Abstract
Purpose. Several studies have been published on Holmium:YAG laser fibers, most of which concentrate on the physical characteristics of these fibers. Utilizing methods that simulate actual clinical use, we investigated the functionality and performance threshold of commercially available Holmium:YAG laser fibers.
Materials and Methods. Testing was conducted on single-use and reusable laser fibers in varying sizes – 200µm, 272µm, 365µm, 550µm and 1000µm. Sizes reflect the true core diameter of each fiber. Fixtures for the testing were built for the 200µm, 272µm, 365µm, 550µm fibers simulating the anatomical curvature that the fiber may be subjected to during a procedure (considered the short-term bend radius), as well as the maximum-allowed deflection of the fiber when placed within the working channel of a flexible ureteroscope. A separate fixture was built for the 1000µm fiber simulating the short-term bend radius only, as its core size does not allow for deflection or use within a flexible ureteroscope. Each fiber was placed into its respective fixture, and power outputs were recorded using the HeNe laser JDSU Model 1137 and Lumenis VersaPulse® 100W PowerSuite™ Holmium:YAG laser generator. The SMA-905 connector of each fiber was first connected to the HeNe laser to determine the fiber’s spot size, and the power output was recorded. The fiber was subsequently connected to the Lumenis VersaPulse® 100W PowerSuite™ Holmium:YAG laser generator, and the generator was set to the maximum-allowed power input for each fiber per the Instructions for Use. The power output was then recorded. Further tests were performed on the reusable fibers following cleaving, stripping, cleaning and resterilization, and following transportation and extreme conditioning, and aging. Tests were also carried out on non-sterile laser fibers to evaluate the complete downstream process effect study. To pass testing, the laser fibers had to meet the acceptance criteria of transmitting 80% or greater of the maximum power inputs for both the HeNe and Holmium:YAG lasers. Acceptance criteria also included no known nonconformances reported with either the laser fiber or the laser generator.
Results. Functionality and performance of the BARD® ENDOBEAM™ Holmium Laser Fibers were confirmed following a four-month testing period consisting of 4,530 total runs – 2,409 performed on the HeNe laser Model 1137 and 2,121 performed on the Lumenis VersaPulse® 100W Powersuite™. All sizes of the ENDOBEAM™ Holmium Laser Fibers demonstrated consistent power outputs greater than or equal to 80% transmission of maximum power input in short-term bend radius and maximum-allowed deflection angles on the two lasers. Conversely, the AMS SureFlex 200µm single-use laser fiber demonstrated 10% less power output compared to the ENDOBEAM™ 200µm single use laser fiber, when subjected to the same testing. In the same model, 25% of SureFlex 200µm single-use laser fibers demonstrated breakage at the apex of the deflection curve and failed to transmit power into the distal tip when subjected to the maximum-allowed power input of 25W. There were no statistical differences among the study endpoint populations.
Conclusions. Commercially available Holmium:YAG laser fibers differ significantly in their performance characteristics when subjected to simulations of clinical use in a bench top model.
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Jacky G. Duchamp, MS
Employee of C. R. Bard, Inc., Covington, Georgia
