In vitro evaluation of LithAssist: a novel combined holmium laser and suction device

The aim of this in vitro study was to evaluate and compare a novel intracorporeal lithotripter, LithAssist (LA; Cook Medical, Bloomington, IN), with the Swiss LithoClast Ultra (SLU; Boston Scientific, Boston, MA) for the fragmentation and removal of artificial stones made of gypsum-based cement.

Ten soft and 20 hard ultracal-30 (U-30) stones were fragmented using two lithotripters. We recorded the stone weight (grams) prior to placing them into a 60-mL syringe for fragmentation. We inserted a 30F percutaneous access sheath into the syringe and positioned the stone within its lumen. Next, we inserted the lithotripter into a right-angled nephroscope. We recorded the times required for first and complete stone disintegration, disintegration to 2 mm, and complete stone removal for each device. In addition, we recorded the stone mass following each minute of stone fragmentation.

In total, we subjected 5 soft and 10 hard stones to SLU and LA, respectively. All soft stones were completely disintegrated and removed with both the SLU and LA device. For soft stones, disintegration to 2 mm (2.83±0.41 vs. 4.15±0.70 minutes, p=0.049), complete disintegration (3.18±0.20 vs. 6.40±1.95 minutes, p=0.038), and complete removal (3.30±0.22 vs. 8.82±1.05 minutes, p=0.001) were faster for the SLU compared with the LA. For hard stones, fragmentation was not accomplished with the SLU, whereas with the LA, mean time for first disintegration, disintegration to 2 mm, complete disintegration, and complete removal was 3.60±1.36, 7.25±3.33, 7.54±2.94, and 8.64±2.78 minutes, respectively.

In this in vitro study, the SLU was more efficient for softer artificial stones, and the LA was more efficient for harder artificial stones.