Section 4 Plastic and Reconstructive Problems

Laser Skin Treatment in Non-Caucasian Patients

Table 2 Variables of lasers

Variable

Function

Example

Hemoglobin, melanin, water

Chromophore Laser target molecule, unique absorption spectrum and peak absorption wavelength

Wavelength

Property of light measured in nanometers that influences how chromophores are targeted

Hemoglobin (variable absorption from 300 nm to infrared) Melanin (gradually decreasing absorption from 250 to 1200 nm) Water (1000 to 1 mm)

Melanosome (250 ns) Vessels (2–10 ms) Hair follicles (100 ms)

Time required for tissue to cool to half the temperature to which it was heated

Thermal

relaxation time

Pulse duration Time to heat tissue to target tissue; choose pulse duration less than or equal to thermal relaxation time of

Pulse duration 10 to 100 ns to target melanosome

target chromophore to avoid damage to surrounding tissue

25 J/cm 2 used by a 1064-nm Nd:YAG for laser hair removal; highest tolerated fluences are 100 J/cm 2 (skin types IV, V) and 50 J/cm 2 (skin type VI)

Energy fluence Joules per square centimeter of energy emitted by a pulsed laser device

centimeter of energy emitted from the laser hand- piece. The laser fluence may need to be decreased to protect the epidermis to safely treat patients with darker skin types compared with those with lighter skin types. Other helpful strate- gies in safely treating patient of color include longer wavelengths, longer pulse durations, and skin cooling before, during, and/or after the proce- dure to avoid overheating the epidermis. 4,6 The major classes of lasers include ablative and nonablative lasers in both nonfractionated and frac- tionated varieties ( Table 3 ). Ablative lasers target water molecules in the epidermis, causing vapor- ization of skin cells and retraction of the dermis with collagen formation. Ablative lasers are more aggressive and function similar to a skin peel with prolonged recovery time and higher adverse event profile. 7 Nonablative lasers preserve the epidermis and target the dermal tissues to promote collagen formation. These nonablative treatments are milder and reduce the adverse event profile and recovery time. Fractionated lasers are designed to target microscopic treatment zones, or microthermal zones (MTZs) to create columns of thermal injury with adjacent normal skin. 4 This procedure pro- motes healing and improves skin texture compared with nonfractionated lasers without the high side- effect profile of ablative lasers. Radiofrequency re- surfacing is a nonablative technique that uses a CLASSES OF LASERS

low temperature to penetrate dermal tissues and promote collagen healing. 7 There are several op- tions for laser therapy, and it is important to deter- mine the expectations of your patient while balancing the risks and benefits associated with laser therapy in patient-specific phototypes.

TREATMENT GOALS

Lasers may be considered for a variety of indica- tions, and the goals of the treatment should reflect the patient presentation.

Skin Laxity

There is an increased desire in all patients to achieve more youthful and refreshed facial skin. Over time, facial skin experiences photodamage, which causes wrinkles, texture changes, and abnormal pigmentation. Additional changes over time include soft-tissue volume loss, rhytides, and increased vascularity. The primary environ- mental factor that affects aging is ultraviolet radia- tion, but given the protective effects of melanin and a thicker epidermis, individuals with dark skin may experience less skin laxity due to gravity and vol- ume loss compared with others with fair skin. 4

Dyschromia

The primary concerns of patients may vary depending on ethnicity and skin type ( Fig. 2 ). Dyschromia is a common presentation of dark-skinned patients, and it is important to