Direct in-scope suction: an in vitro evaluation of a single use flexible ureteroscope with integrated suction capability.

Purpose: To evaluate the stone clearance rate and limitations of a novel integrated suction capability within a single-use flexible ureteroscope according to stone particle size.

Methods: Varying sized stone particles were created using a stone phantom (Begostone Plus, Bego ©, Lincoln, RI, USA). Particle size ranged as follows: 63-125 µm, 125-250 µm, 250-500 µm, 500 µm- 1 mm and 1-2 mm. These were mixed with Normal saline (0.9%) to mimic in vivo conditions. The suction enabled single-use flexible ureteroscope (Pusen, Zhuhai, China) was used to aspirate stone fragments in three trials. Firstly, aspiration of 5 g of each dust range was attempted. Secondly, a direct comparison of the integrated suction to a manual syringe technique was applied to 1 g of each size range. Finally, aspiration was applied to 5 g of a heterogenous 1:1:1:1:1 mixture. Endoscopic clearance rate (g/min) and number of blockages were recorded. Each challenge was repeated three times.

Results: The integrated suction cleared 100% of dust < 250 µm. Endoscopic clearance rates were significantly faster than manual aspiration (3.01 g/min versus 0.41 g/min) for dust between 125 and 250 µm (p = 0.008). Complete endoscopic clearance by 180 s (without encountering test limiting blockages) was unsuccessful for particles > 250 µm. Clearance rates were greatly limited by stone particle size heterogeneity above 250 µm, to 0.09 g/min.

Conclusion: This technology works better in vitro than previously DISS evaluated methods when challenged by stone dust < 250 µm. However, this adaptation is significantly challenged in the presence of stone dust particles > 250 µm.