Thermal effect of holmium laser during ureteroscopic lithotripsy

Abstract

Background: Holmium laser lithotripsy is the most common technique for the management of ureteral stone. Studies founded that holmium laser firing can produce heat which will cause thermal injury towards ureter. The aim of our current study is to explore factors affecting thermal effect of holmium laser during ureteroscopic lithotripsy. Methods: An in vitro experimental model is design to simulate the ureteroscopic lithotripsy procedure. Different laser power settings (10w (0.5JX20Hz, 1.0 JX10Hz), 20w (1.0 JX20Hz, 2.0 JX10Hz), 30w (1.5JX20Hz, 3.0 JX10Hz)) with various firing time (3 s, 5 s, 10s) and irrigation flow rates(10 ml/min, 15 ml/min, 20 ml/min and 30 ml/min) were employed in the experiment. The temperature around the laser tip was recorded by thermometer. Results: The temperature in the "ureter" rises significantly with the increasing laser power, prolonging firing time and reducing irrigation flow. The highest regional temperature is 78.0°C at the experimental setup , and the lowest temperature is 23.5°C. Higher frequency setting produces more heat at the same power. Laser power < =10w, irrigation flow> = 30 ml/min and "high-energy with low-frequency" can permit a safe working temperature. Conclusion: We clarify that the thermal effect of holmium laser is related with both laser working parameters and irrigation flow. The proper setting is the key factor to ensure the safety during ureteroscopic holmium laser lithotripsy.

New Generation Pulse Modulation in Holmium:YAG Lasers: A Systematic Review of the Literature and Meta-Analysis

“…Temperature rise depends on laser power, exposure time, and fluid irrigation. Some recommendations are to keep low power settings (<10–15 W), to use “high-frequency” settings with caution, to perform intermittent laser activity, and to ensure fluid irrigation during the procedure [ 61 ]. In this review, an in-vitro study performed by Winship et al [ 29 ] was included, which studied temperature changes while the laser was activated inside a ureteral access sheath (UAS) with different Lumenis PMs.…”

The clinical efficacy of novel vacuum suction ureteroscopic lithotripsy in the treatment of upper ureteral calculi

“…Vacuum suction greatly decreased the risk of infection. There is plenty of space between the lithotripsy endoscope(6F) and the working sheath (13F); vacuum suction speeded up the circulation of irrigating water, which helps to ensures the clear view of surgical eld and helps to take away the heat generated by the holmium laser [14], thereby reducing thermal injury.…”

Clinical Observation of UreTron Single-Probe Ultrasonic Intracorporeal Lithotripter for Ureteral Calculi

“…The two cases of postoperative ureteral stricture observed in the present study were both in group H. Physical injuries range from minor mucosal burns to perforations and lacerations of varying severity that can result in corresponding adverse outcomes. Another more insidious and unavoidable mechanism of injury is the thermal damage caused by the laser energy output, 16 , 17 which is also an undetectable cause of postoperative ureteral stricture. With the full reorganization of this possible hazard, it can be avoided by controlling the laser output energy, reducing the operation duration, increasing the flow rate of the rinse fluid, and controlling the temperature of the rinse fluid; however, ureteral injury and stricture caused by the thermal effect remains a difficulty of laser lithotripsy.…”