Comparisons of surgical outcomes between transperitoneal and retroperitoneal approaches in robot-assisted laparoscopic partial nephrectomy for lateral renal tumors: a propensity score-matched comparative analysis

Objective To compare the surgical outcomes between the transperitoneal (TP) and retroperitoneal (RP) approaches in robot-assisted laparoscopic partial nephrectomy (RAPN) for lateral tumors. Methods This study included patients who underwent RAPN for lateral renal tumors between 2013 and 2019. Lateral tumors were defined as X of A factors in the RENAL nephrometry score. In total, 290 and 48 patients with TP and RP, respectively, were included in the analysis. To minimize the effects of selection bias, the following variables were adjusted using 1:1 propensity score matching: age, sex, body mass index, American Society of Anesthesiologists score, preoperative estimated glomerular filtration rate, tumor size, and RENAL nephrometry score. Results After matching, 48 patients were allocated to each group. The mean age was 55 years, and the mean preoperative estimated glomerular filtration rate (eGFR) was 68-69 mL/min/1.73 m(2). The mean tumor size was 30-31 mm. The RP group had a shorter operative time (124 vs. 151 min, p = 0.0002), shorter console time (74 vs. 110 min, p < 0.0001), shorter warm ischemic time (14 vs. 17 min, p = 0.0343), lower estimated blood loss (EBL) (33 vs. 52 ml, p = 0.0002), and shorter postoperative length of hospital stay (PLOS) (3.3 vs. 4.0 days, p < 0.0001) than the TP group. The change in eGFR, incidence rate of perioperative complication, and positive surgical margin rate did not significantly differ between the two groups. Conclusion RP had better surgical outcomes, including shorter operative time, lower EBL, and shorter PLOS for lateral renal tumors, which may suggest that RP is the optimal approach for selected lateral renal tumors.