Impact of pulse duration alterable laser ureterorenoscopic lithotripsy for upper urinary tract calculi.

To assess the effectiveness of a pulse duration alterable Holmium-YAG (Ho:YAG) laser on the stone-free rate (SFR) compared to a conventional pulse duration fixed laser after ureterorenoscopic lithotripsy (URSL). The medical records from patients with upper urinary tract calculi of ≥ 9 mm and < 30 mm were retrospectively investigated. URSL using a conventional Ho:YAG Laser (group C) or a pulse duration alterable Ho:YAG system (group A) was included. In total, 228 and 188 patients were enrolled in groups C and A, respectively. A 272 µm optical core bare-ended, reusable laser fiber was used, and the laser system was set to a standard 0.8 J and 10 Hz (8 W of average power) in both groups. URSL adopts active fragmentation using an extraction approach. SF was defined as the complete absence of stone fragments on computed tomography (CT) 1-2 months after URSL. Sex, BMI, stone length, stone volume, stone density, and the number of patients with positive preoperative urine cultures were not significantly different between the groups. However, age, rate of preoperative febrile urinary tract infection (fUTI), and pre-stenting were significantly higher in group A, and the operative times and incidence of postoperative fUTI were comparable. The SFRs were 71.5% and 80.3% in groups C and A, respectively (P = 0.035). Multivariate logistic regression revealed that the use of conventional laser was associated with non-SF (odds ratio [OR] 1.090, 95% confidence interval [CI] 1.01-1.18, P = 0.040). The present study revealed the superior performance of a pulse duration alterable Ho:YAG laser on the SFR after URSL compared to a conventional pulse duration fixed laser delivery system.