Can the R.e.N.a.L nephrometry score preoperatively predict postoperative clinical outcomes in patients undergoing open and laparoscopic partial nephrectomy?

AIM We evaluate whether the preoperative R.E.N.A.L Nephrometry Score (RNS) can predict the postoperative outcomes in patients undergoing either an open or laparoscopic partial nephrectomy. PATIENTS AND METHODS We retrospectively calculated the RNS of 128 patients who underwent either an open partial nephrectomy (OPN) (n = 38) or laparoscopic partial nephrectomy (LPN) (n = 90) between 2003 and 2011. Patients were categorized into low, moderate or high complexity groups based on RNSs. Intra-operative warm ischemic time (WIT), peri-operative surgical outcomes using the Clavien-Dindo classification, postoperative histology, positive surgical margin rates were correlated to the RNS. RESULTS The RNS was associated with the length of the WIT in OPN (low vs. moderate vs. high: 11.4 vs. 13.1 vs. 23.4 minutes, p = 0.025) and blood loss in LPN (low vs. moderate 319 vs. 498 ml, p = 0.009). The positive surgical margins were greater in high versus moderate RNS lesions (40 vs. 7.4%, p = 0.045). No differences were seen in complications, hospital stay or transfusion rates. The RNS was significantly higher in OPN versus LPN (7.45 vs. 6.2, p = 0.0002). CONCLUSION An Increasing RNS was associated with increased WIT in OPN and blood loss in LPN, supporting RNS relationship to tumor complexity. A higher RNS in OPN indicate it may corroborate procedure choice. RNS should allow comparisons between treatment modalities for similar complexity lesions and with further research could aid stratification of individual risk preoperatively.