The stone-free rate declines as stone size increases (5 - 10 mm: 92.4%, 11 - 15 mm: 76.2%, >15 mm: 44.1%; p<0.01), moderate or severe hydronephrosis in the renal side (non hydro -: 79.7%; mild hydro -: 84.2%; moderate or severe hydro -: 42.9%; p<0.01) Conclusion: Overall stone-free rate was 76.1%.