INTRACORPOREAL HOLMIUM:YAG LASER LITHOTRIPSY - CURRENT STAGE

Since Mulvany and Beck first description of Ruby laser for lithotripsy, urologists have been exploiting every possible application of this technology. Relevant to urology is the recently developed Holmium:YAG laser with both soft tissue and lithotripsy applications. The Holmium:YAG laser can effectively fragment calculi of all compositions mainly through a photothermal mechanism. This mechanism result in fewer migrated and smaller stone fragments, compared to electrohydraulic lithotripsy, mechanical lithotripsy or pulsed dye lasers. Because the Holmium:YAG laser can be carried through small flexible quartz fibers, it is ideally suited for the use through small-diameter flexible ureteroscopes in the upper urinary tract. We here provide a comprehensive revision of basic concepts as wavelength, absorption coefficient, chromophores, pulsed laser and the photothermal mechanism of the Holmium:YAG laser lithotripsy. Security concerns, the impact of energy and frequency settings, as well as the influence of different fiber types and its diameters on stone fragmentation are analyzed. The clinical Holmium: YAG laser lithotripsy applications and the series reporting their use are reviewed.