Login to Access Video or Poster Abstract: MP49-03
Sources of Funding: none

Introduction

Robot-assisted partial nephrectomy (RAPN) is reportedly superior to laparoscopic partial nephrectomy (LPN) in renal function preservation. This is partly due to the shortened warm ischemia time (WIT), but related evidence remains unclear. This study aimed to examine the cause of renal functional loss after minimally invasive partial nephrectomy.

Methods

A total of 273 patients underwent LPN (n = 141) or RAPN (n = 132) at a single institution between 2010 and 2015. The factors influencing the >10% decrease in the estimated glomerular filtration rate (eGFR) 6 months postoperatively were evaluated, and the percentage of decrease in eGFR and parenchymal volume were compared in LPN and RAPN matched cohorts.

Results

The mean WIT was significantly longer (24 vs. 18 minutes, p < 0.001) and the postoperative decrease in eGFR 6 months after surgery was significantly higher (-9.9% and -3.4%, p < 0.001) in LPN than in RAPN. Multivariate analysis showed that the >10% postoperative decrease in eGFR was significantly influenced by the surgical procedure (p = 0.0004), but not by WIT (p = 0.07). Patient variables, including age, sex, body mass index, tumor size, RENAL nephrometry score (RENAL-NS), preoperative eGFR, and WIT, were adjusted, and each group included 42 patients (mean tumor size 23 mm, RENAL-NS 6.4, preoperative eGFR 69 mL/min/1.73 m2, WIT 21 minutes). Six months after surgery, the percentage of decrease in eGFR (-9.4% vs. -1.9%, p = 0.0008) and parenchymal volume (-23% vs. -9%, p < 0.0001) was significantly higher in LPN than in RAPN.

Conclusions

The better preservation of renal function in RAPN, compared with LPN, is not caused by shortened WIT but by better preservation of parenchymal volume.

Funding

none