Factors Influencing the Operative Approach to Renal Tumors: Analyses According to RENAL Nephrometry Scores

PURPOSE To evaluate the relationship between RENAL nephrometry score (RNS) and operative approach for renal masses. MATERIALS AND METHODS This study included 206 consecutive patients who underwent renal tumor surgery between January 2008 and October 2012. We divided the patients into four groups by surgical approach: open radical nephrectomy (ORN, 53 patients), laparoscopic radical nephrectomy (LRN, 83 patients), open partial nephrectomy (OPN, 31 patients), and laparoscopic partial nephrectomy (LPN, 39 patients). We retrospectively assessed the RNS for each surgery group and evaluated the relationship between this score and operative approach. RESULTS The mean RNSs of the ORN, LRN, OPN, and LPN groups were 9.75, 8.35, 6.72, and 5.76, respectively. When the RNS was analyzed according to nephron-sparing, the mean RNSs of the RN groups (ORN and LRN) and the PN groups (OPN and LPN) were significantly different (8.89 and 6.09, respectively; p<0.001). All the individual components of the RNS were significantly different between RN and PN. In the RN groups, the criteria for open versus laparoscopic surgery were based on tumor size ('R' score=2.43 for open, 1.54 for laparoscopic, p<0.001) and tumor location relative to the polar line ('L' score=2.55 for open, 2.09 for laparoscopic, p=0.006). In the PN groups, the criteria for open or laparoscopic surgery were based only on exophytic/endophytic property ('E' score=1.87 for open, 1.41 for laparoscopic, p=0.046). CONCLUSIONS The RNS was significantly different in all surgery groups. The decision to take a laparoscopic approach was primarily influenced by the R and L scores for RN and by the E score for PN.