Holmium:YAG (lambda = 2,120 nm) versus thulium fiber (lambda = 1,908 nm) laser lithotripsy

Area of Science:

• Urology
• Laser Medicine
• Biomedical Engineering

Background:

• The holmium:YAG laser is the current standard for laser lithotripsy.
• Thulium fiber lasers show potential for urinary stone vaporization due to higher water absorption coefficients.
• This study investigates the comparative efficiency of thulium fiber lasers versus holmium:YAG lasers for stone vaporization.

Purpose of the Study:

• To directly compare the stone vaporization rates of thulium fiber lasers and holmium:YAG lasers.
• To evaluate the potential of thulium fiber lasers as a more efficient alternative for laser lithotripsy.

Main Methods:

• Ex vivo human uric acid (UA) and calcium oxalate monohydrate (COM) stones were used.
• Both holmium:YAG and thulium fiber lasers were delivered via a 100-microm fiber.
• Laser parameters were standardized for comparison, delivering identical total energy (126 J) per stone.

Main Results:

• Thulium fiber laser resulted in 5-10 times greater mass loss for both UA and COM stones compared to holmium:YAG.
• Average mass loss for UA stones: 12.6 mg (thulium) vs. 2.4 mg (holmium).
• Average mass loss for COM stones: 6.8 mg (thulium) vs. 0.7 mg (holmium).

Conclusions:

• Thulium fiber lasers exhibit superior stone vaporization efficiency over holmium:YAG lasers.
• Thulium fiber lasers show promise as a more efficient tool for laser lithotripsy.
• Further development may establish thulium fiber lasers as a viable alternative to current lithotripsy methods.