Purpose: The conventional flexible ureteroscope has limited access into the lower calix and often causes biomechanical stress to surgeons. Recently, a novel flexible ureteroscope with an omnidirectional bending tip with a joystick-type control unit (URF-Y0016; Olympus, Japan) was developed. We verified the operability and ergonomics of the URF-Y0016 compared with that of the conventional flexible ureteroscope (URF-P6) in bench models. Materials and Methods: Twenty-five medical students with no experience in performing ureteroscopic manipulation were randomly assigned to URF-Y0016 and URF-P6 leading groups in a crossover study. The task was performed using a simple model as an exploratory experiment and an artificial kidney model as an evaluation experiment. We compared the task completion times of both groups, while the factors influencing task completion time were entered into a multivariate model. The ergonomics of endourology were compared using a validated questionnaire. Results: The task completion time in the URF-Y0016 group was significantly shorter than in the URF-P6 group (p < 0.001). The URF-Y0016 group showed no difference in task completion time between each renal calix, whereas in the URF-P6 group the task completion time in the lower calix was significantly longer than that in other calices (p < 0.001). In multivariate analysis, the model of flexible ureteroscope used significantly influenced the task completion time (p < 0.001). The ergonomics of the URF-Y0016 group were significantly better than those of the URF-P6 group (p = 0.001). Conclusions: URF-Y0016 may offer benefits in ureteroscopy performance over the conventional flexible ureteroscope.
Keywords: ergonomics; flexible ureteroscope; joystick-type control unit; omnidirectional bending tip.