In patients with solitary distal ureteral stones, hydronephrosis is associated with prolonged stone clearance following shock wave lithotripsy (SWL), but the degree of hydronephrosis caused by the stones does not affect overall SWL outcome.
Ahmed El-Assmy, MD, and his Egyptian colleagues at the Urology and Nephrology Center of Man-soura University studied 215 patients who had a solitary distal ureteral stone (mean stone size, 11.2 mm) with or without hydronephrosis. All patients underwent SWL. The investigators divided patients into four groups based on their degree of hydronephrosis (as determined by renal ultrasonography). Group 0 had no urinary system dilation (44.2% of patients), group 1 had mild dilation (32.5%), group 2 had moderate dilation (16.3%), and group 3 had severe dilation (7%).
Following treatment, the stone-free rate was 83% in the patients without and 74% in those with hydronephrosis. Also, hydronephrosis was associated with prolonged stone clearance time (18.7 vs. 15.4 days) and the need for repeat treatment (2.2 vs. 1.6).