Use of the Moses Technology to Improve Holmium Laser Lithotripsy Outcomes: A Preclinical Study

Abstract

Objective: To evaluate in vitro and in vivo effects of Moses technology in Holmium laser and to compare it with the Regular mode in terms of lithotripsy efficiency and laser-tissue interactions.

Methods: The Lumenis^® Pulse™ P120H holmium laser system together with Moses D/F/L fibers were used to compare the Regular mode with the Moses modes in stone retropulsion by using a high-speed camera, and stone ablation efficiency. In addition, a porcine ureteroscopy model was used to assess stone fragmentation and dusting as well as laser-tissue interaction with the ureteral wall.

Results: After a laser pulse, in vitro stone displacement experiments showed a significant reduction in retropulsion when using the Moses mode. The stone movement was reduced by 50 times at 0.8 J and 10 Hz (p < 0.01). The pronounced reduction of retropulsion in the Moses mode was clearly observed during fragmentation setting (high energy) and dusting (low energy, high Hz). In addition, stone fragmentation tests showed that the Moses modes resulted in a significantly higher ablation volume when compared with the Regular mode (160% higher; p < 0.001). In vivo assessment also supported the reduction in retropulsion when treating stones in the porcine kidney. Histological analysis of the porcine ureter after direct lasing in the Moses mode suggested less damage than in the Regular mode.

Conclusions: The Moses technology resulted in more efficient laser lithotripsy, in addition to significantly reduced stone retropulsion, and displayed a margin of safety that may result in a shorter procedural time and safer lithotripsy.

Keywords: Holmium-YAG laser; laser lithotripsy; preclinical evaluation; prospective study.

FIG. 1.

(A) Set up for fast camera to measure stone retropulsion. (B) Magnified view of the transparent cube by a high-speed camera.

FIG. 2.

(A) Experimental setup to measure ablation rate. (B) Representative ablation fissures and digitization for analysis.

FIG. 3.

Differences in stone ablation volumes between Regular and Moses modes.

FIG. 4.

(A, B) Gross anatomical examination of porcine ureters after contact lasing at a setting of 0.4 J and 50 Hz. (C, D) Histological examination of porcine ureters after contact lasing at a setting of 0.3 J and 80 Hz.

FIG. 5.

Differences between Regular and Moses modes in ureteral wall damage resulting from contact lasing.

FIG. 6.

Both histological images and calculated tissue impact areas showed no significant differences between Regular and Moses modes. Lasing at 2 to 2.5 mm distance showed no increased risk of ureteral perforation with the Moses mode.

FIG. 7.

Fiber flexibility test.