Bass LS 1998 Erbium:YAG laser skin resurfacing: preliminary clinical evaluation. Annals of Plastic Surgery 40:328-334 Herne KB, Zachary CB 2000 New facial rejuvenation techniques
Seminars in Cutaneous Medical Surgery 19:221-731 Hughes PS 1998 Skin contraction following Erbium:YAG laser
resurfacing Dermatologic Surgery 24:109-1 I I
Kaufmann R, Hibst R 1996 Pulsed Erbium:YAG laser ablation in cutaneous surgery Lasers in Surgery and Medicine I 9 : 3 2 4 - 3 3 0
Perez MI, Bank DE, Silvers D 1998 Skin resurfacing of the face with the Erbium:YAG laser Dermatologic Surgery 2 4 : 6 5 3 - 6 5 8
Polnikorn N, Goldberg DJ, Suwanchinda A, Ng SW 1998 Erbium:YAG laser resurfacing in Asians Dermatologic Surgery 2 4 : 1 3 0 3 - l 3 0 7
Sapijaszko MJ, Zachary CB 2002 ER:YAG laser skin resurfacing Dermatology Clinics 20:87-96
Teikemeier G, Goldberg DJ 1997 Skin resurfacing with the Erbium:YAG laser Dermatologic Surgery 23:685-687 Weinstein C 1999 Erbium laser resurfacing: current concepts
Plastic and Reconstructive Surgery 103:602-6I6
Zachary CB 2000 Modulating the ER:YAG laser Lasers in Surgery and Medicine 26:223-226
Abtative Laser Resurfacing ll
Zakia Rahman, Melissa Bogel
INTRODUCTION
The aging of the global population combined with fast- paced lifestyles have necessitated efficacious treatments for skin senescence and photodamage that carry minimal downtime There is a myriad of research supporting the importance of physical attractiveness as an indicator of teacher judgment of student intelligence (futts et al 1992), juror's judgment in simulated trials [Mazzella and Feingold 1994), predicted job success, and compensation levels (Morrow et al 1990) Attractive peopie expenence greater professional and personal success compared with their less attractive counterparts (Langlois et al 2000) Long gone are the days when wrinkles, lax skin, and pigment spots, such as those seen in many of Rembrandt's masterpieces are socially acceptable
There are currently four major modalities for ablative skin resurfacing. These are the carbon dioxide [COr) laser, erbium : yttrium-aluminum-garnet (Er :YAG) laser, microablative or fractional photothermolysis, and plasma regeneration. Although fractional photothermolysis achieves resurfacing, tissue is coagulated, not ablated The COz and Er:YAG lasers are effective in the treatment of sun-induced wrinkles, brown spots, acne scars, and skin laxrty, but have a disadvantage in that they require a high level of operator skill to avoid complications such as scar- ring, dyspigmentation, and lines of demarcation between treated and untreated areas. They also require meticulous postoperative care by the patient and have downtime periods of a week or more with oozing and denuded skin.
The side effect profile has decreased the number of COz and Er:YAG laser treatments that are performed, as patients demand iow or no downtime procedures
in 2004 Manstein et al introduced the concept of frac- tional photothermolysis usrng the FraxelrM laser by Reliant technologies [Mountain View, CA) in an attempt to dehver results approaching that of traditional ablative laser resurfacing, without the associated risks and lengthy recovery period \{Ihereas traditional laser resurfacing removes the entire top layer of the skin surface, creating a visible wound and loss of the skin's protective function, fractional laser resurfacing treats a small 'fraction'
of the skin at each session This also differs from other nonabla- tive lasers, which require epidermal cooiing whiie they
heat the dermis, hence producing no resurfacing effect.
Intact, undamaged skin around each treated area theo- retically acts as a barrier to infection and a reservoir for rapid healing through migration of surrounding epidermal cells and division of transient amplifying cells from the basal layer.
The FraxelrM laser was the first laser that utilized frac- tional technology at a wavelength of I 5 50 nm to coagulate the epidermis and dermis. Subsequently, a number of other lasers and intense pulsed light (lPL) sources have utilized fractional technology, including Palomar Lux IR FractionalrM Infrared handpiece (850-1350 nmJ, Palomar Lux 1540 FractionalrM handpiece (l540nm), Cynosure AffirmrM and Alma Harmony Pixel@ Device specifica- tions and FDA approvals are summarized in Table z.r.
