Intrarenal Fluid Temperature During Laser Lithotripsy: A Mini Review by the European Association of Urology Endourology Section.

Laser lithotripsy involves thermal risks due to heat generated in the surrounding fluid. The concept of thermal dose, which accounts for both temperature and exposure duration, provides a more nuanced understanding of tissue tolerance than fixed temperature thresholds, considering both the magnitude of the temperature increase and the length of exposure to each specific temperature. The concept of a thermal safety distance defines the spatial extent of potential damage, supporting safe power limits of 10 W in the ureter and 20 W in the kidney. Importantly, the type of laser (holmium:YAG, thulium fiber, or thulium:YAG) does not independently affect the rise in temperature, which is primarily driven by the amount of energy absorbed by water in the surrounding tissue. Temperature-related tissue injury can be mitigated by optimizing the flow of the irrigation fluid and the laser power settings and activation patterns. PATIENT SUMMARY: Laser treatment for stones in the kidney or ureter generates heat, which can harm adjacent tissues. The use of low-power settings and proper fluid flow helps in reducing this risk.