Evaluation of 24 Holmium:YAG Laser Optical Fibers for Flexible Ureteroscopy

Purpose

Prior study has shown that holmium:YAG laser fiber performance differs among manufacturers. We determined the performance and threshold for failure of 24 commercially available holmium:YAG laser fibers.

Materials and Methods

Single use and reusable fibers were tested in small (150 to 300 μm) and medium (300 to 400 μm) core diameter sizes. All fibers were evaluated for flexibility, failure threshold and true fiber diameter. Flexibility was measured by maximally deflecting a Stryker® U-500 ureteroscope with the fiber in the working channel. The diameter of each fiber was measured by a digital micrometer. The failure threshold was assessed by bending the fibers to 180 degrees, beginning with a radius of 1.25 cm. A VersaPulse® 100 W holmium:YAG laser was operated at 1.2 J and 10 Hz for 1 minute or until fiber fracture. The bend radius was decreased in 0.25 cm increments and testing was repeated until a minimum bend radius of 0.5 cm was attained or until the fiber failed.

Results

Of the small core fibers the SureFlex™ LLF-150 and LLF-273, OptiLite™ SMH1020F and Dornier® LG Super 270 had the highest threshold for failure. The Accuflex® 200 had the lowest failure threshold failing at the largest bend radius (1.75 cm). Of the medium core fibers the SureFlex LLF-365, Accuflex 365 and Lumenis® SL 365 had the highest failure threshold, while the Dornier LG 400 and Lumenis EZ SL 365 were the lowest. The reusable Lumenis 365 fiber had a higher failure threshold than the single use Lumenis 365 fiber.

Conclusions

Commercially available holmium:YAG laser fibers differ significantly in their performance characteristics.

Key Words: urinary calculi, lasers, solid-state, lithotripsy, ureteroscopes, optical fibers