ADVANCED TOPICS: TREATMENT TIPS FOR EXPERI ENCED PRACTITION ERS

Rolling-type acne scars respond dramatically to fractional photothermolysis. A combination approach can improve results with ice-pick or boxcar-type scarring. Combination approaches include selected punch excisions or subcision, which may be per- formed at the same visit as the laser procedure Both fractional photothermolysis and plasma treatments can be titrated from low to hish levels.

Fractional photothermolysis carries the least amount of downtime.

Fractional photothermolysis is the treatment of choice for skin tvoes IV-VI.

{. During PSR treatments, selected double passing over deep scars or wrinkles can give additional benefit and improve results with single-pass full-face treatments.

* Plasma treatment energies can be adjusted according to the facial unit for the best results with the least overall recovery time The use of higher energies is tolerated quite well in the perioral area and will allow greater improvement in vertical lip lines.

Nonablative Skin Resurfacing

Ellen S. Marmur, David J. Goldberg

INTRODUCTION

At the forefront of laser and nonlaser light source technology, dermasurgeons continue to lead the way to remarkable innovations in the field of nonablative laser resurfacing. This technically diverse group of systems includes the potassium titanyl phosphate (KTP) (532 nm), pulsed dye [585 nm, 595 nm), neodymium:yttrium-alu- minum-garnet (Nd:YAG; i064-nm Q-switched, 1064- nm long pulse, 1320 nm), diode [450 nm), erbium:glass

[1540nm) lasers, intense pulsed light (500-1200nm), and light-emitting diode devices (FiS. f.1) Photodynamic therapy is a recent innovation utilizing aminolevulinic acid to enhance the effects of light and laser based technology.

Radiofrequency technology also used for nonablative treatments is described in Chapter 4 Historically, abiative lasers were the optimal treatment for photodamaged skin.

Ablative skin resurfacing has become increasingly unpopu- lar with both patients and physicians due to the significant risks of prolonged recovery time, possible permanent hypopigmentation, and/or scarring. Nonablative skin resurfacing has become the treatment of choice for photorejuvenation It offers an elegant, highly effective, non- invasive treatment for problems related to photodamage and aging. This chapter will focus on the use of nonablative skin resurfacing to treat patients with mild-to- moderate photodamage

Ultraviolet-induced photodamage accelerates and mag- nifies the physiologic changes of the normal aging process Ultraviolet exposure produces a myriad of changes in the skin including free radical formation, apoptosis, angiogen- esis, melanogenesis, DNA mutations, oncogenesis, tmmu- nosuppression, matrix metalloproteinase induction, and degradation of connective tissue The histologic manifes- tations of photodamaged skin include loss of collagen and abnormal clumping of elastic fibers in the superficial dermis. In addition, ultrastructural analysis shows a thin epidermis, flattened rete, increased vasculature, chronic inflammation, elastotic changes including the accumula- tion of large amounts of elastic material, wide spaces between the collagen bundies, and random deposition of collagen fibers. These histologic and ultrastructural changes are clinically correlated with rhytides, laxity, yellow dis- coloration, and telangiectasias. Nonablative skin resurfac-

ing triggers a wound healing response to restore the normal architecture of collagen in the dermis Associated vascular damage recruits inflammatory mediators that lead to fibro- plasia and homogenization of the col1agen.

Clinical photodamage is classified into three types (Box 3.r) Type I photodamage includes telangiectasias, solar lentigines, increased skin coarseness, and symptoms of rosacea. Type II photodamage includes rhytides, derma- tochalasis, comedones, and skin laxlty. Type III photodamage includes actinic keratoses, nonmelanoma skin cancers, and melanoma Standard nonablative skin resurfacing is successful in patients with types I and II photodamage Generally photorejuvenation treatments are undertaken on the sun-exposed areas of the face, neck, upper chest, and hands.

The term 'nonablative

skin resurfacing' includes the terrns sub surf acing, noninu asiu e re surf acing, sbin t o n i n g, and wrinh.le reduction This process involves dermal neo- collagenesis, and photorejuuenation due to both epidermal improvement and dermal coliagen remodeling. Each group of nonablative devices will be discussed along with clinical pearls to ensure optimal treatment outcomes, realistic expectations for the patient, and management of potential complications.

