Abstract: PD30-11
Sources of Funding: None

Introduction

Efficient Holmium laser lithotripsy is limited by two main factors: retropulsion and energy transmission in water, which depends on fiber-stone distance. Recently, Lumenis developed the Moses technology, including the Moses D/F/L fibers, using pulse modulation resulting in improved energy transmission through water and reduced retropulsion. The Moses technology modulates the energy pulse that enables emission of a controlled portion of energy to create a bubble, known as the &[Prime] Moses effect &[Prime], while leaving a portion that travels through the bubble to the stone. The aim was to conduct a preclinical study investigating the effect of the Moses technology on Holmium laser lithotripsy comparing the Moses mode to the Regular mode in terms of lithotripsy efficiency and laser-tissue interaction

Methods

Several experiments were performed to explore the advantages of the Moses technology using the Lumenis P120H system and Moses D/F/L fibers. Experiments included: stone fragmentation efficiency at 1 mm distance; effect on retropulsion (reaction to a single pulse) measured by high-speed camera; efficiency of in vitro laser lithotripsy measured by procedural time, and lasing-pause ratios. In addition, a porcine ureteroscopy model was used to assess stone fragmentation and dusting as well as laser-tissue interaction when the laser fiber touched the ureteral wall.

Results

Stone fragmentation tests showed that the Moses mode resulted in significantly higher ablation volume when compared with Regular mode (160% higher; p=0.001). Stone displacement experiments following a single pulse showed significant reduction in retropulsion when using the Moses mode. The stone movement was reduced by 50 times at 0.8J and 10Hz (p=0.01). The pronounced reduction of retropulsion in the Moses mode was clearly observed during in vitro fragmentation settings (higher energy) and during dusting for smaller stones (low energy, high Hz). There was also significant reduction in procedure time (average 35% reduction for fragmentation and 23% for dusting, p=0.01) and longer lasing duration with shorter pauses indicating reduced need to reposition the fiber due to lack of retropulsion. Histological analysis of the porcine ureter after direct lasing in the Moses mode showed less damage than in the Regular mode.

Conclusions

The Moses technology resulted in more efficient laser lithotripsy in addition to significantly reduced stone retropulsion resulting in significantly shorter procedural time and greater margin of safety.

Funding

None