A novel 450-nm blue laser system for surgical applications: efficacy of specific laser-tissue interactions in bladder soft tissue

Low-power blue laser allows clean cutting with little bleeding and no undesired coagulations in adjacent tissues; however, studies on high-power blue laser soft tissue ablation properties, including vaporization and coagulation, have not been reported yet. The purpose of this study is to evaluate and analyze the ablation efficacy and coagulation properties of bladder epithelium tissues with a 30-W 450-nm wavelength blue laser. Well-designed ex vivo experiments compared blue laser and 532-nm LBO green laser, both with laser power up to 30 W, for porcine bladder tissue vaporization and coagulation at different experimental parameter settings. At working distance of 1 mm and sweeping speed of 1.5 mm/s, the vaporization efficiency of blue laser and green laser was 5.14mm³/s and 1.20mm³/s, while the depth of coagulation layer was 460 ± 70 μm and 470 ± 80 μm, respectively. We found both blue laser and green laser have excellent efficacy of tissue vaporization and similar tissue coagulation properties. Moreover, in a set of in vivo experiments simulated laser transurethral resection (TUR) surgery on dogs, we found both blue laser and green laser exhibited similar and satisfactory vaporization and coagulation outcomes. Taken together, our results demonstrate that a 450-nm wavelength high-power diode blue laser, like 532-nm wavelength green laser, is capable to produce high efficient tissue vaporization, low-laser tissue penetration, good tissue coagulation, and has low thermal damage to adjacent tissues. Therefore, a 30-W blue diode laser could be a new and safe alternative for surgeries of superficial bladder diseases.