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Holmium:YAG Laser Pulse Type Affects Irrigation Temperatures in a Benchtop Ureteral Model.
J Endourol 2019JE

Abstract

INTRODUCTION

MOSES™ technology is a Holmium:YAG laser pulse mode shown to minimize stone retropulsion. This may facilitate lithotripsy at higher power settings. However, power and heat production are proportional, and temperatures capable of tissue injury may occur during ureteroscopic lithotripsy. While prior in vitro studies demonstrate the importance of irrigation and activation time on heat production, the impact of pulse type has not been evaluated.

METHODS

A flexible ureteroscope with a 365μm laser fiber was placed in an 11/13Fr access sheath inserted into a 250cmL saline bag to simulate a ureter, renal pelvis, and antegrade irrigant flow. A thermocouple was placed adjacent to the laser tip, and the laser fired for 30 sec at 0.6J/6Hz, 0.8J/8Hz, 1J/10Hz, 1J/20Hz, and 0.2J/70Hz at irrigation pressure of 100mmHg. 4 runs were tested per setting using short pulse(SP), long pulse(LP), MOSES-contact(MC) and MOSES-distance(MD) modes. The mean temperature changes(dT) were compared and thermal dose calculated in Cumulative Equivalent Minutes at 43°C(CEM43) using an adjusted baseline of 37°C. CEM43 ≥120 minutes was considered the tissue injury threshold.

RESULTS

At 0.8J/8Hz, LP produced the greatest dT, significantly higher than MC(p=0.041). CEM43 did not exceed the injury threshold. At 1J/10Hz, dT was significantly higher for LP versus MC and MD(p=0.024, 0.045). Thermal dose remained below the injury threshold. No differences in dT were seen between pulse types at 0.6J/6Hz, 0.2J/70Hz, or 1J/20Hz. At 1J/20Hz, thermal dose exceeded the injury threshold for all pulse types within 3 seconds.

CONCLUSIONS

Laser pulse type and length appears to impact heat production in our ureteral model. Long pulse produced significantly greater temperatures at 0.8J/8Hz and 1J/10Hz relative to MOSES™ settings. Fortunately, thermal dose remained safe at these settings. Both long pulse and MOSES™ technology are known to reduce stone retropulsion; the latter may confer this advantage with reduced heat.

Authors+Show Affiliations

Duke University Hospital, 22957, Urology, DUMC 3167, 40 Duke Medicine Circle, 1573 Duke South, Durham, North Carolina, United States, 27710; brwinship@gmail.com.Duke University Hospital, 22957, Division of Urology, Rm 1573 White Zone, Duke South, DUMC 3167, Durham, North Carolina, United States, 27710; Russell.terry@duke.edu.Duke University Hospital, 22957, Division of Urology, 2301 Erwin Rd, Durham, North Carolina, United States, 27710; kohldon.boydston@duke.edu.Duke University Medical Center, Urology, Durham, North Carolina, United States; evan.carlos@duke.edu.Duke University Hospital, 22957, Division of Urology, 2301 Erwin Road, Durham, North Carolina, United States, 27710; daniel.wollin@gmail.com.Duke University School of Medicine, 12277, 3100 Tower Blvd, Durham, North Carolina, United States, 27707; chloe.peters@duke.edu.Duke-NUS Medical School, 121579, Singapore, Singapore; jingqiuli0808@gmail.com.Duke University Medical Center, Urology, DUMC 3167, Durham, North Carolina, United States, 27710; glenn.preminger@duke.edu.Duke University Medical Center, Surgery, Urology, DUMC 3167, Durham, North Carolina, United States, 27710; michael.lipkin@duke.edu.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

31418291

Citation

Winship, Brenton, et al. "Holmium:YAG Laser Pulse Type Affects Irrigation Temperatures in a Benchtop Ureteral Model." Journal of Endourology, 2019.
Winship B, Terry R, Boydston K, et al. Holmium:YAG Laser Pulse Type Affects Irrigation Temperatures in a Benchtop Ureteral Model. J Endourol. 2019.
Winship, B., Terry, R., Boydston, K., Carlos, E. C., Wollin, D. A., Peters, C., ... Lipkin, M. E. (2019). Holmium:YAG Laser Pulse Type Affects Irrigation Temperatures in a Benchtop Ureteral Model. Journal of Endourology, doi:10.1089/end.2019.0496.
Winship B, et al. Holmium:YAG Laser Pulse Type Affects Irrigation Temperatures in a Benchtop Ureteral Model. J Endourol. 2019 Aug 16; PubMed PMID: 31418291.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Holmium:YAG Laser Pulse Type Affects Irrigation Temperatures in a Benchtop Ureteral Model. AU - Winship,Brenton, AU - Terry,Russell, AU - Boydston,Kohldon, AU - Carlos,Evan Clayton, AU - Wollin,Daniel Arthur, AU - Peters,Chloe, AU - Li,Jingqiu, AU - Preminger,Glenn M, AU - Lipkin,Michael Eric, Y1 - 2019/08/16/ PY - 2019/8/17/entrez JF - Journal of endourology JO - J. Endourol. N2 - INTRODUCTION: MOSES™ technology is a Holmium:YAG laser pulse mode shown to minimize stone retropulsion. This may facilitate lithotripsy at higher power settings. However, power and heat production are proportional, and temperatures capable of tissue injury may occur during ureteroscopic lithotripsy. While prior in vitro studies demonstrate the importance of irrigation and activation time on heat production, the impact of pulse type has not been evaluated. METHODS: A flexible ureteroscope with a 365μm laser fiber was placed in an 11/13Fr access sheath inserted into a 250cmL saline bag to simulate a ureter, renal pelvis, and antegrade irrigant flow. A thermocouple was placed adjacent to the laser tip, and the laser fired for 30 sec at 0.6J/6Hz, 0.8J/8Hz, 1J/10Hz, 1J/20Hz, and 0.2J/70Hz at irrigation pressure of 100mmHg. 4 runs were tested per setting using short pulse(SP), long pulse(LP), MOSES-contact(MC) and MOSES-distance(MD) modes. The mean temperature changes(dT) were compared and thermal dose calculated in Cumulative Equivalent Minutes at 43°C(CEM43) using an adjusted baseline of 37°C. CEM43 ≥120 minutes was considered the tissue injury threshold. RESULTS: At 0.8J/8Hz, LP produced the greatest dT, significantly higher than MC(p=0.041). CEM43 did not exceed the injury threshold. At 1J/10Hz, dT was significantly higher for LP versus MC and MD(p=0.024, 0.045). Thermal dose remained below the injury threshold. No differences in dT were seen between pulse types at 0.6J/6Hz, 0.2J/70Hz, or 1J/20Hz. At 1J/20Hz, thermal dose exceeded the injury threshold for all pulse types within 3 seconds. CONCLUSIONS: Laser pulse type and length appears to impact heat production in our ureteral model. Long pulse produced significantly greater temperatures at 0.8J/8Hz and 1J/10Hz relative to MOSES™ settings. Fortunately, thermal dose remained safe at these settings. Both long pulse and MOSES™ technology are known to reduce stone retropulsion; the latter may confer this advantage with reduced heat. SN - 1557-900X UR - https://www.unboundmedicine.com/medline/citation/31418291/Holmium:YAG_Laser_Pulse_Type_Affects_Irrigation_Temperatures_in_a_Benchtop_Ureteral_Model L2 - https://www.liebertpub.com/doi/full/10.1089/end.2019.0496?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -