Watt's in a name? - The people that focused laser lithotripsy

Document Type

Conference Proceeding

Publication Date


Publication Title

Eur Urol


Introduction & Objectives: Laser applications have been a significant development in urology, revolutionizing urinary stone disease treatment. We sought to examine the pivotal figures associated with laser lithotripsy and understand their contributions to the evolution of this technology.

Materials & Methods: A comprehensive literature review was performed using PubMed database, Google Scholar, and texts regarding the discovery, initial trials and advancements in laser lithotripsy.

Results: In 1957, Gordon Gould debuted an optical device, Light Amplification for the Stimulated Emission of Radiation (LASER). Theodore Maiman laid the cornerstone for laser lithotripsy in 1960, in a pivotal Nature publication utilizing a ruby crystal medium, the foundation for the first in vitro destruction of urinary calculi by William Mulvaney and Carl Beck, using 50-300J of energy. In 1962, FJ McClung and Robert Hellwarth used ‘Qswitching’ where an attenuator stores energy in a medium until a maximum level was reached. This insight allowed J.E. Geusic in 1964 to develop the first commercially available solid-state laser medium and laser – Neodymium-doped-YAG (Nd: YAG). In 1983, Graham Watson, applied a laser pulse technique demonstrating fragmentation capability of Nd:YAG. Q-switching did not generate adequate energy, so Watson used a flashlamp to pump laser energy in short pulses highlighting calculi fragmentation with minimal energy, whilst using small laser fiber sizes – leading to the creation of the ubiquitous 200μm laser fiber. The lack of power from Nd:YAG to fragment all stone types, propagated the development of holmium (Ho:YAG) laser by the Wellman Center for Photo Medicine at Massachusetts General Hospital – providing a range of laser settings for frequency (Hertz), energy (Joule), and ultimately power (Watt). Although not associated with the invention of laser lithotripsy, these eponyms are the fundamental units of laser. James Prescott Joule, an English physicist, determined the first law of thermodynamics; the conservation of energy. In 1852, he collaboratively created the ‘Joule-Thompson effect’, significantly contributing to the refrigeration industry. Heinrich Hertz, a German physicist, proved the existence of electromagnetic waves. James Watt. a Scottish engineer, invented horsepower in the 18th century and his modification of the steam engine transformed the Industrial revolution.

Conclusions: Laser lithotripsy is constantly improving our management of urinary calculi, fundamentally built upon decades of innovative and collaborative minds. No matter the ‘Watts’ in our arsenal, we must remember the ‘who’ behind them.



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