Ultraslow full-power shock wave lithotripsy protocol in the management of high attenuation value upper ureteric stones: A randomized comparative study

Objectives: To evaluate the efficacy and safety of ultraslow full-power shock wave lithotripsy protocol in the management of high attenuation value upper ureteric stones compared with slow-rate, power-ramping shock wave lithotripsy. Methods: This was a randomized trial enrolling patients with a single high attenuation value (≥1000 HU) upper ureteric stones between January 2019 and July 2019. Ultraslow full-power shock wave lithotripsy (54 patients) was applied at a rate of 30 shock waves/min with power ramping from 6 to 18 kV for 100 shock waves, then a safety pause for 2 min, followed by ramping 18–22 kV for 100 shock waves, then a safety pause for 2 min. Then, full power (22 kV) was maintained until the end of the session. Slow-rate, power-ramping shock wave lithotripsy (47 patients) was applied at a rate of 60 shock waves/min with power ramping from 6 to 10 kV during the first 500 shock waves, then from 11 to 22 kV during the next 1000 shock waves, then maintained on 22 kV in the last 1500 shock waves. Up to three sessions were carried out with a follow up 3 months after the last session. The primary outcome was the stone-free rate. Perioperative data of the two protocols were compared. Results: There was no significant difference in preoperative data. The stone-free rate was significantly higher in ultraslow full-power shock wave lithotripsy after single (92.6% vs 23.4%) and multiple (96.3% vs 63.8%) sessions. Most complications were mild, with no significant difference between both groups (9.3% vs 12.8%; P = 0.573). Logistic regression analysis identified ultraslow full-power shock wave lithotripsy protocol as the only significant independent factor for the stone-free rate (odds ratio 12.589, P = 0.025). Conclusion: Ultraslow full-power shock wave lithotripsy for high attenuation value upper ureteric stones is associated with a significantly higher stone-free rate, and with mild complications that are comparable to those of standard shock wave lithotripsy.