Optimizing the Appropriate Mode of the Pulse-modulated Holmium Laser in a Pop-dusting Benchtop Model

Abstract

Objective: To investigate the effectiveness of different holmium:yttrium-aluminum-garnet (Ho:YAG) laser modes for lithotripsy in the “dusting era” and identify the optimal laser mode for producing stone fragments measuring ≤0.5 mm. Methods: We used plaster of Paris-made artificial stones crushed into 2-3 mm pieces, weighing 1 g in total. The primary endpoint was the mass of stone fragments ≤0.5 mm produced by different laser modes. The secondary endpoints were size categories, fragment mass, and changes in irrigation fluid temperature. The Lumenis Pulse 120 H Ho:YAG laser, with a 200-μm fiber, was used in 3 modes (Moses contact [MC], Moses distance [MD], and long pulse [LP], all at 0.5 J × 80 Hz). Laser lithotripsy involved a 20-second exposure with a 10-second pause for 15 cycles, conducted 7 times per mode while measuring the maximum irrigation fluid temperatures for each cycle. Results: The MC mode demonstrated superior performance in producing fragments ≤0.5 mm (P = .0034) compared with the MD mode. No notable differences were observed for other size categories. The MD and LP modes showed higher rates of mass loss in fluid (MD, P = .023; LP, P = .046) compared with the MC mode. In addition, the increase in irrigation fluid temperature was more pronounced in the MD and LP modes than in the MC mode (MD, P = .015; LP, P = .010). Conclusion: In renal stone lithotripsy during the “dusting era,” the MC mode is preferable for generating smaller stone fragments ≤0.5 mm. These insights are valuable for optimizing stone fragmentation techniques.