Introduction and Objectives

Virtual BasketTM, Bubble BlastTM, and Vapor TunnelTM are three laser pulse modulation technologies that modify the holmium: yttrium–aluminum–garnet (Ho:YAG) laser pulse transmission through the creation of bubbles emerging from the fiber tip with different effects on the target stone. The primary outcome of the current study was to test the stone ablation rates for the different pulse modulation modes, Virtual Basket, Bubble Blast, and Vapor Tunnel, using different power, energy, and frequency settings.

Materials and Methods

Quanta Cyber: Ho 150 WTM, a 365 µm PrecisionTM fiber, and hard and soft phantom BegoStonesTM were used in an in vitro experimental configuration in a saline bath. In the Virtual Basket mode, the combinations of power, energy and frequency were tested; 10 W = 0.5 J × 20 Hz, 10 W = 0.5 J × 20 Hz, 60 W = 1 J × 60 Hz and 60 W = 2 J × 30 Hz. In the Bubble Blast mode, the combinations, 12 W = 1.2J × 10 Hz, 60 W = 1.2J × 50 Hz and 60 W = 2 J × 30 Hz, were tested. Similarly, the combination of 10 W = 0.5 J × 20 Hz was tested with Vapor Tunnel mode. High-speed camera captures of the bubble formation and regular photographs of the fragmentation pattern were also taken for each mode.

Results

High power lithotripsy was faster and related to higher ablation rates. The Virtual Basket, Bubble Blast, and Vapor Tunnel modalities showed different ablation rates for the same energy and frequency settings. For hard stones, there was an improvement in the ablation rate using 60 W = 2 J × 30 Hz compared with 60 W = 1 J × 60 Hz and 60 W = 1.2 J × 50 Hz. The highest ablation rates were recorded using the Virtual Basket mode with the high-power settings of 2 J of energy and 30 Hz of frequency.

Conclusions

The Virtual BasketTM pulse-modulation technology was related to the highest ablation rates for both hard and soft stones, compared to the Bubble BlastTM and the Vapor TunnelTM technologies in high-power and low-power lithotripsy respectively. For the same high power settings, higher energy seems to provide higher ablation rates.