Laser resurfacing

Published on 22/05/2015 by admin

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Last modified 22/05/2015

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CHAPTER 76 Laser resurfacing

John L. Burns, A. Jay Burns

History

The history of laser resurfacing is relatively short although it is evolving rapidly. Until the advent of cutaneous laser resurfacing in the late 1980s, physicians used mechanical dermabrasion and a variety of deep chemical peeling agents for facial skin resurfacing. Some authors first reported using continuous wave carbon dioxide lasers for resurfacing. However, this technique was never widely adapted due to the significant thermal damage that resulted from continuous wave lasers, and the resulting high complication rates. In response to this need for safer lasers with fewer side effects, short-pulsed high energy (SPHE) and scanned carbon dioxide lasers became the standard. These lasers are capable of removing layers of photodamaged skin in an impressively precise fashion, leaving only a narrow zone of thermal necrosis.

The continued demand for more precise lasers with even lower side effect profiles led to the development of erbium yttrium-aluminum-garnet (Er:YAG) laser. The 2940-nm wavelength emitted by the Er:YAG laser is absorbed 12–18 times more efficiently than is the 10,600 nm wavelength of the carbon dioxide laser. In the past several years, both the erbium and carbon dioxide lasers have been modified so that the energy is delivered in a fractionated manner thereby preserving adnexal structures. This technology, known as fractional photothermolysis, allows for safe delivery of energy deep into the deep reticular dermis. Fractionated lasers can be safely used off the face and in patients with Fitzpatrick skin types IV and V.

Physical evaluation

1. Assess Fitzpatrick skin type (Table 76.1). Skin types I, II, III are acceptable candidates for ablative resurfacing, but extreme caution should be used in skin types IV or V. Higher Fitzpatrick skin types can be safely treated using newer fractionated ablative or nonablative lasers.

2. Past medical history:

• Propensity for hypertrophic scarring.

• Isotretinoin use within previous six months.

• Paucity of adnexal structures (scleroderma, burn scars, radiation).

• Previous resurfacing procedures.

• Previous surgery (lower eyelid blepharoplasty).

• Previous infection (herpetic lesions) or active infection (acne).

• Hormone use or pregnancy can worsen dyschromia.

3. Dyschromia. Brown lesions present in the superficial dermis will respond whereas deeper dermal lesions will persist. Red dyschromia such as seen with acne rosea can result in copious bleeding during Er:YAG laser treatment.

4. Rhytid location and severity (Table 76.2). Differentiate and document static and dynamic rhytids.

5. Cutaneous disorders such as carcinoma, seborrheic or actinic keratoses, and solar lentigines should be noted.

6. Skin tone, texture, and pore size.

7. Adequate preoperative skin care including sunblocking agents, bleaching agents (hydroquinone), and moisturizing skin care regimen.

Table 76.1 Fitzpatrick skin type classification system

Fitzpatrick skin type	Description
I	Extremely fair skin, always burns, never tans
II	Fair skin, always burns, sometimes tans
III	Medium skin, sometimes burns, always tans
IV	Olive skin, rarely burns, always tans
V	Moderately pigmented brown skin, never burns, always tans
VI	Markedly pigmented black skin, never burns, always tans

Table 76.2 Glogau rhytid/photoaging classification scheme

Glogau scale	Age	Description
Mild	28–35 years	Little wrinkles, no keratosis, requires little or no makeup for coverage
Moderate	35–50 years	Early wrinkling, sallow complexion with early actinic keratosis, requires little makeup
Advanced	50–60 years	Persistent wrinkling, discoloration of the skin with telangiectasias and actinic keratosis, always wears makeup
Severe	65–70 years	Severe wrinkling, photoaging, gravitational and dynamic forces affecting skin, actinic keratosis with or without cancer, wears makeup with poor coverage

Anatomy

Laser resurfacing demands a precise knowledge of skin histology (Fig. 76.1). The epidermis makes up approximately five percent of skin thickness. The epidermis encompasses five distinct layers: stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, stratum germinativum. The stratum corneum is composed primarily of nonviable cells, which are turned over frequently and replaced by precursor cells from underlying layers. Nonablative resurfacing techniques by definition leave the epidermis intact, while ablative resurfacing techniques will remove this layer.