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 (R) assisted LPN without renal hilar vascular control in the survival calf model. Materials and Methods: Staged bilateral LPN using the Hydro-jet (R) 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 (R) 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 (R) 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 fibro-inflammatory pseudomembrane with giant cell reaction was seen. Conclusions: In this more stringent and robust survival calf model Hydro-jet (R) 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.