### Date : 2025-11-15 14:25 # Topic: Pico Fractional Laser ---- # **1. Fundamental Physics** ## **1.1 Pulse Duration: Picoseconds (10⁻¹² seconds)** Traditional Q-switched nanosecond lasers (10⁻⁹) rely on **photothermal** effects. Pico lasers operate at **1,000× shorter pulse durations**, creating: - **Photomechanical / Photoacoustic energy delivery** - **Minimal thermal diffusion** - **Extremely high peak power** This high peak power leads to: ### **LIOB (Laser-Induced Optical Breakdown)** - Occurs when ultra-short pulses exceed the **optical breakdown threshold** of dermal tissue. - Leads to **microcavitation bubbles** within dermis without injuring the epidermis. - Stimulates fibroblasts → new collagen + elastin → textural enhancement. This is the **core mechanism of Pico Fractional**. --- # **2. Selective Wavelengths and Targets** ## **Common Wavelengths** - **1064 nm** (Nd:YAG picosecond) – safest for Asian skin types - **755 nm** (Alexandrite picosecond) – more melanin-targeted, higher pigment clearance - **532 nm** – superficial pigmentation; high PIH risk in Asian skin ## **Fractional Delivery Mode** Pico lasers can operate in 2 modes: ### **1) Non-fractional mode** - Spot-by-spot - Used primarily for pigmentation (melasma, PIH, freckles) ### **2) Fractional mode — our focus** - Diffractive lens array / MLA (Micro-Lens Array) - Converts the beam into **100–200 microbeams** - Concentrates energy into tiny foci → LIOB formation --- # **3. Histologic Reactions (Microscopic Effects)** ## **3.1 Immediate Effects** - Vertical “bubbles” in upper-to-mid dermis - No epidermal ablation - Minimal epidermal heat ## **3.2 Intermediate Effects (1–4 weeks)** - Collagen type I & III upregulation - Elastin remodeling - ECM reorganization - Increased dermal density ## **3.3 Long-term Effects (8–12+ weeks)** - Pore tightening - Scar remodeling - Dermal thickening - Skin tone homogenization --- # **4. Clinical Indications** ## **4.1 Texture** - Enlarged pores - Rough skin texture - Early photoaging ## **4.2 Pigment** - Melasma (adjunct) - PIH - Solar lentigines - Dullness / uneven tone ## **4.3 Acne Scars** - Mild to moderate atrophic scars - Icepick scars respond poorly - Rolling scars respond best ## **4.4 Biorejuvenation** - "Glass skin" treatments - Part of combination protocols (pico + skin boosters + LDM) --- # **5. Expected Clinical Results** ## **5.1 Pores** - LIOB → dermal contraction - Increased dermal density → pore circumference decreases ## **5.2 Acne Scarring** - New collagen deposition → scar elevation - Multiple sessions required ## **5.3 Pigmentation** - More effective and safer than nanosecond - Less thermal damage → lower risk of rebound PIH - Still requires cautious protocols in Fitzpatrick IV ## **5.4 Glow / Brightness** - Improved light-scattering due to smoother dermal-epidermal interface --- # **6. Treatment Protocol and Parameters** These are generalized clinical ranges; device-specific adjustments are required. ## **6.1 Wavelength selection** - For Korean skin: **1064 nm** is primary - 755 nm can be used for resistant pigmentation (higher PIH risk) ## **6.2 Fractional Mode Settings** - Spot size: **6–10 mm** - Energy (fluence): **0.2–0.8 J/cm²** - Repetition rate: **5–10 Hz** - Passes: **1–3 passes**, depending on indication - Density: **High density / low fluence** ## **6.3 Session Intervals** - Every **2–4 weeks** - Typically **5–10 sessions** --- # **7. Pain, Downtime, and Post-care** ## **7.1 Pain** - Mild–moderate - Lower than CO₂ or Erbium fractional ## **7.2 Downtime** - Erythema: 3–24 hours - Minimal swelling - Makeup: next day (often same day) ## **7.3 Post-care** - Immediate cooling - Mild moisturizer - Sun avoidance - Vitamin C or exosomes may support recovery --- # **8. Risks and Complications** ## **8.1 PIH (Post-inflammatory Hyperpigmentation)** - Lower risk than nanosecond or CO₂ - Still possible if excessive passes or fluence ## **8.2 Inadequate results** - Deep scars require ablative fractional options - Melasma may worsen if high fluence is used ## **8.3 Rare adverse events** - Mottled hypopigmentation (rare if protocols are followed) - Temporary dryness - Erythema lasting >48 hours --- # **9. Comparison with Other Fractional Lasers** |Feature|Pico Fractional|Erbium Fractional|CO₂ Fractional| |---|---|---|---| |Mechanism|LIOB (non-ablative)|Ablative|Deep ablative & coagulative| |Downtime|Minimal|Moderate|High| |PIH risk|Low|Medium|High| |Scar efficacy|Mild–moderate|Moderate|Strong| |Safety in Asian skin|Excellent|Good|Caution required| --- # **10. Combination Strategies (Advanced Clinical Practice)** ## **10.1 Pico fractional + Skin booster** Maximizes pore tightening and hydration Timing: Skin booster 1–2 weeks after pico ## **10.2 Pico fractional + LDM** Reduces inflammation and accelerates recovery Often performed **same day** ## **10.3 Pico fractional + Sylfirm X** For pigmentation and vascular melasma ## **10.4 Pico fractional + RF microneedling** For moderate acne scars (synergistic with LIOB) --- # **11. Clinical Pearls (Harvard Dermatology Style)** 1. **High-density, low-fluence** is the safest and most effective strategy for Asian patients. 2. Melasma must always be managed with **very cautious parameters** to avoid rebound hyperpigmentation. 3. Pico fractional is **not** a substitute for genuine ablative resurfacing; deep scars require Er:YAG or CO₂ fractional. 4. For pore treatment, **multiple sessions** are needed because dermal remodeling is incremental. 5. For acne scars, **subcision + pico** or **RF microneedling + pico** produces far superior results than pico alone. --- # If you want, we can now proceed to: 1. **Pico fractional – Device-specific parameter sets** (PicoPlus, PicoSure, Discovery, Enlighten) 2. **Clinical protocols for each indication (pore, melasma, scars)** 3. **Realistic case-based scenarios** 4. After finishing Pico, we move to **Erbium fractional** in equal depth. Which direction would you like next?