Nonablative skin resurfacing technology can be catego- rized into five different general modalities: vascular lasers, mid-infrared lasers, intense pulsed light systems, radiofrequency devices and the recently developed light emitting diode (LED) techniques (Box 3.2) Photodynamic therapy utilizes aminolevulinic acid in conjunction with photoactivation from a light or laser source to enhance photorej uvenation.

Nonablative skin resurfacing is ideally used for the patient with mild-to-moderate photodamage and signs of skin aging This approach is not meant for the patient who r,vants the degree of improvement, and is willing to accept the added risks, associated with more aggressive surgical options. Nonablative technologies stimulate collagen fiber synthesis to reduce wrinkles and lax skin The fina1 effect is clearly more subtle than that seen with more aggressive surgical and laser cosmetic treatments However, nonablative skin resurfacing requires essentially no recovery time.

With nonablative treatments, one avoids the risk of general anesthesia, with most treatments accomplished with little

Lasers and Lights Volume ll

Type I

Lentigenes, telangiectasias, increased coarseness, symptoms of rosacea

Type ll

Rhytides. laxity. derr.ratochalasis Type lll

Actinic keratoses, nonmelanoma skin cancers

Vascular lasers Mid-infrared lasers

Intense pulsed light systems Radiof requency systems L E D

or no topical anesthesia. Such treatments also avoid the risk of infection, a leading cause of morbidity and complication seen after invasive cosmetic surgery. Nonablative skin resurfacing treatments are easily and expeditiously achieved in an outpatient setting. They have become known as 'lunch-time'

laser procedures. The results from these procedures are not as dramatic as those seen after standard surgical procedures. In fact, patients who ulti- mately plan to have more extensive cosmetic surgery

Fig. 3.1 Electromagnetic spectrum and target chromophores

often choose to begin with nonablative skin resurfacing treatments. Invasive dermatologic laser procedures such as laser blepharoplasty and ablative laser resurfacing will be covered elsewhere in this text.

PATIENT SELECTION

Patient selection for nonablative skin resurfacins is based on an evaluation of the individual's degree of plotodam- age and aging. The ideal patient is 35-55 years old with moderate signs of photodamage and aging (Fig. 3.2) Younger patients with mild photodamage may also show improved skin texture after nonablative skin resurfacing;

however the results will be subtle. Conversely, patients with deep rhytides and severe laxity may show minimal to no response. Such patients may be better candidates for ablative resurfacing or other more invasive cosmetic techniques Assessment of the patient's expectations during the consultation is critical in patient selection for nonablative skin resurfacrng.

Darker skin types may preclude the use of certain types of nonablative skin resurfacing In such patients light sources and lasers that target pigment must be used with caution and at settings to minimize thermal damage. Side effects such as blisters, scars, focal atrophy, textural change, and hyper- or hypopigmentation are all more likely to be seen in darker complected individuals. Mid-infrared lasers with emitted wavelengths varying between 1320 and 1540 nm target water in the dermis and theoretically can be used safely in darker skin types. However, when irradi- ated at high-fluences nonspecific laser energy absorptron by melanin can lead to thermal damage and side effects even in darker skin types. The most common albeit rare side effect experienced by patients with darker skin color after nonablative skin resurfacing is transient hyperpig- mentation. This is usually seen with those nonablative

Invisible Invisible

40Omm 7 0 0 m m 1 0 6 0 0 m m

Infrared Mid infrared

1320 1450 1 540 UV

Vascular IPL 532 500-

585 1200

595

' / - i f

Blood vessels

! nI t 2 v

4 5

devices that utilize cryogen epidermal cooling. The hyper- pigmentation may be due to cryoinjury and can be avoided by reducing the amount of cryogen delivered with each pulse. A detailed discussion of laser and nonlaser light sources in the treatment of darker skin phototypes may be found elsewhere in this text. (See Chapter 5 )

There are some individuals who are not appropriate candidates for nonablative resurfacing. Although clearly controversial, these may include those patients who have taken oral retinoids (for 6 months) prior to nonablative treatment, who have had recent ablative resurfacing with either lasers or deeper chemical peels, and/or have active skin disease within the treatment area (Box 3.3). Finally, in the rare patient reactivation of herpetic eruptions may occur. Pre-medication in these Datients is indicated.

