Pressure reduction and suction characteristics of the new digital single use flexible ureteroscope with suction: an in-vitro experimental study.

Purpose: To assess the time taken by the single use 7.5Fr suction flexible ureteroscope to reduce pressure under 40 mm Hg and to characterize the behavior of stones, fragments and dust during suction activation.

Methods: An in vitro setting was developed for this experiment. A saline-filled globe, with the 7.5Fr single-use suction flexible ureteroscope, PU3033AH (ZhuHai Pusen Medical Technology Co, Ltd, Guangdon, China), an automatic irrigation pump and a pressure monitoring set were used at four modalities; i) continuous suction, no irrigation inflow; ii) continuous suction, irrigation inflow on; iii) one-second rate intermittent suction, irrigation inflow on, and iv) half-second rate intermittent suction, irrigation inflow on. The behavior of calcium oxalate stones from 0.5 to 5 mm when being aspirated via the ureteroscope into a plastic container filled with saline was recorded.

Results: Suction with the PU3033AH worked properly with the inflow irritation on. The fastest strategy to lower the pressure was by continuously pressing the suction button with the irrigation inflow on. Overall, the median time to reach 40 mg was roughly 3.5 s. The PU3033AH could aspirate 0.5 mm stones. The suction mode on a continuous pattern allowed the relocation of stones ranging from 1 to 5 mm on an experimental setup with no obstacles.

Conclusion: The PU3033AH was efficient in lowering pressure in a closed cavity mimicking the renal pelvis. Likewise, stone fragments under one millimeter were aspirated by the device whereas stones from one to five mm could be displaced when activating suction in continuous mode on an experimental setup with no obstacles.