Pulsed dye laser lithotripsy for ureteral stone fragmentation.

The efficacy of the second generation dye-laser lithotriptor (Pulsolith) with high power output was studied in 35 patients with ureteral stones. Ninety per cent of the calcium oxalate monohydrate stones were fragmented, although it required more total energy as compared to that delivered to calcium oxalate dihydrate or phosphate stones. Cystine stones remain resistant to dye-laser lithotripsy. The calculi including cystine stone were immersed in rifampicin or tetracycline solutions and the effect of optical coupling on fragmentation efficacy was measured in vitro. The optical coupling seemed to improve photo-acoustic effect, but the fragmentation rate for cystine stones remained only 10 per cent of that for calcium oxalate.