Facial Skin Resurfacing:Laser Modalities

Dr Wong YishengDermatology Resident, National Skin Centre Singapore

Overview

• LaserandLight-TissueInteractions• AblativeLaserResurfacing• Non-ablativeLaserResurfacing• PearlsinTreatmentofAsianSkin• What’sNewInFacialSkinResurfacing

The Ageing Skin

• Clinical features of ageing skin include:

Ø Pigmentary changesØVascular changesØ Textural changesØSagging/laxityØDegenerative changes – benign,

precancerous, cancerous

Modalities Used in Facial Skin Resurfacing

• Non-surgical facial rejuvenation or resurfacing relies on matching the presenting skin pathology to an appropriate intervention that reverses that aspect of aging

• This includes:1. Lasers and non-laser energy sources (i.e. IPL, RF)2. Chemical peels/dermabrasion

Laser: The Basics• LASERlight amplification by stimulated emission of radiation

Fernandaetal,2016

Property of laser light

Bolognia etal,DermatologyEssentials2015

Property of laser light

Laserlightcanbecontinuous,pulsed orQ-switched

Laser-tissue interactions• Laser light can be:- Reflected (4-7%)- Scattered- Absorbed- Transmitted

• When absorption occurs, the photon surrenders its energy to a chromophore

Chromophores• 3primaryskinchromophores1.Water2.Hemoglobin3.Melanin

Concept of selective photothermolysis

• Photothermal effectsLightenergyabsorbed->thermalenergy ->denaturationoftargettissue

• Selectivephotothermolysispermitsselectedheatingoftargetswithinthedermis

Neligan etal,2012

Concept of selective photothermolysisPrinciples of selective photothermolysis:

1.Wavelength: preferentially absorbed by target chromophore

2.Pulse duration/width: shorter or approximately equal to thermal relaxation time (TRT) of target

3.TRT: Time required for targeted heated tissue to lose half its heat

4.Fluence: high enough to destroy target chromophore

Photomechanical effects of laser- Inducedbyhighpower,shortpulse lasers.- Leadstoextremelyrapidthermalexpansionofthetargetandsubsequentphotomechanicaldestruction.

New kid on the block…

• Picosecond lasers• Selective photoacoustic effect• Conversion of light to sound energy• Fragmentation of target with sound

waves• Negligible thermal energy

• Very costly

Selection of type of laser

Dependent on:- Type of target chromophoreØ MelaninØ HbØ Water

- Depth of target chromophoreØ EpidermisØ Dermo-epidermal junctionØ Superficial dermisØ Deep dermis

Depth of optical penetration

• Knowledge of variables affecting laser depth important so as to reach intended target

• Depth of laser dependent on:1. Wavelength (also determines type of laser)2. Fluence3. Spot size

Longer the wavelength, deeper the penetration

Higher the fluence, the deeper the penetration

The larger the spot size, the deeper the penetration

Classification of resurfacing lasers

• Ablative• Non-ablative• Fractional lasers- Can be ablative (i.e. fractional CO2, Erbium:YAG) or non-ablative (i.e. Erbium:glass)

Fractional CO2 laserWavelength:10,600nm

TargetChromophore:Water

Indications:AcnescarsPhotoageing/RhytidesSurgicalscars

Microthermal Zones (MTZ)• Multiple, discrete vertical cylinders of

thermal damage with completely spared intervening areas.

• These microthermal zones (MTZ)measure up to 1.5 mm in depth and 100–400 mm in width and there may be up to 6400 treatment zones per cm2.

• Unaffected tissue act as a reservoir for tissue regeneration by providing nutritional support and an intact microstructure for keratinocyte and fibroblast migration.

Microthermal Zones (MTZ)

Zone of ablation Week 1:Transepidermal elimination of coagulated epidermal/dermal

material and melanin

Week 6:New collagen formed

Manstein D, Herron GS, Sink RK, Tanner H, Anderson RR. Fractional photothermolysis: A new concept for cutaneous remodeling using microscopic patterns of thermal injury. Lasers Surg Med 2004; 34(5):426–438.

