Laparoscopic Renal Hypothermia

Warm ischemia dramatically limits the time available to perform tumor resection and collecting system and parenchymal repair during laparoscopic partial nephrectomy, forcing the surgeon to operate "under the gun" in a race against time. As such, techniques to achieve viable renal hypothermia by minimally invasive methods have been described. The initial described technique of laparoscopic renal hypothermia was reported by Gill et al. (106) first described the technique of laparoscopic renal hypothermia. Intracorporeal surface contact renal hypothermia was performed in 12 patients. After complete mobilization, the kidney was entrapped in an Endocatch-II bagd, whose drawstring was cinched around the intact hilum. The renal hilum was then occluded with a Satinsky clamp; the bottom of the bag was retrieved through a 12 mm port site, opened, and 600-750 mL of ice-slush delivered into the bag with 30 mL syringes within a period of 4-7 minutes. Needle thermocouples confirmed achievement of protective levels of hypothermia, with core renal temperatures in the 5-19°C range.

Janetschek (107) achieved kidney cooling by continuous perfusion of 1000 mL of cold (4°C; perfusion rate = 50 mL/min) Ringer's lactate through an angiocatheter placed into the clamped renal artery in 15 patients undergoing laparoscopic partial nephrectomy for renal cell carcinoma. At a parenchymal temperature of 25°C, a steady state was maintained by reducing the perfusion rate to 25-33 mL/min. Tumor excision was performed in a bloodless field. Mean ischemia time was 40 minutes (range, 27-103). Increased blood loss was noted in two initial patients: in one due to inadequate intralu-minal balloon occlusion and in the other due to perfusion pump malfunction causing venous backflow from the injured renal vein. Blood transfusion was necessary in another patient. Reoperative laparoscopy was performed in one patient for postoperative hemorrhage. The feasibility and safety of cold ischemia via arterial perfusion during laparoscopic partial nephrectomy was demonstrated. However, since optimal hypothermic renoprotection from ischemia occurs with temperatures <15°C, these techniques need further refinement to deliver adequate levels of hypothermia.

Renal hypothermia has also been achieved by retrograde pelvicalyceal cold saline perfusion via a ureteral access sheath. Clinical application of this technique was described in a patient undergoing open radical nephrectomy. Cortical and medullary temperatures obtained were 24°C and 21°C, respectively, which are somewhat higher than optimal hypothermia temperature of 15°C (108).

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