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Evaluation of retropulsion caused by holmium:YAG laser with various power settings and fibers.
J Endourol. 1998 Apr; 12(2):183-6.JE

Abstract

The ideal intracorporeal lithotriper would comminute all types of calculi into small readily excreted particles. It would be small and flexible with an energy source safe for the uroepithelium. It should not break, should be inexpensive, and should not retropulse the stone up the urinary tract. This investigation was designed to quantify the last quality for the holmium:YAG laser. The mechanism of action of the pulsed Ho:YAG laser (wavelength 2100 nm) is the generation of a gas plasma at the stone-fluid interface causing a shockwave. The holmium laser was employed for lithotripsy of model stones composed of silicate with a ferrous coating. Stones were selected with a mass of 2 mg +/- 0.1 mg. We sequentially investigated three variables: energy (0.6, 0.8, and 1.0 J), frequency (10, 16, and 20 Hz), and fiber diameter (200, 365, 550, and 1000 microm). Ten stone trials were performed with each of the 36 possible combinations of energy, pulse frequency, and fiber diameter. Our model ureter consisted of a clear rigid polymer tube filled with 0.9% saline. The system was closed and permitted intertrial flushing of generated air bubbles. The laser fiber was maintained at constant extension from the ureteroscope, with stones positioned at the fiber tip before each trial. Laser energy was applied for 2 seconds, with maximum and net retropulsion recorded in millimeters. Each measurement series was recorded in a database for paired Student t-tests. Net retropulsion was then compared by statistically holding each of the three variables constant (fiber size constant with power and frequency varying; frequency constant with power and fiber size varying; and power constant with fiber size and frequency varying). Most retropulsion occurred with the 365-microm and 550-microm fibers. Most comminution was also noted with these fiber sizes. There was no statistical correlation between observed retropulsion and efficiency of comminution. This self-contained model for laser lithotripsy allowed us to measure retropulsion accurately. Silicate stones are not chemically similar to human uroliths but are of uniform composition. The irregular surface characteristics are similar to human stones, making them ideal for retropulsion investigations.

Authors+Show Affiliations

Division of Urology, St. Peter's Kidney Stone Center, Albany Medical College, New York, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

9607447

Citation

White, M D., et al. "Evaluation of Retropulsion Caused By holmium:YAG Laser With Various Power Settings and Fibers." Journal of Endourology, vol. 12, no. 2, 1998, pp. 183-6.
White MD, Moran ME, Calvano CJ, et al. Evaluation of retropulsion caused by holmium:YAG laser with various power settings and fibers. J Endourol. 1998;12(2):183-6.
White, M. D., Moran, M. E., Calvano, C. J., Borhan-Manesh, A., & Mehlhaff, B. A. (1998). Evaluation of retropulsion caused by holmium:YAG laser with various power settings and fibers. Journal of Endourology, 12(2), 183-6.
White MD, et al. Evaluation of Retropulsion Caused By holmium:YAG Laser With Various Power Settings and Fibers. J Endourol. 1998;12(2):183-6. PubMed PMID: 9607447.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Evaluation of retropulsion caused by holmium:YAG laser with various power settings and fibers. AU - White,M D, AU - Moran,M E, AU - Calvano,C J, AU - Borhan-Manesh,A, AU - Mehlhaff,B A, PY - 1998/6/2/pubmed PY - 1998/6/2/medline PY - 1998/6/2/entrez SP - 183 EP - 6 JF - Journal of endourology JO - J. Endourol. VL - 12 IS - 2 N2 - The ideal intracorporeal lithotriper would comminute all types of calculi into small readily excreted particles. It would be small and flexible with an energy source safe for the uroepithelium. It should not break, should be inexpensive, and should not retropulse the stone up the urinary tract. This investigation was designed to quantify the last quality for the holmium:YAG laser. The mechanism of action of the pulsed Ho:YAG laser (wavelength 2100 nm) is the generation of a gas plasma at the stone-fluid interface causing a shockwave. The holmium laser was employed for lithotripsy of model stones composed of silicate with a ferrous coating. Stones were selected with a mass of 2 mg +/- 0.1 mg. We sequentially investigated three variables: energy (0.6, 0.8, and 1.0 J), frequency (10, 16, and 20 Hz), and fiber diameter (200, 365, 550, and 1000 microm). Ten stone trials were performed with each of the 36 possible combinations of energy, pulse frequency, and fiber diameter. Our model ureter consisted of a clear rigid polymer tube filled with 0.9% saline. The system was closed and permitted intertrial flushing of generated air bubbles. The laser fiber was maintained at constant extension from the ureteroscope, with stones positioned at the fiber tip before each trial. Laser energy was applied for 2 seconds, with maximum and net retropulsion recorded in millimeters. Each measurement series was recorded in a database for paired Student t-tests. Net retropulsion was then compared by statistically holding each of the three variables constant (fiber size constant with power and frequency varying; frequency constant with power and fiber size varying; and power constant with fiber size and frequency varying). Most retropulsion occurred with the 365-microm and 550-microm fibers. Most comminution was also noted with these fiber sizes. There was no statistical correlation between observed retropulsion and efficiency of comminution. This self-contained model for laser lithotripsy allowed us to measure retropulsion accurately. Silicate stones are not chemically similar to human uroliths but are of uniform composition. The irregular surface characteristics are similar to human stones, making them ideal for retropulsion investigations. SN - 0892-7790 UR - https://www.unboundmedicine.com/medline/citation/9607447/Evaluation_of_retropulsion_caused_by_holmium:YAG_laser_with_various_power_settings_and_fibers_ L2 - https://www.liebertpub.com/doi/full/10.1089/end.1998.12.183?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -