laser in asian skin
TRANSCRIPT
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