. Fractional device descriptions
F R A X E L S R ' " A N D F R A X E L S R 1 5 O O T M L A S E R The first fractional resurfacing laser launched in 2004
(FraxelrM, Reliant Technologies Inc., Mountain Mew, CA) uses a diode pumped erbium fiber laser, which emits light at a wavelength of 1550 nm with a variable spot size that is determined by the telescoping lens, targeting water as its chromophore in the skin (Box z.r). The beam is deliv- ered through an optically tracked, microprocessor- controlled handpiece to produce an affay of microthermal zones (MTZs), each approximately 100 pm in diameter, or about the size of a human hair. The depth of an MTZ varies between 300 and 1200 pm deep.
The energy varies from 4lo 40 mJ/cm2. During each treatment, 125 or 250 columns for the Fraxel SRrM device of MTZs are created per cm2 per pass, depending on operator settings. The density of MTZs per pass in the Fraxel SR l500rM device varies from 9 to 4000 MTZs/
pass. The laser incorporates variable densities for each energy and coverage setting. The energy settings are opti- mized to prevent bulk heating at each energy setting while maximizing coverage and depth of tissue coagulation per pass. A water-soluble dye applied in a thin layer to the treatment area allows the laser's optical tracking system to detect contact and movement with the skin and adjust the laser repetition rate depending on hand velocity' This
L a s e r s a n d L i g h t s V o l u m e l l
C o m p a n y
Alma Lasers, Inc.
Caesarea, lsrael
Cynosure, Inc.
Westford, MA USA
Palomar Medical Technologies, Inc.
Burlington, MA USA
Reliant Technologies, Inc.
Mountain View, CA USA
Lux 1 540rM
Device
Pixel@
Affirm 1440rM
AffirmrM
Lux lR
FractionalrM
Fraxel SR 75OTM
Fraxel SR 1 500rM
1540 nm
Energy source
2940 nm Er:YAG
1440 nm Nd: YAG
Xenon pulsed light 560-950 nm
.:, Infrared noncoherent light d,, Wavelength
ranging from 850-1 350 nm
& 1 700- 2500 nm 1 550 nm
diode-pumped, erbium fiber
1 550 nm
diode-pumped, erbium fiber
FractionaI technology:
characteristics
Delivery: Stamping method tor delivery of preprogrammed f ractional pattern Spot size: | 1 x 11 mm treatment area Pattern density: Two settings: 49 pixels or
81 pixels per 121 mm'?spot set Maximum fluence: 1400 mJ/oulse Maximum reD. rclei 2Hz
Delivery: Stamping method for delivery through multilensed handpiece to create columns of high fluence interspersed with uniform low-fluence background irradiation.
Spot size: 10 mm treatment area Maximum fluence: 8 J/cm2 Maximum rco. 'ate'.2Hz
Delivery: Stamping method {or delivery through multilensed handpiece to create columns of high lluence interspersed with uniform low{luence background inadiation.
Spot size: 11 x 55 mm (6 cm'?) Maximum fluence: 20 Jlcm2 Maximum reo. rate:0.33 Hz
Delivery: Stamping method for delivery of preprogrammed f ractional pattern through multilensed handpiece Spot size: 10 mm or 15 mm treatment Pattern density: Two settings: 100 or 320
spots per cm' Cooling: Contact cooling
Delivery: Pulsed delivery for energy fractionation of hyperthermic beams.
Spot size: 12-28mm treatment area Pattern density: Thermal pulses delivers
an array of variable density Cooling: Contact cooling
Delivery: Scanning and focusing continuous motion handDiece Spot size: 140pm
Pattern density: Up to 4000 microthermal treatment zones oer cmz
Energy settings 6-40 mJ/MTZ Maximum handsoeed: 6 cm/s
Delivery: Scanning and focusing continuous motion handoiece with autozoom teChnology
Spot size: Adjustable, ranging from 50-300 pm
Pattern Density: Up to 4000 microthermal treatment zones oer cm2
Energy Settings: 4-4O \J|MTZ Maximum handsoeed: 6cm/s
Cteared indications
"$ Ablalion of soft tissue .:. Skin resurfacing .:. Treatment of wrinkles .1. Epidermal nevi .1. Spider veins
"l' Keratoses
%t- Ablation and coagulation of soft tissue
S Periorbital and periocular wrinkles
,1" Pigmented lesions
.:. Ablation and coagulation of soft tissue
.1" Periorbital and periocular wrinkles
* Pigmented lesions
"i' Dermatologic procedures requiring the coagulation of soft tissue
.3 Dermatologic procedures requiring the coagulation ot soft tissue, including treatment of wart and tattoos
""r Dermatologic procedures requiring the coagulation of soft tissue
4" Skin resurfacing proceoures
* Pigmented lesions, including lentigos, solar lentigos, melasma and dyschromia
$ Periorbital wrinkles {. Acne scars and surgical
scars
ri Dermatologic procedures requiring the coagulation of soft tissue
