Bubble Trouble: The Thermal Risk of Ureteral Laser Lithotripsy in an Air Bubble

Résumé fourni par la source

Introduction: During ureteroscopic laser lithotripsy (URSL), unsafe elevations in ureteral temperature are thought to contribute to ureteral stricture formation. Cellular damage begins at 43°C, and proteins denature instantly at 60°C. Air bubbles may inadvertently migrate into the collecting system during URSL. The purpose of this study was to evaluate ureteral temperatures during simulated URSL in an air bubble with a holmium (Ho:YAG) and thulium fiber laser (TFL). Methods: BegoStone phantoms were positioned distal to the ureteropelvic junction in a model kidney and ureter submerged in a 35°C saline bath. A 7.5 Fr flexible ureteroscope was advanced to the stone, and continuous saline irrigation at 22°C was maintained at 15 mL/min. A needle thermocouple positioned 2 mm from the laser fiber tip monitored ureteral wall temperature. A 200 µm laser fiber was then advanced until it contacted the stone. The Ho:YAG and TFL were used in 5 trials each to ablate stones at 3, 10, and 20 W in saline and in a 3 mL air bubble. Results: In the control condition, neither laser exceeded 43°C at 3, 10, or 20 W. In an air bubble, ureteral temperatures exceeded 43°C after 1 second at 3 W for both TFL and Ho:YAG. At 10 W, the Ho:YAG exceeded 43°C after 1 second, while the TFL exceeded 60°C. The average temperature exceeded 60°C at 20 W for both lasers after 1 second. Both lasers generated much higher temperatures in an air bubble than in saline at all time points ( p = 0.008), with maximum temperature exceeding 250°C for both lasers. Conclusion: In this benchtop model, laser activation in an air bubble for 1 second exceeded the thermal safety threshold at ≥ 3 W and risks protein denaturation at ≥ 20 W. This study highlights the importance of avoiding air bubbles during URSL to maintain safe ureteral temperatures. Further studies are needed to validate these findings in vivo .

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.