Does fractionated carbon dioxide (CO2) laser penetrate to the dermal layer?

Does Fractionated CO2 Laser Penetrate to the Dermal Layer?

Yes, fractionated CO2 laser definitively penetrates to the dermal layer and can reach deep into the reticular dermis up to 6mm at higher energy settings. 1

Mechanism of Penetration and Depth

Fractionated CO2 lasers work by creating microscopic thermal zones (MTZs) of injury that extend from the epidermis into the dermis. The depth of penetration depends on several factors:

• Energy settings: Higher energy levels (up to 210 mJ/DOT) can penetrate the full thickness of the dermis, reaching depths of up to 6mm 1
• Scanning system: Newer CO2 laser scanning systems can achieve deeper penetration throughout the entire dermal thickness 1
• Treatment parameters: Pulse duration, spot size, and density affect penetration depth

Evidence of Dermal Penetration

Histological studies provide clear evidence of dermal penetration:

• Ex vivo human skin studies show microablation columns extending from the epidermis through the papillary dermis and into the reticular dermis 1
• In vivo confocal microscopy demonstrates collagen remodeling in the dermis following fractionated CO2 laser treatment 2
• The laser creates microcolumns of thermal damage surrounded by zones of coagulated collagen in the dermis 1

Dermal Effects and Collagen Remodeling

The penetration into the dermis produces several important effects:

• Collagen remodeling: The existing collagen is replaced by newly formed collagen with long, bright, straight fibers arranged in parallel 2
• Increased TGF-β1 expression: Peaks at days 1-7 post-treatment, stimulating fibroblast proliferation 3
• Increased dermal thickness: Significant increase in dermal thickness by days 28-56 post-treatment 3
• Increased type I collagen: Significant increase by days 28-56 post-treatment 3

Clinical Applications Based on Dermal Penetration

The ability to reach the dermis makes fractionated CO2 laser effective for:

• Acne scars: Particularly effective for ice pick or V-shaped acne scars 4
• Deep scarring: The deep penetration allows treatment of morbid scars and deep complications 1
• Skin rejuvenation: Effective for treating rhytides and photodamage 5
• Collagen stimulation: The dermal penetration triggers long-term collagen remodeling that persists for at least 3 months 2

Common Pitfalls and Considerations

• Depth control is critical: Excessive energy can lead to penetration beyond the dermis into fat and muscle tissue 1
• Recovery time: Deeper penetration correlates with longer recovery periods
• Side effect profile: While fractionated CO2 has a better safety profile than traditional CO2 lasers, deeper penetration increases risk of side effects 5
• Patient selection: Skin thickness varies by anatomical location and between patients, affecting penetration depth

The ability of fractionated CO2 laser to penetrate to the dermis is what makes it particularly effective for treating conditions that require dermal remodeling, such as deep scars and significant photoaging.