Association between tumor contact surface area and parenchymal volume change in robot-assisted laparoscopic partial...

To evaluate the change in the operated parenchymal volume during robot-assisted partial nephrectomy limited to the enucleation technique, and to analyze the predictors of decrease in operated parenchymal volume, including the tumor contact surface area.

The study included 135 patients who underwent robot-assisted partial nephrectomy for T1 renal tumors using the enucleation technique. Measurements of the parenchymal volume, tumor volume and contact surface area were obtained in the venous phase on enhanced computed tomography. All measurements, including volumetric and renal function analysis, were carried out <2 months before and 6 months after surgery.

The mean age of included participants was 56 years, and the mean tumor size was 33 mm. The mean tumor volume was 26 cc, and the mean contact surface area was 22 cm² . In the complete cohort, the mean preoperative and postoperative normal parenchymal volumes of the operated kidney were 158 and 141 cc, respectively. The mean change in parenchymal volume of the operated kidney was -10%. In contrast, the mean change in global estimated glomerular filtration was just -4.0%. Univariate analysis showed that the RENAL nephrometry score, contact surface area, tumor volume and warm ischemia time were associated with the change in the operated kidney parenchymal volume. However, in the multivariate analysis, a large contact surface area was the only independent predictor of decreased operated parenchymal volume <10 cm³ .

Contact surface area is a strong predictor of the decrease in the parenchymal volume in the operated kidney during robot-assisted partial nephrectomy carried out using the enucleation technique for T1 renal tumors.