Our laboratory is studying the experimental Thulium fiber laser (TFL) as an alternative lithotripter to clinical gold
standard Holmium:YAG laser. Safety studies characterizing undesirable Holmium laser-induced damage to Nitinol
stone baskets have been previously reported. Similarly, this study characterizes TFL induced stone basket damage.
A TFL beam with pulse energy of 35 mJ, pulse duration of 500 μs, and pulse rates of 50-500 Hz was delivered
through 100-μm-core optical fibers, to a standard 1.9-Fr Nitinol stone basket wire. Stone basket damage was graded
as a function of pulse rate, number of pulses, and working distance. Nitinol wire damage decreased with working
distance and was non-existent at distances greater than 1.0 mm. In contact mode, 500 pulses delivered at pulse rates
≥ 200 Hz (≤ 2.5 s) were sufficient to cut Nitinol wires. The Thulium fiber laser, operated in low pulse energy and
high pulse rate mode, may provide a greater safety margin than standard Holmium laser for lithotripsy, as evidenced
by shorter non-contact working distances for stone basket damage than previously reported with Holmium laser.