Moon KB et al, 2012: Optimal shock wave rate for shock wave lithotripsy in urolithiasis treatment: a prospective randomized study
Moon KB, Lim GS, Hwang JS, Lim CH, Lee JW, Son JH, Jang SH.
Department of Urology, Bundang Jesaeng General Hospital, Seongnam, Korea.
PURPOSE: We aimed to compare the effects of a fast shock wave rate (120 shocks per minute) and a slow shock wave rate (60 shocks per minute) on the shock wave lithotripsy (SWL) success rate, patient's pain tolerance, and complications.
MATERIAL & METHODS: A total of 165 patients with radiopaque renal pelvis or upper ureter stones were included in the study. Patients were classified by use of a random numbers table. Group I (81 patients) received 60 shock waves per minute and group II (84 patients) received 120 shock waves per minute. For each session, the success rate, pain measurement, and complication rate were recorded.
RESULTS: No statistically significant differences were observed in the patients according to age, sex, body mass index, stone size, side, location, total energy level, or number of shocks. The success rate of the first session was greater in group I than in group II (p=0.002). The visual analogue pain scale was lower in group I than in group II (p=0.001). The total number of sessions to success and the complication rate were significantly lower in group I than in group II (p=0.001).
CONCLUSIONS: The success rate of SWL is dependent on the interval between the shock waves. If the time between the shock waves is short, the rate of lithotripsy success decreases, and the pain measurement score and complications increase. We conclude slow SWL is the optimal shock wave rate.
Korean J Urol. 2012 Nov;53(11):790-4. doi: 10.4111/kju.2012.53.11.790. Epub 2012 Nov 14.
PMID: 23185672 [PubMed] PMCID: PMC3502739. FREE ARTICLE
The authors nicely quote some of the old literature (Greenstein A, Matzkin H. Does the rate of extracorporeal shock wave delivery affect stone fragmentation? Urology 1999; 54: 430-2.; Delius M, Jordan M, Eizenhoefer H, Marlinghaus E, Heine G, Liebich HG, et al. Biological effects of shock waves: kidney haemorrhage by shock waves in dogs--administration rate dependence. Ultrasound Med Biol 1988; 14: 689-94) which many years ago documented what is nowadays looked at as a new massage.
They discuss N-acetyl-beta-D-glucosaminidase (NAG) as indicator of renal damage, which they did not measure.
In a recently reviewed publication (A prospective, randomized study of the clinical effects of shock wave delivery for unilateral kidney stones: 60 versus 120 shocks per minute. Ng CF, Lo AK, Lee KW, Wong KT, Chung WY, Gohel D.J Urol. 2012; 188(3): 837-42) the authors have also shown a better stone disintegration with 60 shocks/min but a lower NAG excretion after ESWL with 60 versus 120 shocks per minute. Both groups used an EDAP electroconductive lithotripter, a Sonolith Vision in the latter series and a Sonolith Praktis in the present series. I had put some question marks behind the paper by Ng et al. The study in the present paper seems to have been better planned: the patients were randomized and they were all treated in the same time period by a single operator.