Impact of microwave tissue coagulation during laparoscopic partial nephrectomy on postoperative renal function

Laparoscopic partial nephrectomy for small renal tumors has been performed with increasing frequency over the past few years. We prospectively evaluated preoperative and postoperative differential renal function in patients with functioning contralateral kidneys who underwent laparoscopic partial nephrectomy using a microwave tissue coagulator without hilar clamping. Seven patients (five men and two women) in this prospective protocol underwent laparoscopic partial nephrectomy for exophytic tumors using a microwave tissue coagulator when the tumor was 2 cm or less in diameter. Renal scanning with ⁹⁹technetium-labeled diethylenetetraminepentaacetic-acid scan was performed preoperatively and postoperatively at 7 days and 6 months after surgery in all patients. The mean tumor size and surgical duration were 17.0 ± 2.3 mm and 161.1 ± 20.5 min, respectively. Intraoperative blood loss was 35.6 ± 40.7 ml. The preoperative glomerular filtration rate (GFR) and differential split renal function (SF) in the affected kidney were 45.7 ± 12.8 ml/min and 50.5 ± 3.3%, respectively. On postoperative day 7 and at 6 months, GFR and SF in the affected kidney were 36.2 ± 9.0 and 36.8 ± 10.9 ml/min and 44.3 ± 4.1 and 45.0 ± 5.1%, respectively. No postoperative complications occurred. Laparoscopic nonischemic partial nephrectomy using a microwave tissue coagulator has the advantage of technical ease and adequate hemostasis. However, its indication should be restricted to small exophytic renal tumors due to the expected collateral damage causing renal impairment.