WCE 2017: The Effect of Stone Dust & Collecting System Flow on Shockwave Lithotripsy
The in-vitro study first began with comparing the breaking properties of artificial stones in enclosed and open environments. The artificial stones that were used were Begostone Plus stones, which are known to produce dust when fragmented. When the stones were fragmented via SWL in an open environment, there was no noticeable disadvantage to the proportion of the stone treated. However, in an enclosed environment (simulating normal physiological characteristics), the proportion of stone treated dropped by nearly 55%, hinting at a clear drawback to SWL for dust-producing stones.
The second in-vitro procedure described by Dr. Ahn involved a proposed solution to this problem by adding irrigation to a simulated SWL procedure. Begostone Plus stones were again used within an anatomic gel kidney, which included an 18-gauge irrigation needle inserted in the middle calyx, opening at the renal pelvis. At 35 cc/hr – 70 cc/hr of irrigation (simulating normal physiological renal irrigation), no significant change occurred in the proportion of stone treated. At 420 cc/hr, though, there was about a 2.5 times improvement in the proportion of stone treated by SWL.
In the conclusion of his presentation, Dr. Ahn advised to the audience that human stones that produce a large amount of dust may not respond as well to SWL. He also mentioned that although the data showed improvement of stone treatment by using irrigation, it is not yet ready for in-vivo trials, due to the lack of a feasible methodology.
Presented by: Justin Ahn, MD
Authors: Justin S Ahn, Akshay Randad, Wayne Kreider, Michael Bailey, Adam D Maxwell, Jonathan D Harper, Mathew D Sorensen
Affiliation: University of Washington, University of Washington Medical Center
Written by: Zachary Valley, Department of Urology, University of California-Irvine at 35th World Congress of Endourology – September 12-16, 2017, Vancouver, Canada