A decade of pediatric laser lithotripsy: Location-driven outcomes and a targeted analysis of lower-pole stone clearance.

INTRODUCTION: Endoscopic laser lithotripsy is becoming the mainstay for pediatric urolithiasis management, and the location of stones strongly influences the stone-free outcome. This study reports location-specific stone-free rates and evaluates factors associated with the clearance of lower-pole stones. METHODS: We conducted a single-center, retrospective review of all children ≤18 years undergoing endoscopic laser lithotripsy between January 2015 and December 2024. Stone-free status was defined as the absence of a residual fragment >2 mm on imaging, obtained at least eight weeks postoperatively. Location-specific clearance was compared, and predictors of lower-pole clearance were evaluated. RESULTS: Among 164 cases (mean age 10.4±5.4 years), the overall stone-free rate was 73.8%. Outcomes varied significantly by location (p<0.001): bladder 96.4%, distal ureter 96.2%, upper calyx 71.4%, renal pelvis 68.4%, proximal ureter 66.7%, and lower pole 52.5%. Repeat procedures were required in 14% of cases. In the lower-pole cohort (n=40), clearance was associated with thulium fiber laser use (77.8% vs. 31.8% for holmium:YAG, p=0.004), single vs. multiple stones (80% vs. 36%, p=0.007), favorable composition (mixed calcium or cystine, p=0.036), and older age (>12 years, p=0.04). Stone size was not associated with the stone-free rate. CONCLUSIONS: Endoscopic laser lithotripsy is effective across most pediatric stone sites, but lower-pole stones remain challenging, with clearance achieved in only half of cases. Adoption of thulium fiber laser, careful counseling for younger children or those with multiple stones, and tailored operative strategies may improve outcomes. Prospective, multicenter studies are warranted.