Nonischemic laparoscopic partial nephrectomy using a novel wet monopolar device in a porcine model

Laparoscopic partial nephrectomy (LPN) is the minimally invasive standard of care for the management of a cT(1a) renal mass. We evaluated a novel saline enhanced electrosurgical resection (SEER) device for performance of a nonischemic LPN.

Six pigs were used in a nonsurvival pilot study. Energy penetration was characterized by applying the SEER to the lower pole of each kidney for 30 seconds, 1 minute, and 3 minutes using pure cutting energy at 100W and a drip rate of 1 drip per second. Energy testing was performed with the hilum clamped in six kidneys and without clamping in six kidneys. Subsequently, a nonischemic upper pole LPN was performed with the SEER device, and the kidneys were harvested. The areas of necrosis were sectioned and stained with hematoxylin and eosin. Depth of necrosis was visualized grossly and microscopically for each time point. We also recorded time to perform LPN, estimated blood loss (EBL), and subjective severity of bleeding.

The average operative time was 15.4 minutes. The mean EBL was 44.2 mL with nine (75%) cases classified as minimal, 2 (17%) moderate, and 1 (8%) severe bleeding. The mean depth of necrosis on the kidney remnants was 2.97 mm. The mean depth of necrosis for unclamped kidneys at 30 seconds, 1 minute, and 3 minutes was 0.38 mm, 0.88 mm, and 1.27 mm, respectively. The mean depths for the clamped kidneys were 2.73 mm, 3.23 mm, and 8.68 mm respectively. Depth of necrosis was significantly higher in the clamped kidneys at 3 minutes (P=0.0035).

In the porcine model, the SEER transected parenchyma and collecting system with low resection times and minimal blood loss. Use of coagulation during resection is the main advantage of a monopolar resection compared with cold scissors. Testing performed for 3 minutes during hilar clamping demonstrated a significantly deeper level of necrosis.