Pulsed-Dye Laser Fragmentation of Urinary and Biliary Calculi In Vitro

Abstract

The relative fragility of urinary and biliary calculi of different chemical compositions in response to the pulsed-dye laser was studied in vitro. Urinary calculi received 1000, 1500, 2000, and 2500 pulses. Biliary calculi received 500, 1000, and 1500 pulses. Cystine and calcium oxalate monohydrate stones were the least fragile, followed by calcium phosphate dihydrate, uric acid, struvite, and calcium oxalate dihydrate. Mixed-pigment cholesterol calculi were easier to fragment than 100% cholesterol calculi, and all biliary calculi fragmented with fewer pulses than were necessary for urinary stones. An induction phase was observed in all the calculi tested, followed by a phase of rapid fragmentation. Physical factors that may enhance the fragmentation of calculi in response to the pulsed-dye laser are discussed.