Ureteroscopic lithotripsy for distal ureteral calculi: comparative evaluation of three different lithotriptors.

INTRODUCTION AND OBJECTIVES We report the results of a randomized controlled trial comparing three different lithotriptors using semirigid ureteroscopy (URS) for distal ureteral stones. METHODS Between September 2009 and November 2010 69 patients undergoing ureteroscopy were randomized to three groups: LithoClast classic (Group 1), Holmium Laser (Group 2), and StoneBreaker™ (Group 3). A 7.5F semirigid ureteroscope was used in all procedures. The primary outcome was differences in fragmentation time. Secondary outcomes were stone-free rates, intraoperative complications, stone-up migration, hospital stay, analgesic requirement, and need for auxiliary procedures. Patients were followed up at 15 days, 30 days, and 3 months. The stone-free status was defined with noncontrast computed tomography performed at first control. Univariate and multivariate analysis were performed to determine clinical and surgical factors that have direct impact on the success of ureteroscopy. Chi-square test and Analysis of Covariance (ANCOVA) tests were used for statistical comparisons. RESULTS There were no differences between sociodemographic variables. Average stone size was 7.17±2.04 mm in Group 1; 7.89±2.73 mm in Group 2; and 7.79±2.97 mm in Group 3 (p=0.79). Fragmentation time were similar between lithotriptors; 27.12±4.07 minutes in Lithoclast group; 21.78±2.81 minutes in Laser group, and 27.14±4.71 minutes in StoneBreaker group (p=0.74). Stone-free rates were 96%±11.18% (group 1), 96.9%±8% (group 2), and 96.9%±8.4% (group 3) (p=0.1). No difference was observed in stone-up migration, postoperative Double-J stent placement, or auxiliary procedures. Stone size and the placement of a second working wire were associated with shorter fragmentation time (p<0.01). CONCLUSIONS The three lithotripsy devices evaluated behaved similarly in terms of the ability to fragment stones, and were equally effective for distal ureteral stones. Adequate fragmentation and fragment removal are mainly dependant on stone size and surgical technique (use of auxiliary wire).