Abstract
Introduction: The objective of this study was 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. 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). Conclusion: 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.