Fractionated Laser Technologies: Just the Fracts…

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Sandy Tsao, MD

In this presentation, Dr Tsao discusses fractional resurfacing and its efficacy in clinical practice. A lot of information has become available to clinicians regarding improving the aging process for their patients.  Fractionated resurfacing technologies have been designed to provide benefits for many aspects of aging by taking the best of the ablative and non-ablative technologies.  In comparison to other non-ablative technologies, fractional non-ablataive resurfacing demonstrates greater efficacy.  It is important to remember that fractional resurfacing is safer for non-facial areas.. It is also safer for darker skin phototypes. , Fractional resurfacing demonstrates a safer side effect profile when compared to traditional ablative devices.. The recovery time is markedly reduced and there are no permanent lines of demarcation to date.

There are a number of fractional technologies available; however, dermatologists should remember that there is not one particular laser that can target all of the concerns regarding photoaging. When you are thinking about these devices, you need to consider what you are actually trying to target. Dr Tsao comments that the ultimate goal in fractional resurfacing  , is to create a localized thermal injury. Thermal injury is thought to be the key for tissue repair. Heat-induced inflammation results in immediate collagen shrinkage and tissue contraction and, subsequently, fibroblast stimulation and neocollagenesis. This concept, Dr Tsao mentions, is very similar to the ablative devices; however, the side effects and down time are much less. There is a zone of irreversible thermal damage and its associated inflammation which must heal before re-epithelialization begins. Prolonged inflammation due to infection, hypersensitivity, or extensive thermal damage due to vigorous treatment can result in complications.

How do fractional resurfacing devices work?

As previously mentioned, there are a number of fractional ablative and non-ablative technologies available,. It is important to match treatment depth and treatment parameters with the clinical  indication(s), i.e., are you targeting pigment (superficial to mid dermis), mild rhytids (mid reticular dermis), moderate rhytids (deep reticular dermis) or surgical scars, burn scars and acne scars (deep remodeling). This is the real learning curve with these devices…you need to know what you are targeting and whether or not you may need a combination of these therapies to achieve your clinical goals.

Each of the devices has a different way of administering the microthermal zones. These devices include continuous motion scanning and traditional lens array stamp pattern, which can be a little bit harder to administer because of the potential of overlap or skip regions.

Non-Ablative  Fractional Resurfacing

Every pulse creates a localized injury or,  microthermal zone (MTZ). You are actually creating columnated areas of heat inflammation. The depth and diameter depend on the type of device that you are using, as well as the parameters selected for treatment. The fractional non-ablative devices create the columnated thermal injury while leaving the normal intact skin in between; therefore, retaining  viable stem cells in between the microthermal zones of injury. This allows for the skin to repopulate much faster, resulting a limited healing period.

Fractional non-ablative laser treatment results in complete re-epithelialization in 24 hours. In human tissue, you can see clear collagen denaturization from papillary dermis into mid reticular dermis. The healing occurs from viable tissue and the zones of spared tissue which contain clusters of epidermal stem cells and Transit Amplifying (TA) cells. What is unique about the non-ablative technologies is that they leave the epidermis intact. The downtime for most of these technologies is about three days of some redness and swelling. This is a very manageable outcome for most patients.

Dr Tsao also comments that over the past two or three years, we have been very fortunate to have a new fractional non-ablataive device available at 1927 nanometers which matches one of the water absorption peaks in the mid infrared spectrum . This wavelength absorption is stronger than most non-ablative wavelengths and weaker than ablative wavelengths. This device fulfills the role to more selectively target lentigines, pigmentation,  actinic keratoses and seborrheic keratoses

Ablative Fractional Resurfacing

These devices work exactly like the non-ablative devices in that they create microthermal zones; however, the big difference is that the epidermis is shed along with a portion of the dermis.  This creates more thermal damage, requiring a longer recovery time. Replacement of the skin surface requires about one week. Patients must be aware of the longer downtime with the fractional ablative devices. Ultimately, what you are aiming to achieve is a healthier more youthful epidermis and dermis.

How does this translate clinically?

If a patient does not want surgery or ablative treatment, then fractional non-ablative or ablative resurfacing could be a viable option. It is important to set realistic expectations with your patients as far as achievable outcomes.  Non-ablative fractional devices will provide improvement of superficial rhytids and dyspigmentation, but not likely provide significant benefit for deeper rhytides.  The fractional non-ablative devices provide marked improvement of atrophic and acne scars.  The fractional ablative devices provide greater benefit for moderate to deep rhytides and dyspigmentation, especially perioral rhytids.

Downtime

It makes a tremendous difference to patients if you can have photos available to show them the expected downtime so that they can make a more informed decision regarding their treatment.

  • Microlaser peel- 7 days of peeling, 2 weeks of pink hue
  • Fractionated non-ablative
    • 1410nm- 1 day mild erythema and edema
    • 1550nm- 2-3 days erythema and edema
    • 1927nm- 4-5 days erythema and edema and pinpoint crusting; 1 week of pink hue
    • 2940nm- 7 days erythema and edema, 2 weeks of pink hue
  • Fractionated ablative- 1-2 days pinpoint bleeding, 7 days erythema and edema; 4-6 weeks of pink hue
    • Ablative-14 days erythema and edema; 2-3 months of pink hue
Clinical Pearls

When treating the eyes, you have to be extremely careful to prevent ocular damage. Less aggressive treatment is necessary  to prevent ectropion formation. It is also important to use  metal protective eyeshields when treating the eyelids. Proparacaine anesthesia and erythromycin ointment to coat the eyeshields can be used for lens placement. It is also important to use particular caution in patients with prior surgical procedure history, such as a prior facelift or blepharoplasty, as the facial anatomy may be altered .

With regards to darker skin phototypes, less is more (fluence, density, passes). You may want to consider a laser test site. You should also stress the need for strict photoprotection and discuss the increased risk for PIH. , You may consider pre-treatment use of retin-a or hydroquinones. You should also use greater cautionwhen using ablative fractional devices, as the risk of side effects is greater.

Remember that when you apply these treatments to non-facial regions you have to be very cautious as there are not as many pilosebaceous units to assist in re-epithelialization, resulting in an increased risk of scar formation when treating these areas with both fractional non-ablative and fractional ablative devices.