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Holmium:YAG lithotripsy efficiency varies with energy density
G J Vassar1, J M Teichman, R D Glickman
1Department of Ophthalmology, University of Texas Health Science Center, San Antonio, USA.
The Journal of Urology
|July 29, 1998
Summary
Holmium:YAG lithotripsy efficiency depends on laser energy density and optical fiber size. The 365-micrometer fiber is optimal for most procedures, while the 272-micrometer fiber is best for lower energy settings.
Area of Science:
- Urology
- Laser Technology
- Biomedical Engineering
Background:
- Holmium:YAG (Ho:YAG) laser lithotripsy is a common procedure for breaking kidney stones.
- Optimizing Ho:YAG lithotripsy efficiency is crucial for patient outcomes and procedural success.
- Optical fiber characteristics significantly influence laser energy delivery and treatment effectiveness.
Purpose of the Study:
- To investigate the impact of optical fiber diameter and energy settings on Ho:YAG lithotripsy efficiency.
- To determine the optimal fiber size and energy density for calcium oxalate monohydrate stone fragmentation.
- To assess the durability and energy transmission of different optical fibers during lithotripsy.
Main Methods:
- Utilized 272, 365, 550, and 940 micrometer optical fibers to deliver Ho:YAG laser energy to calcium oxalate monohydrate calculi.
- Varied energy output per pulse from 0.2 to 1.5 Joules.
- Measured stone mass loss and characterized stone crater width for each fiber and energy setting.
- Compared fiber energy outputs before and after lithotripsy procedures.
Main Results:
- Stone mass loss showed an inverse correlation with optical fiber diameter (p <0.05).
- Higher energy settings (0.2-1.5 J/pulse) led to increased stone loss for 365, 550, and 940 micrometer fibers (p <0.001).
- The 272 micrometer fiber demonstrated reduced efficiency and susceptibility to damage at energy levels of 1.0 J/pulse or greater compared to the 365 micrometer fiber (p <0.01).
Conclusions:
- Ho:YAG lithotripsy efficiency is directly influenced by pulse energy output and optical fiber diameter, correlating with energy density.
- The 365 micrometer fiber is recommended for most lithotripsy applications due to its balance of efficiency and durability.
- The 272 micrometer fiber is suitable for specific scenarios, such as use with small-caliber ureteroscopes or when maximal deflection is needed, at energy levels below 1.0 J/pulse.