Nonablative Fractional Laser Skin Rejuvenation

Summary and Key Features

• Nonablative fractional resurfacing (NAFR) is a safe and effective treatment that has become the cornerstone for facial rejuvenation and acne scarring.

• It is effective in treating a variety of conditions, including scarring, mild-to-moderate photoaging, and some forms of dyspigmentation.

• Nonablative fractional photothermolysis has minimal downtime with almost no restrictions on activity immediately following treatment.

• Erythema and edema are common sequelae after treatment and resolve within a few days. Long-term complications are exceedingly rare.

• All Fitzpatrick skin phototypes can be treated, provided settings are adjusted accordingly.

• The preoperative consultation is a vital component of the treatment regimen to ensure optimal outcomes.

• Fractional picosecond lasers and fractional microneedle radiofrequency devices are newer tools for NAFR.

• Technology in the field is changing rapidly, and the selection of equipment is based on individual preference.

Introduction

Fractional photothermolysis (FP), a concept introduced in 2004 by Anderson and Manstein, revolutionized the field of skin rejuvenation. Although multiple treatment sessions are required to achieve the desired outcome, advantages of nonablative fractional resurfacing (NAFR) are markedly reduced discomfort compared to ablative resurfacing lasers and minimal recovery period after the procedure—downtime is limited to an average of 3 days of redness and swelling, as opposed to an average of 7–10 days after aggressive nonfractional ablative resurfacing. Combined with an excellent safety profile, NAFR has become the cornerstone of laser skin rejuvenation for the treatment of photoaging, scarring, and a variety of other clinical applications.

Pathophysiology

In FP, an array of pixelated light energy produced with each scan or stamp of the laser creates microscopic columns of thermally denatured skin called microscopic treatment zones (MTZs) ( Fig. 6.1 ) surrounded by normal unaffected skin. This targeted damage with MTZ is believed to stimulate neocollagenesis and collagen remodeling leading to the clinical improvements seen in scarring and photoaging. Since the discovery of FP, multiple different lasers have been developed to take advantage of this technologic advance. Each laser has parameters that can be modified to alter the density, depth, and size of the vertical columns of MTZs. Additionally, the wavelength of fractional nonablative lasers varies depending on the device which affects the coefficient of absorption and how the laser forms the MTZs.

The histologic changes seen after FP were elegantly described in the original study by Manstein et al. Immediately following treatment, lactate dehydrogenase (LDH) viability staining showed both epidermal and dermal cell necrosis within a sharply defined column correlating with the MTZ. There was continued loss of dermal cell viability 24 hours after treatment, but the epidermal defect was repaired via keratinocyte migration. One week after treatment, individual MTZs were still evident by LDH staining, but after 3 months there was no histologic evidence of loss of cell viability.

Hantash et al. demonstrated a unique mechanism of tissue repair with FP. In 2006, they demonstrated, using an elastin antibody, that damaged dermal content was incorporated into columns of microscopic epidermal necrotic debris (MEND) and shuttled up through the epidermis and extruded in a process of transepidermal elimination. This mechanism, which had not been described with previous laser technologies, explains the elimination of altered collagen in photoaging and scars and was also hypothesized to provide novel treatment strategies for pigmentary disorders, such as melasma, as well as depositional diseases, such as amyloid and mucinoses.

Fractional picosecond lasers are a newer tool in the fractional nonablative resurfacing toolbox. These lasers confine areas of high fluence to microspots with the majority of the treated area receiving low background fluence. The high-energy microspots create areas of laser induced optical breakdown (LIOB) which are epidermal vacuoles with preservation of surrounding epidermis. These LIOBs subsequently trigger collagen remodeling and can improve skin texture and dyspigmentation.

Epidemiology

According to the 2018 American Society of Dermatologic Surgery Annual Survey on Dermatologic Procedures, which provides a comprehensive estimate on the total number of cosmetic procedures performed by dermatologic surgeons in the United States, laser, light, and energy-based treatments have increased by more than 74% since 2012. The majority of laser skin resurfacing procedures are nonablative and performed on women.

Equipment

As the technology of FB continues to evolve, new devices continually come to market. A list of currently available NAFR systems is given in Table 6.1 . The table is not comprehensive and, as one can imagine, subject to change based on market availability. This section will provide a brief description of a few of the more commonly used devices.

The original nonablative fractional resurfacing system described by Manstein and Anderson featured a scanning handpiece with a 1500-nm wavelength. The updated, currently available model, the Fraxel Dual (Solta Medical, a division of Bausch Medical, Bothell, WA), combines a 1550-nm erbium glass laser with a 1927-nm thulium laser in the same platform. The thulium laser provides a more superficial treatment option and better addresses dyspigmentation, whereas the 1550 nm penetrates deeper to stimulate collagen remodeling. The device has tunable settings to adjust the density of the MTZs and energy depending on the treatment. The system increases flexibility, allowing the practitioner to switch between the two lasers to tailor treatment accordingly. Cooling, which helps to minimize procedural discomfort, is built in with the Fraxel Dual.

