Nephrometry Scores: The Effect of Imaging on Routine Read-out and Prediction of Outcome of Nephron-sparing Surgery

Background/aim: This study investigated the impact of available preoperative imaging on the reliability and predictive accuracy of RENAL and PADUA nephrometry-scoring systems for renal tumors.

Patients and methods: Five urologists determined RENAL and PADUA scores using preoperative imaging data (computed tomography and magnetic resonance imaging) of 100 patients admitted for partial nephrectomy with the following combinations: T0: transverse planes without excretory phase (EP), TC0: transverse and coronal planes without EP, TC1: transverse and coronal planes with EP. Reference standard was obtained by a uro-radiologist. Ischemia time was used as surrogate for surgical complexity.

Results: Assignment of EP significantly reduced interobserver-variability among urologists (p<0.0001). Predictive accuracy for surgical complexity or correct assignment to nephrometry risk groups did not depend on image planes or EP.

Conclusion: Interobserver variability, but not predictive accuracy of nephrometric systems, is affected by additional usage of EP.