Facial Aging

Facial aging is associated with a gradual thinning of the skin and loss of elasticity over time accompanied by the diminishment of dermal collagen, hyaluronic acid, and elastin. Ultraviolet (UV) radiation from sun exposure accelerates this process at a higher rate than does chronologic aging. This UV aging process is termed photoaging. To appreciate the contribution of photoaging to the appearance of aged skin, one needs only compare photoprotected skin, such as skin on the inside of the upper forearm or under the chin, to the appearance and texture of skin on face and back of the hands. Photoaged skin typically exhibits the following changes (Figure 19-1 for a computer-enhanced image demonstrating these signs)⁵:

FIGURE 19-1 Photoaging changes (computer-enhanced image).

(Copyright Rebecca Small, MD.)

In a study by New York plastic surgeon Dr. D. Antell on aging in identical twins, extrinsic factors, such as prolonged sun exposure, resulted in advanced aging changes (Figure 19-2A) relative to the intrinsic aging seen in non–sun-exposed twins (Figure 19-2B).⁶ Habitual facial expressions also contribute to formation of visible lines and wrinkles, particularly in the upper one-third of the face, because repetitive muscle contractions etch in frown lines between eyebrows and crow’s feet radiating from the corner of the eyes. In addition to skin laxity, volume loss, and dynamic musculature, facial aging also results from biometric facial changes such as descent of malar fat pads, which contributes to deepened nasolabial folds, and resorption of maxillary and mandibular bone, which contributes to radial lip lines and mental crease formation.^7,8

FIGURE 19-2 Facial aging differences in identical twins. Advanced photoaging changes of (A) skin wrinkling and laxity with prolonged sun exposure and (B) mild changes with minimal sun exposure.

(Courtesy of Dr. D. Antell, New York City, www.Antell-md.com.)

Skin Anatomy

The skin is divided into three layers: the epidermis, dermis, and hypodermis or subcutaneous layer (Figure 19-3). The epidermis is the top layer of the skin and is composed of four cell types: keratinocytes, melanocytes, Langerhans cells, and Merkel cells. The epidermis is further divided into the outermost nonliving layer, the stratum corneum, and the living cellular layers of the stratum granulosum, stratum spinosum, and stratum basale.

FIGURE 19-3 Skin anatomy.

(Modified from White CR, Bigby M, Sangueza OP. What is normal skin? In: Arndt KA, LeBoit PE, Robinson JK, Wintroub BU, eds., Cutaneous Medicine and Surgery. Philadelphia: Saunders; 1996:3–41.)

The stratum corneum is composed of corneocytes and lipids, which serves as a barrier against microbial pathogens and environmental irritants and also keeps the skin hydrated and protected from injury. Constant renewal is necessary for the epidermis to maintain its integrity and function effectively. In healthy young skin, it takes approximately 1 month for keratinocytes to migrate from the living basal layer of the epidermis to the stratum corneum surface and desquamate, during the process of epidermal renewal. Figure 19-4 shows the structure of the epidermis with the keratinocyte maturation highlighted. Photoaged skin demonstrates slower keratinocyte maturation and abnormal retention of cells in the epidermis. This results in a rough and thickened stratum corneum with impaired barrier function, reduced hydration capabilities, and increased pigmentation from retention of melanin-laden keratinocytes in the epidermis.

FIGURE 19-4 Epidermis structure showing keratinocyte maturation process from basal keratinocyte to desquamating corneocyte.

The distribution of melanin within the epidermis determines skin coloration. While the number of melanocytes is similar for both light and dark skin types, melanin is concentrated in small aggregated melanosomes in light skin and is more disbursed in darker skin.⁹

The dermis lies beneath the epidermis and is divided into the more superficial papillary dermis and deeper reticular dermis. The main cell type in the dermis is the fibroblast, which is more abundant in the papillary dermis and sparse in the reticular dermis. Below the dermis and above the underlying muscle is the subcutaneous layer, also called the hypodermis, subcutis or superficial fascia. This layer has both fatty and fibrous components.