"3 Skin resurfacing procedures {' Pigmented lesions,
including lentigos, solar lentigos, melasma and dyschromia
* Periorbital wrinkles
) r
F r a c t i o n a l p h o t o t h e r m o l y s i s w a s d e v e l o p e d to a p p r o a c h
r A ^ ^ t ^ ^ ^ t ^ + { i ^ ^ ^ . , ^ { + " ^ ! i + ^ ^ ^ t t ^ ^ ^ . " ^ ^ " { ^ ^ i ^ ^ , ^ , i + A I Y U r r I u 4 r g r i l u d u y u t U d u t t u r a t r d S Y I g J u r r d u r / r g v v r u I l o c c r o n n ' r o n i r ' m a a n d a n i m n r n r r a r i c d o o f f o n t n r n f l o
E a r l y c n i c a l e v l d e n c e r e v e a l s f r a c t i o n a l r e s u r f a c n g l o b e p a r l i c u l a r l y u s e f u i n t h e t r e a t m e n t o f p h o t o a g n g , m i d l o - m o d e r a t e rh y t i d e s , a c n e s c a r r i n g , a n d s u p e r f i c i a l p i g r n e n t a r y d i s o r d e r s in c l u d i n g m e l a s m a
The dev ce ls safe for treatrnent of nonfacial areas such a S l h e n e c h , c h e s l , b a c r . . a - d e x l , e m li e s
T h e e n e r g y s e t t i n g c o n t r o l s th e d e p t h o f i n l u r y , w h i l e th e d e n s t y s e t t n g c o . t r o r s t h e p e r c e n t a g e o f s k i n t h a t i s - r e a t c d Hin^trr trntrrn\/ s t r t - i ^ o s t h ' r s h a v e 2 o r a 2 t e . tr f f c a t i n t h e t r e a t m e n t o f r h y t i d e s a n d s c a r r n g , w h i l e l o w - e n e r g , s e t t i n g s a r e s u f f i c i e n t fo r s u p e r f i c i a l p g m e n t a r y d i s o r d e r s
is very similar to an optical mouse for computers When the handpiece moves more quickly, the laser repetition rate is higher, and when the handpiece moves more slowly, the laser repetition rate is lower. This assures a uniform, reproducible pattern of microthermal treatment columns independent of operator velocity. The ability of the laser to adapt to the operator's preferred speed makes treat- ment with the device simple to master.
Treatment columns are approximateiy 300 to 1200 pm deep, in contrast to the typical 200 to 300 pm depth of multiple pass CO2 resurfacing (Laubach et al 2005). A zone of normal skin surrounds each microscopic treatment column, leaving the barrier function of the epidermis intact and no visible woundins. The stratum corneum remains intact during and after laser firing. Patients can often apply make-up or sunscreen following treatment (Fig. z.r) The normal intervening tissue allows for rapid re-epithelialization by keratinocyte migration and divislon of transient amplifying cells into the treatment column After 2-3 days, the tops of the wounded areas are shed as microscopic epidermal necrotic debris (MENDs;
Tannous et al 2005). \44ren there is disruption of the basement membrane, dermal as well as epidermal con- tents are expelled in the MENDs This has clinical impli- cations in the treatment of dermal pigmentary disorders Further collagen remodeling continues in the MTZ over the next 3 to 6 months. On average, each session treats about 20% of the skin surface, so four to six treatments are needed for optimal results
Several companies are now incorporating the fractional concept into laser technology. Presentiy three different approaches are being taken. The first approach delivers columns of laser light to the skin to fractionally heat and irreversibly damage the epidermis and hlgh dermis using an Er:YAG laser delivered through a multilensed hand- piece [540nm Fractional Er:YAG, Palomar Medical Technologies Inc , Burlington, MA and 1440 nm Nd:YAG laser, AffirmtM, Cynosure Inc , Westford MA). The second approach uses a fractional infrared handpiece to deliver noncoherent light in the 825-1350 nm range as a regular array of small hyperthermic beams with contact cooling
Abtative Laser Resurfacing ll
Microthermal zone
Fig. 2.1 A schematic of fractional photothermolysis treatment oi the skin Note conical shaped zones of tissue coagulation (microthermal zones) surrounded by normal tissue.
to heat the deep dermis to induce coliagen change and skin tightening (Starlux LuxlR FractionalrM, Palomar Medical Technologies, Inc., Burlington, MAJ. The third approach is not defined as fractional by the company, but incorporates columns of high fluence interspersed with uniform low-fluence background irradiation This is labeled Combined Apex PulserM (CAP) technology by the maker of the device [Cynosure) Other devices, including a frac- tional COz laser, are rn development.
