Comparison of treatment outcomes according to output voltage during shockwave lithotripsy for ureteral calculi: a prospective randomized multicenter study.
OBJECTIVE
To investigate the effect of fixed versus escalating voltage during SWL on treatment outcomes in patients with ureteral calculi (UC).


METHODS
A prospective, randomized, multicenter trial was conducted on 120 patients who were diagnosed with a single radiopaque UC. The patients were randomized into group C (n = 60, constant 13 kV, 3,000 shock wave, 2 Hz) or group E (n = 60, 11.4-12.0-13 kV per 1,000 shock waves, 2 Hz). They were evaluated by plain abdominal radiography and urinalysis at 1 week after a single session of SWL, and repeat SWL was performed if needed. The primary endpoint was stone-free rate at 1 week (SFR1) after SWL. Secondary endpoints were post-SWL visual pain score (VPS), oral analgesic requirements during 1 week, and cumulative SFRs after the second and third sessions of SWL.


RESULTS
Groups C and E were well balanced in terms of baseline patients and stone characteristics, including pre-SWL VPS, stone location, and stone size (6.24 ± 1.92 vs. 6.30 ± 2.13 mm). SFR1s were not significantly different between groups C and E (60.0 vs. 68.3%, p = 0.447). Analyses stratified by stone size (<6 vs. ≥6 mm) showed no difference in SFR1 (p = 0.148 vs. 0.808). In the analyses stratified by stone location, group E tended to be more effective in distal UC (81.0 vs. 50.0%, p = 0.052), whereas no difference was seen in proximal UC (p = 0.487). Secondary endpoints were also similar between the two groups.


CONCLUSIONS
Our results suggest that voltage escalation during SWL in UC may not provide superior stone fragmentation compared to fixed voltage.
Department of Urology, Eulji University Hospital, Eulji University School of Medicine, Daejeon, Repubic of Korea.
Jinsung
J
Park
Hong-Wook
HW
Kim
Sungwoo
S
Hong
Hee Jo
HJ
Yang
Hong
H
Chung
D000328:Adult; D023381:Endpoint Determination; D005260:Female; D006801:Humans; D008096:Lithotripsy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D016896:Treatment Outcome; D014514:Ureteral Calculi / Q000175:diagnosis / Q000473:pathology / Q000628:therapy*