Thermal coagulum formation and hemostasis during repeated multipulse Nd:YAG laser treatment of cutaneous vascular lesions: animal experiment study

A feasible way to explore real blood vessels thermal responses to laser irradiation by combing optical clearing and the reflectance spectra measurements: animal experiment study

Laser therapy has been widely used to treat port-wine stains (PWS) and other cutaneous vascular lesions via selective photothermolysis. Animal models are a valuable tool for investigating thermal responses beneath the skin. However, in previous animal experiments, such as the dorsal skin chamber model, one side of the skin was removed, resulting in the loss of mechanical support for the target blood vessel. In this study, the optical clearing technique was applied to the dorsal skin, allowing direct observation of real thermal responses within the tissue without removing the covering skin. The target blood vessels were irradiated with a pulsed 1064 nm Nd: YAG laser. The corresponding thermal responses were recorded using a CCD camera. Additionally, variations in skin reflectance spectra were measured before and after laser irradiation. Due to the optical clearing and reflectance spectra measurement, vessel responses such as contraction, reperfusion, and full occlusion were correlated with specific variation patterns in reflectance spectral signals.

Dye Laser to Treat an Arteriovenous Malformation of the Tongue: 40-Month Follow-Up

Arteriovenous malformations (AVMs) are abnormal connections between blood vessels that bypass the normal capillary bed. To avoid the invasiveness of the gold standard surgical excision, the use of dye laser has been suggested as an alternative. A 53-year-old man in good overall health presented with a large bluish-red nodular growth covered by intact mucosa on the left side of his tongue. The growth had a hard-elastic consistency and was not painful to touch. Imaging investigations revealed a capsulated growth consistent with a diagnosis of AVM. The patient underwent two sessions of rhodamine dye laser treatment using the following parameters: fluence of 12 J/cm2, 6 mm laser spot, a single pulse with repetition up to 1.0 Hz, and a pulse duration of 3.0 ms. Follow-up examinations were conducted at 12, 24, 36, and 40 months after the treatment. At the 40-month follow-up, the lesion had reduced in size, with a more organized vascular network, and was not clinically detectable. Considering the limitations of this case report, the application of dye laser appears to be a potentially successful treatment option for AVMs.

Evaluation of the safety and efficacy of long pulsed Nd: YAG laser in the treatment of vascular lesions in vivo

Long-pulsed neodymium:yttrium-aluminum-garnet (Nd:YAG) lasers have recently been used for the treatment of vascular lesions refractory to conventional vascular lasers. The aim of this study was to evaluate the clinical efficacy and safety of long-pulsed Nd:YAG laser treatment for vascular disorders. Laser irradiation was performed using two approaches: the 532 nm Nd:YAG laser was used to irradiate the dorsal skin fold in mice and the 1064 nm Nd:YAG laser was used to irradiate the leg of mice without skin incision. The specimens were observed immediately after laser treatment using a laser Doppler perfusion imaging system. Red blood cell (RBC) extravasation and hemorrhage were observed using the hematoxylin and eosin stain. The diameter of blood vessel under 30 μm was disrupted with a laser pulse at a fluence of 12 J/cm² and a wavelength of 532 nm regardless of pulse duration. The veins and arteries of approximately 1 mm in size were ablated with laser pulses at a fluence of 140 J/cm² and above and a wavelength of 1064 nm. Selective photopyrolysis can be achieved with either 532- or 1064 nm Nd:YAG laser pulses in vascular diseases based on the depth and size of the vessel.