Does the degree of stone-induced hydronephrosis affect the outcome of shock-wave lithotripsy in patients with proximal ureteral stones?

Abstract

Background Shock-wave lithotripsy (SWL) is an effective, well-established approach for treating ureteral calculi. Some studies have shown that patients with collecting system obstruction and ureteral stones had lower stone-free rates after SWL than patients with nonobstructed stones. In contrast, other studies acknowledge that stone-induced urinary obstruction does not decrease success with SWL for ureteral stones. The purpose of this study was to assess whether the degree of stone-induced hydronephrosis in patients with solitary proximal ureteral stones influences the outcome and clearance rates after SWL. Patients and methods This prospective study included 30 patients, with solitary proximal ureteric stones and different degrees of hydronephrosis, who were treated with SWL. Patients were divided into three groups according to the degree of stone-induced hydronephrosis. Group 1 (33.33%) had mild dilation, group 2 (33.33%) had moderate dilation, and group 3 (33.33%) had severe dilation. The Dornier MFL 5000 lithotripter was used to treat the patient groups. The results were compared in terms of stone-free rates, number of shock waves, number of sessions, incidence of complications, number of secondary interventions, and time to stone clearance. Results The average stone size was between 8 and 18 mm. The overall success rate was found to be 80% in patients with severe back pressure compared with 90 and 86.6% success rate in moderate and mild hydronephrosis groups, respectively (P=0.749). Furthermore, there was no statistical significance between the three studied groups regarding clearance time (P=0.721). Conclusions The degree of hydronephrosis secondary to proximal ureteral stones of between 6 and 20 mm has shown not to affect the duration till stone clearance or overall treatment success following SWL treatment.