LIGHT.EMITTING DIODES
PHOTODYNAMIC THERAPY
Photodynamic therapy (PDT) was introduced in the beginning of the 20th century as an experimental treat- ment that combines a photosensitizing dntg, a photoacti- vating light, and phototoxic oxygen to destroy cancer cells.
It was first used in the treatment of tumors of the bladder, bronchus, esophagus, and the skin The PDT mechanism of action involve the biosynthetic pathway for heme where precursor compounds are metabolized into phototoxic compounds such as protoporphyrin IX (PpIX). Although effective, early treatment applications of PDT using systemic photosensitizing drugs, were severely limited by prolonged phototoxicity. In 1990, the field of PDT was revitalized with the introduction of S-aminolevulinic acid [AtA), a potent topical photosensitizer.
Topical AtA is a precursor of PpIX in the heme bio- synthesis pathway. AIA ls preferentially absorbed by rapidly dividing cells in the epidermis and the superficial dermis. PplX has maximum absorption at 470,630, and 690 nm. With light activation, PpIX produces free radicals that cause cellular destruction. This process is called photodynamic therapy and has been FDA-cleared for the treatment of actinic keratoses. Currently, topical A[,A, used in PDT, is being studied for the treatment of photorejuvenation, actinic photodamage, nonmelanoma skin cancer, mycoses fungoides, warts, and moderate-to- severe acne using 560-1200 nm light sources
ALA-PDT has a well established role in the trearmenr of type III photodamage. Ultrastructurai evidence shows robust, new collagen formation in the skin after treatment with ALA-IPL compared with that seen after IPL treat- ment alone. Current light activators include IPL, PDL, and LEDs.
The most common adverse events reported with AtA- PDT are transient pain, irritation, and edema during and directly after treatment. Patients are potentially photo- sensitive for 24-48 hours and should wear appropriate sun protection. Dyschromia and scarring may also occur. One Iimitation to topical photosensitizers is their minimal depth of penetration. Prior microdermabrasion or topical acetone application may enhance penetration. New and promising topical medications and penetration enhancers such as ethylenediaminetetraacetic acid (EDTA) and dimethylsulfoxide (DMSO) are in development.
OVERVIEW OF TREATMENT STRATEGY . Treatment approach
The treatment approach for nonablative skin resurfacing starts with a consultation. The most important informa- tion to obtain during the consultation is a determination of patient goals. If the patient complains of erythema or rosacea, the IPL, FLPDL, or KTP lasers are the best choices. If the patient is concerned about skin textural changes, such as large pores or acne, IPL or LED are good choices. If the patient is concerned only about wrinkles, Fig. 3.10 Captain LED device
either the 1320-nm Nd:YAG. 1450-nm diode, 1540-nm erbium: glass lasers or radiofrequency devices are the treatments of choice For any combination of concerns such as erythema, rosacea, hyperpigmentation, acne, or poor skin texture, the IPL with possible adjunctive LED treatments may provide the best treatment option.
Once the problem is defined by the patient, the con- sultation can focus on the appropriate treatment options It is helpful to explain to a patient that lasers and light sources use computers that generate light to target an undesired aspect of aging skin. IPL and LED therapy entails a series of treatments depending on the desired clinical effect. Caution the patient that initial changes may be subtle and therefore invisible for at ieast one or two treatments. Final clinical results often require 6 months to I year to appreciate The risks of nonablative resurfac- ing must be addressed. These include transient erythema and pain during the procedure. In addition, the rare risk of scarring and pigmentary changes after treatment should be discussed The consultation should conclude with the patient having the opportunity to ask questions
o Treatment techniques
V A S C U L A R L A S E R S ( 5 3 2 - 5 9 5 N M )
Treatment with the FLPDL or KTP lasers begins with a consultation. Vascular lasers are used primarily for telan- giectasias, and less commonly for dyschromia and rhyt- ides. The consent form and discussion should focus on the risks of purpura, dyschromia, crusting, possible scarring, and the probable need for a series of treatments. Param- eters are then chosen based on skin type, degree of laxity, size and depth of vessels, or type of dyschromia to be treated For examples of general treatment settings see T a b l e 3 . 3
The area is cleansed prior to treatment. Al1 make-up is removed and preoperative photographs are taken. Usually, no topical anesthesia is required. However, such anesthe- sia may be applied for I hour prior to treatment especially if higher laser fluences are to be used or if the patient requests pain control
The patient is placed in a supine position in case of the rare event of a vasovagal reaction. Appropriate external
Nonablative Skin Resurfacing
eye protection must be worn by all persons present in the laser room. The patient's eyes are covered by clean, dry gauze, or opaque goggles. For treatment of eyelid vessels, intraorbital eye shields must be used. As with all laser and light systems, any reflective surface in the room must be covered. The outside door of the laser room should hold a warning sign prohibiting persons without eye protection from entering the area during treatment.
