Effect of Using Automated Irrigation Systems on the Risk of Infectious Complications after Endoscopic Combined Intrarenal Surgery: A Retrospective Cohort Study

<b><i>Objective:</i></b> Endoscopic combined intrarenal surgery (ECIRS) is a treatment option for kidney stones comparable with other standard methods. One reported complication of ECIRS is infection associated with high intrarenal pressure (IRP), and the irrigation system is an important factor affecting the IRP. Therefore, this study aimed to compare the operative outcomes and infectious complications between manual and gravity irrigation and automated irrigation systems for ECIRS. <b><i>Materials and Methods:</i></b> This single-center, retrospective cohort study enrolled patients who underwent ECIRS between January 2016 and August 2021. We compared operative results and complications between the two irrigation systems, and a multivariate analysis was performed to identify the factors associated with each outcome. <b><i>Results:</i></b> A total of 294 patients were enrolled in this study. The operative time was significantly longer in the manual and gravity irrigation group than in the automated irrigation group (122 ± 45 <i>vs</i> 108 ± 37 minutes, <i>p</i> = 0.003). Postoperative fever occurred in 25% of the patients in the manual and gravity group compared with 10% in the automated group (<i>p</i> < 0.001). In multivariate analysis, the use of a manual and gravity irrigation system was a significant factor associated with postoperative fever (<i>p</i> = 0.001) and longer operative time (<i>p</i> < 0.001). <b><i>Conclusions:</i></b> Using an automated irrigation system for flexible ureteroscopy in ECIRS reduces the risk of postoperative fever and the operative time.