title: Fiber optic muzzle brake tip for reducing fiber burnback and stone retropulsion during thulium fiber laser lithotripsy.
abstract: The experimental thulium fiber laser (TFL) is being explored as an alternative to the current clinical gold standard Holmium:YAG laser for lithotripsy. 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. 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. However, distal fiber tip burnback increases as fiber diameter decreases. Previous studies utilizing hollow steel sheaths around recessed distal fiber tips reduced fiber burnback but increased stone retropulsion. A “fiber muzzle brake” was tested for reducing both fiber burnback and stone retropulsion by manipulating vapor bubble expansion. TFL lithotripsy studies were performed at 1908 nm, 35 mJ, 500 ?? ? s , and 300 Hz using a 100 - ? m -core fiber. The optimal stainless steel muzzle brake tip tested consisted of a 1-cm-long, 560 - ? m -outer-diameter, 360 - ? m -inner-diameter tube with a 275 - ? m -diameter through hole located 250 ?? ? m from the distal end. The fiber tip was recessed a distance of 500 ?? ? m . Stone phantom retropulsion, fiber tip burnback, and calcium oxalate stone ablation studies were performed ex vivo. Small stones with a mass of 40 ± 4 ?? mg and 4-mm-diameter were ablated over a 1.5-mm sieve in 25 ± 4 ?? s
authors.affiliation: University of North Carolina at Charlotte, Department of Physics and Optical Science, 9201 University City Boulevard, Charlotte, North Carolina 28223, United States.
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Hutchens
authors.affiliation: University of North Carolina at Charlotte, Department of Physics and Optical Science, 9201 University City Boulevard, Charlotte, North Carolina 28223, United States.
authors.forename: David A
authors.initials: DA
authors.lastname: Gonzalez
authors.affiliation: Carolinas Medical Center, McKay Department of Urology, 1023 Edgehill Road South, Charlotte, North Carolina 28207, United States.
authors.forename: Pierce B
authors.initials: PB
authors.lastname: Irby
authors.affiliation: University of North Carolina at Charlotte, Department of Physics and Optical Science, 9201 University City Boulevard, Charlotte, North Carolina 28223, United StatesbCarolinas Medical Center, McKay Department of Urology, 1023 Edgehill Road South, Charlotte, North Carolina 28207, United States.
authors.forename: Nathaniel M
authors.initials: NM
authors.lastname: Fried
mesh_terms: D005336:Fiber Optic Technology; D017602:Lithotripsy, Laser / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods; D055100:Optical Fibers; D013932:Thulium
chemical_list: D013932:Thulium