Laser Treatment of Cutaneous Lesions
Lasers are devices that amplify or generate highly specialized light energy. They can mobilize immense heat and power when fo-cused at close range and are valuable tools in surgical procedures. The argon laser, carbon dioxide (CO2) laser, and tunable pulse-dye laser are used in dermatologic surgery. Each type of laser emits its own wavelength within the color spectrum.
The argon laser produces a visible blue-green light that is ab-sorbed by vascular tissue and is therefore useful in treating vas-cular lesions: port-wine stains, telangiectases, vascular tumors, and pigmented lesions. The argon beam can penetrate approxi-mately 1 mm of skin and reach the pigmented layer, causing pro-tein coagulation in this area. An immediate effect is that tiny blood vessels under the skin coagulate, causing the area to turn a much lighter color. A crust forms within a few days.
During the procedure, the patient may require local anesthe-sia (lidocaine) but only if the lesion, such as a port-wine stain, is wider than 0.5 cm. Laser beams, regardless of type, are reflected and scattered in all directions during the treatment. Laser radia-tion is hazardous to the eye, and the eyes of the patient and all personnel involved in the surgical procedure and those who are within the immediate surgical environment must be protected with orange, argon light–absorbing safety goggles.
Cold compresses are usually applied over the treatment area for approximately 6 hours to minimize edema, exudate, and loss of capillary permeability. The nurse advises the patient that swelling will subside in 1 to 2 days and will be followed by a crust that will last 7 to 10 days. The nurse instructs the patient to avoid picking at the crust, to apply an antibacterial ointment sparingly until the crust separates, to avoid applying makeup until the wound heals, and to avoid exposure to the sun. Sunscreen is to be used when exposure is unavoidable.
The CO2 laser emits invisible light in the infrared spectrum that is absorbed at the skin surface because of the high water content of the skin and the long wavelength of the CO2 light. As the laser beam strikes tissue, it is absorbed by the intracellular and extra-cellular water, which vaporizes, destroying the tissue. The CO2 laser is a precise surgical instrument that vaporizes and excises tis-sue with minimal damage. Because the beam can seal blood and lymphatic vessels, it creates a dry surgical field that makes many procedures easier and quicker. It is therefore safe to use on pa-tients with bleeding disorders or those receiving anticoagulant therapy. It is useful for removing epidermal nevi, tattoos, certain warts, skin cancer, ingrown toenails, and keloids. Incisions made with the laser beam heal and scar much like those made by a scalpel.
In addition to wearing safety goggles, the patient and person-nel wear laser-grade surgical masks to avoid inhaling the byprod-uct smoke, referred to as a plume.
Immediately after undergoing CO2 laser surgery, the treated area turns a charcoal color. The wound is covered with antibacterial ointment and a nonadhesive dressing. The patient is instructed to keep the wound dry except for gentle cleansing with mild soap several times each day. After the skin is cleaned, a prescribed oint-ment and light dressing are applied.
Because nerve endings and lymphatic vessels are sealed by the laser, less edema and pain follow the laser procedure than follow conventional surgery. A mild analgesic is sufficient to maintain patient comfort. Wound healing occurs by secondary intention, with granulation tissue appearing within a week; complete heal-ing occurs in several weeks. Sun exposure to the area should be avoided for approximately 6 months. Application of a sunscreen with an SPF value of at least 15 is recommended. People at high risk for skin cancer from sun exposure are advised to use a sun-screen with an SPF greater than 15 to block ultraviolet-B and ultraviolet-A light.
The tunable pulse-dye laser with various wavelengths is the latest laser available for dermatologic surgery. It is especially useful in treating cutaneous vascular lesions such as port-wine stains and telangiectasia. Eye protection used for the argon and CO2 lasers is insufficient when the pulse-dye laser is in use. Special eye-glasses, such as those made of didymium glass, are required for the patient and all personnel. The procedure is generally painless. For procedures requiring anesthesia, lidocaine without epineph-rine is sufficient because local vasoconstriction (which epineph-rine induces) is unnecessary.
The patient should be informed that there may be stinging in the treated area for several hours. Applying ice to the area and a light antibacterial ointment followed by a nonstick dressing (eg, Telfa) usually eases discomfort.
If crusting occurs, the patient is advised to wash the area gen-tly with soap and water and reapply the antibacterial cream twice daily until the crust disappears. The nurse also advises the patient to avoid wearing makeup until all crust is removed. Sun exposure should be avoided as well; sunscreens with an SPF value of 15 or greater should be used for 3 to 4 months after the treatment. Complete removal of the lesion at one session, especially a port-wine stain, is rare. The patient should be informed that several treatments may be necessary.
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