Introduction:The present study aimed to compare the assessment of volume preservation and perioperative outcomes during partial nephrectomy (PN), according to the surface-intermediate-base (SIB) score.Methods:This prospective study included 80 patients diagnosed with renal cell carcinoma who underwent PN for a renal mass from 2014 to 2017. SIB score was macroscopically evaluated immediately after the surgery. Preoperative assessment of volume preservation (PAVP), surgeon assessment of volume preservation (SAVP), duration of ischemia, perioperative complications, pathological data, and the values of preoperative and postoperative estimated glomerular filtration rate (eGFR) were recorded.Results:A strong correlation was determined between PAVP and SAVP (R= 0.82,R-2 = 0.68,p< 0.0001) and between vGFR-PAVP and vGFR-SAVP calculated using the adapted eGFR (preop eGFR x [PAVP or SAVP]) (R= 0.97,R-2 = 0.95,p< 0.001). In multivariate analysis, preoperative tumor size, SIB score (1-2 vs. 3-5), and vGFR (PAVP and SAVP model) were significant predictors of postoperative eGFR. A low base score was associated with surgical margin positivity, and a high SIB score (>= 3) was associated with perioperative complications (p= 0.017;p= 0.028).Conclusion:The SIB score can be considered a reliable surrogate for volume preservation after PN because it is strongly associated with both PAVP and SAVP. SIB score is useful in predicting functional outcomes, complications, and surgical margin positivity.