Spherical cap surface model: A novel method for predicting renal function after partial nephrectomy.

Area of Science:

• Nephrology
• Urologic Oncology
• Medical Imaging Analysis

Background:

• Partial nephrectomy is crucial for renal cell carcinoma treatment.
• Assessing functional kidney volume preservation is vital for predicting postoperative renal function.
• Current methods for estimating functional volume preservation have limitations.

Purpose of the Study:

• To introduce and validate a novel spherical cap surface model for estimating percent functional volume preservation from preoperative images.
• To determine if this model can preoperatively predict renal function after partial nephrectomy.
• To assess the model's ability to predict acute kidney injury and long-term renal function decline.

Main Methods:

• A retrospective study included 233 patients undergoing partial nephrectomy.
• The spherical cap surface model calculated estimated percent functional volume preservation from preoperative CT scans.
• Preoperative estimated glomerular filtration rate (eGFR) was used to predict postoperative eGFR.
• Univariate/multivariate regression and ROC analysis evaluated the model's predictive performance and acute kidney injury risk.

Main Results:

• The model significantly correlated with nadir and late percent eGFR preservation (P=0.021, P=0.043).
• Volume preservation and warm ischemia time were significant predictors of acute kidney injury (P<0.001, P=0.040).
• Volume preservation was the sole significant predictor of significant late renal function decrease (P=0.044).

Conclusions:

• Functional kidney volume preservation is the primary determinant of outcomes after partial nephrectomy.
• The spherical cap surface model shows promise for predicting postoperative renal function.
• This novel method can aid in preoperative risk assessment and surgical planning.