Comparison of Kidney Function in the Early Postoperative Period in Transperitoneal Robot-Assisted Laparoscopic Partial Nephrectomy Between Anterior and Posterior Renal Tumors: A Propensity Score-Matched Study.

OBJECTIVE: To compare early postoperative renal function in transperitoneal robot-assisted laparoscopic partial nephrectomy (RAPN) for anterior and posterior renal tumors.

PATIENTS AND METHODS: This study included 227 patients who underwent transperitoneal RAPN for anterior or posterior renal tumors. Tumor position was defined by RENAL nephrometry score. To minimize selection bias between anterior and posterior tumors, patient variables were adjusted using 1:1 propensity score matching.

RESULTS: Of the 227 patients, 125 were classified as having anterior tumors and 102 as having posterior tumors. After matching, 82 patients were included in each group. The mean preoperative estimated glomerular filtration rate (eGFR) was 66 mL/min/1.73 m2 . The mean tumor size was 28 to 29 mm. The decrease in early postoperative nadir eGFR (-10% vs -4.0%, p = 0.0103) was significantly higher for posterior tumors than for anterior tumors. However, the difference improved 6 to 12 months after surgery (-6.0% vs -6.2%, p = 0.9564). The other surgical outcomes, including operative time, warm ischemia time (WIT), complications, surgical margin status, and length of hospital stay, were not significantly different between the two groups. In multivariate analysis of the entire cohort, posterior tumors (vs anterior tumor, odds ratio [OR]: 2.30, p = 0.0051), longer WIT (OR: 3.10, p = 0.0019), and high tumor complexity (vs low complexity, OR: 3.46, p = 0.0264) were independent predictors for development of a 10% decrease in early postoperative eGFR.

CONCLUSIONS: Posterior tumors had a greater decrease in early postoperative nadir eGFR than anterior tumors, with equivalent surgical outcomes, including similar renal function, 6 to 12 months after surgery in the setting of transperitoneal RAPN.