Steady-state versus burst lasing techniques for thulium fiber laser

Area of Science:

• Urology
• Laser Lithotripsy
• Medical Device Technology

Background:

• Thulium fiber laser (TFL) lithotripsy is a key technology for stone ablation.
• Understanding the impact of different lasing modes on efficacy and safety is crucial for clinical application.
• Continuous (C) and burst (B) lasing techniques offer distinct energy delivery patterns.

Purpose of the Study:

• To compare the stone ablation efficiency of TFL lithotripsy using continuous versus burst lasing modes.
• To evaluate the direct thermal damage to the ureteral model associated with each lasing technique.
• To assess the influence of surgeon experience on these outcomes.

Main Methods:

• An in vitro ureteral model submerged in saline was used with the TFL Drive.
• Seven settings were tested comparing steady-state continuous lasing and intermittent burst lasing.
• Ten urologists (five junior, five experienced) performed the procedures on phantom stones, with ureteral damage graded based on thermal lesions.

Main Results:

• No significant difference in stone ablation mass was observed between continuous and burst lasing techniques or by surgeon experience.
• Continuous lasing resulted in mild ureteral lesions, with no significant differences across settings or experience levels.
• Burst lasing showed higher-grade direct thermal lesions compared to continuous lasing (p=0.048), irrespective of settings or experience.

Conclusions:

• Both continuous and burst lasing techniques achieve comparable stone ablation rates in vitro.
• The burst lasing mode is associated with a higher degree of direct thermal ureteral damage.
• Continuous mode, particularly at lower frequencies, is recommended to minimize ureteral wall injury until further in vivo safety data is available.