The Palomar brand of Cynosure (Westford, MA) offers the Icon platform with individual handpieces that attach to a single unit to cover a wide range of uses. The Lux1440 and Lux1540 handpieces provide two wavelength options (1440 and 1540 nm) for fractional nonablative photothermolysis. In addition, the company has developed an XD Microlens for their nonablative laser handpieces which consists of a sapphire window with micro-pins. In their study the company claims that the combination of manual compression and the micro-pins help to compress the dermis and displace interstitial water from the dermal–epidermal junction into the surrounding spaces. With less water to absorb, scattering of the laser light is reduced, enabling increased absorption of the light by deeper targets.

There are quite a few lasers on the market which allow for fractionated delivery of picosecond pulses. These devices include the PicoSure laser with the Focus Lens Array handpiece (Cynosure, Chelmsford, MA), the PicoWay laser with the Resolve handpieces (Syneron Candela, Wayland, MA), and the Enlighten laser with the PICO Genesis FX handpiece (Cutera, Brisbane, CA). The Focus Lens Array handpiece on the PicoSure laser consists of a fixed 6-mm spot size with a fixed fluence. The handpiece fractionates the 750–850-picosecond pulsed 755 nm light so that 70% of the total energy is focused toward only 10% of the total treatment area with the remaining 30% of the energy distributed to 90% of the remaining surface. Similarly, the PicoWay laser (Syneron Candela, Wayland, MA) has beam splitting handpieces for both the 532 and 1064 nm wavelengths which deliver an array of 100 microbeams of 450-picosecond pulses per 6 × 6 mm area. The Enlighten laser (Cutera, Brisbane, CA) has a Micro Lens Array attachment which can be used with the 1064 nm wavelength. This handpiece delivers fractionated laser light through an adjustable spot size with each microbeam fluence approximately 10× higher than the console setting.

Applications

Although NAFR 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, it has been reported to be used in many other clinical settings ( Box 6.1 ).

Photoaging

Photoaging is the process by which ultraviolet radiation induces changes in the skin such as loss of elasticity, dyschromia, and rhytids. Fractional nonablative lasers provide an excellent treatment modality that can address, at least to some degree, nearly every sign of photoaging. While ablative lasers remain the gold standard for skin tightening, NAFR can provide modest improvement as demonstrated by the sentinel study of the prototype fractional 1550-nm laser in 2004. In this study linear shrinkage of 2.1% was measured 3 months after the last treatment and the wrinkle score improved by 18%. This study also demonstrated that the sequence of skin tightening with NAFR appeared to be similar to ablative resurfacing with tightening within the first week after treatment, apparent relaxation at 1 month, and retightening at 3 months (Case Study 1). Another study utilizing rat skin also demonstrated the skin tightening potential of NAFR lasers and showed a 4.3% reduction in surface area of treated skin along with regenerated collagen. Notably, a recent study by Borges et al. demonstrated that patients treated with 1540-nm NAFR had reorganization of collagen type I and II and had signs of fibroblast activation 3 months after treatment.

While the skin tightening effects of fractional nonablative lasers may be modest, improvement of sun-induced pigmentation and lentigines can be more dramatic. Geronemus et al. demonstrated that two treatments with a 1927-nm nonablative fractional thulium laser produced moderate to marked improvement in the treatment of facial sun-induced pigmentation with high patient satisfaction. Similarly, Narurkar et al. demonstrated efficacy in the appearance of photodamage and pigmentation after a series of up to four treatments with 1550 and 1927 nm wavelength lasers. A series of treatments with the 1927-nm nonablative thulium laser is our treatment of choice for photoaging especially when sun-induced pigmentation is prominent.

Fractional picosecond lasers also provide a novel treatment modality to address photoaging. Brauer et al. demonstrated the effectiveness of a fractional 755 nm picosecond laser in treating mild textural changes and pigmentation associated with photoaging. A fractional 532 and 1064 nm picosecond laser improved photoaged skin and significantly decreased elastosis scores in patients with Fitzpatrick skin types I–V treated for facial wrinkles. Additionally, a histological study showed improvement of epidermal and dermal age-related atrophy after treatment with a fractional picosecond laser.

Case Study 1 The Right Patient

A 58-year-old white male with mild rhytides and mild-to-moderate photodamage with scattered facial lentigines presents for consultation. You recommend a series of nonablative fractional resurfacing laser procedures. Six months after the sixth laser procedure, you see the patient back in follow-up. He is delighted with his improvement in both texture and skin tone and subsequently refers a couple of his friends to see you.

This patient is the ideal patient for nonablative fractional resurfacing. These results are typical of the improvement we see in our patients when selected appropriately. Fractional 1927-nm light is best for epidermal dyspigmentation related to photoaging, and the 1550 and 1540 nm wavelengths are best for texture. In this case a combination of wavelengths performed with each visit or alternating devices yields the best possible improvement; 1927-nm NAFR is usually recommended first because of the high degree of rapid improvement in color. Texture is slower to improve.

