The Application of RENAL Nephrometry Scoring System in Predicting the Complications After Laparoscopic Renal Radiofrequency Ablation

Purpose: To investigate the clinical significance of R.E.N.A.L. nephrometry scoring system in evaluating the complications after laparoscopic radiofrequency ablation (LRFA) of renal tumors. Patients and Methods: We conducted a retrospective review of the records of all patients who underwent LRFA of renal tumors from February 2006 to March 2012 in our institution. Tumors were categorized as low (4-6), moderate (7-9), or high complexity (10-12) according to R.E.N.A.L. nephrometry score (NS), which was determined by analyzing preoperative imaging. Perioperative data were analyzed to determine the presence of complications. Results: LRFA was performed on 170 tumors in 170 selected patients with preoperative imaging available. Mean patient age was 55.9 years (range 26 to 81), and mean tumor size was 2.8 cm (range 0.9 to 4.9). Mean NS was 6.6 (range 4 to 12). Of the total tumors, 105 (61.7%) were categorized as low-, 46 (27.1%) as moderate-, and 19 (11.2%) as high-complexity lesions. Overall, there were 21 (12.4%) complications, including 6 (3.6%) grade IIIa and 15 (8.8%) grade I-II complications. There was a significant difference in complication rates among the low-(105 patients, 0%), moderate-(46 patients, 4.3%), and high-complexity (19 patients, 100%) groups, respectively (p < 0.05). NS was independently associated with a higher risk of postoperative complications (odds ratio 2.87, 95% CI 1.17-3.04, p = 0.02) on multivariate analysis. Conclusions: The results of patients undergoing LRFA show that the R.E.N.A.L. NS is independently associated with the occurrence of complications. Therefore, the R.E.N.A.L. nephrometry scoring system is useful in predicting the complication risks of patients who undergo LRFA, and may help with surgical decision making.