Introduction

The field of skin rejuvenation has seen tremendous change within the past decade. Since its introduction in 2004, fractional resurfacing has revolutionized laser surgery. The laser technology, which was developed by Anderson and Manstein,¹ creates columns of thermal damage within the dermis. With the original design, the stratum corneum remained histologically intact and was thus termed non-ablative fractional photothermolysis. In contrast to previous resurfacing technologies, non-ablative fractional photothermolysis is associated with minimal downtime and little discomfort. Furthermore, it is effective in treating a variety of conditions including acne scarring and mild-to-moderate photoaging. Non-ablative fractional photothermolysis has become the treatment of choice for laser skin rejuvenation.

Pathophysiology

In fractional photothermolysis, a regular array of pixilated light energy creates focal areas of epidermal and dermal tissue damage or microthermal treatment zones (MTZs). The vertical columns of thermally denatured skin are surrounded by islands of healthy tissue resulting in a much quicker healing process when compared to traditional ablative skin resurfacing. In the original study, Manstein et al¹ showed the histological changes seen after non-ablative fractional resurfacing. Immediately after treatment there is a sharply defined column of both epidermal and dermal necrosis, followed by repair of the epidermal defect within 24 hours. Over a period of weeks to months, the MTZs heal with no histologic evidence of loss of cell viability. The targeted damage with the MTZ is hypothesized to stimulate neocollagenesis and collagen remodeling, which has led to its application in conditions of disrupted dermal collagen and pigmentation. 

Uses

Non-ablative fractional photothermolysis is currently approved by the US Food and Drug Administration for the treatment of benign epidermal pigmented lesions, periorbital rhytides, skin resurfacing, melasma, acne and surgical scars, actinic keratoses and striae but has been reported to be used in many other clinical settings.

We most commonly use non-ablative fractional photothermolysis in the treatment of scarring, particularly acne scarring. As non-ablative fractional resurfacing leads to collagenolysis and neocollagenesis, nearly all forms of acne scarring can be improved by a series of resurfacing treatment. The improvements in acne scarring of all types have been well documented by many studies,^2-5 and we believe non-ablative fractional resurfacing is the treatment of choice for facial acne scarring. Figure 1 shows a typical result after non-ablative fractional resurfacing. Other forms of scarring, including hypertrophic and atrophic scarring, can be effectively treated with this technology as well.^6-9

We also use non-ablative fractional resurfacing commonly to treat photoaging. We find it especially effective for mild-to-moderate changes but less effective for deep wrinkles and creases. Originally shown to be effective in treating periorbital rhytides,¹ it has also been shown to be effective in treating photodamage of both facial and non-facial sites.^10-13

Improvements in skin pigmentation, roughness and wrinkling make non-ablative laser resurfacing an indispensable treatment option for the aging patient.

The procedure

The most important aspects of the procedure are the pre-operative consultation and appropriate patient selection. We always show before and after photos of typical results to help set patient expectations regarding the efficacy of treatment. In our experience, four to six treatments, which are typically spaced out about every 4 weeks, are required to attain the desired results. The procedure can be performed safely on patients with all Fitzpatrick skin types; however, patients with darker skin types should be treated carefully as dyspigmentation is more common.

Women who are pregnant or lactating, those with active infection (particularly herpes simplex virus [HSV]), patients with a history of isotretinoin use in the past 6 months and individuals with unrealistic expectations should not be treated.

Prior to the procedure, we recommend patients avoid sun exposure and wear a broad-spectrum sunscreen. While some clinicians recommend discontinuing retinoids, there is no evidence to support this, and we do not have patients routinely discontinue them. Herpes simplex prophylaxis is given only to those with a history of herpes simplex infection; although, in some centers, all patients are covered with antiviral therapy. Prophylactic antibiotics are not needed as the epidermis is not thoroughly ablated. The procedure itself is not without pain, and we recommend topical anesthesia be applied 1 hour prior to the treatment. Several different topical preparations exist; however, we have found that 30% lidocaine in an ointment base provides the most comfort with the least amount of reactive erythema to the formulation. Oral anxiolytics and analgesics are only required for a very small number of patients who cannot tolerate the procedure with topical anesthesia alone. Metal eye protection should be worn by the patient, and all people in the treatment room should also have eye protection. An air cooling device should also be used during the treatment as this can help with patient comfort.¹⁴

There are a number of devices that are available for treatment, and a discussion of all devices is beyond the scope of this article. Most of the devices use mid-infrared wavelengths at 1440, 1540 or 1550 nm. The selection of device is often based on personal preference and availability. The main differences between the many devices are the wavelengths of light implemented and the type of hand piece used (scanning versus stamping). Treatment parameters can be adjusted with each laser device to vary the amount of energy delivered and the density of the fractionated laser. The number of passes performed by the physician can also change the intensity of the treatment.

Following treatment, we have our patients ice their skin for several minutes and then periodically over the next few hours to help aid with comfort and reduce swelling. Gentle skin cleansing and non-comedogenic moisturizers are recommended as the skin rejuvenates. Redness usually lasts 3 days and swelling 2 to 3 days.

Safety and complications

Non-ablative fractional resurfacing is a well tolerated procedure with an excellent safety profile.^15,16 Virtually all patients develop post-procedural erythema with the majority exhibiting some degree of xerosis, edema and flaking of the skin.¹⁵ The duration of these changes are short-lived. Seventy-two percent of patients in one study reported limiting social activities by an average time of only 2.1 days which is much less than previous resurfacing technologies. Complications, especially long-term ones, are extremely rare.¹⁶ The most common complications are acneiform eruptions, HSV outbreaks and erosions, which occur in only 1-2% of patients.

Conclusions

Non-ablative fractional resurfacing has revolutionized the field of laser skin rejuvenation. With an excellent safety profile, limited downtime, and excellent results, the technology has become the cornerstone of treatment for acne scarring and photoaging. As the field evolves, further uses of non-ablative fractional resurfacing continue to be discovered.   

Figure 1. Improvement in acne scarring 1 month after 5 treatments with Fraxel 1550 (photo courtesy of Solta Medical)