What is the appropriate gravel size during ureteroscopy lithotripsy? An in vitro evaluation

Abstract

Objective To propose the suitable diameter of calculus debris produced during flexible ureteroscopy lithotripsy (fURL). Methods A glass tube was used to simulate the stone excretion process during Furl. Different stone diameters (0.50–1.00 mm, 0.25–0.50 mm, and 0.10–0.25 mm) with three sizes of flexible ureteroscopy (fURS) (Fr7.5, Fr8.7, and Fr9.9) and ureteral access sheath (UAS) (12/14Fr) with or without negative pressure suction were employed in the experiment. The intraoperative calculi excretion (ICE) was recorded according to the stones discharged from the gap between Furs and UAS. Results The ICE raised significantly in thinner fURS and UAS due to the smaller ratio of endoscope-sheath diameter (RESD). The gravel size ≤ 0.25 mm was conducive to drainage with traditional UAS, while using fURS with negative-pressure UAS could significantly improve ICE. The gravel size ≤ 0.5 mm was conducive to expulsion. Conclusion We clarify that ICE during ureteroscopy relates to RESD and negative pressure suction. The proper size of the stone fragment is critical in ensuring the expulsion during fURL, ≤ 0.25 mm in traditional UAS and ≤ 0.50 mm in negative-pressure UAS, respectively.

Optimal placement of flexible ureteral access sheath in retrograde intrarenal surgery

“…This eventually leads to an increase in IRP. The IRP can be reduced by connecting a vacuum device; an f-URS and a UAS at the same level and connected to a vacuum device might better improve the stone free rate and reduce intrarenal pressure [12][13][14][15][16].…”