Intrarenal thermal and pressure dynamics during ureteroscopy: an in vitro study

Area of Science:

• Urology
• Medical Devices
• Laser Technology

Background:

• Intrarenal temperature (IRT) and pressure (IRP) are critical factors during laser lithotripsy.
• Understanding determinants of IRT and IRP is essential for optimizing procedural safety and minimizing thermal injury.

Purpose of the Study:

• To investigate in vitro factors influencing intrarenal temperature (IRT) and pressure (IRP) during laser lithotripsy.
• To identify predictors of IRT and IRP in a simulated renal environment.

Main Methods:

• Laser lithotripsy was performed on artificial stones in a silicone urinary tract model.
• Three laser sources and four energy settings were tested with varying irrigation methods (gravity vs. hand-pump) and ureteral access sheaths (standard vs. FANS).
• Multivariable regression analysis was used to determine predictors of IRT and IRP.

Main Results:

• Higher laser power significantly increased IRT, with the thermal-risk threshold exceeded frequently at 40W.
• Hand-pump irrigation reduced IRT compared to gravity, while the flexible and navigable suction sheath (FANS) decreased IRP.
• Laser source did not affect IRT when power and irrigation were comparable.

Conclusions:

• Laser power and irrigation strategy are key determinants of IRT during laser lithotripsy.
• High-power settings pose a significant thermal risk, which can be mitigated by specific irrigation and sheath configurations.
• Advanced irrigation-aspiration systems are needed for dynamic control of flow, pressure, and temperature to enhance procedural safety.