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

Table 76.1 Fitzpatrick skin type classification system

Table 76.2 Glogau rhytid/photoaging classification scheme

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.

Fig. 76.1 Layers of the skin.

The dermis is divided into a papillary and reticular layer. Most ablative resurfacing techniques will remove the papillary and superficial reticular dermis. The papillary dermis begins at the basement membrane and has a high type III collagen content. The papillary dermis is relatively thin measuring about 100 µm in thickness.

The reticular dermis makes up the majority of skin thickness (2000–2500 µm). It is primarily composed of type I collagen organized in large fibers and interwoven bundles. Large, mature, band-like elastic fibers extend between collagen bundles. Elastic and collagen bundles increase in size progressively towards the hypodermis. The deep reticular dermis is characterized clinically by a lacey or fragmented appearance and is a reliable endpoint during Er:YAG laser resurfacing.

Technical steps

Before any laser treatment is undertaken, appropriate safety precautions should be taken by strict application of the guidelines listed in Table 76.3. Wavelength appropriate eyewear should be provided to all operating room personnel and eyeshields should be used for the patient.

Table 76.3 Laser Safety Guidelines

Preoperatively, all patients should receive antiviral prophylaxis for two days prior to the procedure and postoperatively until the wound has re-epithelialized. The use of antibacterial or antifungal prophylactic medications is controversial and is not commonly prescribed. Patients at risk for post-inflammatory hyperpigmentation should be pretreated with hydroquinone. Patients should wash their face preoperatively with antibacterial soap and the face should be prepped with Phisohex® cleaner, washed with sterile saline, and blotted dry. The laser field should be sterilely draped with wet sterile towels and the endotrachial tube wrapped with sterile wet towels. The teeth should be protected with sterile cotton plegets for protection.

The authors preferred method of ablative laser resurfacing uses the Dual Mode Er:YAG laser (Sciton Contour™). The vaporization threshold of the Er:YAG laser has been calculated between 0.5 and 1.5 J/cm². Therefore, each joule/cm² will vaporize 2–4 µm of tissue with minimal collateral thermal effect. At the recommended overlap of 50%, fluences up to 100 J/cm² can be used for aggressive vaporization of tissue. Using a straightforward touchscreen panel, the surgeon can program microns of ablation and the microns of coagulative thermal damage to be induced. To avoid thermal damage, we recommend a virtually complete ablative protocol reserving coagulation for areas where skin tightening is paramount such as the lower eyelids. Meticulous attention to clinical endpoints is necessary as there is no customary “chamois” color associated with thermal necrosis as is seen in carbon dioxide lasers.

With the understanding that each case is unique and poses its own set of circumstances, the following protocol is standard (Table 76.4). The face is first treated with three separate passes at 100 microns of ablation with no coagulation using a scanning pattern. This will result in a uniform depth of ablated tissue of 300 microns. While this laser is collimated for ease of use, the handpiece should be held a constant distance from the skin at a perpendicular angle. Meticulous care should be taken to deliver the energy in a uniform manner, taking care not to skip areas or overlap. After each pass, denuded skin is removed with sterile moist gauze and assessed for depth by using the following clinical endpoints: wrinkle ablation, reticular punctate bleeding pattern, and lacey or fragmented appearance of the midreticular dermis. At the caudal border of the mandible, taper to 200 microns and then to 100 microns at the neck transition. Using a four millimeter spot size, spot treat deeper rhytids with rapid fire 30 micron pulses, paying attention to clinical endpoints with the goal of wrinkle ablation. To blend the laser treated skin with untreated skin, taper these transitional areas by spot treating the margins using 30 microns of ablation. When skin tightening is needed, the surgeon can choose to add 25 microns of coagulation during the third pass with the understanding that this may result in prolonged postoperative erythema. The authors typically reserve this for treatment of the lower eyelids. Smoke evacuation is typically done by the first assistant during all phases of treatment.

Table 76.4 Specific guidelines for Er:YAG laser resurfacing based on skin thickness

NOTE: Acne scars can be treated with a single pass at 100 microns of ablation followed by spot treatment of crater scars.