Vascular laser devices employ different cooling methods from cryogen spray, to air cooling, to contact cooling, to no cooling. Full-face treatment without overlapping pulses is recommended. The handpieces with cryogen spray or air cooling should be placed at a preset distance away from the skin to prevent injury. Each system provides an attach- ment for the handpiece to ensure proper focal distance Contact cooling handpieces are placed directly onto the skin surface \4rhen the pulse is fired, the patient will experience a brief hot snap comparable to a rubber band snap against the skin. The patient may still see a bright flash of light, but as long as they have properly fitted eye protection covering the orbit, they are safe.
Erythema, edema, blanching of the vessels, and tran- sient hyperpigmentation or dyschromia may be seen immediately or shortly after the treatment. If purpura rs noted, the utilized fluence is generally too high. Patients may choose to apply cool gel packs when the treatment is completed to alleviate discomfort. No wound care ts usually required.
Pearls and pitfalls when using the vascular lasers are numerous. Patients with darker skin types (Fitzpatrick IV-VIJ are at a greater risk of developing hypopigmenta- tion. These patients might consider a laser patch test in an inconspicuous area prior to full-face treatment.
However, such test patches are not foolproof. Topical retinoids, glycolic acid cream, and ascorbic acid have been used successfully for a course of 4-6 weeks prior to and during treatment in patients with darker skin types to prevent hypopigmentation No overlap of pulses is recom- mended to prevent FLPDL-induced purpura. It may be helpful to decrease the repetition rate of each pulse (Hz) in order to space out each pulse accordingly. Energy set- tings should be changed based on the anatomy of the treat- ment area. The periorbital area is particularly prone to
Trade name
V Star V Beam N Lite Aura Versapulse Diolite
Spot size (mm)
1 0 1 0
1 + 0 . 5
Pulse duration (ms)
6-1 0
o - l u
350 ms 1 0
I J
10-20
Fluence (l/cm')
5 - l
5-7
1 0 1 0 253
Lasers and Lights Volume ll
developing purpura whereas the paranasal area requires higher fluences, larger spot sizes, and longer pulse durations compared with the cheeks. Precooling the skin permits the use of higher laser fluences without damaging the skin, but cryoinjury to the epidermis must be avoided especially in darker skin types Persistent blanching is a danger sign for the potential development of blistering. If a burn or blister- ing is suspected, the patient should apply topical antibiotics for 2 weeks and avoid sun exposure. It is wise to offer frequent follow-up visits for these patients.
M r D - T N F R A R E D L A S E R S ( 1 0 5 4 - 1 5 4 0 N M )
Treatment with the mid-infrared devices begins with a consultation. Mid-infrared lasers are used for improve- ment of overall skin texture, laxity, and mild rhytides.
Consent is signed outlining the risks of dyschromia, scar- ring, pain, erythema, or crusting. Initial parameters are set according to skin type and treatment area. Suggested starting treatment parameters for the three mid-infrared systems are seen in Tabte 3.4.
The skin is cleansed to remove oil, make-up, or sub- stances that will impede the laser light delivery to the dermis and to minimize the possibility of infection. There is some controversy as to whether topical anesthesra can be used. It has been postulated that since topical anesthet- ics increase the epidermal water content, the target of mid-infrared lasers, they might decrease the ensuing laser- delivered thermal damage. This is unproven and many patients will require topical anesthesia when treated with higher fluences.
Appropriate eye protection in the form of clear plastic or glasses is worn by all present in the room. The patient's eyes may be protected with clean dry gauze or opaque goggles The patient is placed comfortably in a suprne position.
Al1 currently available mid-infrared lasers utilize either epidermal-sparing cryogen spray or sapphire-tip contact cooling The 1320-nm laser handpiece has a thermal sensor that provides feedback readings of the peak epider- mal temperature that corresponds to the temperature of the dermis. The fluence is increased incrementally until the thermal sensor reads between 42 and 48"C. The 1450-nm and the 1540-nm devices do not offer this option One pass is given over the forehead where the dermis is thinnest and the intensity of pain the greatest.
The cheeks, chin, and upper lip are generally treated with between two and five passes.
No wound care is required after treatment. A common side effect is transient erythema and mild edema. Patients may wish to apply cool packs for a short period of time until the pain subsides.
