Wound healing process in beagles after vaporization of the prostate with a novel 200W 450-nm laser.

In comparison to other commercially used lasers, the coagulation layer of the novel 450-nm laser is thinner, and this coagulation layer's thickness is a key factor influencing wound healing. In this study, we investigated whether the novel 200W 450-nm laser system (BR6800, Blueray Medical Ltd., Shaanxi, China) is superior to classic transurethral resection of the prostate (TURP) for wound healing in beagles. Twenty-two 6-to 8-year-old male beagles were treated with TURP or blue laser vaporization of the prostate (BLVP). Prostate wounds were observed via cystoscopy at 3 h and at 1, 2, 3, and 5 weeks post-operation (two beagles per group). Additionally, two elderly beagles without surgery served as normal controls. After cystoscopy examination, prostate samples were collected and fixed for hematoxylin and eosin (H&E) and immunofluorescence staining to observe wound healing progression under microscopy. The urethras of prostates under cystoscopy in BLVP groups were healed three weeks after surgery, while in the TURP group, they were healed five weeks after surgery. H&E staining confirmed that the coagulation necrosis layer in the TURP group was thicker than that in the BLVP group and it took longer to remove coagulation necrosis after surgery. Macrophage polarity transformation was also earlier in the BLVP group. The new 200W 450-nm laser was superior to TURP for wound healing. The thinner coagulation layer of the 450-nm laser was the primary reason for this process.

450-nm blue diode laser: a novel medical apparatus for upper tract urothelial lesions.

OBJECTIVE: To explore the feasibility, safety and effectiveness of the 450-nm blue diode laser (BL), novel blue laser in the treatment of upper tract urothelial carcinomas (UTUCs) and other lesions in a porcine model. MATERIAL AND METHODS: For in vitro experiment, the ureter tissue was vaporised and coagulated with BL, green-light laser (GL) and Ho:YAG laser (Ho). The efficiency, width and depth of vaporisation, and depth of coagulation were recorded and compared. For in vivo experiments, four swines weighing 70 kg were used. In the acute group, different modes of operations were performed to evaluate the thermal damage, perforation and bleeding. In the chronic group, the overall appearance of the ureter and laser wound healing were observed by the naked eyes and H&E staining 3 weeks after surgery. RESULTS: In in vitro study, the BL showed a higher efficiency of tissue vaporisation and less tissue coagulation for fresh ureter compared to GL and Ho. In the in vivo study, the power of BL set at 7 W was better, and the thickness of thermal damage varied with different surgery types in the range of 74-306 µm. After 3 weeks, the wound healed well static in vaporisation (SV), moving vaporisation (MV) and H&E staining indicated mucosal healing rather than scar healing. CONCLUSION: 5-10W blue diode laser achieved a higher efficiency of tissue vaporisation and less tissue coagulation in a porcine model, indicating its potential application in the endoscopic surgery of UTUC as an optional device with high performance and safety.

Effect of near-infrared laser treatment on improving erectile function in rats with diabetes mellitus.

BACKGROUND: Diabetes mellitus-induced erectile dysfunction is difficult to treat. The oxidative stress created by diabetes mellitus is a major cause of injuries to the corpus cavernosum, thereby resulting in erectile dysfunction. Near-infrared laser has already been shown to be effective in treating multiple brain disorders because of its antioxidative stress effect. OBJECTIVES: To investigate whether a near-infrared laser improves the erectile function of diabetes mellitus-induced erectile dysfunction rats through its antioxidative stress effect. MATERIALS AND METHODS: Knowing its advantage of reasonable deep tissue penetration and good photoactivation on mitochondria, a near-infrared laser with wavelength of 808 nm was used in the experiment. Since the internal and external corpus cavernosum were covered by different tissue layers, the laser penetration rates of the internal and external corpus cavernosum were measured separately. Different radiant exposure settings were applied: in the initial experiment, 40 male Sprague-Dawley rats were randomly assigned to five groups, normal controls, and streptozotocin-induced diabetes mellitus rats that 10 weeks later received various radiant exposures (J/cm2 ) from the near-infrared laser (DM0J(DM+NIR 0 J/cm2 ), DM1J, DM2J, and DM4J) in the subsequent 2 weeks. Erectile function was then assessed 1 week after near-infrared treatment. It was found that the initial radiant exposure setting was not optimal according to the Arndt-Schulz rule. We performed a second experiment using a different radiant exposure setting. Forty male rats were randomly divided into five groups (normal controls, DM0J, DM4J, DM8J, and DM16J), and the near-infrared laser was again applied according to the new setting, and erectile function was assessed as in the first experiment. Histologic, biochemical, and proteomic analyses were then conducted. RESULTS: Recovery of erectile function of varying degrees was observed in the near-infrared treatment groups, and radiant exposure of 4 J/cm2 achieved optimal results. The DM4J group showed improvement in mitochondrial function and morphology in diabetes mellitus rats, and it was found that oxidative stress levels were significantly reduced by near-infrared exposure. The tissue structure of the corpus cavernosum was also improved by near-infrared exposure. The proteomics analysis confirming multiple biologic processes were changed by diabetes mellitus and near-infrared. DISCUSSION AND CONCLUSION: Near-infrared laser activated mitochondria, improved oxidative stress, repaired the damage to penile corpus cavernosum tissue structures caused by diabetes mellitus, and improved erectile function in diabetes mellitus rats. These results thus raise the possibility that human patients with diabetes mellitus-induced erectile dysfunction may respond to near-infrared therapy in a manner that parallels the responses we observed in animal study.

