Holmium:YAG laser ureteroscopic lithotripsy for ureteric calculi in children: predictive factors for complications and success

To evaluate the impact of age, stone size, location, radiolucency, extraction of stone fragments, size of ureteroscope and presence and degree of hydronephrosis on the efficacy and safety of holmium:YAG (Ho:YAG) laser lithotripsy in the ureteroscopic treatment of ureteral stones in children. Between October 2011 and May 2013, a total of 104 patients were managed using semirigid Ho:YAG ureterolithotripsy. Patient age, stone size and site, radiolucency, use of extraction devices, degree of hydronephrosis and size of ureteroscope were compared for operative time, success and complications. In all, 128 URS were done with a mean age of 4.7 years. The mean stones size was 11 mm. Success rate was 81.25 %. Causes of failure were 12.5 % access failure, 1.5 % extravasation and 4.7 % stone migration. Overall complications were 23.4 %. Failure of dilatation and extravasation were detected only in children < 2 years old. Extravasation was significantly higher in smaller ureters and cases with stone size > 15 mm. Stone migration was significantly higher in upper ureteric stones. Failure and complications rates in Ho:YAG ureterolithotripsy were significantly affected by younger age (< 2 years), upper ureteric stones and smaller ureters but were not related to stone radiolucency or degree of hydronephrosis. Larger stones (> 15 mm) were associated with increased complications. After multivariate analysis, the age of the patients remained significant predictor for failure of dilatation and stone migration, while size of the ureter was the only significant predicting factor for failure.