrument and transected. Followup involved biochemical, radiological and histopathological evaluation at designated sacrifice intervals of 1 and 2 weeks, and 1, 2 and 3 months, respectively. Results: All LPNs were completed successfully without open conversion. Of 20 LPNs 18 (90%) were performed without hilar clamping. Pelvicaliceal suture repair was necessary in 5 of 10 chronic kidneys (50%). Mean Hydro-jet® partial nephrectomy time was 63 minutes (range 13 to 150), mean estimated blood loss was 174 cc (range 20 to 750) and mean volume of normal saline used for hydro-dissection was 260 cc (mean 50 to 1,250). No animal had a urinary leak. Histological sections from the acute specimen revealed a thin (1 mm) layer of adherent coagulum at the amputation site with minimal thermal artifact. At 2 weeks a layer of adherent fibroinflammatory pseudomembrane with giant cell reaction was seen. Conclusions: In this more stringent and robust survival calf model Hydrojet® assisted LPN can be performed without hilar vessel control, thus, completely avoiding warm ischemia. This approach has the potential to decrease the level of technical difficulty inherent in LPN.