Utility of the RENAL nephrometry scoring system in the real world: predicting surgeon operative preference and complication risk

Study Type – Prognosis (individual cohort) Level of Evidence 2b What's known on the subject? and What does the study add? RENAL nephrometry is a quantitative, reproducible scoring system that characterizes RENAL masses and standardizes reporting. Previous work has suggested that the system may be useful in predicting outcomes after partial nephrectomy. This study is the first to correlate RENAL nephrometry score with operative approach or risk of complication in patients undergoing either partial or radical nephrectomy.

OBJECTIVE

• ? To evaluate the utility of the RENAL scoring system in predicting operative approach and risk of complications. The RENAL nephrometry scoring system is designed to allow comparison of renal masses based on the radiological features of (R)adius, (E)xophytic/endophytic, (N)earness to collecting system, (A)nterior/posterior and (L)ocation relative to polar lines.

METHODS

• ? A retrospective review of all patients at a single institution undergoing radical nephrectomy (RN) or partial nephrectomy (PN) for a renal mass between July 2007 and May 2010 was carried out.
• ? Preoperative RENAL score was calculated for each patient. Surgical approach and operative outcomes were then compared with the RENAL score.

RESULTS

• ? In all, 249 patients underwent either RN (158) or PN (91) with average RENAL scores of 8.9 and 6.3, respectively (P < 0.001).
• ? Patients who underwent RN were more likely to have hilar tumours (64% vs 10%, P < 0.001) than patients who underwent PN, but were no more likely to have posteriorly located tumours (50% each).
• ? There were more complications among patients with RN (58%) vs patients with PN (42%, P= 0.02).
• ? RENAL scores were higher in patients with PN who developed complications than in patients with PN who did not develop complications (6.9 vs 6.0, P= 0.02), with no difference noted among patients with RN developing complications (8.9 vs 8.9, P= 0.99).

CONCLUSION

• ? The RENAL system accurately predicted surgeon operative preference and risk of complications for patients undergoing PN.