Aesthetic Consultation

Aesthetic consultation is an important part of successfully performing aesthetic treatments. The patient’s medical history is reviewed, including past medical history, medications, allergies, and past cosmetic history (including results from previous treatments and side effects if any, surgeries, and satisfaction with outcomes). Figure 19-5 is an example of an aesthetic intake form that clinicians may use. Repeated dissatisfaction with past aesthetic treatments can be associated with unrealistic expectations or body dysmorphic disorder and is a contraindication to treatment.

FIGURE 19-5 Aesthetic patient intake form.

The main areas of concern should be determined and prioritized by the patient at the time of consultation. It is recommended that the patient view these areas using a handheld mirror, so that the provider and patient may simultaneously examine the desired treatment areas. Asymmetries, such as uneven eyebrow height, are pointed out to the patient, noted in the chart, and photographed.¹⁰ Pigmented lesions in the treatment area are evaluated and lesions suspected of melanoma biopsied with results reviewed prior to proceeding with treatments.

Early on in the consultation process, providers should assess whether patients will benefit most from surgical intervention, or if minimally invasive treatments will address their concerns adequately particularly for patients presenting with severe wrinkles and excessive skin laxity. Treatment options and recommendations should be discussed along with anticipated results, risks of side effects and complications, recovery time, and costs. Based on this discussion, an individualized aesthetic rejuvenation treatment plan is created.

Baseline assessments of the patient’s skin type and severity of photoaging are typically performed at the time of consultation using the Glogau classification of photoaging and Fitzpatrick skin type classification, respectively, as discussed next.

Photodocumentation

Photodocumentation, where photographs are used to demonstrate clinical findings, is an essential component of aesthetic treatments both for the patient’s reference and for medical-legal purposes.¹² Photographs prior to treatment, midway through a series of treatments, and post-treatment are helpful and recommended. Consent for photographs is typically included in the procedure consent form and obtained prior to taking photographs. Recommended photographs include the full face and specific treatment areas which are photographed from the front, 45 and 90 degrees while the patient is positioned fully upright looking straight ahead. For injection treatments, photographs are taken with the face at rest and with active facial movement of the treatment areas. There are commercial photographic systems available that provide standardized angles and lighting to facilitate consistent photography.

Informed Consent

Patients seeking elective aesthetic treatments typically have high expectations of treatment outcomes and low tolerance for side effects. It is recommended that all aspects of the informed consent process be addressed¹³:

Safety Zones

The recommended regions for treatment on the face are identified as Safety Zones throughout the book and are intended as a guide for providers getting started with aesthetic procedures. Providers with more advanced procedural skill may choose to treat areas outside of the Safety Zones.

Laser Treatment Principles

Laser* devices produce monochromatic light of a single wavelength that is highly focused in a collimated beam (defined as parallel rays of light that disperse minimally). Intense pulsed light (IPL) devices emit a spectrum of wavelengths and employ filters to refine the energy output. Treatments with lasers and IPL devices (collectively referred to as lasers in this book) are based on the principle of selective photothermolysis. According to this principle, light of a specific wavelength is selectively absorbed by the “undesired” target in the skin such as a solar lentigo; the target is heated, damaged, and eliminated, while the surrounding skin is left unaffected. Figure 19-6 illustrates the principle of selective photothermolysis with treatment of solar lentigines and telangiectasias.¹⁴

FIGURE 19-6 Selective photothermolysis. Wavelengths of light are selectively absorbed by targets in the skin, such as lentigos and telangiectasias (A). During laser treatments the targets are heated (B), damaged and eliminated while the surrounding skin is left unaffected (C).

When laser energy impacts skin, the beam may be absorbed, reflected, transmitted, or scattered. All four interactions occur to some degree, but absorption is the most important clinically. The degree of absorption depends on the chromophores, or light-absorbing substances, in skin. The primary chromophores in skin are melanin, oxyhemoglobin, and water, and each has a unique wavelength absorption spectrum (Figure 19-7). Treatment wavelengths are selected such that they are absorbed better by the target chromophores than by chromophores in the surrounding skin. Target chromophores for laser treatments are shown in Table 19-3.

