Fractional skin resurfacing technologies like Fraxel, Lumenis ActiveFX, DeepFX, Palomar Starlux 1540 and Starlux 2940, and are quickly becoming familiar to many cosmetic, dermatology, plastic surgery and medical spa practices.

The history of laser skin resurfacing goes back to 1995, when the first full face CO2 laser resurfacing for wrinkle removal was performed. The procedure was a revolution in facial laser surgery. A flock of lasers were developed primarily for plastic surgeons. The procedure was done under general anesthesia and created a burn wound, which took 7-10 months to heal. The hypo pigmentation that followed for about another 10-12 months was normal and fairly well accepted for a few years due to lack of other options.

The next advance in laser skin resurfacing was the development of Erbium (Er:YAG) lasers. They became available to plastic and dermatology surgeons around the year 2000. These were, and continue to be very effective for the resurfacing. Erbium lasers are a lot safer and cause a significantly reduced downtime for the patient. At about the same time fewer patients wanted to have a full face resurfaced as a nicely done areas around the eyes and mouth created a very comparable overall aesthetic result with even faster healing and shorter downtime. A mild laser peel will give most patients an excellent result with about one week of “take it easy” time.

Fractional laserswere introduced to the aesthetic market in 2002-2003 with a big bang and glitzy and very effective promotions by Reliant, which pioneered the fractional photothermolysis. The idea was to bring about a laser that would be non-ablative,  but as effective as the ablative lasers (the CO2 and Erbium) before it.

Fraxel laser by Reliant was the first non-ablative fractional laser for the cosmetic medical market and it gave birth to the first generation of non-ablative fractional lasers. While there were a lot of hype about these non-ablative fractional lasers, the clinical fact is that they had categorically fallen short of the goal of ‘profound results with zero downtime.’ As we have seen with these devices, patients had to tolerate painful treatment in multiple sessions while still enduring disruption of the epidermis and thus multiple episodes of downtime, before the final outcome, which also failed to meet expectations. Fraxel has been upgraded and improved by a number of other competing fractional laser skin resurfacing technologies such as the Lumenis DeepFX and ActiveFX, Palomar Starlux 1540, and Starlux 2940. The newest fractional skin resurfacing technologies employ the use of erbium lasers and may be non-ablative (Fraxel re:fine, Fraxel re:store, Palomar Starlux 1540) or ablative (the newest generation of fractional lasers). The laser beam is ‘fractionated’ into tiny micro-lasers, treating only a small portion of the skin (MTZ – microthermal zone, or sometimes called microscopic treatment zones) and leaving surrounding skin tissue undamaged. The goal is to speed up the healing.   These MTZs cause enough injury to the dermis to trigger new collagen production and stimulate the replacement of collagen damaged by aging and sun exposure. This production of new collagen ‘fills in’ or ‘plumps’ the underlying dermal tissues and smoothes wrinkles. The surrounding, untreated skin speeds the healing process to a mere 3-4 days. Since most of the pigment cells remain intact, hypo pigmentation is effectively prevented. The Fraxel re:fine, Fraxel re:store and Palomar Starlux 1540 are non-ablative lasers that don’t actually vaporize or remove the skin. Instead, the laser instantly heats MTZs, causes the thermal damage, which stimulates new collagen growth during the healing process. Results for wrinkle removal and skin tightening are less dramatic than with any ablative lasers, but some patients may appreciate the benefit of reduced recovery time and fewer side effects.

Fractional Ablative Laser Resurfacing

The newest generation of fractional lasers (Starlux 2940, Lumenis ActiveFX and DeepFx systems and Fraxel re:pair) use the ablative skin resurfacing, i.e. CO2 10600 nm or Erbium 2940 nm. They are designed to offer the best of both worlds: fractional treatments with less downtime and reduced complications and ablative laser skin resurfacing for better wrinkle removal and facial rejuvenation. These lasers actually remove tissue in the micro treatment zones, providing much better cosmetic result for patients with heavily wrinkled and sun damaged skin. These lasers provide “rapid remodeling from the inside out”: the fractional treatment results in both rapid reepitheliazation of the epidermis as well as collagen remodeling to depths of 1.6 mm. The skin heals much faster than if the entire area were treated at once, because the treatment uses the body’s natural healing process to create new, healthy tissue that replaces skin imperfections – such as wrinkles, melasma, dyschromia, actinic ketatosis, pigmented lesions, acne scars and surgical scars.

Fractional treatment works on and off the face, including delicate areas like the neck, chest and hands. This is a huge advantage over previous generations of ablative lasers, which required a truly skilled hand to work on these areas.

There is some increase in recovery time:  clinical downtime of 2-3 days (reepitheliazation of epidermis) and 5-7 days of social downtime (time for patients to resume regular activities). Thus the overall downtime is comparable to the downtime after a traditional non-fractional erbium ablative laser treatment.

LaserOffers.com comment

Leaving the laser skin resurfacing by pulsed non-fractionated CO2 lasers in the past (where it belongs now), most experts agree that the newest generation of fractional lasers, which uses ablative technologies (Erbium or CO2), have approached the clinical efficacy achieved by traditional Erbium resurfacing. The pain for the patient, downtime and potential side effects are comparable. It is up to the physician to define what patient will benefit more from the subtle difference between these lasers. In time when value and ROI are particularly important, the cost of acquisition of either type of the ablative laser will be the best helpers to the physician.

Arch Facial Plast Surg. 2005 Jul-Aug;7(4):251-5

Authors: Carniol PJ, Vynatheya J, Carniol E

OBJECTIVE: To evaluate the efficacy of treatment of established acne scars with a sequential combination of treatment using a 1450-nm, midinfrared, nonablative diode laser with dynamic cooling spray and 30% trichloroacetic acid peels.

