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[Factors affecting the outcome of extracorporeal shockwave lithotripsy for upper urinary tract stones].

OBJECTIVE
To investigate the factors affecting the efficacy of extracorporeal shockwave lithotripsy (ESWL) for upper urinary tract stones.


METHODS
Between January 2003 and January 2006, 366 patients with upper urinary tract stone underwent ESWL, and the results were identified by regular KUB/IVU or ultrasonography and evaluated 3 months after the treatment. The treatment success was defined as complete clearance of the stones without residual fragments. The stone-free rate was analyzed in relation to the stone features and the patients' clinical characteristics, and the factors identified to significant affect the results were further analyzed using multivariate regression analysis.


RESULTS
Three months after the treatment, the overall stone-free (success) rate was 63.4% (232/366) in these patients. Chi square test and t test identified the disease course, stone length and width as the factors with significant impact on the stone-free rate. Multivariate analysis excluded the disease course and stone width from the logistic regression model, and identified the stone length as the independent factor affecting the outcome of ESWL.


CONCLUSION
The stone length is an independent factor influencing the efficacy of ESWL for upper urinary tract stones.