Fractional CO2 technology

Carbon Dioxide laser emits infrared light (at 10,600 nm) in a focused beam which is well absorbed by water.
CO₂ lasers were first used in facial resurfacing in 1991 and rapidly became the “gold standard” for treatment of severe photo‐damage (the visible signs of sun‐damaged skin including wrinkles). However this use of CO₂ lasers involved fully ablating the skin and required an experienced laser surgeon. There was a risk of causing pigment changes or long term erythema, and although the use of CO₂ lasers was extremely effective the treatments declined in popularity – with patients selecting either full surgery or less effective (but more comfortable) alternatives.

In the last three years or so, various laser wavelengths have been customized into fractional treatments. The term is used when only small parts of the skin (called micro thermal zones) are treated, leaving behind areas of intact, undamaged skin. The concept behind fractional treatment is that these untreated areas speed up the healing process by allowing migration across the skin as well as formation of new epidermal tissue. Since the skin can be said to have a “memory” or more accurately can be said to follow a design plan, the replacement tissue more accurately follows the design plan than the removed tissue which has been subject to damage from sunlight.

CO₂ is unique as it offers both epidermal skin ablation (heating the tissue to 100°C and instantly vaporising it) and heat damage (where both surrounding epidermal tissue and underlying dermal tissue is heated to a temperature where proteins denature).
While the ablation of the epidermis is all that is required to improve dyschromias and repair epidermal pigmentation, the heat damage causes stimulation of dermal cells called fibroblasts that are responsible for the structural integrity (the extracellular matrix) of the skin and which are responsible for formation of new collagen.
The heat damage stimulates a wound‐healing process causing a collagen remodelling process to take place.
This means that Ellipse Juvia is suitable for treatment of pigment damage such as solar lentigines, mild to moderate wrinkles, skin texture (both pore size and coarseness), and acne scarring. By comparison, Erbium lasers ablate with minimal heat, and multiple passes are required to ablate the dermis, if collagen remodelling is desired.

The secret of successful treatment is to precisely control both the depth of ablation and the amount of lateral heat damage. The ablation depth is dependent on the power used, and because of the different epidermal thicknesses, the power will need to be changed to reach the epidermal‐dermal junction in different treatment areas, in order to optimize the collagen remodelling process. By increasing the dwell time (the pulse time) it is possible to alter the lateral damage, and therefore the amount of coverage. This combination of parameters makes it possible to determine a treatment zone (a combined depth where ablation or thermal damage occurs) from 100μm to 400μm, and this can be improved upon further by pulse stacking. An alternative method of increasing coverage can be obtained by altering the scan density pattern, from 49 to 81 or 121 micro thermal zones (MTZ) per square centimetre. Histology clearly shows a separate ablative and thermal effect from treatment.

The initial post treatment process varies a little according to the settings chosen. Immediately following treatment erythema will be observed, and there may be an immediate effect of skin tightening (this is caused by denaturisation of the proteins in the skin). At more powerful settings, a little whitening (char) of the skin and some oedema may be observed. The erythema is followed after a few days by a micro‐crusting of photo‐oxidized pigment which gives the skin a bronze hue, and which clears within a day or two (initially from the centre of the face). Once erythema has resolved and bronzing is observed, the patient can use makeup and resume normal work.
Following fractional CO₂ treatment, replacement epidermal cells form quickly, resulting in post treatment erythema and oedema disappearing within 5 to 14 days, while the collagen remodelling process is slower and peaks approximately 3‐6 months after treatment.