Oral retinoids-6 months Ablative resurfacing 6 months

Chemical peels-medium or deep, 6 months Active skin disease within the treatment area-herpes,

impetigo, autoimmune disease

Trade name

V Star V Beam N Lite Aura Versapulse Diolite

Nonablative Skin Resurfacing

VASCULAR LASERS (slz-ro6+ NM)

The flashlamp-pumped pulsed dye laser (FLPDL) was the first vascular laser (Table 3.r) that was developed based on the principle of selective photothermolysis. It was specifically designed to treat port-wine stains. Although initially used with a 577-nm wavelength (a hemoglobin absorption peak) and a 450-ps pulse duration fshorter than the thermal relaxation time of targeted cutaneous vascular lesions), currently available pulsed dye lasers emit wavelenghs between 585 nm and 595 nm with pulse durations between 350 us and 40 ms. Variable wavelengths and pulse durations lead to the targeting of a variety of different vessel sizes.

The FLPDL uses a high-power flashlamp to excite elec- trons in an organic dye (rhodamine). Originally, this led to emission of yellow light at 577 nrn. The dye has been modified to emit photons at different wavelengths cor- responding with the absorption peaks of hemoglobin in its various states of oxygenation. Longer wavelengths in theory target larger and deeper blood vessels in the skin.

Enhanced safety cooling systems include cryogen-spray cooling delivered in millisecond bursts prior to laser pulsing or air cooling delivering chilled air to skrn con- tinuously throughout laser pulsing. Most recently, elon- gated pulse duration laser systems known as variable-pulse Jye lar.rs [V-Beam@, Candela, Wayland, MA; V Star@ and Cynergy@, Cynosure, Chelmsford, MA) have been designed to allow for effective yet gentle, uniform heating of vessels without resultant purpura.

Over the past decade, dermasurgeons who have used the FLPDL for treatment of vascular lesions have noticed anecdotal improvement in skin elasticity, dyschromia, and texture. Some physicians have also reported improvement of skin striae with vascular lasers. Finally treatment of hypertrophic scars and keloids with pulsed dye lasers has been shown to produce both clinical and histopathologic improvement of dermal collagen. With FLPDL treatment the absorbing chromophore would appear to be dermal vasculature containing hemoglobin. The exact mechanism of action of pulsed-dye laser induced collagen formation is unclear. Theoretically, laser induced damage to vascular endothelium produces cytokines that lead to dermal

Putse duration (ms)

0.5-40 0.45-40 350 1-50 1-50 1 - 1 0 0 Fig. 3.2 ldeal nonablative patient for photorejuvenation

Spot size (mm)

7 , 1 0 , 1 2 7 , 1 0

1 , 2 , 4 2-6 5 , 7 , 1 0 , 1 4

Wavetength (nm)

585, 595

532 532 532

L a s e r s a n d L i g h t s V o l u m e l l

remodeling of collagen and improvement in the appearance of rhytides

Traditional pulsed-dye laser treatment is often compli- cated by purpura. This lack of cosmetic elegance with older FLPDLs limited the usefulness of this device for nonablative resurfacing Current pulsed-dye lasers that play a role in nonablative resurfacing include the previ- ously described V-star@ series from Cynosure (air cooling, varying wavelengths between 585 nm and 600 nm and varyrng pulse durations), V-beam@ series from Candela (cryogen cooling, 595 nm .rvavelength, and varying pulse durations), the Nlite@ laser from USA Photonics (585 nm, 350 tr^ts, 3 J system), and the new Cynergy@ laser from Cynosure (air cooling, combined 595 and 1064-nm wavelengths with varying pulse durations).

Several studies have shown that increased collaeen production can occur with a lower fluence, purpura free puised dye laser treatment. Zelickson et al showed improvement in dermal collagen after one pass usrng the 585-nm FLPDL (450 msJ Multiple passes of the FLPDL (either the 585 nm or the 595 nm) at sub- purpuric fluences were not shown to be superior in creat- ing dermal collagen as compared to the results from a single pass

In one study, Goldberg and Sarradet analyzed both clinical rhytid improvement and electron microscopic evi- dence of ultrastructural changes after treatment with a nonablative 595-nm, flashlamp pulsed-dye laser. At 6 months after two laser treatments, 400/o of the treated subjects noted mild improvement in rhytid appearance Non-treating physician evaluation revealed some degree of improvement in 50% of the treated subjects. Mild improvement in quality and texture of the skin was also reported by 50% of the subjects. Electron microscopic evaluation showed ultrastructural chanees consistent with new collagen formation (Fig. f .f).