METHODS: In this prospective study 9 patients with atrophic rolling, boxcar, or both types of scars received 4 monthly treatments using a 1450-nm, midinfrared, nonablative, diode laser with dynamic cooling spray followed by 2 bimonthly treatments with 30% trichloroacetic acid peels. Blinded evaluators and the patients rated the results.

RESULTS: The group of patients in this study had a greater improvement in their acne scars than has been reported for nonablative laser treatments by other authors. Comparing the results of treatment 2 months after the laser treatments with 2 months after the chemical peels, the patients had a greater improvement after the additional chemical peels. There were no complications in this study. The patients were able to continue all of their regular activities throughout the study.

CONCLUSION: This sequential treatment regimen using the 1450-nm, midinfrared, nonablative diode laser with dynamic cooling spray and 30% trichloroacetic acid peels produced a noticeable improvement in the acne scars without any associated morbidity.

PMID: 16027346 [PubMed - indexed for MEDLINE]

S. Brown, PhD et al

Characterization of Non-thermal Focused Ultrasound for Non-invasive Selective Fat Cell Disruption (lysis): Technical and Pre-clinical Assessment

currently available on PRS Advance Online at http://www.plasreconsurg.com

In this new paper, Spencer Brown MD et. al. performs four pre-clinical experiments to elucidate the acute biological effects of the Ultrashape device for non-invasive fat cell disruption.  Brown’s five co-authors are Ultrashape employees.  In general, the presented work appears to be careful and the results accurate.  Unlike the previously reviewed Zeltiq pre-clinical study, however, several important pre-clinical experiments were not performed, so we still do not know how the acute biological effects of the Ultrashape device are related to ultimate clinical outcomes.

In the first two experiments, the authors characterize the energy delivery of the UltraShape probe in water, which is a standard method for characterizing ultrasound energy fields.  Brown shows that the device focuses the ultrasound energy in a volume that has a diameter of about 8mm, and a depth that ranges from about 5mm to about 25mm from the probe.  Brown shows that the energy density (power per cm2) at the probe-water interface is very small, as desired.  Further, the authors showed that the ultrasonic energy created air bubbles in the focal region, consistent with a non-thermal cavitation effect.  Quantitative measures of ultrasonic power density were performed at 0mm and 14mm depth, and showed an absence of “hot spots.”  An improvement to the study would have included power density measurements at 1.5-2mm (approximately the depth of the dermal-fat junction) and 25mm (to characterize the extent of the ultrasonic energy transmission).

In the third experiment, the UltraShape probe was characterized in a gel phantom intended to simulate the ultrasound transmission properties of skin and fat.  In this case the focal volume was 9mm in diameter (slightly less focused than in water) and extended about 18mm in depth (the distance from the surface was not reported, but appears to extend from about 4mm to 22mm from the probe according to the figure).  Again, bubbles were seen in the focal region in this model, consistent with a non-thermal cavitation effect. 

In the fourth experiment, porcine skin was treated and then immediately evaluated with both frozen sections and histologically stained sections.  Untreated control skin was also evaluated to ensure that results were not due to processing artifact.  Importantly, no effect on skin color or skin appearance was seen on the animals receiving this treatment, and histology showed that the dermis and epidermis appeared to be completely unaffected by the treatment.  The subcutaneous fat, however, showed evidence of tissue injury in both the frozen sections and the histology.  Histological staining for LDH activity using NTBC (elevated levels of LDH indicate tissue breakdown) demonstrated a layer of adipocyte cell breakdown extending from about 15mm to 25mm of tissue depth.  In the treated tissue, but not the control tissue, frozen sections and two other histological stains (H&E and Masson’s Trichrome) indicated a “defined area of tissue destruction” extending from approximately 8mm to 18mm of tissue depth.  This region showed clear disruption of fat cells, while connective tissue, blood vessels and nerves remained intact.  No evidence of any thermal damage was seen in any treated tissue, again “consistent with initial cavitation followed by the mechanical destruction of cells.”  The authors state that fourteen animals were treated in this study, and the results were “consistent over time” despite the use of “multiple devices, [and] multiple transducers [by] numerous users.”  No quantification of subject-to-subject variability was provided.  For example, the authors should have measured the zone of tissue damage in each animal, and presented the results as averages with 95% confidence intervals.

So far, the results are promising, with clear evidence of non-invasive damage to subcutaneous fat and no apparent impact to the dermis.  Unfortunately, the analysis stops there.  For example, it is clear from the presented images that not all fat cells in the treated region were disrupted, but the authors do not quantify the percentage of the treatment volume that was disrupted.  Further, the response of the animal to this treatment was not studied.  Biopsies of treated and control areas were not performed at meaningful time durations subsequent to treatment (such a 1 day, 1 week, 1 month and 3 months post-treatment).  Unlike the recent Zeltiq study, we have no idea how the skin and subcutaneous fat respond to these injuries.  Does inflammation occur?  While no changes to the histology of the dermis were seen immediately post-treatment, could an inflammatory response occur over time?  Are non-viable cells removed or replaced?  Does this treatment cause meaningful changes in fat thickness compared to control volumes over time, and if so, when do these changes occur?  Lastly, blood lipid profiles were not analyzed in this study.  We cannot know if release of lipids from the disrupted adipocytes has any systemic effect, either on blood lipids or the liver.

The authors state that these study “observations do not directly lead to predict clinical results,” and they recommend further clinical evaluation.  However, the real need is for further pre-clinical evaluation.  Perhaps this partly explains why this device, widely available in Europe and Canada, is not yet cleared by the FDA.