Investig Clin Urol.  2021 Jan;62(1):72-78. 10.4111/icu.20200285.

Extremely-slow, half-number shockwave lithotripsy for asymptomatic renal stones <20 mm

• Ito K
• Takahashi T
• Kanno T
• Okada T
• Higashi Y
• Yamada H

• KMID: 2509854
• DOI: http://doi.org/10.4111/icu.20200285

Abstract

Purpose
To compare the treatment success rate and safety of reduced (30 shocks/min, 1,200 shocks/session) versus standard (60 shocks/min, 2,400 shocks/session) extracorporeal shockwave lithotripsy for the management of renal stones.
Materials and Methods
We retrospectively analyzed 404 patients who underwent extracorporeal shockwave lithotripsy for 5–20-mm renal stones between April 2011 and March 2019. Patients selected the reduced or standard protocol (group R and S) after explaining the potential benefits and disadvantages. The primary outcome was treatment success within 12 weeks, which was defined as no residual fragment or fragments <4 mm on ultrasonography and plain radiograph.
Results
In total, 94 and 310 patients underwent shockwave lithotripsy with a reduced and standard protocol, respectively. The background characteristics of the participants did not significantly differ. The treatment success within 12 weeks was achieved in 78 (83.0%) patients in group R and 259 (83.5%) in group S (p=0.88). The median number of the session was 3 (interquartile range, 2–4) in both groups (p=0.53). The total complication rates were 5.4% in group R and 6.1% in group S. Three (1.0%) patients in group S experienced perirenal hematoma, which was conservatively treated. The reduced protocol was not associated with treatment success in the multivariate analysis adjusted for potential confounders (odds ratio, 0.91; 95% confidence interval, 0.46–1.80; p=0.78).
Conclusions
The new treatment amendment with a slower delivery rate successfully reduced the total number of shocks need to fragment renal stones <20 mm without compromising the stone-free rate.

Keyword

Extracorporeal shockwave therapy; Kidney calculi; Lithotripsy; Nephrolithiasis; Urolithiasis