Single-use versus reusable ureterorenoscopes for retrograde intrarenal surgery (RIRS): systematic comparative analysis of physical and optical properties in three different devices

IntroductionRetrograde intrarenal surgery (RIRS) represents a standard option for kidney stone removal. However, RIRS is considered a cost-intensive procedure. Single-use flexible ureterorenoscopes have been introduced to improve budget predictability in RIRS. We assessed differences in physical and optical properties of single-use devices compared to standard reusable endoscopes.MethodsIn two single-use (LithoVue, Boston Scientific; Pusen Uscope UE3011), and one reusable ureterorenoscope (Flex-Xc, Karl Storz), we investigated flow rates, deflection, illuminance, and intrapelvic pressure in a porcine kidney model. Subjective image quality was assessed using a standardized questionnaire. Common insertable devices were applied to investigate additional influence on physical properties.ResultsSignificant variability in maximum flow rates was observed (Flex-Xc: 25.8ml/min, LithoVue: 30.3ml/min, Pusen: 33.4ml/min, p<0.05). Insertion of a guide wire resulted in the highest reduction of flow rates in all endoscopes. Flection led to a reduction of absolute flow rates up to 9.4% (Flex-Xc). Light intensity at 20/50mm distance was 9090lx/1857lx (Flex-Xc) and 5733lx/1032lx (LithoVue) and 2160lx/428lx (Pusen), respectively (p<0.05). Subjective image quality score was highest using the Flex-Xc endoscope. During manipulation, maximum intrarenal pressure up to 66mmHg (Pusen) was measured.ConclusionsSignificant differences in physical and optical properties of single-use or reusable flexible ureterorenoscopes are present, with putative influence on surgical efficacy and complications. Further comparative evaluation of single-use and reusable endoscopes in a clinical scenario is useful. Moreover, utilization of ureteral access sheaths may be considered to avoid renal damage.