Mechanism of Action
The CO₂ laser emits energy at a wavelength of 10,600 nm, which is strongly absorbed by intracellular water. Fractional technology divides this beam into thermal micro-columns that penetrate the epidermis and reach the dermis, leaving areas of intact skin between treatment points.
Collagen denatures at approximately 66.8°C, causing rapid fiber contraction to about one-third of their original length. This contraction is the primary mechanism of skin tightening. Ablation of superficial layers promotes re-epithelialization from residual skin appendages—sweat glands and hair follicles.
The laser activates the wound repair mechanism, regulates the skin barrier, coordinates collagen rearrangement, and improves local microcirculation.
Advantages of Fractional Method
Unlike fully ablative CO₂, fractional technology creates columns of ablation surrounded by normal untreated skin, allowing re-epithelialization within 2 to 3 days. This approach reduces recovery time while maintaining significant results.
The cytokine secretory pathway changes according to re-epithelialization and different laser fluences. Parameters can be adjusted to control depth, density, and pulse duration according to individual needs.
Validated Indications
Clinical studies confirm the efficacy of fractional CO₂ laser for:
- Atrophic acne scars: stimulation of collagen and dermal fibroblasts, leading to remodeling and skin retraction
- Photoaging: improvement of texture, fine lines, and hyperpigmentation
- Hypertrophic scars: thickness reduction through inhibition of type I and III collagen
- Skin laxity: tightening effect through collagen contraction
Appropriate Candidates
The ideal candidate is between 40 and 60 years old, Fitzpatrick phototype I to III, with thin to moderate skin thickness. However, with adapted protocols, treatment can be safe for phototypes IV and V without post-inflammatory hyperpigmentation.
Contraindications
Active facial infections are considered a contraindication by 95% of experts. Burns, recent sun exposure, pregnancy, and breastfeeding are also contraindicated.
Other established contraindications:
- Active herpetic lesions
- Uncontrolled active acne
- Healing disorders
- Unrealistic expectations
Treatment Protocol
Topical anesthesia applied 1 to 2 hours before the procedure is generally sufficient, although general anesthesia or tumescent anesthesia may be used.
Prophylaxis: More than 90% of practitioners employ bacterial and antiviral prophylaxis. Antiviral treatment is standard in all patients to prevent herpetic reactivation.
Duration: 20 to 60 minutes depending on the treated area.
Complications and Management
Common complications include temporary hyperpigmentation, less likely with fractional laser than with previous generation CO₂ lasers, particularly for phototypes IV and V.
Possible complications:
- Prolonged erythema
- Infection (requiring microbiological culture)
- Contact dermatitis (irritant or allergic)
- Temporary pigmentary changes
- Permanent hypopigmentation (rare with adapted protocols)
Infection is the most frequent cause of scarring, typically manifesting as an area of delayed healing several days after the procedure.
Results and Timeline
By day 7 post-treatment, upregulation of collagen binding, collagen fiber, and collagen-containing extracellular matrix is observed. The remodeling process continues for several months.
Number of sessions: depending on indication, 1 to 4 sessions spaced 2 to 6 months apart may be necessary.
