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Holmium:Yttrium-Aluminum-Garnet Laser Pulse Type Affects Irrigation Temperatures in a Benchtop Ureteral Model.
J Endourol 2019; 33(11):896-901JE

Abstract

Introduction: MOSES™ technology is a holmium:yttrium-aluminum-garnet 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. Although previous 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 365 μm laser fiber was placed in an 11/13 F access sheath inserted into a 50 mL 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 seconds at 0.6 J/6 Hz, 0.8 J/8 Hz, 1 J/10 Hz, 1 J/20 Hz, and 0.2 J/70 Hz at irrigation pressure of 100 mmHg. Four runs were tested per setting using short pulse, long pulse (LP), MOSES-contact (MC), and MOSES-distance (MD) modes. The mean temperature changes (dT) were compared and thermal dose was 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 0.8 J/8 Hz, LP produced the greatest dT, significantly higher than MC (p = 0.041). CEM43 did not exceed the injury threshold. At 1 J/10 Hz, dT was significantly higher for LP versus MC and MD (p = 0.024 and 0.045, respectively). Thermal dose remained below the injury threshold. No differences in dT were seen between pulse types at 0.6 J/6 Hz, 0.2 J/70 Hz, or 1 J/20 Hz. At 1 J/20 Hz, thermal dose exceeded the injury threshold for all pulse types within 3 seconds.

Conclusions:

Laser pulse type and length seemed to impact heat production in our ureteral model. LP produced significantly greater temperatures at 0.8 J/8 Hz and 1 J/10 Hz relative to MOSES settings. Fortunately, thermal dose remained safe at these settings. Both LP and MOSES technology have been shown to reduce stone retropulsion. At power ≤10 W, the latter may confer this advantage with decreased heat production.

Authors+Show Affiliations

Division of Urologic Surgery, Duke University Medical Center, Durham, North Carolina.Division of Urologic Surgery, Duke University Medical Center, Durham, North Carolina.Division of Urologic Surgery, Duke University Medical Center, Durham, North Carolina.Division of Urologic Surgery, Duke University Medical Center, Durham, North Carolina.Division of Urology, Brigham and Women's Hospital, Boston, Massachusetts.Duke University School of Medicine, Durham, North Carolina.Duke-NUS Medical School, Singapore.Division of Urologic Surgery, Duke University Medical Center, Durham, North Carolina.Division of Urologic Surgery, Duke University Medical Center, Durham, North Carolina.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

31418291

Citation

Winship, Brenton, et al. "Holmium:Yttrium-Aluminum-Garnet Laser Pulse Type Affects Irrigation Temperatures in a Benchtop Ureteral Model." Journal of Endourology, vol. 33, no. 11, 2019, pp. 896-901.
Winship B, Terry R, Boydston K, et al. Holmium:Yttrium-Aluminum-Garnet Laser Pulse Type Affects Irrigation Temperatures in a Benchtop Ureteral Model. J Endourol. 2019;33(11):896-901.
Winship, B., Terry, R., Boydston, K., Carlos, E., Wollin, D., Peters, C., ... Lipkin, M. (2019). Holmium:Yttrium-Aluminum-Garnet Laser Pulse Type Affects Irrigation Temperatures in a Benchtop Ureteral Model. Journal of Endourology, 33(11), pp. 896-901. doi:10.1089/end.2019.0496.
Winship B, et al. Holmium:Yttrium-Aluminum-Garnet Laser Pulse Type Affects Irrigation Temperatures in a Benchtop Ureteral Model. J Endourol. 2019;33(11):896-901. PubMed PMID: 31418291.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Holmium:Yttrium-Aluminum-Garnet Laser Pulse Type Affects Irrigation Temperatures in a Benchtop Ureteral Model. AU - Winship,Brenton, AU - Terry,Russell, AU - Boydston,Kohldon, AU - Carlos,Evan, AU - Wollin,Daniel, AU - Peters,Chloe, AU - Li,Jingqiu, AU - Preminger,Glenn, AU - Lipkin,Michael, Y1 - 2019/09/25/ PY - 2019/8/17/pubmed PY - 2019/8/17/medline PY - 2019/8/17/entrez KW - laser KW - thermal injury KW - ureteroscopy KW - urolithiasis SP - 896 EP - 901 JF - Journal of endourology JO - J. Endourol. VL - 33 IS - 11 N2 - Introduction: MOSES™ technology is a holmium:yttrium-aluminum-garnet 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. Although previous 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 365 μm laser fiber was placed in an 11/13 F access sheath inserted into a 50 mL 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 seconds at 0.6 J/6 Hz, 0.8 J/8 Hz, 1 J/10 Hz, 1 J/20 Hz, and 0.2 J/70 Hz at irrigation pressure of 100 mmHg. Four runs were tested per setting using short pulse, long pulse (LP), MOSES-contact (MC), and MOSES-distance (MD) modes. The mean temperature changes (dT) were compared and thermal dose was 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 0.8 J/8 Hz, LP produced the greatest dT, significantly higher than MC (p = 0.041). CEM43 did not exceed the injury threshold. At 1 J/10 Hz, dT was significantly higher for LP versus MC and MD (p = 0.024 and 0.045, respectively). Thermal dose remained below the injury threshold. No differences in dT were seen between pulse types at 0.6 J/6 Hz, 0.2 J/70 Hz, or 1 J/20 Hz. At 1 J/20 Hz, thermal dose exceeded the injury threshold for all pulse types within 3 seconds. Conclusions: Laser pulse type and length seemed to impact heat production in our ureteral model. LP produced significantly greater temperatures at 0.8 J/8 Hz and 1 J/10 Hz relative to MOSES settings. Fortunately, thermal dose remained safe at these settings. Both LP and MOSES technology have been shown to reduce stone retropulsion. At power ≤10 W, the latter may confer this advantage with decreased heat production. SN - 1557-900X UR - https://www.unboundmedicine.com/medline/citation/31418291/Holmium:Yttrium_Aluminum_Garnet_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 -