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Pulse modulation with Moses technology improves popcorn laser lithotripsy.
World J Urol. 2020 Jun 06 [Online ahead of print]WJ

Abstract

PURPOSE

Moses™ technology has been developed to improve holmium laser fragmentation at 1-2 mm distance from the stone. Because popcorn lithotripsy is a non-contact technique, we compared short pulse (SP) and Moses distance (MD) modes in an in vitro model.

METHODS

BegoStones were fragmented using a 120 W Ho:YAG laser (P120 Moses) and a 230 μm core fiber introduced through a ureteroscope. 20 W (1 J × 20 Hz; 0.5 J × 40 Hz) and 40 W (1 J × 40 Hz; 0.5 J × 80 Hz) settings (total energy 4.8 kJ) were tested using SP and MD modes. We assessed fragment size distribution and mass lost in fluid (initial mass-final dry mass of all sievable fragments). High-speed video analysis of fragmentation strike rate and vapor bubble characteristics was conducted for 1 J × 20 Hz and 0.5 J × 80 Hz. Laser strike rate (number of strikes divided by frequency) was categorized as: (1) direct-a visual plume of dust ejected from stone while in contact with fiber tip; (2) indirect-a visual plume of dust ejected with distance between stone and fiber tip.

RESULTS

For 1 J × 20 Hz (20 W), MD resulted in more mass lost in fluid and a lower distribution of fragments ≥ 2 mm compared to SP (p < 0.05). 0.5 J × 80 Hz (40 W) produced no fragments ≥ 2 mm, and there were no significant differences in fragment distribution between MD and SP (p = 0.34). When using MD at 1 J × 20 Hz, 96% of strikes were indirect vs 61% for SP (p = 0.059). In contrast to the single bubble of SP, with MD, there was forward movement of the collapsing second bubble, away from the fiber-tip.

CONCLUSIONS

For lower frequency and power popcorn settings, pulse modulation results in more fragmentation through true non-contact laser lithotripsy.

Authors+Show Affiliations

Medical Sciences Unit I, Division of Endourology, Department of Urology, University of Michigan, 1301 Catherine St, Room 4432, Ann Arbor, MI, 48109, USA. krismbla@med.umich.edu.Medical Sciences Unit I, Division of Endourology, Department of Urology, University of Michigan, 1301 Catherine St, Room 4432, Ann Arbor, MI, 48109, USA.Department of Urologic Sciences, University of British Columbia, Vancouver, BC, Canada.Medical Sciences Unit I, Division of Endourology, Department of Urology, University of Michigan, 1301 Catherine St, Room 4432, Ann Arbor, MI, 48109, USA.Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.Medical Sciences Unit I, Division of Endourology, Department of Urology, University of Michigan, 1301 Catherine St, Room 4432, Ann Arbor, MI, 48109, USA. Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.Medical Sciences Unit I, Division of Endourology, Department of Urology, University of Michigan, 1301 Catherine St, Room 4432, Ann Arbor, MI, 48109, USA.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

32506386

Citation

Black, Kristian M., et al. "Pulse Modulation With Moses Technology Improves Popcorn Laser Lithotripsy." World Journal of Urology, 2020.
Black KM, Aldoukhi AH, Teichman JMH, et al. Pulse modulation with Moses technology improves popcorn laser lithotripsy. World J Urol. 2020.
Black, K. M., Aldoukhi, A. H., Teichman, J. M. H., Majdalany, S. E., Hall, T. L., Roberts, W. W., & Ghani, K. R. (2020). Pulse modulation with Moses technology improves popcorn laser lithotripsy. World Journal of Urology. https://doi.org/10.1007/s00345-020-03282-0
Black KM, et al. Pulse Modulation With Moses Technology Improves Popcorn Laser Lithotripsy. World J Urol. 2020 Jun 6; PubMed PMID: 32506386.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Pulse modulation with Moses technology improves popcorn laser lithotripsy. AU - Black,Kristian M, AU - Aldoukhi,Ali H, AU - Teichman,Joel M H, AU - Majdalany,Sami E, AU - Hall,Timothy L, AU - Roberts,William W, AU - Ghani,Khurshid R, Y1 - 2020/06/06/ PY - 2020/03/12/received PY - 2020/05/26/accepted PY - 2020/6/8/entrez KW - Dusting KW - Fragmentation KW - Holmium KW - Laser KW - Moses technology KW - Ureteroscopy JF - World journal of urology JO - World J Urol N2 - PURPOSE: Moses™ technology has been developed to improve holmium laser fragmentation at 1-2 mm distance from the stone. Because popcorn lithotripsy is a non-contact technique, we compared short pulse (SP) and Moses distance (MD) modes in an in vitro model. METHODS: BegoStones were fragmented using a 120 W Ho:YAG laser (P120 Moses) and a 230 μm core fiber introduced through a ureteroscope. 20 W (1 J × 20 Hz; 0.5 J × 40 Hz) and 40 W (1 J × 40 Hz; 0.5 J × 80 Hz) settings (total energy 4.8 kJ) were tested using SP and MD modes. We assessed fragment size distribution and mass lost in fluid (initial mass-final dry mass of all sievable fragments). High-speed video analysis of fragmentation strike rate and vapor bubble characteristics was conducted for 1 J × 20 Hz and 0.5 J × 80 Hz. Laser strike rate (number of strikes divided by frequency) was categorized as: (1) direct-a visual plume of dust ejected from stone while in contact with fiber tip; (2) indirect-a visual plume of dust ejected with distance between stone and fiber tip. RESULTS: For 1 J × 20 Hz (20 W), MD resulted in more mass lost in fluid and a lower distribution of fragments ≥ 2 mm compared to SP (p < 0.05). 0.5 J × 80 Hz (40 W) produced no fragments ≥ 2 mm, and there were no significant differences in fragment distribution between MD and SP (p = 0.34). When using MD at 1 J × 20 Hz, 96% of strikes were indirect vs 61% for SP (p = 0.059). In contrast to the single bubble of SP, with MD, there was forward movement of the collapsing second bubble, away from the fiber-tip. CONCLUSIONS: For lower frequency and power popcorn settings, pulse modulation results in more fragmentation through true non-contact laser lithotripsy. SN - 1433-8726 UR - https://www.unboundmedicine.com/medline/citation/32506386/Pulse_modulation_with_Moses_technology_improves_popcorn_laser_lithotripsy L2 - https://dx.doi.org/10.1007/s00345-020-03282-0 DB - PRIME DP - Unbound Medicine ER -
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