Nephrometry scoring systems RENAL, PADUA, C-index, SPARE, and ZONAL NePhRO for prediction of partial nephrectomy outcomes

Background. Modern imaging methods make it possible to detect kidney tumors at early stages which, along with active development of laparoscopic technologies, has led to an increase in the number of nephron-sparing surgeries and their effectiveness. The RENAL, PADUA, C-index, ZONAL NePhRO, and SPARE nephrometry score systems are actively used to predict outcomes of partial nephrectomy.

Aim. To evaluate the effectiveness of nephrometry scores in predicting the results of minimally invasive partial nephrectomy.

Materials and methods. The data on 90 patients who underwent laparoscopic or robotic partial nephrectomy at the Urology Center of the Mariinsky Hospital from September 2021 to May 2023 were retrospectively evaluated. There were 43 men (47.8 %) and 47 women (52.2 %). The median age of patients was 61 years (interquartile range (IQR) 48–69). Tumor of the left kidney was diagnosed in 46 (51.1 %) patients, and tumor of the right kidney in 44 (48.9 %) patients.

Results. Mean operative time was 132 ± 39 minutes. Median warm ischemia time and intraoperative blood loss were 15 minutes (IQR 12–20 min) and 150 mL (IQR 70–257.5), respectively. Mean hemoglobin level and red blood cell count before surgery were 132 ± 15 g/L and 4.6 ± 0.63 × 10¹²/L, respectively. After the surgery, the mean values were 119 ± 16 g/L and 4.06 ± 0.6 × 1012/L, respectively. Median creatinine and mean glomerular filtration rate before surgery were 83.5 µmol/L (IQR 72–97 µmol/L) and 76.9 ± 21 mL/min, respectively; in the early postoperative period, 83 µmol/L (IQR 70–100 µmol/L) and 76.4 ± 24 mL/min, respectively. The strongest relationship was established between the RENAL and PADUA scores (r = 0.907; p <0.001), a slightly weaker relationship was found for the PADUA and SPARE scores, as well as PADUA and C-index (r = 0.856; p <0.001 and r = –0.785; p <0.001, respectively). The RENAL score showed high predictive value in assessing the volume of intraoperative blood loss and operative time (r = 0.881; p = 0.001 and r = 0.854; p <0.001, respectively). The PADUA scale demonstrated high predictive efficiency for warm ischemia time (r = 0.775; p = 0.001). C-index significantly predicted the volume of intraoperative blood loss and operative time (r = –0.807; p <0.001 and r = –0.797; p = 0.001, respectively).

Conclusion. All of the above nephrometry scores showed high predictive efficiency, but the RENAL and PADUA scores were the most valuable.

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