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Laser resurfacing – fractional

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Laser resurfacing – fractional

Fractional laser resurfacing was first described in 2001 by Dr Rox Anderson, a prominent laser dermatologist from Boston. In Australia, the first generation of fractional lasers was introduced in 2007. Numerous further developments and refinements have occurred since.

Fractional laser resurfacing devices deliver very narrow columns of heat into the skin whilst sparing the intervening skin between the pinpoint injuries.

There are two types of fractional laser – non-ablative and ablative. Fractional non-ablative lasers leave the tissue intact with an injury that is subsequently removed and repaired by the body. Fractional ablative lasers such as Erbium Yag and CO2 result in complete vaporisation of the tissue columns resulting in a microscopic “Swiss cheese” appearance of holes within the skin.

What is the difference between fully ablative lasers and fractional lasers?

Unlike fully ablative lasers, fractional laser resurfacing, as the name suggests, only treats a fraction of the skin. The percentage of the skin’s surface that is treated can typically vary from 2% to 95% depending on the device and number of passes. The depth of the column of laser injury can also be controlled by the operator.

What is the science behind fractional laser resurfacing?

In the context of laser resurfacing, skin contains two layers, the epidermis or outer layer and the dermis or mid layer. The outer layer of skin produces pigment-producing cells called melanocytes and scale forming skin cells called keratinocytes. Aging and sun damage give rise to abnormal keratinocytes and uneven pigmentation derived from melanocytes.

The dermis provides the scaffolding for skin. It is largely made up of collagen, elastin and blood vessels. Trauma, acne and burn scars may cause an abnormality of the ordered arrangement of collagen. Additionally, sun damage can alter the consistency of the dermis, fragmenting collagen and elastin.

Depending on the wavelength and energy output, fractional lasers can either target the outer layer or deeper layers of the skin.

The body responds to the multiple tiny injuries in the skin by removing the damaged tissue and replacing it with healthy, new, non-damaged epidermal cells that are probably derived from stem cells present in hair follicles. The body also produces new collagen and elastin to replace the damaged tissue. As only a fraction of the skin has been treated, there is a large supply of healthy surrounding cells to repair the damage.

The amazing thing about fractional resurfacing is that it improves the overall appearance evenly, even though only a fraction of the skin has been treated.

Acne scars before and after fractional laser treatment. Images reproduced with permission of Dr Davin Lim
Acne scars before and after fractional laser treatment. Images reproduced with permission of Dr Davin Lim

 

Acne scars before and after three treatments with CO2 fractional ablative laser. Images reproduced with permission of Dr Davin Lim
Acne scars before and after three treatments with CO2 fractional ablative laser. Images reproduced with permission of Dr Davin Lim

When do dermatologists employ fractional laser resurfacing?

Fractional lasers can treat the following dermatological conditions:

  • Acne scars. Both non-ablative fractional lasers and ablative fractional lasers have been shown to be effective in treating acne scars, especially rolling scars, atrophic scars and boxcar scars. Fractional lasers have significant advantages over fully ablative lasers in terms of decreasing downtime and side effects such as the post laser, skin colour changes frequently seen with fully ablative lasers.
  • Surgical, traumatic and burn scars
  • Skin rejuvenation
  • Sun damage and sun spots
  • Melasma (as a last resort in carefully selected cases)
  • Miscellaneous skin conditions reported to improve with fractional laser resurfacing include syringomas, mild rhinophyma, vitiligo, epidermal naevi and birthmarks.
Sun damage, before and eight days after fractional non-ablative laser resurfacing treatment. Images reproduced with permission of Dr Davin Lim
Sun damage, before and eight days after fractional non-ablative laser resurfacing treatment. Images reproduced with permission of Dr Davin Lim

What are the possible side effects of fractional laser resurfacing?

In trained specialist hands, side effects are rare and much less common than after fully ablative laser resurfacing procedures. Side effects include:

  • Skin colour changes, most commonly darkening of the skin
  • Infection
  • Delayed healing
  • Prolonged redness
  • Scarring
  • Acne-like eruptions during the healing period

How long does it take to heal from fractional laser resurfacing?

Healing times vary according to the wavelength, power, percentage of skin treated and the treatment site. Fractional treatments on the face recover more quickly than treatments on the neck, décolletage and limbs. Ablative fractional lasers have a longer healing time compared to non-ablative lasers.

The following is a guide for recovery times after fractional laser resurfacing:

For non-ablative:

  • 3 to 7 days for treatments on the face
  • 5 to10 days for treatments on the neck, chest or limbs

For ablative:

  • 10 to14 days for treatment on the face
  • 14 days or more for treatment on other areas.
Images of chest and décolletage area, before and after two fractional non-ablative laser treatments. Images reproduced with permission of Dr Davin Lim
Images of chest and décolletage area, before and after two fractional non-ablative laser treatments. Images reproduced with permission of Dr Davin Lim

What types of lasers are used for fractional laser resurfacing?

There are many brands of fractional lasers but these can be divided broadly into ablative and non-ablative lasers.

  • Ablative fractional lasers penetrate the upper layers of the skin called the stratum corneum. Examples of fractional lasers include erbium and CO2.
  • Non-ablative fractional lasers leave the upper layers of skin intact. Currently there are over a dozen different wavelengths in use in Australia.

How many sessions of fractional laser resurfacing are needed?

Unlike fully ablative laser resurfacing, fractional laser resurfacing will often require several treatment sessions for the best results. Depending on the skin condition and skin type, you may require between 2 to 5 treatments spaced between 6 to 8 weeks apart to ensure the best outcome.

How do I know if fractional laser resurfacing is right for me?

Your dermatologist will guide you as to the laser best suited to treat your skin condition. The choice between fractional and fully ablative lasers will depend on your skin type (skin colour), your downtime and your skin condition.

This information has been written by Dr Davin Lim and Dr Phillip Bekhor
Updated 25 January 2016

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