FIGURE 19-7 Absorption spectra for tissue chromophores: melanin, oxyhemoglobin, and water.

TABLE 19-3 Target Chromophores for Laser Treatments

Figure 19-8 summarizes lasers commonly used for treatment of aesthetic conditions including: dyschromia, vascular ectasias, rhytids, and hair reduction.

FIGURE 19-8 Lasers commonly used for aesthetic skin conditions.

Laser Parameters

To achieve efficacious treatments with maximal safety, the provider must have an understanding of basic laser parameters, as well as the properties of the targets being treated in the skin. Laser parameter definitions and key concepts are summarized below¹⁵:

A typical laser is shown in Figure 19-9 with its component parts, including a computerized touch screen commonly used to select laser parameters, a laser handpiece and distance guide.

FIGURE 19-9 Laser parts.

(RevLite™ courtesy of HOYA ConBio, Fremont, CA, with modifications.)

Fractional Lasers

“Fractional” refers to a method of laser energy delivery, it does not refer to a particular wavelength. Fractional devices deliver laser energy in microscopic columns, called microthermal zones (Figure 19-10). The two main types of fractional laser devices are ablative (e.g., CO₂ and Er:YAG) and nonablative (e.g., 1550 and 1410 nm). Most fractional devices are used for skin resurfacing to reduce wrinkles and improve dyschromia. Only a portion of the skin is treated with this fractional method of delivery, resulting in significantly shortened recovery times particularly for ablative lasers.

FIGURE 19-10 Fractional laser energy delivery.

Laser Safety

When using lasers, a laser safety officer should be designated, the American National Standards Institute (ANSI) laser safety requirements met,^16–18 and specific device manufacturer’s guidelines for safety and maintenance follow. Wavelength-specific eyewear must be worn to protect patients and providers from ocular injury. Mirrors and windows are covered, laser warning signs posted, and a laser safety checklist reviewed prior to performing each treatment.

Skin Resurfacing

Skin resurfacing is a common aesthetic rejuvenation practice based on the principles of wound healing. By wounding and removing superficial skin layers (also called exfoliation) in a controlled manner, epidermal and dermal renewal is stimulated. Many methods of skin resurfacing are available. They can be broadly classified according to the method of skin injury:

Skin resurfacing can be performed to varying degrees of aggressiveness based on the depth of skin penetration. Figure 19-11 shows standard definitions for very superficial (stratum corneum), superficial (typically to the base of the epidermis, but may include the upper papillary dermis), medium (upper reticular dermis), and deep (midreticular dermis) skin resurfacing. Figure 19-12 illustrates the typical depths achieved with different resurfacing procedures. In general, the greater the depth of wounding, the more dramatic the results achieved. However, greater wound depths are also associated with longer recovery time, more intensive postprocedure care, and greater risks of side effects and complications. Penetration into or below the papillary dermis, which is usually associated with bleeding, has a greater risk of scarring than more superficial resurfacing of the epidermis.

FIGURE 19-11 Skin resurfacing terminology.

FIGURE 19-12 Depths of penetration with common skin resurfacing procedures.

Aesthetic Procedures: Getting Started

Many of the aesthetic procedures discussed in this book are ideal for providers who wish to incorporate aesthetic care into practice. They are highly efficacious with rapid results that require minimal recovery time and they have relatively low risks of side effects. These core aesthetic procedures include:

Once skill and proficiency with these core procedures has been acquired, providers may choose to undertake more advanced aesthetic procedures. Advanced procedures can be associated with longer recovery times, as with ablative lasers, or demonstrate subtle results, as with nonablative lasers for wrinkle reduction. Certain procedures require advanced procedural skill and knowledge. These include botulinum toxin injections in the lower two-thirds of the face and neck, and dermal filler injections that utilize layering techniques and semipermanent products and are used for facial contouring. In addition, procedures can be intensified and results enhanced by combining procedures over several visits or on the same day in multimodality visits.

Resources