In addition, other types of vascular laser systems such as the 532-nm KTP, 755-nm alexandrite, 81O-nm diode and 1064-nm Nd:YAG lasers have been shown to be effective in nonablative resurfacing. The absorbing chromophores for the 1064-nm laser may include melanin, hemoglobin, and water contained within the skin.

One study by Lee evaluated using the long-pulsed KTP 532-nm and long-pulsed Nd:YAG 1064-nm lasers sepa- rately and combined for nonablative resurfacing (Lee 2003). After a series of three to six treatments, patients treated with a combination of 532-nm and 1064-nm lasers showed the greatest improvement in both types I and II photodamage. The KTP laser used alone showed superior results compared with when the Nd:YAG laser was used alone. However, both lasers when used alone produced inferior results when compared with the observed findings when patients received treatment with both lasers. Similar to studies evaluating intense pulsed light sources that emit polychromatic wavelengths and address multiple signs of photodamage, this was the first study to use two lasers rn combination to address both the epidermal and dermal elements of photoaging

Fig. 3.3 FLPDL patient: (A) pre-treatment; (B) post-treatment

Thus, it would appear that vascular laser treatment for nonablative photorejuvenation is appropriate for patients with one or more components of types I or II photodamage (Fig. 3.4) Patients with dyschromia, skin coarseness, redness, or rhytides may benefit. Uncommon side effects include purpura, dyschromia, blistering, or scarring (Fig.

3.5). Darker skin types may be treated more safely at appropriate fluences with the 1064-nm Nd:YAG laser.

Due to the potential side effect profile, especially in darker skin types, with the current vascular laser systems, other modalities may still be preferable for the treatment of rhytides.

MID-INFRARED LASERS (r3zo NM, 1450 NM,1540 NM)

A substantial number of studies have examined the clinical and histologic effects following treatment with mid- infrared lasers. The group of mid-infrared lasers includes the 1320-nm Nd:YAG (CoolTouch@; CoolTouch Corp, Auburn, CA), 1319-nm Nd:YAG (Profile, Sciton, Palo Alto, CA), the 1450-nm diode fsmoothbeam@; Candela Corp., Wayland, MA), and the 1540-nm erbium:glass (Aramis@, Quantel Medical, Clermond-Ferrand, France) lasers (Table 3.2).

The first specifically nonablative laser to be solely marketed to the physician community was the 1320-nm

Nd:YAG laser. The goal of this system, similar to that of all nonablative resurfacing devices, is improvement of rhytides without the creation of an epidermal wound. The 1320-nm wavelength is advantageous because of its high scattering coefficient. Thus, the emitted laser irradiation scatters throughout the treated dermis after nonspecific absorption of dermal water. The ensuing thermal injury theoretically triggers vascular damage and a cascade of events leading to remodeling of dermal collagen and clinical improvement of rhytides (Fig. f .6)

The currently available model of the I320-nm Nd:YAG laser is accompanied by a unique handpiece with three portals. One portal contains the cryogen spray that coois the epidermis prior to, during, and after treatment, one

Trade name

Cooltouch Smoothbeam Aramis

Nonablative Skin Resurfacing

Pulse duration (ms)

200 250 Fig. 3.5 FLPDL complication: purpura

Fig. 3.4 FLPDL patient: (A) pre-treatment; (B) post-treatment Fig. 3.6 Pre (A) and post (B) Mid-infrared laser treatmenl

Spot size (mm)

1 0 4 , 6 4

Wavelength (nm)

1 320 1450 1 540

Dalam dokumen Lasers and Lights (Halaman 51-60)

ADVANCED TOPICS: TREATMENT TIPS FOR EXPERI ENCED PRACTITION ERS

FURTHER READING

Nonablative Skin Resurfacing

Ellen S. Marmur, David J. Goldberg

INTRODUCTION

PATIENT SELECTION

Trade name

VASCULAR LASERS (slz-ro6+ NM)

Putse duration (ms)

Spot size (mm)

Wavetength (nm)

MID-INFRARED LASERS (r3zo NM, 1450 NM,1540 NM)

Trade name

Pulse duration (ms)

Spot size (mm)

Wavelength (nm)