Robotic-assisted laparoscopic cryo-partial nephrectomy: a novel technique using cryoablation in lieu of hilar clamping in a porcine model.

Laparoscopic and robotic-assisted partial nephrectomy has become an increasingly viable approach for the resection of renal tumors. There are several technical limitations in performing laparoscopic partial nephrectomy, the most significant being the inability to easily obtain cold ischemia which allows for an extended operative time. In this study, we evaluated the feasibility and efficacy of cryoablation as an alternative to hilar clamping to maintain hemostasis during robotic-assisted laparoscopic partial nephrectomy in a porcine model. Twelve female swine underwent nine open and eight robotic-assisted laparoscopic partial nephrectomies using modified cryoablative methods to create hemostasis. Renal perfusion imaged with indocyanine green (ICG) and histological analysis was assessed immediately after the procedure and at 3 weeks post-operatively. With two freeze/thaw cycles, all nine open and eight robotic-assisted laparoscopic partial nephrectomies were successfully completed without the need for hilar clamping. The mean blood loss for the open and robotic-assisted groups was 230.6 and 99.4 ml, respectively. In all cases, maintenance of renal perfusion was confirmed by the presence of a renal pulse and intraoperative ICG imaging immediately and 3 weeks post-operatively. The histological anatomy was well preserved in the resected segment following cryo-resection. After 21 days following cryo-resection, histological analysis demonstrated normal viable tissue with minimal scarring in the remaining kidney. The use of cryoablation created a zone of hemostasis without compromising the vascularity of the remaining kidney, while preserving the renal cytoarchitecture of the segment remove for pathological analysis. Further studies will help to delineate its usefulness in laparoscopic partial nephrectomy.