Introduction:
The global prevalence of urolithiasis tends to increase worldwide, leading to the need for safe and effective treatment methods1. In parallel with the advances in technology, flexible ureterorenoscopes, effective lithotripters and innovations in auxiliary equipment have enabled the treatment most of the renal stones with flexible ureterorenoscope with no need for open surgery or percutaneous nephrolithotomy)2. Although the percutaneous nephrolithotomy (PNL) is recommended as first-line treatment for renal stones larger than 20 mm in size, flexible ureterorenoscopy (FURS) or shock wave lithotripsy (SWL) may be considered as a treatment method for stones larger than 20 mm in size according to EAU-2019 guideline on urolithiasis especially in case that PNL is not an option because of other reasons3.
Due to the increasing spread of FURS, it should be addressed in all aspects, including infection rates. Postoperative infections seem one of the most common complications of FURS and the parameters that affect infective complications following FURS were analysed in some studies in the literature4,5. However, the effect of operation time (OT) and the relationship of the ureteral access sheath (UAS) with the infection rates is unclear in this size of renal stones.
We aimed to investigate the relationship of the OT and the UAS usage with the infection rates and to determine a cut-off value in terms of OT, where infection rates increase more, by using ROC curve analysis.