Laser lithotripsy: in-vitro comparison of different systems

Laser lithotrpsy has shown an increasng potential during the last few years to have a rational n the treatment of ureteral calcufl. !n-vtro measurements of the fragmentation rates of the Nd:YAG laser, pulsed dye laser and alexandrfte laser have been performed using natural human calculi. Both, the dye and the alexandrite laser gave reasonably effective fragmentation rates against most types of calculi tested. The effect of different fiber diameters and different energy levels on the fragmentation rates were studied, in order to define the optimal working parameters for each system. Limited energy range and the requirement of an optomechanical coupler were the main disadvantages of the Nd:YAG laser. The dye laser showed optimum effects using a 200 um fiber at 5O..60 mJ pulse energy. At higher energy levels, the system worked better and produced more effective fragmentation using a 300 um fiber. At comparable energy levels, fragmentation effects were higher for alexandrite and dye laser systems compared to the Nd:YAG laser system.