Microthermal Zones (MTZ)

Metalloproteinases (MMP)MMP-1 & 3

Wound healing:Requires cell migration, ECM degradation, tissue reorganisation

Procollagen I & III

MMP-1: Keratinocyte migrationMMP-3: Wound contraction

Kim JE, Won CH, Bak H, Kositratna G, Manstein D, Dotto GP, Chang SE. Gene profiling analysis of the early effects of ablative fractional carbon dioxide laser treatment on human skin. Dermatol Surg 2013; 39(7):1033–1043.

Atrophic Acne Scarring: Fractional CO2 laser

• Retrospectivestudyof107patientsatNationalSkinCentrewhounderwentfractionalCO2laser(Mixto)foracnescars

• 65menand42women

• FitzpatrickskintypesII-V

Ochi H,TanL,TanWP,Goh CL.Treatment ofFacial Acne Scarring WithFractional Carbon Dioxide Laser inAsians,aRetrospective AnalysisofEfficacy and Complications.Dermatol Surg.2017Sep;43(9):1137-1143.

Results

AcneType Mean

IcePickscars 1.50

IcePickscarsandBoxscars 1.43

Boxscars 1.36

BoxscarsandRollingscars 1.20

Rollingscars 0.50

Total 1.32

qAquartilegradingscalewasusedfortheevaluations:-Grade1,<25%,minimal to noimprovement-Grade2,26–50%,moderateimprovement-Grade3,51–75%,markedimprovement-Grade4,>75%,neartotalimprovement

Objectiveassessmentswereperformedby2blindeddermatologistsbasedondigitalphotographs

Meanno.oftreatment:2(range1-7)

Numberoftreatment/passesandclinicaloutcomes

q Nostatisticallysignificantdifferenceswerenotedinclinicalefficacyregardlessofnumberofpassesandtreatments

q Overall,meandurationofpost-treatmentpainwas1.9daysandmeandurationoferythemawas6.3days.

AdverseeffectsoffractionalCO2laser

Ablative lasers: CO2 (1064nm) vs. Erbium:YAG(2940nm)• Er:YAG absorbed by water 10–16-fold more than with a

carbon dioxide laser• More superficial ablation which

• reduces healing time• markedly increases patients’ tolerance

• Significant downside of superficial ablation are • loss of adequate collateral heating of the underlying

dermis. • Reduction in tissue is seen with CO2 lasers

An Asian randomised split-face study showed no significant difference in clinical improvement of acne

scars between both CO2 and Er:YAG fractional lasers. But those using CO2 reported more discomfort, longer

healing time. Nil significant difference in adverse events.(Manuskiatti et al. 2013)

Fractional CO2 laser - Rhytides

Heidietal,2017

• Ablative fractional is effective in cutaneous rejuvenation ofAsian patients with proven long-termclinical result.

• However, PIH as an adverse sequelaestill common. Significant downtime.

• Non-ablative alternative may be preferred in Asians.

Hypertrophic scarring: Fractional CO2Fractionated CO2 improved scar pliability and thickness – correlates histologically with collagen remodelling and upregulation of MMP-9

Can use in conjunction with pulse-dye laser (erythema component of scar)

Hypertrophic scar after induced burn injury (A) and (B) 3 months after three treatments of CO2 ablative fractional laser 3-4mthly, combined with 16 treatments of non-ablative fractional laser monthly (Krakowski et al, 2017)

Non-ablative lasersFractionalornon-fractional

Indications:PhotoageingScarsMelasma (usewithcaution)SkinlaxityLargepores

Non-ablative fractional lasers

• Advantagesoverablativefractionallasers:

- Minimaldowntime- Rapidhealingtime(erythema~3-5daysvs1-4winablative)

- Onlymildswelling1-3days- Noblisters,crusting,oozingusually- Noopenwounds

Fractional non-ablative laser:i.e. Erbium:glass (Fraxel)• The most widely known and extensively evaluated fractionated non-ablative

laser, the 1550 nm erbium-glass laser, typically produces erythema and oedema lasting 2 -7days post-procedure.

• More favorable adverse effect profile compared to ablative lasers

Neligan etal,2012

Atrophic Acne Scarring: Non-ablative fractional laser (NAFL)

• Intact epidermis with minimal disruption to dermo-epidermal junction = shorter down-time, milder adverse effects

• However, multiple sessions may be required for desired results

Chan NP, Ho SG, Yeung CK, Shek SY, Chan HH. The use of non-ablative fractional resurfacing in Asian acne scar patients. LasersSurg Med 2010; 42(10):710-715.

qChanetal5 comparedfull- NAFL(8passes,3treatments)andmini-NAFL(4passes,6treatments)

qNostatisticallysignificantdifferenceswerenotedinclinicalefficacybetweenthetworegimes.

qForfull-NAFL,thePIHriskwas18.2%comparedto6.0%formini-NAFL.

