Optimization of Extracorporeal Shock Wave Lithotripsy Delivery Rates Achieves Excellent Outcomes for Ureteral Stones: Results of a Prospective Randomized Trial.

PURPOSE Management of ureteral stones remains controversial. To determine whether optimizing the extracorporeal shock wave lithotripsy delivery rate would improve the treatment of solitary ureteral stones we compared the outcomes of 2 delivery rates in a prospective randomized trial. MATERIALS AND METHODS From July 2010 to October 2012, 254 consecutive patients were randomized to extracorporeal shock wave lithotripsy at a shock wave delivery rate of 60 and 90 pulses per minute in 130 and 124, respectively. The primary study end point was the stone-free rate at 3-month followup. Secondary end points were stone disintegration, treatment time, complications and the rate of secondary treatments. Descriptive statistics were used to compare end points between the 2 groups. The adjusted OR and 95% CI were calculated to assess predictors of success. RESULTS The stone-free rate at 3 months was significantly higher in patients who underwent extracorporeal shock wave lithotripsy at a shock wave delivery rate of 90 pulses per minute than in those who received 60 pulses per minute (91% vs 80%, p = 0.01). Patients with proximal (100% vs 83%, p = 0.005) and mid ureteral stones (96% vs 73%, p = 0.03) accounted for the observed difference but not those with distal ureteral stones (81% vs 80%, p = 0.9, respectively). Treatment time, complications and the rate of secondary treatments were comparable between the 2 groups. On multivariable analysis the shock wave delivery rate of 90 pulses per minute, proximal stone location, stone density, stone size and an absent indwelling Double-J® stent were independent predictors of success. CONCLUSIONS Optimizing the extracorporeal shock wave lithotripsy delivery rate can achieve excellent results for ureteral stones.