Pediatric semirigid ureteroscopy: instrument size matters

Abstract

The aim of this study is to analyse the efficacy (stone free rate), safety (complication rates) and associated independent predictive factors (age, stone location, stone size, pre-stenting etc.) of semi-rigid URS in the paediatric population. In this study, 243 ureterorenoscopy (URS) operations performed in 238 renal units in a single centre between 2001 and 2023 were retrospectively examined. Age, sex, whether a procedure was performed before or after the surgery, whether DJ stent was placed preoperatively or postoperatively, stone size, number and location, size of the instrument used, lithotripsy method, postoperative stone-free rate and complications were examined as variables. 243 patients were included. The mean age at operation was 71.6 months (7-204). Most of the patients had distal 1/3 ureter stones (70%) and a single stone (n = 190, 78.2%). The median number of stones and stone size were 1.42 and 7.58 mm (ranged 1-22 mm) respectively. SFR at single session was 87.7%. Stone location (SFR of 90.5% in distal, 71.4% in proximal stones) and stone multiplicity (SFR of 90% in single, 79.2% in multiple) were the only factors affecting the success rate in univariate analysis, yet no factors were statistically significant in multivariate analysis. Intraoperative complication (all ureteral perforations) rate was 2.05% (n = 5) and postoperative complication (all pyelonephritis) rate was 4.5% (n = 11). Stone multiplicity is the only independent predictive factor for intraoperative complications with higher complication rates in multiple stones(p = 0.037), but it is not statistically significant in multivariate analysis. Stone location and instrument size (4.5F vs 8F) were the only factors significantly associated with postoperative complication rates. Semi-rigid URS is an effective and safe procedure in paediatric population. Stone location and size of the instrument are the main factors affecting the postoperative and total complication rate. Despite semi-rigid URS can technically be used in any ureteral stones, yet flexible URS should be considered due to increased risk of complications and decreased SFR in proximal stones. To minimize the complication rates, choosing appropriate size of the instrument is essential.