Lower Incidence of Postoperative Acute Kidney Injury in Robot-Assisted Partial Nephrectomy Than in Open Partial Nephrectomy: A Propensity Score-Matched Study.

Abstract

Background: Acute kidney injury (AKI) after partial nephrectomy is attributed to parenchymal reduction and ischemia, but the extent of its effect remains unclear. This study aimed to compare the incidence of postoperative AKI among surgical modalities, robot-assisted partial nephrectomy (RAPN), laparoscopic partial nephrectomy (LPN), and open partial nephrectomy (OPN), and to evaluate the validity of RAPN by comparing it with LPN and OPN in terms of postoperative AKI, perioperative complications, and long-term renal function. Patients and Methods: Patients who underwent RAPN, LPN, and OPN for renal tumors at our institutions between 2004 and 2018 were retrospectively analyzed. RAPN and LPN were performed under warm ischemia and OPN under cold ischemia. En bloc hilar clamping was employed for LPN and OPN and arterial clamping for RAPN. AKI was defined as % decrease in estimated glomerular filtration rate (eGFR) >25% from preoperative eGFR to postoperative nadir eGFR. Multivariate regression analysis was used to test associations of AKI with perioperative factors. Then, we compared the incidence of AKI with two propensity score-matched cohorts: RAPN vs OPN and RAPN vs LPN. Results: This study included 1762 cases (RAPN: 959, LPN: 215, and OPN: 588). After matching, 147 cases each from RAPN and LPN groups and 368 cases each from RAPN and OPN groups were selected. RAPN had shorter warm ischemia time than LPN, lower incidence of AKI, and lower % decrease in eGFR after 6 months. RAPN had a shorter ischemia time and a lower incidence of AKI than OPN, although the % decrease in eGFR after 6 months did not differ significantly. Conclusions: AKI incidence was lower in RAPN than in LPN or OPN, which may be due to the shorter ischemia time or clamping of only arteries in RAPN. Although long-term renal outcomes did not differ between RAPN and OPN, RAPN can help prevent AKI. This supports the validity of RAPN for patients with chronic kidney disease.