Subsequent reports have confirmed the efficacy of NAFR beyond just periorbital lines. Wanner et al. showed statistically significant improvement in photodamage of both facial and nonfacial sites, with 73% of patients improving at least 50%. In 2006 Geronemus and colleagues also reported their experience with fractional photothermolysis, finding it to be effective in treating mild-to-moderate rhytides. Figs. 6.2 and 6.3 show typical improvement in rhytides and pigmentation after treatment with nonablative fractional resurfacing. For deeper rhytides, such as the vertical lines of the upper lip, improvement is also seen but not nearly to the same degree as in ablative approaches.

NAFR is also considered to be an effective and safe treatment modality for photoaging off the face, including the neck, chest, scalp, arms, hands ( Fig. 6.4 ), legs, and feet. These body sites are typically very challenging to treat with other treatment modalities, given either increased risks of complications (e.g., scarring) associated with ablative technologies or lack of efficacy that has been previously observed with other nonablative devices. Jih et al. reported statistically significant improvement in pigmentation, roughness, and wrinkling of the hands in 10 patients treated with nonablative fractional resurfacing. In our experience, we have found NAFR on all body sites to be very safe when settings are adjusted accordingly.

Scarring

Scarring can induce a tremendous psychologic, physical, and cosmetic impact on individuals. Previous therapeutic modalities in scar treatment include surgical punch grafting, subcision, dermabrasion, chemical peeling, dermal fillers, as well as laser resurfacing with ablative and nonablative devices. Published studies have demonstrated that NAFR can be successfully used in the treatment of various forms of scarring with a very favorable safety profile ( Fig. 6.5 ). Mechanistically, FP allows controlled amounts of high energy to be delivered deep within the dermis, resulting in collagenolysis and neocollagenesis, which smooths the textural abnormalities of scarring. It has been shown that collagen continues to remodel up to 6 months after NAFR possibly due to laser-induced regulation of matrix metalloprotein (MMP) and interleukin expression. These alterations on gene expression level could play a role for the dermal remodeling, anti-inflammatory effects and increased epidermal differentiation which lead to the improvement of scars.

With such a good efficacy and safety profile, many clinicians, including the authors, prefer NAFR to ablative FP when it comes to treating acne scarring. In a large clinical study, Weiss showed a median 50%–75% improvement of acne scars, using a 1540-nm fractionated laser system after three treatments at 4-week intervals, with 85% of patients rating their skin as improved. Alster showed similarly impressive results in a study of 53 patients with mild-to-moderate acne scarring; 87% of patients who received three treatments at 4-week intervals showed at least 51%–75% improvement in the appearance of their acne scars.

Pearl 1

Patients with deep acne scarring or severe rhytides often require high-energy settings, which correlates with deeper penetration of the laser and subsequent remodeling of collagen deeper in the cutis.

Fractional picosecond lasers provide a new, effective treatment option for acne scarring. A recent split-face study in 25 Asian patients compared treatment with a fractional picosecond 1064-nm laser and fractional carbon dioxide (CO ₂ ) laser for the treatment of acne scars. The authors found that skin texture and atrophy significantly improved with both treatments with no significant difference between the two sides. No patients experienced postinflammatory hyperpigmentation on the fractional picosecond treated side whereas 24% experienced mild PIH on the fractional CO ₂ treated side.

NAFR can also be safely used to treat acne scarring in darker-pigmented patients ( Fig. 6.6 ). A study of 27 Korean patients with skin types IV or V that were treated with three to five nonablative fractional resurfacing treatments revealed no significant adverse effects, specifically pigmentary alterations. Furthermore, all forms of acne scarring, including ice-pick, boxcar, and rolling scars, improved, with 8 patients (30%) reporting excellent improvement, 16 patients (59%) significant improvement, and 3 patients (11%) moderate improvement. Low density settings appear to reduce the risk of hyperpigmentation in skin of color patients. If hyperpigmentation occurs, it is typically mild and short-lived.

Although there are limited studies, NAFR can also improve contracted and hypertrophic scars. While contracted scars were historically treated with ablative resurfacing, a case study showed both subjective and objective improvement in range of motion in a patient with contracted extremity scars after 1927 nm and 1550 nm NAFR. In a study of eight patients with hypertrophic scarring, all patients had improvement in their scars based on the physician’s clinical assessment, with a mean improvement of 25%–50%. Although the flashlamp-pumped pulsed dye laser (PDL) had long been considered the laser of choice for treating hypertrophic scars, NAFR has shown tremendous promise when compared with PDL. In a study of 15 surgical scars in 12 patients, NAFR outperformed PDL in the improvement of surface pigmentation, texture change, and overall scar thickness. Although more studies are needed, NAFR should be considered as a therapeutic option to be used in conjunction with or as an alternative to PDL.