Status and prospect of pulse laser lithotripsy for urinary calculi

Although laser technology has been widely applied to treat urinary disease, it must be faced with many challenges. The paper analyzes the different mechanism of Ho:YAG laser, frequency-doubled double pulse (FREDDY) laser, and Er:YAG laser, which are used to fragment urinary calculi. Er:YAG laser possesses many advantages over other lasers, but it can not be used for clinical usage just because of no practical fiber for transmitting the laser. The fragment mechanisms of Ho:YAG laser and FREDDY laser are photothermal effect and photoacoustical effect, respectively. The damage for normal tissue induced by FREDDY laser will be less than that induced by Ho:YAG laser.