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ARTICLE | FACIALAESTHETICS | peels and dermabrasion, CO2


thermal injury diffusing to adjacent tissue. As with other resurfacing modalities such as chemical lasers completely remove


the epidermis and part of the dermis, resulting in wound remodelling with the subsequent formation of new collagen and elastin fibre formation, creating firmer and tighter skin. Studies have shown that the depths of ablation are 20–30 µm and 30–50 µm after one pass using pulsed and scanning laser technology, respectively10, 11


. The


residual thermal damage is 20–40 µm per pass, which does not increase to more than 150 µm on the third pass. The thermal damage produced by the newer CO2


lasers can be controlled by varying


the pulse duration, which makes the treatment safer, more reproducible, and more predictable.


prior to treatment, and their condition can be improved significantly by introducing topical retinoic acid and topical antibiotics to their post-resurfacing regimen. Post-inflammatory hyperpigmentation (Figure 1) tends


modalities such as chemical peels and dermabrasion, CO


As with other resurfacing lasers


2 completely remove the epidermis


and part of the dermis, creating firmer and tighter skin.


Patient selection It is advised to avoid resurfacing of any kind in Fitzpatrick skin types IV and higher, and also to those patients who have been taking Accutane for at least 1 year prior to treatment.


In addition to the indications and


contraindications, choosing between non-ablative fractional and ablative fractional devices will require some discussion with regard to lifestyle and down time. While non-ablative treatments tend to require multiple sessions with 1 day of downtime per session, ablative treatments generally require only one session with 48 hours of healing and up to 5 days of downtime.


Complications Similar to other resurfacing modalities, the incidence of complications after CO2


laser resurfacing is primarily


linked to the depth attained during treatment12


. One of the most


commonly expected complications is post-resurfacing swelling, which generally peaks at 2–3 days and subsides after 1 week. Intravenous betamethasone intraoperatively and a course of oral prednisone postoperatively for 5 days can help to decrease any swelling. Erythema, to some degree, is


observed in all patients. It is related to increased blood flow, collagen remodelling,


inflammation, and


increased metabolic activity. Pruritus is also common after laser resurfacing, but may signal infection, contact dermatitis, or early scarring. In the absence of these conditions, pruritus responds to an oral antihistamine. Milia and acne can also be seen 2–3days postoperatively and are partially related to the use of occlusive ointments. Many of these patients are acne prone


38 ❚ November/December 2012 | prime-journal.com


to occur 2–3 weeks after therapy, especially in patients who have darker skin tones. Any patient may develop transient hyperpigmentation, but this side-effect is more common in darker skin types. Approximately 40% of patients with Fitzpatrick skin types I– III


will hyperpigmentation.


experience In


transient contrast,


66–100% of patients with Fitzpatrick skin types IV–VI will develop some degree of hyperpigmentation. While the aetiology of this side-effect is not definitively known, it is presumed that the greater concentration of melanosomes in darker skin absorbs more


laser energy — even at a lower fluence. Pre-conditioning


the skin with retinoic acid and hydroquinone prior to CO2 resurfacing may decrease incidence, severity, and duration of this phenomenon, and aggressive post- resurfacing skin reconditioning using hydroquinone 2–4% twice per day, retinoic acid (0.05–0.1%) at bedtime, and daily broad-spectrum sun protection can quickly resolve the problem. Unexpected complications associated with CO2


laser


resurfacing include infection (bacterial, viral, yeast, fungal). A typical presentation is a papulopustular eruption with itching or pain and delayed healing. Irritant or allergic contact dermatitis can also be seen secondary to topical antibiotics (e.g. neomycin, bacitracin). Hypopigmentation in darker-skinned individuals can be a risk, which increases with increased depth of laser penetration and can be disguised with total facial treatment as opposed to regional therapy. Additional


unexpected


complications include sharp demarcation lines, which can be avoided by creating a transitional zone of resurfaced skin. The development of hypertrophic


and keloid scars can occur and are related to the depth of resurfacing achieved, development of infection, postoperative wound care, genetic predisposition, and the treatment of


non-facial areas.Ectropion of the lower eyelid has also been reported and is usually the result of an over-aggressive treatment, a pre-existing laxity, activation of a previous blepharoplasty scar, or development of an infection. It can be avoided by testing the lid for laxity before resurfacing, by limiting the depth of resurfacing to the papillary dermis, and by decreasing the power settings. Tooth enamel and


corneal damage can occur, but are easily avoided if the correct protection is used.


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