Technical considerations using a pulsed neodym-YAG laser for endoscopic shock wave lithotripsy

Area of Science:

• Urology
• Laser Medicine
• Biomedical Engineering

Background:

• Q-switched pulsed Neodymium-YAG lasers offer promising results for laser lithotripsy.
• Optimal use requires understanding irrigant composition and laser frequency.
• Previous studies have not fully elucidated these parameters for intracorporeal lithotripsy.

Purpose of the Study:

• To determine the necessity of iron (Fe3+)-enriched irrigants for Neodymium-YAG laser lithotripsy.
• To identify the optimal frequency for Neodymium-YAG laser lithotripsy efficacy.
• To provide evidence-based recommendations for clinical application.

Main Methods:

• An in vitro model was used to assess laser-induced breakdown (LIB) with varying Fe3+ concentrations in sodium chloride irrigant.
• The disintegrative efficacy of the laser was tested on a plaster cube stone model at different frequencies (1, 10, 40, 50 Hz).
• Photographic analysis was employed to measure LIB, and stone disintegration was evaluated quantitatively.

Main Results:

• Fe3+ enrichment significantly improved laser-induced breakdown (LIB).
• However, Fe3+ enrichment did not show a significant difference in stone disintegration efficacy compared to standard sodium chloride irrigant.
• Lower laser frequencies (1-10 Hz) demonstrated significantly greater disintegrative efficacy compared to higher frequencies (40-50 Hz).

Conclusions:

• Fe3+ enriched irrigants may be beneficial for enhancing LIB when optical breakdown is insufficient, at a concentration of 0.5 mg Fe3+/dL.
• The optimal frequency for Neodymium-YAG laser lithotripsy is recommended to be between 1-10 Hz for improved stone fragmentation.
• These findings support optimizing Neodymium-YAG laser parameters for safer and more effective clinical lithotripsy.