Table 3.
Prior experimental studies exploring operating characteristics of the Thulium fiber laser
| References | Year | Aim of the study | Study settings | Laser settings | Primary outcome | Secondary outcomes |
|---|---|---|---|---|---|---|
| Fried et al. [59] | 2005 | To explore the Thulium fiber laser in pulsed mode for lithotripsy | 300 µm core diameter fiber | 1.0 J × 10 Hz at 20,000 µs pulse duration | In pulsed mode, Thulium fiber laser is capable of lithotripsy of COM and UA stones | – |
| Scott et al. [40] | 2009 | To explore ≤ 200 µm core diameter fibers for Thulium fiber laser lithotripsy | Laser fibers with 100, 150, and 200 μm core diameters; lithotripsy on COM and UA stones | 0.07 J × 10–30 Hz at 1000 µs pulse duration | No damage to 100, 150, and 200 μm fibers below 40, 60, and 80 W, respectively | Endoscope irrigation flow decreased by 26%, and 42% for 100 and 200 μm fibers, compared to empty working channel; much more uniform laser beam in favor of the Thulium fiber laser compared to Holmium:YAG laser |
| Blackmon et al. [60] | 2010 | To explore a new tapered distal laser fiber tip for Thulium fiber laser lithotripsy | 150 µm core diameter fiber with a 300 µm distal diameter | 0.07 J × 10 Hz at 1000 µs pulse duration | Lower fiber damage in favor of the tapered tip | No impact of the tapered tip design on stone ablation efficiency, scope deflection, and irrigation flow rates |
| Blackmon et al. [61] | 2012 | To explore electronic modulation for Thulium fiber laser lithotripsy | 100 µm core diameter fiber; lithotripsy on COM and UA stones | 0.035 J × micro-pulse mode or 0.035 J × standard pulse mode | 2 times higher ablation efficiency in favor of the micro-pulse mode | Comparable fiber deterioration and stone retropulsion between micro-pulse and standard mode |
| Hutchens et al. [62] | 2013 | To explore a new detachable distal fiber tip for Thulium fiber laser lithotripsy | New construct of a detachable 300 µm core diameter distal fiber tip that can be attached to a conventional 150 µm core diameter fiber; lithotripsy on COM stones | 0.03 J × 20 Hz at 500 µs pulse duration | The detachable distal tip is operable | Similar stone ablation rates compared to conventional tapered distal fiber tip |
| Hutchens et al. [63] | 2013 | To explore a new hollow steel at the distal fiber tip for Thulium fiber laser lithotripsy | 150 µm core diameter fiber with a new construct of a 1-cm long steel tube that was glued to the distal tip; lithotripsy on COM stones | 0.034 J × 150 Hz at 500 µs pulse duration | Significantly lower fiber deterioration in favor of the new hollow steel construct | Comparable stone ablation rates to conventional 150 µm core diameter fiber; increased stone retropulsion with the new hollow steel construct |
| Hardy et al. [64] | 2014 | To explore Thulium fiber laser lithotripsy at 500 Hz | 100 µm core diameter fiber; lithotripsy on COM and UA stones; a nitinol basket is used | 0.035 J × 500 Hz at 500 µs pulse duration | Lithotripsy at 500 Hz is feasible | – |
| Blackmon et al. [42] | 2014 | To explore a 50 µm core diameter fiber for Thulium fiber laser lithotripsy | 50 µm core diameter fiber; lithotripsy on COM stones | 0.035 J × 50 Hz at 500 µs pulse duration | Delivery of up to 15 W under extreme bending (5 mm radius) | Endoscope irrigation flow decreased by only 10% compared to empty working channel; up to 3 mm fiber deterioration at the distal tip after 2 min of lithotripsy |
| Wilson [65] | 2015 | To explore damages to a nitinol basket by the Thulium fiber laser | 100 µm core diameter fiber; laser firing with varying working distance to nitinol wires | 0.035 J × 50–500 Hz at 500 µs pulse duration | No nitinol damage at a distance ≥ 1 mm | – |
| Wilson [66] | 2016 | To explore a new 100 µm core diameter fiber with a distal ball-tip design for Thulium fiber laser lithotripsy | 100 µm core diameter fiber with a 300 µm distal ball-tip design; lithotripsy on COM stones | 0.035 J × 300 Hz at 500 µs pulse duration | Similar lithotripsy efficiency compared to conventional fibers | Rapid deterioration of the ball-tip design |
| Hardy et al. [54] | 2016 | To explore bubble formation at the distal fiber tip with the Thulium fiber laser | 105 and 270 µm core diameter fibers; firing in saline | 0.005–0.065 J × at 200–1000 µs pulse duration | Maximal bubble length of 1.2 and 1.1 mm for the 105 and 270 µm fibers, respectively | – |
| Hutchens et al. [67] | 2017 | To explore a new fiber muzzle brake at the distal fiber tip for Thulium fiber laser lithotripsy | 100 µm core diameter fiber with a new muzzle brake tip construct; lithotripsy on COM stones | 0.035 J × 300 Hz at 500 µs pulse duration | 2-times lower stone retropulsion in favor of the new muzzle brake construct | No signs of distal tip fiber deterioration after lithotripsy with the new muzzle brake |
| Gonzales et al. [68] | 2018 | To characterize vapor bubble dynamics of five different distal fiber tip designs | 100 and 170 µm bare fiber tip, 150–300 µm tapered fiber tip, 100 and 300 µm ball tip fiber tip, 100 and 340 µm hollow steel tip, as well as 100 and 560 µm muzzle brake tip design | 0.0034 J at 500 µs pulse duration | Maximal bubble length and highest stone retropulsion with the hollow steel design | Minimal bubble length and lowest stone retropulsion with the muzzle brake design |
COM calcium oxalate monohydrate, UA uric acid