Does a slower treatment rate impact the efficacy of extracorporeal shock wave lithotripsy for solitary kidney or ureteral stones?
OBJECTIVE
We compared the efficacy of an SR (70 to 80 shocks per minute) and an FR (120 shocks per minute) for ESWL for solitary stones less than 2 cm located in the kidney or proximal ureter.


METHODS
A total of 349 patients with a solitary, radiopaque kidney or ureteral stone underwent ESWL on a DoLi(R) 50 lithotriptor. Patients were grouped based on stone size, stone location and whether SR or FR treatment was performed. Of the 349 patients 135 had a renal stone between 1and 2 cm, 137 had a renal stone less than 1 cm and 77 had a proximal ureteral stone with a surface area of between 30 and 90 mm. SFRs were determined at approximately 1 month by plain x-ray of the kidneys, ureters and bladder.


RESULTS
In comparison to the FR groups SR groups required fewer shocks and had significantly lower power indexes. Of patients with renal stones between 1 and 2 cm 24 of 52 (46%) in the FR group were stone-free compared to 56 of 83 (67%) in the SR group (p <0.05). For stones with a surface area of 30 to 90 mm located in the kidney or proximal ureter there was a trend toward an improved SFR in the SR group but differences between the SR and FR groups were not statistically significant.


CONCLUSIONS
For solitary renal stones between 1 and 2 cm an SR results in a better treatment outcome than an FR for ESWL. However, when stone size is less than 1 cm, SFR differences in the SR and FR treatment groups become less significant.
Chacko
Job
J
Departments of Surgery and Medicine, University of Colorado Health Sciences Center and Kidney Stone Center of the Rocky Mountains, Denver, Colorado, USA.
Moore
Michael
M
Sankey
Noel
N
Chandhoke
Paramjit S
PS
D005260:Female; D006801:Humans; D007669:Kidney Calculi / Q000628:therapy*; D008096:Lithotripsy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013997:Time Factors; D014514:Ureteral Calculi / Q000628:therapy*