Prolonged exposure to UV-radiation induces photo-aging and a variety of visible skin changes such as lentigines, actinic keratoses and solar elastosis. Laser skin resurfacing using ablative lasers (CO(2) or Erbium:YAG) is a popular procedure to reduce these marks and improve the aesthetic appearance of photoaged facial skin . Skin resurfacing is defined as an ablation of the epidermis (the upper layers of facial skin).

The use of pulsed or scanning Carbon Dioxide, and pulsed Erbium-YAG lasers allows the programmable and reproducible photocoagulation of thin layers of the epidermis and superficial dermis. Thermal damage depends on the type of laser and is greater with CO(2) lasers. The degree of neocollagenesis is proportional to the thermal damage and is better with CO(2) lasers. Their main indication is the correction of photoaged facial skin but they can also be used for corrective dermatology, e.g. for scars and genodermatosis.

Ablative laser resurfacing is the most effective treatment for many conditions of the photoaged skin. Results are highly satisfactory but the technique is invasive, edema and prolonged erythema are commonand, and the patient experiences a social hindrance of about 7 to 10 days (“downtime”). Possible side effects are hyperpigmentation, hypopigmentation and, at worst, scarring.

A new concept of laser called fractional photothermolysis has been designed to create microscopic thermal wounds to achieve skin rejuvenation without significant side-effects. The fractional techniques such as the 1,550 nm erbium fiber laser (Fraxel Laser , Reliant Technologies) are used to treat non-adjacent microzones without ablation of the epidermis. Around 25 p. 100 of the affected region is treated per session without ablation of the epidermis. Each fraction is only mini-invasive and is performed under local anesthesia. Social hindrance is reduced. Fractional laser was an attempt to bridge the gap between the ablative and nonablative laser modalities to treat the epidermal and dermal signs of skin aging. By targeting water as its chromophore, the laser induces a dense array of microscopic, columnar thermal zones of tissue injury that do not perforate or impair the function of the epidermis. The significant skin remodeling that ensues can be used to treat, with limited downtime, epidermal pigmentation, melasma, and rhytides, as well as textural abnormalities that include acne-related and surgical scars. comment

Nonetheless, the results are inferior to those obtained with ablative lasers, especially regarding deep wrinkles. The treatment is costly and four sessions are usually required to treat the whole affected area.