In vitro evaluation of the safety and efficacy of a high-power 450-nm semiconductor blue laser in the treatment of benign prostate hyperplasia.

A 450-nm blue laser may be suitable to treat benign prostate hyperplasia (BPH) due to its haemoglobin absorption characteristic. The present study compared a novel high-power 450-nm semiconductor blue laser with other lasers marketed for in vitro soft tissue ablation, to evaluate the safety and efficacy of the 450-nm laser in BPH surgery. With the in vitro tissues on an experimental platform in water, the vaporization efficiency and coagulation layer thickness of the novel 450-nm laser and commercially available 532-nm, 980-nm, and 1470-nm lasers were measured at the same power (120 W). The damage to the adjacent tissue and the working noise were also measured. The vaporization efficiency was proved to be 450-nm laser > 532-nm laser > 1470-nm laser > 980-nm laser. Comparison of coagulation layer thickness was as follow: 980-nm laser > 1470-nm laser > 532-nm laser > 450-nm laser. The degree of tissue damage caused by the 450-nm and 532-nm lasers increased with the decrease in distance and increase in time (these are safe when a sufficient distance and short irradiation time are maintained). The heating ability of 980-nm and 1470-nm lasers was much greater than that of 450-nm and 532-nm lasers. The working noise was lower in 450-nm and 1470-nm lasers. The novel 450-nm laser has the advantages of highly efficient tissue vaporization, creating a thin coagulation layer, and low working noise. These characteristics suggest that the novel 450-nm laser may be a promising choice for the surgical treatment of BPH.

A Novel 450 nm Semiconductor Blue Laser System for Application in Colon Endoscopic Surgery: An Ex Vivo Study of Laser-Tissue Interactions.

Objective: Our study aimed to detect whether 450 nm blue laser can be applied effectively and safely in endosocopic submucosal dissection (ESD) system for surgery in colonic tissue. Background data: Semiconductor blue laser has been applied in surgery due to its excellent cutting property, however, whether blue laser can be applied in colonic surgery has not been reported. Materials and methods: Porcine colon tissues were vaporized by 450 nm blue semiconductor laser at 10-25 W and at working distances from 0.5 to 3 mm, with a three-dimensional scanning system. Moreover, we designed an ESD model and applied blue laser at 10 W on porcine colonic tissues with this system. Dimensions of the vaporized tissues and coagulation zones were assessed under microscopy. Results: Since the thickness of colonic wall is no more than 1 mm, first we determined the cutting property and safety of blue laser on porcine colon tissue and found that blue laser at 10 W made lesions shallower than 1 mm and the depth of vaporization can be controlled effectively within muscularis mucosa and submucosa. Moreover, a large scale of porcine colonic tissue was vaporized precisely by blue laser at power of 10 W with the ESD system ex vivo. Conclusions: Our results indicate that 450 nm blue laser at 10 W can be well controlled for laser-tissue interaction with excellent cutting efficiency and less thermal damage in adjacent tissues especially side of the submucosa. Therefore, 450 nm semiconductor blue laser could be a safe alternative approach for colonic surgery.

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.