To evaluate the long-term hemostatic efficacy of a new high-intensity collimated ultrasonic (HICU) applicator for open subhilar partial nephrectomy (PN) in the porcine model.

An applicator was designed with a planar 3.78-MHz HICU transducer and a reflector to optimize the delivery of acoustic energy to coagulate renal tissue. Six female pigs underwent right PN, followed at day 7 by left PN. The 6 pigs were killed on day 14. The treatment consisted of delivering HICU to a lower pole subhilar location, under a vascular clamp, then releasing the clamp, and cutting the kidney lower pole. The immediate and delayed hemostatic efficacy, treatment parameters, blood loss, complications, and renal function were evaluated at each surgical event and at necropsy.

Perfect hemostasis was achieved with all 12 kidneys, with a mean treatment time of 7.2 minutes (range 5 to 9.2). The mean proportion of resected parenchyma was 21% (range 14% to 32%). No renal function impairment and no major complications were recorded. At necropsy, no secondary hematoma was observed, and three urinomas (25%) were found.

Our HICU applicator has shown promising results during PN in the pig model with no other method of hemostasis. More studies are needed to refine our probe for laparoscopic surgery, improve its ergonomics, and extend our experiments to human laparoscopic nephron-sparing surgery.