Presentation Authors: Wilson Molina*, Kansas City, KS, Ben Chew, Vancouver, Canada, Bodo Knudsen, Columbus, OH
Introduction: The holmium-YAG (Ho:YAG) laser system (LS) is the prevailing standard of care for laser lithotripsy (LL). The Super Pulse Thulium Fiber Laser (SPTF) has emerged as an effective alternative. The temperature profiles of 120 W Ho:YAG and a 60 W SPTF LS were evaluated for thermal damage during lithotripsy.
Methods: Anterograde semi-rigid ureteroscopy with LL was performed in ex-vivo porcine urinary tracts with 3 mm Begostones. Room temperature (22C) saline was instilled using a hand pump for irrigation. Intra-ureteral temperature was measured using one probe proximal and one distal to the site of lithotripsy. LL was performed using a 200 micron core fiber utilizing dusting (SPTF- 0.1J, 200hz, Short Pulse; Ho:YAG- 0.3J, 70hz, Long Pulse) and fragmenting (0.8J, 8Hz, Short Pulse for both) parameters for 5 secs. Fifteen repetitions were recorded for each laser at each setting. Tissue samples of the ureter for each setting and system at each site of lasering were collected for histological analysis.
Results: There was a temperature rise for both laser systems at both settings, but was greater at dusting settings; however, both systems remained below the threshold for cellular injury (42C). The temperatures were greater for the Ho:YAG on the dusting setting (41.13C vs 40.46C , p=0.011). On the fragmenting setting, the temperature was greater for the SPTF (31.87C vs 29.3C, p=0.001), Fig 1. Histological analysis did not show any signs of injury or necrosis in any of the tested settings.
Conclusions: Higher power settings used for dusting have a higher temperature rise in the ureter during lasering. Ureteral intra-luminal temperature rise during LL was more pronounced on the Ho:YAG during dusting and higher in the SPTF during fragmentation, but neither reached the threshold for thermal injury and are considered safe.
Source of Funding: Olympus Corporation of the Americas.