EAU 2017: Comparison Of Holmium Laser Fibers: Evaluation Of Fiber Durability And Flexibility Introduction & Objectives

London, England (UroToday.com) With increasing incidence and prevalence of stone disease, technology used for surgical treatment is constantly evolving. Holmium YAG lasers are used in an increasing manner with ureteroscopy and percutaneous stone treatments. There are new generations of laser fibers and there is a need for tests to assess their durability and efficacy. Laser fiber characteristics and design differ between the different laser fiber manufacturers and despite many past and ongoing studies, there remains a lack of comparative information regarding the decrease in energy transmission and laser fiber thermal breakdown with bending radius and different laser settings (high frequency, low energy vs medium frequency, medium energy vs low frequency, high energy).

Different laser fibers present different physical properties in terms of durability and flexibility and thus may have a different effect on the actual stone treatment. As part of the evaluation of a new ball-tip fiber, we compared four laser fibers from four different brands with regards to flexibility, diameter and resistance to high frequency and energy in a bench-testing model.

Authors used the Lumenis® Pulse 120H a 120 Watts laser with up to 80Hz properties for these experiments. Two 200µm ball-tip fibers (Lumenis SlimLine™ 200 D/F/L, and Boston Scientific (BSC) Flexiva TracTip™ 200), a standard 270µm (Dornier SingleFlex™) and a standard 272µm were compared. Authors measured the inner and outer diameters using an optical microscope. Flexibility of lasers were assessed by testing deflections with 6 different flexible ureteroscopes and a bending test was performed by lasering in different radiuses from 12 to 6mm. Fiber durability was assessed by measuring power output before and after using maximum parameters of the laser, suitable for these fibers, in terms of frequency and energy (0,5J-80Hz and 2J-30Hz for 15kJ and 2J-10Hz for 10kJ). Only the ball-tip fibers were tested, validated to endure these high-power settings. Power output was measured with a watt-meter at 5W. Every experiment was repeated 5 times for flexibility and size, 4 times for durability.

Study demonstrated that the average inner diameter of any laser fibers tested in the study. Flexibility measurements showed that Lumenis SlimLine™ 200 fibers had the lowest deflection loss compared to the others (p<0.001 ). None of the Lumenis SlimLine™ fibers broke at the bending test whereas one BSC Flexiva TracTip™ (20%) broke at 6mm radius, two Rocamed® MF272ST (40%) broke at 10mm and 6mm radius and four Dornier SingleFlex™ (80%) at 8mm (20%) and 6mm (60%) radius. At maximum parameters, authors found no differences between Lumenis SlimLine™ and BSC Flexiva TracTip™ fibers (p>0.05), all the fibers reached over 95% of their baseline power after shooting 10 to 15kJ.

In conclusion, flexibility and durability of the Holmium laser fibers are the main characteristics affecting safe and efficient lithotripsy. With the best flexibility from the study results, and equivalent durability compared to a premium fiber in the market, Lumenis SlimLine™ 200 fibers demonstrated the optimal characteristics for lithotripsy.

Speaker(s): Steve Doizi, MD

Authors: Haddad, M., Berthe, L., Doizi, S., Traxer, O.

at the #EAU17 - March 24-28, 2017- London, England

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