High-Power Thulium Fiber Laser Ablation of Urinary Tissues at 1.94 µm

TLDR

Rapid vaporization of prostate and precise incision of urethral/bladder‑neck strictures will require higher‑power thulium fiber lasers and shorter pulse lengths before clinical use. This study preliminarily evaluates the thulium fiber laser as a potential replacement for the holmium:YAG laser in urological applications. A 40‑W thulium fiber laser at 1.94 µm was delivered in continuous‑wave or 10‑ms pulsed mode through 300‑ or 600‑µm low‑OH silica fibers to vaporize canine prostate and incise ureter and bladder‑neck tissues. The laser vaporized prostate tissue at 0.21 ± 0.02 g/min, produced 500–2000 µm coagulation zones for hemostasis, and achieved 400–600 µm coagulation in bladder and ureter incisions, offering smaller size, higher efficiency, more precise incisions, and dual‑mode operation compared to holmium:YAG.

Abstract

Purpose: This paper describes the preliminary testing of a new laser, the thulium fiber laser, as a potential replacement for the holmium:YAG laser for multiple applications in urology. Materials and Methods: A 40 W thulium fiber laser operating at a wavelength of 1.94 µm delivered radiation in a continuous-wave or pulsed mode (10 msec) through either 300-µm- or 600-µm-core low-OH silica fibers for vaporization of canine prostate and incision of animal ureter and bladder-neck tissues. Results: The thulium fiber laser vaporized prostate tissue at a rate of 0.21 ± 0.02 g/min. The thermal-coagulation zone measured 500 to 2000 µm, demonstrating the potential for hemostasis. Laser incisions were also made in bladder tissue and ureter, with coagulation zones of 400 to 600 µm. Conclusions: The thulium fiber laser has several potential advantages over the holmium laser, including smaller size, more efficient operation, more precise incision of tissues, and operation in either the pulsed or the continuous-wave mode. However, before clinical use will be possible, development of higher-power thulium fiber lasers and shorter pulse lengths will be necessary for rapid vaporization of the prostate and more precise incision of urethral/bladder-neck strictures, respectively.