Fractional Photothermolysis: Why Fractional Lasers Heal Faster
What Is Fractional Photothermolysis?
Proposed by Manstein and Anderson in 2004, fractional photothermolysis splits laser or RF energy into many microscopic treatment zones (MTZs) a few hundred microns wide, covering only a fraction of the area (e.g., 5-40%) per session. Intact skin between MTZs enables rapid keratinocyte migration and repair, dramatically shortening downtime and lowering scar risk.
Ablative vs Non-Ablative Fractional
- Ablative fractional: CO2 (10600 nm) or Er:YAG (2940 nm) vaporizes tissue into microcolumns through epidermis and dermis — strongest results, ~5-7 days downtime, first-line for acne scars and marked photoaging.
- Non-ablative fractional: 1540/1550/1470 nm create coagulative MTZs with intact epidermis — 1-3 days of downtime, gentler, more sessions.
Key Parameters
- MTZ depth: set by point energy; scar rebuilding often needs deep dermal depth.
- Density: MTZs per unit area, balancing coverage and recovery.
- Passes and patterns: affect uniformity of coverage.
Why Fractional Also Tightens
Dermal remodeling around each MTZ triggers a wound-healing cascade — fibroblast proliferation and new collagen and elastin deposition — whose cumulative effect rebuilds dermal structure and texture, the histologic basis for treating scars and fine lines.
FAQ
Is higher density always better?
No. Excessive density approaches full-field ablation with longer downtime and higher risk. Proper practice balances depth and density for the indication across staged sessions.
Can I wear makeup after fractional treatment?
With ablative fractional, avoid makeup until crusting fully resolves (about 5-7 days); after non-ablative sessions, normal skincare usually resumes in 24-48 hours.