ComparisonofAFLvsNAFLinatrophicacnescars

You HJ, Kim DW, Yoon ES, Park SH. Comparison of four different lasers for acne scars: Resurfacing andfractional lasers. J Plast Reconstr Aesthet Surg 2016;69(4):e87-e95.

Clinical improvement scores were significantlylower in the NAFL group (Fraxel SR) whichreceived a mean of 4 treatments compared tofractional CO2 laser.

PIH incidence high in AFL group.

Hypertrophic Scars: Non-ablative fractional laser (NAFL)

2monthsafterseventreatmentsof1,550-nmnon-ablativefractionallaser(Heidietal.)

Rejuvenation/”Laser toning”fine lines and wrinkles, skin elasticity, mottled dyspigmentation, deep rhytides, pore size, and skin texture

Fine lines and pigment under eye (A) and (B) 1 month after four treatments of 1,440-nm fractional non-ablative laser

Chan NP, Ho SG, Yeung CK, Shek SY, Chan HH. Fractional ablative carbon dioxide laser resurfacing for skin rejuvenation and acne scars in Asians. Lasers Surg Med 2010; 42(9):615–623.

Special Considerations of Lasers on Asian Skin

Post-inflammatory Hyperpigmentation

Tay etal,2012

Chaowattanapanit etal.JAADOct2017

Management of PIH

Pitfall: “Laser toning” in MelasmaVariable success based on studies.

High risks of rebound hyperpigmentation, guttate leukoderma

Pigmentary clearance is typically temporary with 1,550-nm erbium and 1,927-nm thulium devices with the potential for rebound hyperpigmentation at 3–6 months following treatment.

Wongetal,2015

Guttate hypopigmentationinducedbyfrequentlow-fluence large-spot-sizenon-ablativelasertreatments

Wongetal,AnnalsofDermatology2015

Guttate hypopigmentationinducedbyfrequentlow-fluence large-spot-sizenon-ablativelasertreatments

EthnicDifferencesinPhotoageing

Laser skin resurfacing:Patient selection, risks and

precautions

Laser skin resurfacing:Patient selection, risks and precautions• Are the lesions amenable to ablative laser resurfacing?

All suspicious lesions require biopsy before treatment

Lentigo simplex vs lentigo maligna

Laser skin resurfacing:Patient selection, risks and precautionsDoes the patient have a history of HSV?

Does the patient have an immunologic deficiency or autoimmune disease?

Is the patient taking any medication that is contraindicated?

Does the patient have propensity for hypertrophic or keloid scars/skin diseases with Koebnerisation?

Does the patient have realistic expections for laser skin resurfacing?

Laser skin resurfacing:Patient selection, risks and precautions• Has the areas been treated before?

-Resurfacing lasers can unmask hypopigmentation or fibrosis produced by prior dermabrasion, cryosurgery or phenol peels.

-Those with prior lower blepharoplasties have greater risk of ectropion

Post laser care• Warnpatientthattherewillbeaburningsensationonskin60min-6hposttreatment

• Analgesiacouldbegiven• Coldcompressescanminimise discomfort/swelling• Avoidstrenous activitiesforseveraldays• Explaintopatienttreatmentmayresultinbronzedappearancefor1st week• Finepixellated scabswillformandispartofthehealingprocess• Moisturiser shouldbeused• Makeupshouldbeavoidedinablativelasersuntilscabshavefallenoff• Avoidsunexposureforatleast3monthsandsunblockshouldbeused

FractionatedRadiofrequencyDevices

Yeungetal,LasersSurg Med2016

Conclusion

• Fractionalphotothermoysis representsasignificantadvancementinfacialskinlaserresurfacing.

• Laserfacialskinresurfacingcanachieveoptimalresultsifdonesafelyandnotoverzealously.Startlow,goslow.

• Patientsneedtobeadvisedaboutthepossiblesideeffectsandexpectedimprovement.

• Asianskin,especiallythoseofdarkerphototypes,mustbetreatedwithcaution.

Thank you