Collateral damage to the ureter and Nitinol stone baskets during thulium fiber laser lithotripsy

Wilson, Christopher R.; Hardy, Luke A.; Irby, Pierce B.; Fried, Nathaniel M.

doi:10.1002/lsm.22348

Cited by 28 publications

(14 citation statements)

References 36 publications

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“…Table shows a trend of increasing bubble dimensions (both length and width) as pulse energy increases. The mean TFL bubble length of 1200 ± 90 µm for the 105 µm fiber is consistent with results found in our previous studies, in which undesirable TFL ablation and collateral damage to the ureter and Nitinol stone baskets stalled out at working distances greater than 1.0 mm . Table exhibits similar trends as Table , however, bubble widths are larger for 270 µm fiber than for 105 µm fiber.…”

Section: Resultsmentioning

confidence: 99%

“…The bubble expansion only had to counteract pressure acting from an angle of 180 degrees instead of 360 degrees. This explanation is also consistent with observations that TFL provides improved ablation in contact mode . When the fiber was a short distance away from the stone surface, a portion of the energy was used for creating multiple bubbles between the fiber and stone surface.…”

Section: Discussionmentioning

confidence: 99%

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Analysis of thulium fiber laser induced bubble dynamics for ablation of kidney stones

Hardy

Kennedy

Wilson

et al. 2016

Journal of Biophotonics

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The Thulium fiber laser (TFL) is being explored as an alternative to the Holmium : YAG laser for lithotripsy. TFL parameters differ in several fundamental ways from Holmium laser, including smaller fiber delivery, more strongly absorbed wavelength, low pulse energy/high pulse rate operation, and more uniform temporal pulse structure. High speed imaging of laser induced bubbles was performed at 105,000 frames per second and 10 μm spatial resolution to determine influence of these laser parameters on bubble formation and needle hydrophone data was also used to measure pressure transients. The TFL was operated at 1908 nm with pulse energies of 5-65 mJ, and pulse durations of 200-1000 μs, delivered through 105-μm-core and 270-μm-core silica optical fibers. Bubble dynamics using Holmium laser at a wavelength of 2100 nm with pulse energies of 200-1000 mJ and pulse duration of 350 μs was studied, for comparison. A single, 500 μs TFL pulse produced a bubble stream extending 1200 ± 90 μm and 1070 ± 50 μm from fiber tip, with maximum bubble widths averaging 650 ± 20 μm and 870 ± 40 μm (n = 4), for 105 μm and 270 μm fibers, respectively. These observations are consistent with previous studies which reported TFL ablation stallout at working distances beyond 1.0 mm. TFL bubble dimensions were four times smaller than for Holmium laser due to lower peak power and smaller fiber diameter used. The maximum pressure transients measured 0.6 bars at 35 mJ pulse energy for TFL and 7.5 bars at 600 mJ pulse energy for Holmium laser. These fundamental studies of bubble dynamics as a function of specific laser and fiber parameters may assist with optimization of the TFL parameters for safe and efficient lithotripsy in the clinic. Image of bubble formation during fiber optic delivery of Thulium fiber laser energy in saline (35 mJ, 500 μs).

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Analysis of thulium fiber laser induced bubble dynamics for ablation of kidney stones

Hardy

Kennedy

Wilson

et al. 2016

Journal of Biophotonics

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“…5(c)]. 33 The longer cavitation bubble stream observed using the ball-tip fiber [ Fig. 5(a)] may potentially translate into noncontact TFL lithotripsy at even longer working distances than 1 mm, but this remains to be studied in more detail.…”

