Comparative Laser Efficacy and Clinical Outcomes of Pulsed Thulium: YAG versus standard Holmium: YAG Lithotripsy.

PURPOSE: To compare the efficacy and clinical outcomes of ureteroscopic lithotripsy using the Holmium: YAG laser (Ho: YAG) and pulsed Thulium: YAG laser (p-Tm: YAG: RevoLix HTL, LISA Laser Products, Germany) for upper urinary tract stones. MATERIALS AND METHODS: This retrospective single-center study included patients who underwent ureteroscopy for kidney or ureteral stones between August 2023 and August 2025. Patients with bilateral stones, concomitant procedures, stones ≥20 mm, or without preoperative computed tomography imaging were excluded. Endpoints included operative time, laser efficacy (ratio of cumulative stone volume to operative time), and the stone-free rate (SFR). RESULTS: We analyzed 104 patients (Ho: YAG, n=54; p-Tm: YAG, n=50). The p-Tm: YAG group exhibited significantly shorter operative time (46.0 vs. 66.5 min, P<0.001), and higher laser efficacy (0.237 vs. 0.175 mm³/min, P=0.016). Subgroup analysis revealed that p-Tm: YAG exhibited significantly shorter operative times (49.0 vs. 96.0 min, P<0.001) and superior laser efficacy (0.252 vs. 0.183 mm³/min, P=0.008) for stones measuring 10-20 mm, whereas similar outcomes were observed for stones <10 mm between the two groups. The Ho: YAG and p-Tm: YAG groups exhibited similar SFRs on postoperative day 1 (79.6% vs. 88.0%, P=0.182) and at 1 month (87.0% vs. 92.0%, P=0.325). CONCLUSIONS: Both lasers achieved comparable and high SFRs for stones <20 mm. However, the p-Tm: YAG laser offers higher laser efficacy and significantly shorter operative times, particularly for larger stones (10-20 mm), supporting its use as an efficient alternative to the Ho: YAG laser.