Thulium fiber laser lithotripsy: an in vitro analysis of stone fragmentation using a modulated 110-watt Thulium fiber laser at 1.94 microm.
OBJECTIVE
The high-power Thulium fiber laser has previously been shown to rapidly vaporize and coagulate soft urinary tissues (e.g., prostate). This is the first preliminary study of a high-power Thulium fiber laser for fragmentation of urinary stones.


METHODS
A continuous-wave, high-power Thulium fiber laser operating at a wavelength of 1.94 microm, was modulated to operate in pulsed mode with an output pulse energy of 1 J through a 300-microm-core silica fiber at a 20 milliseconds pulse length and repetition rate of 10 Hz. The fragmentation time to reduce uric acid (UA) (n = 13) and calcium oxalate monohydrate (COM) (n = 6) stones into particles < 2 mm was measured.


RESULTS
Mean initial mass of the UA and COM stones measured 860+/-211 and 763 +/- 204 mg. Fragmentation rates measured 388 +/- 49 and 25 +/- 2 mg/minute. Average time needed to fragment the UA and COM stones into particles < 2 mm was 2.25 +/- 0.63 and 30.7 +/- 8.4 minutes, respectively.


CONCLUSIONS
The high-power Thulium fiber laser, when operated in pulsed mode, is capable of fragmenting both soft (UA) and hard (COM) urinary stones. The Thulium fiber laser may be useful as a single laser system for use in multiple soft and hard tissue laser ablation applications in urology.
Fried
Nathaniel M
NM
Department of Urology, Johns Hopkins Medical Institutions, Hopkins Bayview Medical Center, 4940 Eastern Avenue, Bldg. A, Baltimore, MD 21224, USA. nfried@jhmi.edu
D002129:Calcium Oxalate / Q000528:radiation effects; D006801:Humans; D066298:In Vitro Techniques; D017602:Lithotripsy, Laser / Q000379:methods*; D008670:Metals / Q000627:therapeutic use; D013932:Thulium / Q000627:therapeutic use; D014527:Uric Acid / Q000528:radiation effects; D014545:Urinary Calculi / Q000628:therapy*
D008670:Metals; D002129:Calcium Oxalate; D014527:Uric Acid; D013932:Thulium