P A L O M A R L U X I R F R A C T I O N A L T M I N F R A R E D H A N D P r E C E ( A S O - r r S O N I l \ )
Palomar Medical introduced a handpiece attachment in 2005: Lux IR, which is FDA approved for the coagulation of soft tissue. This employs an IPL noncoherent light in the handpiece attachment to the StarluxrM system.
P A L O M A R L U X 1 5 4 0 F R A C T I O N A L T M H A N D P T E C E ( r S + O r' r n n )
Palomar introduced the LUX 1540 handpiece in 2006 Zelickson et al [2006) presented a clinical comparison of the FraxelrM laser to the Palomar Lux 1540 FractionalrM handpiece. This is a 1540nm Er:YAG laser delivered through a multilensed circular aperture that is either 10 or 15 mm in diameter The handpiece lays down 100 or JIU spots per cm-.
)
A F F I R M T M , A F F I R M T M 1 4 4 0
The Cynosure AffirmrM comes in two different heads, the AffirmrM, which is a xenon pulsed light, and the AffirmrM
Lasers and Lights Volume ll
1440, which is a l440nm neodymium [Nd):YAG laser.
The AffirmrM also distinguishes itself as not being frac- tional, but having a CAP technology The Cynosure AffirmrM has FDA approval for the ablative and coagula- tion of soft tissue, periorbital and periocular wrinkles and pigmented lesions. In 2006, Weiss et al published the use of the AffirmrM device for the treatment of photodamage and scars. Twenty subjects underwent treatment with the l0 mm diameter tip at fluences of 3-7 J/cm2 at a repeti- tion rate of 7-2Hz with a stamping handpiece. Histologic evaluation demonstrated depth of penetration to 300 pm, which is believed to limit the depth of penetration to the epidermis and papillary dermis. The majority of sub- jects underwent five treatment sessions and 760lo of the subjects were graded as having 26-500/o improvement by investigators.
H A R M O N Y P I X E L @
The Harmony Pixel@ (Alma Lasers Ltd, Ceasarea, Israel) device is a 2940 nm attachable module for the Harmony base platform device or a dedicated Harmony Pixel system. The Pixel@ device ablates the tissue, unlike the other devices that coagulate tissue fractionally There have been no clinical reports of this device to date
o Plasma technology
Plasma skin regeneration (PSR) technology was developed at roughly the same time as fractional photothermolysis.
Although high-temperature plasmas have been used in surgery for over a decade, plasma has been used primarily as a conduction medium for electric current With PSR, the plasma itself produces controlled thermal damage to the skin surface. The technology can be used at varying energies for different depths of effect, from superficial epidermai sloughing to deeper dermal heating (Box z.z).
Plasma skin regeneration is unique in that it uses energy delivered from plasma rather than light or radiofrequency.
Plasma is the fourth state of matter in which electrons are stripped from atoms to form an ionized gas. Unlike lasers, it does not rely on the principles of selective photother-
molysis to target water-containing tissue and effect con- trolled tissue vaporization. Rather, ionized inert nitrogen gas (plasma) is emitted in a millisecond pulse to deliver heat energy to tissue directly upon contact.
The plasma skin regeneration device consists of an ultra high frequency (UHF) radiofrequency generator which excites a tuned resonator and imparts energy to a flow of inert nitrogen gas within the hand piece (Fig. z.z). The activated, ionized gas is termed plasma. Nitrogen is used for the gaseous source because it is able to purge oxygen from the surface of the skin, minimizing the risk of unpre- dictable hot spots and charring. Upon formation, the plasma appears as a characteristic lilac glow that transi- tions to a yellowish light ca11ed a Lewis-Raleigh afterglow.
Plasma is directed through a qrartz nozzle out of the tip of the handpiece and onto the skin. Energy is rapidly transferred to the skin surface upon contact, causing instantaneous heating in a controiled, uniform manner, without an explosive effect on tissue or epidermal removal.
The depth and area of thermal effect are determined by the energy setting and spot size of the handpiece. The energy can be adjusted from I to 4 J per pulse. The intended spot size of 6 mm is reached when the device is held approximately 5 mm from the surface of the skin, however the thermal effect can be increased or decreased by defocusing the handpiece either closer or farther away from the skin surface. High temperatures during each puise erode the tungsten resonator in the handprece/ so the handpiece must be replaced after each use. Because the nitrogen gas flushes oxygen from the treatment area, there is no charring, and the skin remains in place to act as a biologic dressing on the treated area. This simplifies postoperative care and decreases the risk of adverse effects such as infection and scarrins