RENAL nephrometry score predicts surgical outcomes of laparoscopic partial nephrectomy

• To assess the use of the RENAL Nephrometry Score (RNS), which has been proposed as an anatomical classification system for renal masses, aiming to predict surgical outcomes for patients undergoing laparoscopic partial nephrectomy (LPN).

• In the present study, 159 consecutive patients who underwent LPN were reviewed and RNS was calculated for 141 patients with solitary renal masses who had complete radiographic data. • Renal tumours were categorized by RNS as low (nephrometry sum 4-6), intermediate (sum 7-9) and high (sum 10-12).

• Of the 141 patients, there were 43 (30%) low, 91 (65%) intermediate and seven (5%) high score lesions. There was no statistically significant difference in the demographics of the three groups. • There was a significant difference in warm ischaemia time (16 vs 23 vs 31 min; P < 0.001), estimated blood loss (163 vs 312 vs 317 mL; P= 0.034) and length of hospital stay (1.2 vs 1.9 vs 2.3 days; P < 0.001) between the low, intermediate and high score groups, respectively. There was no difference in overall operative time (P= 0.862), transfusion rate (P= 0.665), complication rate (P= 0.419), preoperative creatinine clearance (P= 0.888) or postoperative creatinine clearance (P= 0.473) between the groups. • Sixty-one lesions (43%) were anterior and 80 (57%) were posterior. No difference was found among any intra-operative, pathological or postoperative outcomes when comparing anterior vs posterior lesions.

• In patients undergoing LPN, a higher RNS was significantly associated with an increased estimated blood loss, warm ischaemia time and length of hospital stay. • The RNS may stratify tumours based on the technical difficulty of performing LPN.