Vascular Lesion Therapy:
Patients frequently seek treatment of cutaneous vascular lesions for both medical and cosmetic reasons. Advances in the use of lasers and light sources enable physicians to effectively treat vascular lesions that were previously untreatable. Given the plethora of devices available, selecting the appropriate laser system and treatment parameters can be confusing for the laser surgeon.
Vascular lesions are often a cause of great concern to patients. Treatment is sought for a variety of reasons including cosmesis, pain, bleeding, or disfigurement. In the late 1960s and early 1970s, physicians began treatment of vascular anomalies with continuous-wave lasers such as the argon laser.
Although these lasers were effective, they often caused unacceptable side effects such as scarring and permanent dyspigmentation. These outcomes limited the widespread use of this modality. In the 1980s, Anderson and Parrish described the theory of selective photothermolysis and revolutionized the treatment of vascular lesions. Determining the appropriate wavelength, pulse duration, and fluence enables physicians to selectively target hemoglobin within blood vessels without damaging the surrounding tissue. As a result, side effects such as dyspigmentation and scarring are minimal.
The ultimate goal of laser treatment is to induce vessel wall damage through destruction of hemoglobin while minimizing injury to adjacent structures. Vessel destruction occurs either through photomechanical or photothermal means. When short pulse-widths (or pulse durations) are used, photomechanical damage occurs. This causes intravascular cavitation, vessel wall rupture, and hemorrhage. Clinically, one sees purpura after treatment. With longer pulse-widths or stuttered pulses, photothermal damage occurs. This causes slow heating of the vessel, intravascular coagulation, and collagen contraction. Clinically, one sees immediate blanching or subtle darkening of the vessel followed by subsequent erythema and edema.
The first consideration in the selection of a laser is to determine the spectral absorption peaks of the target chromophore. In the case of vascular lesions, this is deoxyhemoglobin or oxyhemoglobin. Hemoglobin shows absorption peaks in the blue, green, and yellow bands (418, 542, and 577 nm) as well as a peak further out in the near-infrared portion of the spectrum (700 to 1100 nm). Laser systems used to treat vascular lesions emit wavelengths near these peaks. Melanin is a strong competing chromophore at shorter wavelengths. Therefore, it is preferable to select longer wavelengths whenever possible. This is especially important for patients with darker skin, such as those with Fitzpatrick skin types IV to VI. If shorter-wavelength lasers are used, melanin may absorb the laser energy intended for hemoglobin and result in dyspigmentation. The wavelength also determines depth of penetration through the epidermis and dermis. Longer wavelengths may be preferred for deeper vascular lesions such as leg veins, whereas shorter wavelengths may be suited for superficial vascular lesions such as facial telangiectasias.
Once the appropriate laser is selected, it is important to choose the correct parameters. These include the pulse duration, fluence, and spot size. The pulse duration is determined by the thermal relaxation time (TRT) of the target. Essentially, this is defined as the time required for the heated tissue to lose about half of its heat. It is roughly proportional to the square of the target’s diameter. Therefore, the TRT of larger vessels such as leg veins will range in hundreds of milliseconds, whereas the TRT of smaller vessels such as telangiectasias will range in tens of microseconds. A laser pulse that is shorter than or equal to the TRT will cause damage limited to the vessel. A laser pulse that is greater than the TRT will cause heat diffusion outside of the vessel into surrounding structures, causing scarring or textural changes. Fluence is defined as the energy per unit area. It is inversely proportional to the fraction of light absorbed by the target. A higher fluence will be necessary if a target is deep within the dermis or the wavelength that the laser emits is weakly absorbed. Spot size should approximate the diameter of the target vessel to minimize surrounding damage. Larger spot sizes tend to have less scattering of the laser beam and deeper dermal penetration.
In treatment of all vascular lesions, cooling of the skin surface is crucial to minimize epidermal damage and allow maximal fluences. These cooling methods can be found within the laser system or can be externally applied. Integrated cooling devices include chilled tips, cooled glass chambers, or pulsed cryogen sprays. External cooling devices include forced-air cooling, ice packs, or cool gels applied to the surface of the skin prior to treatment.
Treating Vascular Lesions
There are almost as many types of vascular lesions as there are potential treatments, but the most commonly used lasers include pulsed dye laser, long-pulsed Nd:YAG laser, long-pulsed 32-nm green light laser and intense pulsed light (IPL), with wavelengths ranging from 500 nm to 1200 nm, depending on the type and location of the lesion. Vascular lesions are a type of common skin blemish that can be successfully treated with Quarkum Q-switched lasers. The procedure is fast, simple to perform, and has virtually no side effects.
About Vascular Lesions
Vascular lesions are blood vessels that are visible through the skin. The harmless lesions look blood-colored, with either a red or purplish hue. Standard types of vascular lesions include: spider veins, telangiectasia, port wine stains, and hemangioma. They can occur on almost any part of the body, but are especially common on the face or legs.
There are many causes of vascular lesions, and they often appear as a side effect of aging. As such, laser treatment of vascular lesions has become a popular cosmetic procedure for people concerned about their skin appearance.
For treatment of vascular lesions, pulses of Q-switched laser light are directly applied to the entire area of the blemish. The veins and capillaries of the lesion absorb the laser’s energy while the surrounding skin tissue does not. The treatment causes the exposed vessels to break down and become less visible.
Procedure time for vascular lesion treatments depends on the size of the lesion, but never takes more than a few minutes. Side effects from the procedure are minimal – patients may experience some slight discomfort or redness in the area.
Small vascular lesions can often be removed in a single treatment, while other lesions may take several treatments to become less visible. Regardless, most patients see significant improvement in appearance after a single laser session with an Quarkum Q-switched lasers.