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

INTRODUCTION: Retrograde 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.

METHODS: In 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.

RESULTS: Significant variability in maximum flow rates was observed (Flex-Xc™: 25.8 ml/min, LithoVue™: 30.3 ml/min, Pusen™: 33.4 ml/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 20/50 mm distance was 9090 lx/1857 lx (Flex-Xc™) and 5733 lx/1032 lx (LithoVue™) and 2160 lx/428 lx (Pusen™), respectively (p < 0.05). Subjective image quality score was highest using the Flex-Xc™ endoscope. During manipulation, maximum intrarenal pressure up to 66 mmHg (Pusen™) was measured.

CONCLUSIONS: Significant 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.