The Holmium:YAG laser is preferred by urologists because of its multiple uses in cutting or coagulating a variety of soft tissues and fragmentation of kidney stones, due to its relatively low cost, high power, and high water absorption in tissue at the emission wavelength of 2120 nm. This instrument is passed to the stone’s location in the urinary tract where the stone is fragmented in place. 1 To treat urinary stone disease, an endoscopic approach is commonly used with a laser fiber inserted through the working channel of a ureteroscope. In 2013, 49 million kidney stone cases occurred globally. population will suffer from urinary stone disease in their lifetime. Small stones with a mass of 40 ± 4 mg and 4-mm-diameter were ablated over a 1.5-mm sieve in 25 ± 4 sĪpproximately 10% of the U.S. Stone phantom retropulsion, fiber tip burnback, and calcium oxalate stone ablation studies were performed ex vivo. The fiber tip was recessed a distance of 500 μ m.

The optimal stainless steel muzzle brake tip tested consisted of a 1-cm-long, 560 - μ m-outer-diameter, 360 - μ m-inner-diameter tube with a 275 - μ m-diameter through hole located 250 μ m from the distal end.

TFL lithotripsy studies were performed at 1908 nm, 35 mJ, 500 μ s, and 300 Hz using a 100 - μ m-core fiber. A “fiber muzzle brake” was tested for reducing both fiber burnback and stone retropulsion by manipulating vapor bubble expansion. Previous studies utilizing hollow steel sheaths around recessed distal fiber tips reduced fiber burnback but increased stone retropulsion. However, distal fiber tip burnback increases as fiber diameter decreases. A smaller fiber is desirable because it provides more space in the ureteroscope working channel for increased saline irrigation rates and allows maximum ureteroscope deflection. The near single-mode TFL beam allows coupling of higher power into smaller optical fibers than the multimode Holmium laser beam profile, without proximal fiber tip degradation. The experimental thulium fiber laser (TFL) is being explored as an alternative to the current clinical gold standard Holmium:YAG laser for lithotripsy.

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