Authors: Zhamshid Okhunov, Elizabeth A Baldwin, Daniel Jhang, Ruben Crew, Ninous Betdashtoo, Kallan Richards, Grant Sajdak, Joshua Ghoulian, D Duane Baldwin 

Abstract

Introduction: Novel Direct-ln-Scope-Suction ureteroscopes (DlSS-U) have recently been introduced to facilitate removal of small stone fragments. The purpose of this study was to compare two novel DlSS-U to a conventional ureteroscope to determine efficiency for suctioning fluid and stone dust at different deflection angles.

Methods: Three disposable ureteroscopes were evaluated, including two DISS-U with 5.1-Fr and a 3.6-Fr channels, and  were compared to a conventional ureteroscope with 3.6-Fr channel. For DISS-U trials, a conventional suction system was  set at maximal settings and tested at deflection of 0, 90, and 140°, to simulate upper, interpolar, and lower pole kidney stone  evacuation under 3 conditions (empty channel, 2.2-Fr basket, and 0.038 guidewire). For the conventional ureteroscope, suctioning was performed manually using a 60-mL Luer lock syringe. Five trials were performed to measure the time in seconds  to remove 1 gram of CaOx density BegoStones (0.25, 0.5, and 1 mm) and 50-mL of saline.

Results: The 5.1-Fr DISS-U was the only scope that evacuated 0.5 mm stone fragments and evacuated them significantly  faster from the upper and interpole compared to the lower pole (111.0±27.7, 128.0±29.1, and 377.7±63.4 s at 0, 90, and  140°, respectively; p<0.002). The 5.1-Fr DISS-U evacuated 1 g of dust faster than the 3.6 DISS-U and conventional ureteroscope at all angles (p<0.007). The 5.1-Fr DISS-U and the 3.6-Fr DISS-U required less suction time for 50 mL of saline  compared to the conventional ureteroscope at all angles (p<0.001 for all). Using a 2.2-Fr basket increased suction time by  66.0% (p<0.001) for the 3.6-Fr DISS-U and by 44% (p<0.001) for the 5.1-Fr DISS-U, while the 0.038 guidewire increased  suction time by 96% and 111%, respectively (p<0.001). No ureteroscope was able to suction 1 mm stone fragments without  clogging.

Keywords: Direct in scope suction; Lithotripsy; Ureteroscopy; Urolithiasis.

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