LAUSR

OBJECTIVES To complement our previous findings regarding effect of UAS use, we checked RIRSearch database for patients who operated without using UAS. The aim of the study was to understand these new data better by comparing outcomes of RIRS which continued sheathless after a failed UAS insertion versus those planned and completed sheathless. MATERIALS AND METHODS Data of 195 patients who underwent sheathless RIRS for kidney and/or ureteral stones between 2011-2021 were retrieved from the database. Patients divided into two groups; cases which was planned and completed sheathless (n=110, group 1) and those which proceeded without UAS after insertion failure (n=85, group 2). After propensity score matching (PSM), each group consisted of 76 patients. RESULTS After PSM, stone-free rate for group 1 (90.8%) was significantly higher compared to stone-free rate of group 2 (76.3%) in sheathless RIRS (p=0.02). Also postoperative complication rate was significantly lower in group 1 (10.5%) compared to group 2 (27.6%) (p=0.007). In group 2, median operating time was longer (60 min, IQR: 40-80) and more unplanned auxilliary procedure (22.4%) was needed compared to group 1 (45 min, IQR 40-50 and 3.9%) (both p=0.001). Stone burden (OR: 1.002, p=0.019), stone density (OR 1.002, p=0.003) were associated with high risk of residual stones after RIRS. Higher hydronephrosis grades were associated with increased stone-free rates (OR 0.588 for residual stone risk, p=0.024). Cases which completed sheathless by dusting all available stones, as planned preoperatively, were more likely to have stone-free status after RIRS compared to those which proceeded sheathless after UAS insertion failure (OR 2.645, p=0.024). CONCLUSIONS Operation course after UAS insertion failure may be more challenging. In cases which performed without using UAS, surgeons who proceed procedure sheathless after UAS insertion failure may more frequently run into complications and may fail achieving stone-free status compared to sheathless-planned cases.