De Novo Extracorporeal Shock Wave Lithotripsy for Ureteral Stones

Abstract

De novo extracorporeal shock wave lithotripsy (SWL) for ureteral stones is appealing because no instrumentation is used and stone-free rates of 90% ⁺ are reported with low-power lithotripteis using minimal or no anesthesia. This makes SWL an attractive alternative to ureteroscopic stone extraction and to ureteral stent/ SWL, which give similar stone-free rates but require instrumentation and major anesthesia. De novo SWL using high-power lithotripters (Dornier HM3 and Mestone STS) and general anesthesia was used on 100 patients with impacted ureteral stones of 2 weeks' duration or longer (upper ureter 80, mid 6, lower 14). There were 78 single stones and 22 multiple stones. The retreatment and post-SWL secondary procedure rates with single stones were 6% and 14%, respectively, and with multiple stones were 9% and 18%, respectively. The stone-free rate at 3 months was 78% with single stones and 73% with multiple stones. The difference in stone-free rates between low- and high-power lithotripters performing de novo SWL for ureteral stones is difficult to explain except for the theory that low-power machines fragment stones into smaller particles that are more readily passed down the ureter or the fact that low-power lithotripters are used by some urologists for the immediate treatment of acute renal colic caused by small ureteral stones that would have passed spontaneously with a short period of observation.