Zonal NephRo Score: external validation for predicting complications after open partial nephrectomy

Area of Science:

• Urology
• Nephrology
• Surgical Oncology

Background:

• Open partial nephrectomy (OPN) is a standard procedure for kidney tumor removal.
• Accurate assessment of tumor complexity is crucial for predicting surgical outcomes and complications.
• The Zonal NePhRO Score (ZNS) was previously developed to quantify renal tumor complexity.

Purpose of the Study:

• To externally validate the Zonal NePhRO Score (ZNS) as a predictor of perioperative complications and outcomes in patients undergoing open partial nephrectomies (OPNs).
• To assess the ZNS's superiority over other nephrometry scores in predicting OPN outcomes.

Main Methods:

• A retrospective analysis of 200 consecutive patients who underwent OPN was conducted.
• Preoperative CT or MRI scans were analyzed to stratify tumor complexity using the ZNS (low, moderate, high).
• Univariate and multivariate logistic regression models identified predictors of perioperative complications and surgical parameters.

Main Results:

• The ZNS score was significantly associated with higher complication rates (OR 1.25), longer ischemia times (β = 1.19), decreased eGFR post-surgery (β = -1.86), and increased collecting system openings (OR 1.72).
• Tumor complexity was graded as low in 19.8%, moderate in 50.3%, and high in 29.9% of cases.
• Age and BMI were also identified as independent predictors of complications.

Conclusions:

• This study provides the first external validation of the ZNS for predicting perioperative complications in OPN.
• A higher ZNS score is a reliable indicator of increased operative difficulty, longer ischemia times, and adverse postoperative renal outcomes.
• The ZNS is a valuable tool for surgical planning and patient counseling in OPN procedures.