Comparison of stone retropulsion between Moses mode and virtual basket mode: an in vitro study using artificial stones.

This study aimed to evaluate stone retropulsion in various laser pulse modes in both Moses mode (MM) and virtual basket mode (VBM). Experiments were performed using a channel-shaped rubber rail and artificial stones. We compared short pulse mode and long pulse mode in both MM and VBM with the laser tip positioned so that it was touching and at 1 and 2 mm distances from the stone surface. Stone retropulsion was measured after the laser fired for 10 s in three different laser settings: 0.5 J/8 Hz, 0.8 J/8 Hz and 1.0 J/8 Hz. When the laser tip was touching the artificial stone, stone retropulsion in MM was significantly shorter than that in VBM in all laser settings (P < 0.01, P = 0.02 and P = 0.02, respectively). At 1-mm distance, stone retropulsion in MM was significantly shorter than that in VBM in 0.8 J/8 Hz and 1.0 J/8 Hz settings (P < 0.01 and P = 0.01, respectively). At 2-mm distance, however, there were no differences between MM and VBM in stone retropulsion in any laser settings. Stone retropulsion was not significantly different between the laser settings at 1-mm distance in MM, or when touching in VBM. In conclusion, stone retropulsion distance in MM can be shorter than that in VBM. Stone retropulsion in MM and VBM may be differently influenced by laser settings and laser tip position.