Novice laser surgeons should practice using the handpiece before treatments as there can be an initial steep learning curve. It is recommended to use a smaller scanning pattern initially to avoid skipped or overlapped areas. When spot treating, slower pulses are initially recommended (three pulses per second) to avoid stacking pulses and overly aggressive treatment. Surgeons should also be aware that using the purely ablative protocol with no hemostatic coagulation energy will result in copious petechial bleeding which is even more evident after wiping off denuded skin between passes. Again, meticulous attention to clinical endpoints will prevent over-aggressive treatment.

Nonablative fractionated lasers

Nonablative fractionated lasers play an important role in our facial rejuvenation armamentarium. The Fraxel Restore utilizes an Erbium glass laser (1550 nm) for nonablative skin rejuvenation. This laser can be delegated to a well-trained physician extender and is efficacious for improving skin dyschromia, tone, pore size, and texture. It use for treatment of rhytids and gravitational aging in the face is very limited and these indications are more appropriate for the ablative or fractionally ablative systems.

Fig. 76.2 Flexan occlusive postoperative wound care dressing.

Fig. 76.3 A&B, Clinical examples of ablative laser resurfacing with the Dual Mode Er:YAG laser. A, Preoperative; postoperative – 12 months. B, Preoperative; postoperative – 6 months.

Fig. 76.4 Perioral resurfacing: comparison of results attainable with: (A) Er:YAG ablative laser. (B) Ablative fractionated carbon dioxide laser (Fraxel Repair). (C) Nonablative fractionated Erbium glass laser (Fraxel Restore).

Postoperative care

While surgeons debate the efficacy of occlusive and nonocclusive wound care protocols, it is well-established that a moist environment must be maintained. Because occlusive dressings have been shown to accelerate the rate of re-epithelialization and decrease postoperative pain, we advocate using an occlusive wound care regimen. Immediately after surgery, the wound is dressed with Flexan® which is precisely cut to cover as much treated skin as possible. Flexan is a sterile, ultra-thin, highly conformable, semi-occlusive polyurethane foam adhesive dressing that protects wounds while maintaining a moist healing environment. The Flexan dressing is left in place and Bacitracin and Aquaphor ointments are alternated every four hours over exposed areas and lightly over dressing. Eyes can be rinsed as needed, the head is strictly elevated to alleviate swelling, and antiviral prophylaxis is continued until postoperative day seven. Postoperative day three, the patient is seen in the office and the Flexan dressing is removed and replaced. The face is cleaned with mild vinegar soaks and gently debrided of nonviable tissue. Flexan dressing is replaced and Bacitracin and Aquaphor ointment is applied as previously. Postoperative day six, Flexan dressing is removed, the face is washed with mild vinegar soaks and gently debrided. An open wound technique is employed until day ten as follows: clean face with Cetaphil® and apply Aquaphor four times per day with an appropriate sunblocking agent. By day ten, the skin will have re-epithelialized and patients can begin to apply post-treatment makeup. Sun exposure should be strictly avoided during the next several months and preoperative skin care regimens can be slowly introduced keeping the skin moist during this transitional period.

Complications

Diligent and frequent evaluation of the patient during the re-epithelialization period after ablative laser resurfacing is vital to optimizing the clinical result and preventing complications. Expected but minor adverse events related to ablative cutaneous laser resurfacing include transient edema, erythema, pain, and pruritus. Mild complications include dermatitis, acne vulgaris outbreak, and milia. Moderate complications include bacterial, viral, or fungal infection, prolonged erythema, and pigmentary alterations including transient post-inflammatory hyperpigmentation and delayed hypopigmentation. More severe complications include scarring, fibrosis, disseminated infection, and deformity such as ectropion of the lower eyelid. It is generally accepted that because the Er:YAG laser has a much closer absorption coefficient to water, there is a shortened period of re-epithelialization and erythema compared to equivalent carbon dioxide systems. This precise tissue ablation and small zone of residual thermal damage results in an improved side effect profile.