Modified Mechanical Percussion for Upper Urinary Tract Stone Fragments After Extracorporeal Shock Wave Lithotripsy: A Prospective Multicenter Randomized Controlled Trial.

OBJECTIVE: To investigate the effectiveness of modified mechanical percussion for eliminating upper urinary tract stone fragments after extracorporeal shock wave lithotripsy.

MATERIALS AND METHODS: We assigned patients aged 18-60 years with upper urinary tract calculi to the modified mechanical percussion (trial) or observation (control) group. Kidney-ureter-bladder radiography and ultrasound were used for diagnostic evaluation. The primary outcome was the stone-expulsion rate (SER) at 6 hours. The first stone-expulsion time, the SER at 3, 12, and 24 hours, the stone-free rate, additional interventions, and adverse events (AEs) were recorded.

RESULTS: A total of 120 patients underwent randomization: 60 for each group. The mean first stone-expulsion time in the trial and control groups was 6.75 and 13.58 hours, respectively (P = .001). The SERs at 3, 6, and 12 hours in the trial group were 51.8%, 75.4%, and 76.8%, respectively, which were higher than the control group (all P <.05). Among patients who expelled fragments within 6 hours, the stone-free rates were improved at 1 week (P = .002) and at 2 weeks (P = .000). Patients needed fewer additional interventions in the trial group (P = .035). AEs occurred in 42.9% (24 of 56) and 67.9% (38 of 56) of the patients in the trial and control groups, respectively (P = .008). Age, gender, stone size and location, and SER at 24 hours did not differ significantly among the groups.

CONCLUSION: Modified mechanical percussion significantly improved SERs and accelerated stone passage after shock wave lithotripsy, resulting in a stone-free status with a lower risk of AEs and reduced need for additional interventions.