Practical & Effective Laser Lithotripsy
Laser lithotripsy, specifically the use of lasers to fragment urinary calculi, is a well-established and acknowledged clinical treatment. Various factors influence the fragmentation effectiveness and efficiency including pulse energy, pulse frequency, pulse width, fiber size and the physical properties of the calculi.
While traditional (short pulse width) fragmentation of the calculi and subsequent basket retrieval has been the most common procedure, technical innovation, specifically as it relates to pulse frequency and pulse width, has facilitated new fragmentation techniques including a new procedure commonly referred to as “stone dusting”. Basically a more controlled and precise version of fragmentation, stone “dusting” fragments the stone into very small pieces (typically ablated from the perimeter of the stone), which can then be naturally passed by the patient, eliminating the requirement for retrieval. By eliminating the requirement for basket retrieval, the procedure becomes a more efficient one.
While short pulsed higher energy can be effective at fragmentation, higher energies and shorter pulse widths also increase the risk of stone migration and retropulsion. Conversely, longer pulse width lasers increase the stability of the stone and therefore minimize the risk of stone migration1.
The primary objective of “dusting” is to decrease the stone in size (ideally to very small dust-like particles) in an effort to eliminate the requirement for basket retrieval. With innovations in technology, multiple hypotheses of “dusting” have emerged. One is the utilization of high frequency and low pulse energy settings. Another is to use a longer pulse width and low pulsed energy settings. Both theories ostensibly seek to accomplish a similar treatment objective which is to increase the total “on” time of the laser during each cycle, which in turn facilitates a more effective photo-thermal interaction.
The HYPHO Compact (115V) holmium laser’s innovative technology enables efficient and effective short pulsed fragmentation as well as “stone dusting”, by delivering the longest pulse of any currently available holmium laser, which facilitate both a greater photo-thermal interaction2 and increased stability of the stone3. One final advantage of longer pulse width lasers is (all other things equal) longer pulse width lasers maintain the integrity of the fiber(s) better than shorter pulse length lasers.
1 Impact of pulse duration on Ho:YAG laser lithotripsy: fragmentation and dusting performance
Markus J. Bader · Thomas Pongratz · Wael Khoder · Christian G. Stief · Thomas Herrmann · Udo Nagele · Ronald Sroka Received: World J Urol (2015) 33:471–477 DOI 10.1007/s00345-014-1429-8 19 July 2014 / Accepted: 19 October 2014 / Published online: 4 November 2014 © The Author(s) 2014. This article is published with open access at Springerlink.com
2 Chan KF, Vassar GJ, Pfefer TJ, Teichman JM, Glickman RD, Weintraub ST, et al. Holmium:YAG laser lithotripsy: a dominant photothermal ablative mechanism with chemical decomposition of urinary calculi. Lasers Surg Med (1999) 25(1):22–37. doi:10.1002/(SICI)1096-9101(1999)25:1<22::AID-LSM4>3.3. CO;2-Y
3 Impact of pulse duration on Ho:YAG laser lithotripsy: fragmentation and dusting performance
Markus J. Bader · Thomas Pongratz · Wael Khoder · Christian G. Stief · Thomas Herrmann · Udo Nagele · Ronald Sroka