Fraxel ‚Fractional Laser Treatments

FRAXEL TREATMENT PAPER

Leading dermatologists reveal some of the most important up-and-coming technologies and techniques in the practice of dermatology.

Improving Skin Pigmentation and Texture with the Fractional 1550 nm Laser

By Jeffrey S. Dover, M.D., F.R.C.P.C., Murad Alam, M.D., and Zakia Rahman, M.D.

We've had much success in treating epidermal pigmentation, melasma, and rhytides, as well as textural abnormalities, including acne-related and surgical scars, with fractional resurfacing using the Fraxel laser (Reliant technologies). (Two other devices were released this summer: Palomar's Lux1540, an Er:YAG-based device, and Cynosure's Affirm 1440 nm, which is an Nd:YAG-based device. Other devices are coming.) The Fraxel is a 30-watt, diode-pumped, 1550-nm erbium fiber laser that targets water as its chromophore. With fractional resurfacing, deep microthermal zones (70 to 100 µm wide, 250 to 800 µm deep) of tissue coagulation are produced. Tissue is not vaporized; the stratum corneum remains intact. The epidermal coagulated tissue is expelled and replaced by keratinocyte migration. Upon significant damage to the basement membrane zone, dermal contents are also expelled as microscopic epidermal and dermal necrotic debris (MENDs). In this way, epidermal and dermal pigmentation are treated without specifically targeting melanin as the chromophore. Zones of collagen denaturation in the dermis trigger the inflammatory cascade, which leads to collagen remodeling and new collagen formation.

The Fraxel SR 1500, a second-generation Fraxel device, is now available commercially, and it has a telescopic lens with variable spot size (smaller as well as larger) at varying energies.

Fractional laser treatment may be used to resurface any nonfacial part of the body, but is particularly useful on the neck, chest and hands. For selected applications, fractional laser treatment may have greater efficacy than some other non-ablative modalities with similar downtime. Since November 2003, the Fraxel laser has received several FDA-approved indications. The first was for coagulation of soft tissue; other indications include treatment of periorbital rhytides, pigmented lesions, melasma, skin resurfacing, acne scars and surgical scars.

At this point, 2 years of clinical data and studies are available with this device, and this information has enabled us to optimize treatment parameters and improve patient outcomes. Here are tips on treating some specific conditions with the Fraxel. Review the table for more detailed parameters.

Photodamage, including pigmentation and rhytides. A greater number of "gentler" treatments (five or six) with less downtime are required to achieve the same cumulative results as fewer (perhaps three) "high-level" treatments, which entail greater down time. The probability of achieving 100% tissue coverage is far greater with five 20% treatments as opposed to 10 10% treatments.

Scars (acne and surgical). Higher-energy treatments obtain better results when compared to lower-energy treatments. At equal surface area coverage of 20%, a 20 mJ/cm2 treatment treats twice the volume of tissue as a 10 mJ/cm2 treatment. This explains the greater efficacy seen for deep rhytides and acne scars with higher-energy treatments.

Melasma. Results in treating this condition are encouraging. Before treatment, patients should be placed on a bleaching regimen and must practice strict sun avoidance and use high-SPF sunscreens. Retinoids should be stopped 1 week prior to treatment because they can interfere with rapid re-epithelialization.

Ideally, patients should be treated monthly at low energies of 6 to 8 mJ/cm2 at 1000-2000 MTZ/cm2. Three to six total treatments with a "touch-up" at 6 months is commonly prescribed, but not always necessary. Post-inflammatory changes, particularly in patients who have hyperactive melanocytes, may occur; however, in our experience these changes are usually more homogeneous and better tolerated by patients than the mottled, uneven pigmentation of melasma. Melasma can recur, particularly when the causative melanocytes and hormonal profile are present. Pain management. This is one of the most significant hurdles of the procedure. Discomfort from the laser treatment is managed by use of topical anesthetic prior to procedure and forced cool air during the procedure.

Post-treatment edema and possible hyperpigmentation. Some patients have little swelling; the average patient experiences 1 to 3 days, and less than 5% of patients swell for up to a week.

Studies indicate an approximately 10% to 12% overall incidence of temporary hyperpigmentation after fractional treatments. Hyperpigmentation is uncommon in patients with light skin types (I and II).

* This piece is modified from a manuscript in press in the Skin Therapy Letter.

Dr. Dover is a Director of SkinCare Physicians in Chestnut Hill, MA. He is Associate Clinical Professor of Dermatology at Yale University School of Medicine. He is also Adjunct Professor of Medicine (Dermatology) at Dartmouth Medical School. Dr. Alam is Chief of the Section of Cutaneous and Aesthetic Surgery, Department of Dermatology, Northwestern University in Chicago. Dr. Rahman is Clinical Instructor of Dermatology (Affiliated) at Stanford School of Medicine. In addition, she's Assistant Chief of Dermatology, PAVAHCS, Livermore Division.