The concept of non-ablative fractional photothermolysis was introduced to the market in 2003 as an answer to the need for effective, yet low risk, skin resurfacing techniques. Unlike conventional ablative (CO2 and Erbium) and non-ablative lasers, fractional ablative and non-ablative photothermolysis treats only a fraction of the skin, leaving up to a maximum of 95% of the skin uninvolved. The undamaged surrounding tissue allows for a reservoir of viable tissue, permitting rapid epidermal repair.

Non-ablative fractional photothermolysis is currently approved by the US Food and Drug Administration (FDA) for the treatment of pigmented lesions, periorbital rhytides, skin resurfacing, melasma and soft tissue coagulation, acne and surgical scars, and actinic keratoses. However, its off-label use is clearly more extended. Many practitioners would agree that this first wave of fractional lasers has delivered very limited clinical efficacy.

See larger chart

fractional-ablative-laser-treatment

In 2007 the concept was further developed, and ablative fractional photothermolysis was introduced, using an erbium yttrium aluminium garnet (Er:YAG) or carbon dioxide (CO2) laser. These devices are FDA cleared to treat wrinkles, rhytides, furrows, fine lines, textural irregularities, pigmented lesions and vascular dyschromia.

Contrary to the conventional ablative laser modalities, which cover an entire area of skin, fractional laser treats only fractions of the skin, by inducing small three-dimensional zones of thermal damage, referred to as “Microscopic Thermal Zones” or MTZs. The surrounding tissue is not involved, which allows fast epidermal repair via migration of the viable cells, hence the term fractional.

Depending on the chosen parameters of laser energy per MTZ and the density of MTZs per square centimeter, anywhere from 3 to 40% of the skin can be treated. MTZ are usually small than 400 nm in diameter and can go as deep as 1,300 nm into the skin.

The target chromophore for all ablative devices, including fractional, is water. This allows selective thermal damage to various water-containing structures, such as collagen, blood vessels and epidermal keratinocytes.

This new wave of fractional lasers is a lot more efficacious for the treatment of indicated conditions. How much less effective than conventional ablative lasers? How much less downtime than conventional lasers? And many other questions remain a topic of debate among medical practitioners and manufacturers. Cost of lasers and laser treatments for the patient are still in favor of conventional lasers.