Laser lithotripsy was invented at the Wellman Center for Photomedicine at Massachusetts General Hospital in the 1980s to remove impacted urinary stones. Optical fibers carry light pulses that pulverize the stone. Candela licensed the technology and released the first commercial laser lithotripsy system. Initially 504 nm dye lasers were used, then holmium lasers were studied in the 1990s. Several companies currently produce holmium lasers for lithotripsy including Lumenis, DirexGroup, Trimedyne, and Electro Medical Systems.
A urologist inserts a scope into the urinary tract to locate the stone. The scope may be a cystoscope, ureteroscope, renoscope or nephroscope. An optical fiber is inserted through the working channel of the scope, and laser light is directly emitted to the stone. The stone is fragmented and the remaining pieces are washed out of the urinary tract.
Laser lithotripsy (LL) has been evalulated against Extracorporeal Shock Wave lithotripsy (ESWL), finding both to be safe and effective. ESWL may be safer for small stones (<10 mm), but less effective for 10–20 mm stones. A 2013 meta-analysis found LL can treat larger stones (> 2 cm) with good stone-free and complication rates.
Holmium:YAG lasers have wavelength of 2100 nm (infrared) and are used for medical procedures in urology and other areas. They have qualities of CO2 and Nd:Yag lasers, with ablative and coagulation effects. Holmium laser use results in smaller fragments than 320 or 365 micron pulsed dye lasers or electrohydraulic and mechanical methods.
Thulium lasers are being investigated.
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