To evaluate the clinical efficacy and safety of dual shockwave lithotripter in treating urinary calculi.

Data of 371 cases treated with Direx-Magna dual shockwave lithotripter was retrospectively collected from July 2016 to June 2017, including 263 male and 108 female.Their age ranged from 15 to 66 years old (mean 36.5±11.0). There was 117 patients with kidney stone, 183 patients with upper ureteral and 71 patients with middle or lower stone. The average diameter of stones was (11.3±1.5)mm (ranging 6.9-16.3 mm). The lithotripter was set at 60 times/min/head. Comparative analysis was made between 106 cases in dual mode and 265 cases in single mode. Comparative items included shock frequency, treating time, treating energy, pain scale, stone clear successive rate and complication. Patients were followed by KUB or NCCT at 1 and 2 weeks after the procedure. Stone clear successfully was defined as stone free or with fragment <4 mm.

The overall success rate was 87.3% (324/371). Among the patients who failed in first session, 21 cases were successful with a second session, 7 cases were treated with retrograde intrarenal surgery. There were 19 cases lost. Clavien grade III complication rate was 0.8% and no server grade complications. The average treating time was (25.2 ± 8.4)minutes and the average shock was (1 419±440)times.The dual shockwave subgroup achieved higher success rate [93.4%(99/106) vs. 84.9%(225/265), P<0.05] with less treating time [(15.7±3.8)min vs. (29.0±6.5)min], lower energy [(8.9±2.0)kV vs. (10.7±2.8)kV] and fewer shocks (833±149 vs.1 654±261), compared with that of the single shockwave subgroup (P<0.01). Also, pain scales and other complications were less than those of single shockwave subgroup (P<0.01).

Our study shows the new dual shockwave lithotripsy is safe and effective in both dual and single shock wave mode. Dual mode has higher success rate and fewer complications.

Extracorporeal shock wave lithotripsy; Dual shockwave lithotripter; Urinary stone