Feasibility of Microwave Scissors-Based Off-Clamp Laparoscopic Partial Nephrectomy in a Porcine Model

Abstract

Objectives To assess the feasibility of off-clamp laparoscopic partial nephrectomy using microwave scissors. Methods We performed transperitoneal laparoscopic partial nephrectomy, without hilar clamping or renorrhaphy, using only microwave scissors for renal resection in a porcine model. For each kidney, 2 types of procedures were performed: a middle pole resection excising an area of 2-cm diameter and approximately 1-cm depth and a lower pole resection at the level of the lower polar line. The renal calyces exposed during renal resection were sealed and transected using microwave scissors. After 3 days of follow-up, the pigs were reoperated to inspect for postoperative complications. Euthanasia was performed to collect the remaining kidneys for histopathological examination. Results Ten procedures were successfully performed, without hilar clamping or suturing of the renal calyces and parenchyma, in 5 kidneys from 3 pigs. The median resecting time, blood loss, and lateral thermal injury were 23.2 min, 47.1 mL, and 6.8 mm in the middle pole resection, and were 15.1 min, 26.5 mL, and 6.9 mm in the lower pole resection, respectively. No complications were noted during reoperation, such as postoperative hemorrhage and major urine leakage. Extravasation occurred in 2 middle pole resections and 3 lower pole resections during retrograde pyelogram. Hematoxylin and eosin staining revealed thermal injury characterized by tissue microwave fixation in the near zone and acute coagulative necrosis in the intermediate zone. Conclusions Microwave scissors-based off-clamp laparoscopic partial nephrectomy is feasible in pigs and can be used for clinical applications.

Comparison of off-clamp microwave scissors-based sutureless partial nephrectomy versus on-clamp conventional partial nephrectomy in a canine model

“…Although the usefulness of off-clamp MSPN was demonstrated, its procedural success might be attributed to the open-surgery modality because the MWS was omnidirectionally manipulated, facilitating tissue coagulation and bleeding control in a short time. To inspect the impact of degrees of freedom on MWS manipulation in the minimally invasive surgery modality, we conducted a preliminary experiment in five kidneys from three pigs ( 21 ) following the present study. It demonstrated that off-clamp sutureless laparoscopic partial nephrectomy (LPN) using MWS is feasible for both middle and lower pole resections, mimicking various tumor locations in clinical scenarios.…”

“…Even though hilar clamping was not performed, the off-clamp sutureless LPN using MWS ( 21 ) recorded shorter PT and lesser BL compared to porcine on-clamp LPNs ( 37 , 38 ), in which renal bleeding was controlled with renal suturing ( 37 , 38 ), renal suturing with hemostatic agents ( 38 ), or electrocautery with hemostatic agents ( 37 ), respectively. In addition, its BL ( 21 ) was lesser than that of off-clamp open PN using ultrasonic ( 39 ) or radiofrequency ablation devices ( 39 ), in similar porcine renal resections reported previously. To our knowledge, the cost of MWS is lower than that of other devices usually employed for dissection in conventional LPN, such as bipolar radiofrequency or ultrasonic devices.…”

“…When the operators gently grasp tissue using scissor blades, irradiate microwaves, and then mechanically cut them, the MWS can seamlessly seal the tissue like bipolar radiofrequency and ultrasonic sealers ( 18 , 20 ). When the operators close or partially open the scissor blades, and touch the scissor-blade side to the bleeding tissue while irradiating microwaves ( 18 , 21 ), the interblade microwave irradiation induces an electric field around the scissors, causing dielectric heat that can coagulate tissue and stop bleeding.…”