An in vitro model study on the temperature changes in the central area of ureteroscopic holmium laser lithotripsy

Objective To explorer the temperature changes in the central area of ureteroscopic holmium laser lithotripsy. Methods (1) In vitro test tube model: By measuring the saline temperature changes after 15 s of continuous working of 30 W holmium laser (group A); after 15 s of continuous working of 20 W holmium laser (group B); and after 10 s of continuous working of 20 W holmium laser (group C). (2) In vitro rubber tube model (simulating human urinary tract): By measuring the saline temperature changes after 5 s of continuous working of 30 W holmium laser in rubber tube (group D); after 3 s of continuous working of 30 W holmium laser in rubber tube (group E); after 5 s of continuous working of 20 W holmium laser in rubber tube (group F); and after 3 s of continuous working of 20 W holmium laser in rubber tube (group G). Results The saline temperature in group A was significantly higher than that in group B (P=0.000). The temperature in group B was higher than that in group C[(69.80±3.23), (63.20±2.26), (57.10±2.31) ℃, P=0.000]. The temperature in group D was higher than that in group E (P=0.000), and that in group F was higher than that in group G (P=0.000). The temperature in group D was higher than that in group F (P=0.000), and that in group E was higher than that in group G [(82.30±4.33), (75.50±2.41), (67.40±1.36), (58.20±3.43) ℃, P=0.000]. Conclusion This study indicated that the working of holmium laser will heat the saline in working area. The lower working power and the shorter time the laser continuously worked, the less the water temperature of laser working area would rise. Key words: Holmium laser; Lithotripsy; Ureteroscopy; Local temperature