Predicting Complications After Robotic Partial Nephrectomy: Back to Simplicity.

Background: Robotic partial nephrectomy (RPN) has a significant morbidity. Nephrometry scores have been described to predict the occurrence of complications. Their usefulness is debated.

Objective: To evaluate the clinical utility of three nephrometry scores (radius, exophytic/endophytic, nearness, anterior/posterior, location [RENAL], preoperative aspects and dimensions used for an anatomical [PADUA], and simplified PADUA Renal [SPARE]) to predict perioperative outcomes and compare their performance to the simple measurement of tumor size in a large cohort of patients who underwent RPN.

Design, Setting, And Participants: We analyzed 1581 consecutive patients who underwent RPN for small renal masses.

Outcome Measurements And Statistical Analysis: Tumor size, RENAL, PADUA, and SPARE scores were calculated based on preoperative imaging. Correlation between scores, estimated blood loss (EBL), operative time (OT), and warm ischemia time (WIT) were calculated. Logistic regression analyses were performed to identify predictors of overall and major complications. The area under the curve was used to identify models with the highest discrimination. Decision curve analyses determined the net benefit associated with their use.

Results And Limitations: The median age was 62 yr (interquartile range [IQR]: 52-70) and the median tumor size was 35 mm (IQR: 25-47). Postoperative complications were observed in 346 patients (21.9%), including 5.6% of major complications. All scores were significantly correlated with EBL, OT, and WIT. However, correlation coefficients were all <0.3, suggesting a weak association. Nephrometry scores and tumor size were significant predictors of overall complications in univariate and adjusted multivariable logistic regression model analysis. However, decision curve analysis demonstrated net benefit of tumor size comparable with all nephrometry scores. Finally, neither nephrometry scores nor tumor size was found to be associated with the risk of major complications.

Conclusions: Tumor size has the same ability as nephrometry scores to predict perioperative outcomes of RPN.

Patient Summary: We evaluated the association between tumor size, nephrometry scores, and perioperative outcomes of robotic partial nephrectomy (RPN). We found that tumor size could predict perioperative outcomes of RPN as well as nephrometry scores.