Section: Discussionmentioning

confidence: 99%

Miniature ball-tip optical fibers for use in thulium fiber laser ablation of kidney stones

et al. 2016

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Optical fibers, consisting of 240-μm-core trunk fibers with rounded, 450-μm-diameter ball tips, are currently used during Holmium:YAG laser lithotripsy to reduce mechanical damage to the inner lining of the ureteroscope working channel during fiber insertion and prolong ureteroscope lifetime. Similarly, this study tests a smaller, 100-μm-core fiber with 300-μm-diameter ball tip during thulium fiber laser (TFL) lithotripsy. TFL was operated at a wavelength of 1908 nm, with 35-mJ pulse energy, 500-μs pulse duration, and 300-Hz pulse rate. Calcium oxalate/phosphate stone samples were weighed, laser procedure times were measured, and ablation rates were calculated for ball tip fibers, with comparison to bare tip fibers. Photographs of ball tips were taken before and after each procedure to track ball tip degradation and determine number of procedures completed before need for replacement. A high speed camera also recorded the cavitation bubble dynamics during TFL lithotripsy. Additionally, saline irrigation rates and ureteroscope deflection were measured with and without the presence of TFL fiber. There was no statistical difference (P > 0.05) between stone ablation rates for single-use ball tip fiber (1.3 AE 0.4 mg∕s) (n ¼ 10), multiple-use ball tip fiber (1.3 AE 0.5 mg∕s) (n ¼ 44), and conventional single-use bare tip fibers (1.3 AE 0.2 mg∕s) (n ¼ 10). Ball tip durability varied widely, but fibers averaged greater than four stone procedures before failure, defined by rapid decline in stone ablation rates. Mechanical damage at the front surface of the ball tip was the limiting factor in fiber lifetime. The small fiber diameter did not significantly impact ureteroscope deflection or saline flow rates. The miniature ball tip fiber may provide a cost-effective design for safe fiber insertion through the ureteroscope working channel and into the ureter without risk of instrument damage or tissue perforation, and without compromising stone ablation efficiency during TFL lithotripsy.

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“…In 2005, the first report on Thulium fiber laser lithotripsy adapted a continuous-wave generator to operate in a pulsed mode and demonstrated the feasibility of lithotripsy on COM and UA stones [59]. Thereafter, fibers with a core diameter as small as 50-150 µm were repeatedly reported to efficiently deliver Thulium fiber laser beam on urinary stones [40,42,54,[60][61][62][63][64][65][66][67][68]. Also, cumulative evidence from a series of studies on distal fiber tip design suggests the muzzle tip design for prevention of stone retropulsion during Thulium fiber laser delivery [60,62,63,67,68].…”

Section: Higher Frequencymentioning

confidence: 99%

Thulium fiber laser: the new player for kidney stone treatment? A comparison with Holmium:YAG laser

2019

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Purpose To compare the operating modes of the Holmium:YAG laser and Thulium fiber laser. Additionally, currently available literature on Thulium fiber laser lithotripsy is reviewed. Materials and methods Medline, Scopus, Embase, and Web of Science databases were searched for articles relating to the operating modes of Holmium:YAG and Thulium fiber lasers, including systematic review of articles on Thulium fiber laser lithotripsy. Results The laser beam emerging from the Holmium:YAG laser involves fundamental architectural design constraints compared to the Thulium fiber laser. These differences translate into multiple potential advantages in favor of the Thulium fiber laser: four-fold higher absorption coefficient in water, smaller operating laser fibers (50-150 µm core diameter), lower energy per pulse (as low as 0.025 J), and higher maximal pulse repetition rate (up to 2000 Hz). Multiple comparative in vitro studies suggest a 1.5-4 times faster stone ablation rate in favor of the Thulium fiber laser. Conclusions The Thulium fiber laser overcomes the main limitations reported with the Holmium:YAG laser relating to lithotripsy, based on preliminary in vitro studies. This innovative laser technology seems particularly advantageous for ureteroscopy and may become an important milestone for kidney stone treatment.

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Collateral damage to the ureter and Nitinol stone baskets during thulium fiber laser lithotripsy

Cited by 28 publications

References 36 publications

Analysis of thulium fiber laser induced bubble dynamics for ablation of kidney stones

Analysis of thulium fiber laser induced bubble dynamics for ablation of kidney stones

Miniature ball-tip optical fibers for use in thulium fiber laser ablation of kidney stones

Thulium fiber laser: the new player for kidney stone treatment? A comparison with Holmium:YAG laser

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