[Comparative study of two latest generation flexible ureterorenoscopes]. / Etude comparative de deux urétérorénoscopes souples de dernière génération.

INTRODUCTION AND OBJECTIVES: Miniaturization and development of flexible instruments have led to the development of flexible ureterorenoscopy. The objective of this study was to compare the capacities of active deflection of two latest generation flexible ureterorenoscopes and to evaluate alteration of deflection and flow of irrigating fluid in the presence of instruments in the operating channel. MATERIAL AND METHODS: Two ureterorenoscopes were evaluated in this study. The Karl STORZ Flex-X and the ACMI DUR-8 Elite. Comparison of deflection movements was performed ex situ by super-imposing all active movements of the two ureterorenoscopes. Alteration of deflection was performed by alternately placing an extraction or fragmentation instrument of variable dimensions in the operating channel. Alteration of flow was also assessed in the presence of the same instruments. RESULTS: The ex situ deflection capacities of the DUR-8 Elite flexible ureterorenoscope were more extensive than those of the Flex-X, but it was more complicated to manipulate. Alterations of deflection and flow of irrigation fluid were comparable for the two ureterorenoscopes. CONCLUSION: On the basis of these data, we can confirm that the two latest generation ureterorenoscopes present comparable capacities, but different functioning modalities. We therefore recommend that each operator test the two ureterorenoscopes to become familiar with their manipulation. Other studies are necessary to evaluate the optical properties, ease of use in clinical practice and fragility of these new ureterorenoscopes.