Novel thulium laser fiber appears to outperform Holmium:YAG laser

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Chicago-A new tool for kidney stone ablation demonstrates strong potential to dust and fragment stones more quickly and efficiently than devices currently available in the United States. However, clinical studies must be performed before this technology can be used during lithotripsy nationally.

Ben H. Chew, MD, MSc, associate professor of urologic sciences at the University of British Columbia, Vancouver, presented a study of the Super Pulse Thulium Fiber (SPTF) laser during a moderated poster session at the 2019 AUA annual meeting in Chicago. The study compared the SPTF laser’s ability to dust and fragment Begostones to that of a commercially available 120W Holmium:YAG laser, the current lithotrite of choice.

“The SPTF is much smaller and uses less power than the Ho:YAG laser. We basically wanted to show the best foot forward for each of them to compare their efficacy,” Dr. Chew told Urology Times.

Also see - Robotic ureteroscopy: The future of stone management?

The results of the study-performed with Bodo E. Knudsen, MD, of The Ohio State University Wexner Medical Center, Columbus, and Wilson Molina, MD, of the University of Kansas Medical Center, Kansas City-show greater potential to control stone fragmentation than lithotrites that are currently used for patient care.

Advancements to the Holmium:YAG laser have supercharged this technology for clinical use, but downsides remain, including high amperage power requirements, upper limits of pulse frequency, and limitations regarding fiber size. The SPTF laser uses Thulium Fiber-not to be mistaken with Thulium:YAG-that offers low-pulse energy settings and pulse frequencies over 600 Hz.

The authors tested the SPTF and a 120W Holmium:YAG laser in ablating standard, homogenous 5-mm³ BegoStones until remaining particles were smaller than 1 mm. To test fragmentation and dusting, resulting particle sizes were measured after delivering a total of 0.5 kJ and 2 kJ, respectively.

The results were striking. At both fragmentation and dusting settings, the SPTF was significantly faster and more efficient at ablating the entire BegoStone into fragments less than 1 mm in size.

Next: Fewer >1-mm fragments with SPFT

Fewer >1-mm fragments with SPFT

In addition, SPFT produced significantly fewer fragments that were larger than 1 mm than the 120W Holmium:YAG laser. The impact in clinical practice: fewer basket passes.

The 120W laser produced smaller fragments, but also produced more fragments. On average, use of the 120W laser would require 7.2 stones to be removed following ablation, accounting for 55% of the stones’ weight. Treatment with SPTF would require removal of 2.1 stones accounting for 85% of the stones’ weight.

SPTF produced a significantly higher number of very fine particles of dust (0.5 mm) compared with the 120W laser. Fragmentation of stones using SPTF results in finer dust compared with the 120W laser. This is likely due to the ability of the SPTF laser to generate very high frequencies and low energy settings that are not available on the 120W laser, Dr. Chew said.

Read: Stone management often falls short

Additional pre-clinical testing on the SPTF laser also was presented at the AUA annual meeting, Dr. Chew told attendees.

“We believe this approach should be more efficacious with fragmenting as well as dusting,” he said.

The study authors are paid consultants of Olympus Corp. of the Americas.