Nephrometry score-guided off-clamp laparoscopic partial nephrectomy: patient selection and short-time functional results

BACKGROUND: Laparoscopic partial nephrectomy (LPN) is not a novel but a relatively technically challenging surgical procedure. Off-clamp LPN with zero ischemia can completely eliminate ischemic reperfusion injury to the kidney. The purpose of this study was to evaluate the safety and functional outcome of nephrometry score-guided off-clamp technique in LPN. METHODS: A total of 44 patients underwent LPN between January 2015 and July 2015 for renal mass with radius, exophytic/endophytic, nearness to sinus, anterior/posterior location (RENAL) score 4 were enrolled. Twenty-two of them underwent off-clamp LPN with zero ischemia, and the other 22 received standard LPN with common renal artery clamp. Estimate blood loss (EBL), total operation time, resection time, renorrhaphy time, preoperative estimated glomerular filtration rate (eGFR), postoperative eGFR, eGFR change, and drainage after surgery were compared between these two groups using t test. RESULTS: Patients’ characteristics including gender, age, BMI, tumor size, and RENAL score were balanced between the two groups. Average EBL was more in the off-clamp group than in the on-clamp group (134.32 versus 70.23 ml, p = 0.001). Average eGFR change was less in the off-clamp group than in the on-clamp group (−1.56 versus −6.45, p < 0.001). Average drainage after surgery was 203.41 ml for the off-clamp group and 145.46 ml for the on-clamp group, p = 0.062. No urinary leakage and hematuria occurred in both groups. There were no statistical difference in total operation time, resection time, renorrhaphy time, preoperative eGFR, and postoperative eGFR between the two groups. CONCLUSIONS: Off-clamp LPN is a safe and feasible approach to excise certain kidney tumors with RENAL score 4. This technique can better preserve kidney function without ischemic reperfusion injury.