Pelvicaliceal Volume and Fluid Temperature Elevation During Laser Lithotripsy

Area of Science:

• Urology
• Biomedical Engineering
• Laser Physics

Background:

• High-power laser systems are crucial for treating complex ureteral stones.
• Laser activation can significantly increase fluid temperature within the collecting system.
• Potential thermal injury to adjacent tissues is a concern during ureteroscopic laser procedures.

Purpose of the Study:

• To quantify fluid temperature elevation during laser activation.
• To calculate the thermal dose in simulated collecting system volumes.
• To assess the impact of fluid volume and irrigation on thermal effects.

Main Methods:

• Simulated varying calix/pelvis volumes using glass bulbs (0.5–60.8 mL).
• Exposed bulbs to Ho:YAG laser activation (40 W) in 37°C deionized water.
• Applied room temperature irrigation (0–40 mL/min) and measured temperature and thermal dose.

Main Results:

• Temperature elevation and thermal dose were inversely proportional to fluid volume and irrigation rate.
• The smallest volume (0.5 mL) reached thermal injury threshold in 3 seconds without irrigation.
• High irrigation (40 mL/min) prevented reaching injury threshold in all volumes within 1 minute.

Conclusions:

• Fluid volume is a critical factor in managing laser-induced temperature elevation.
• Smaller fluid volumes lead to higher thermal doses and faster onset of potential tissue injury.
• Adequate irrigation is essential for mitigating thermal risks during ureteroscopic laser lithotripsy.