Treatment pearls and pitfalls are relatively few com- pared with the other nonablative laser modalities. When treated with conservative fluences for the initial treat- ment, it is rare to incur serious side effects with the mid- infrared devices Before currently used safe treatment parameters were defined, atrophic and hypertrophrc scar- ring was fairly commonly seen with these devices. Because mid-infrared devices are used with some form of cooling, cryoinjury of the skin must be a consideration. This is more commonly seen in darker skin types Today, when rare atrophic scarring does occur, it is unpredictable. Post- laser induced hyperpigmentation generally requtres no treatment and will fade over the course of I year. Hypopig- mentation is an unfortunate and permanent side effect, albeit very rare.
I N T E N S E P U L S E D L I G H T
IPL treatment begins with a consultation to define the patient's goals. The IPL may provide the best treatment option for any combination of concerns such as essential telangiectasias, solar lentigines, rosacea, hyperpigmenta- tion, acne, poor skin texture, and early rhytides. Param- eters are selected based on skin type and target tissue For example, for facial telangiectasias in patients with type I-III skin the initial setting might be 500-560 nm filter, ).5-20 J/cm2, with single or double varying pulse duration delivered pulses. Due to the extensive list of available devices, see each manufacturer's literature for suggested parameters Follow the guidelines for consultation estab- lished in the vascular laser section
The skin is cleansed to remove make-up or any material that may interfere or absorb the IPL energy. No topical anesthesia is necessary in most patients unless high flu- ences are to be used. Urticarial plaques may occur at higher fluences especially without adequate intraoperative cooling. Be sure to test higher fluences prior to fu11-face treatment even in a well-known patient. In patients with a lower pain threshold, l5-30 minutes of pre-treatment topical anesthetic cream may be sufficient.
Trade name
Cooltouch Profile Smoothbeam Aramis
Spot size (mm)
1 0
6 (scanne0 4
Fluence (llcm')
16-20 12-18 1 0 - 1 3 1 0
Pulse duration (ms)
200 200 250
J . C
Appropriate eye protection in the form of dark lenses is required for the surgeon and staff present. An assistant places gauze or opaque goggles over the patient's eyes.
Some operators wear light-colored lenses to enable them to see the treatment site clearly. After placing the hand- piece in the desired location, these operators close their eyes for further eye protection when they fire the IPL.
The IPL emits a bright flash of light that may be seen by the patient even with eye protection. Ifthe eye is covered, this incidental light is not harmful.
The skin is generally covered with a layer of cool coupling gel such as ultrasound gel. The handpiece is piaced on the skin with uniform contact. \Mhen the pulse is fired the patient will experience a brief sensation of pain and heat. At low fluences, multiple passes over the chin, nose, and cheeks may be used. At higher fluences, non-overlapping pulses with single or double passes are generally successful.
Side effects are uncommon. Transient erythema occurs in nearly all patients This is due to the cooling gel, the mechanical pressure of the handpiece, plus the IPL effect Blistering and scarring are extremely rare fsee Fig 3 9). Some patients develop slight swelling post- operatively. Topical steroid cream applied once is usually sufficient.
Pitfalls to avoid during IPL treatment are multiple.
When treating the skin of the forehead, care must be taken to avoid vaporizing the eyebrow hair. Place the handpiece at least I mm away from hair-bearing areas (unless photoepilation is a desired endpoint.) Lipstick and all cosmetics must be completely removed, other- wise the patient may suffer an unintentional burn due to energy absorption by the pigment in the cosmetics. It is also reasonable to start with conservatively low fluences when treating patients with moderate-to-severe signs of rosacea in order to prevent unexpected side effects such as intensified pain, prolonged erythema, or second-degree burns.
L I G H T - E M I T T I N G D I O D E S
After the initial consultation, LED treatment may be used alone or as multitherapy in conjunction with other light and laser devices It is also safe to use after injectabies The number of treatments depends on the indication.
Many patients receive monthly treatments to maintain the beneficial effects of their anti-aging or anti-acne treatments.
The vast majority of patients report LED treatment to be painless, even relaxing. Make-up is removed completely prior to treatment If LED is to be used with PDT, prior microdermabrasion for at least 5 minutes to each side of the face followed by application of ALA for 30 minutes to 3 hours is recommended by some clinicians. The patient is positioned in front of the LED panel and opaque eye protective goggles are worn for 20 minutes of treatment.
Blue light versus red light versus combination therapy is predetermined by the physician
Nonablative Skin Resurfacing
Immediately after treatment, the patient may apply make-up. If the treatment involved PDT, sun protection is essential for 24 hours
P H O T O D Y N A M I C T H E R A P Y
For nonablative photorejuvenation, PDT may be used in conjunction with other techniques discussed within this chapter. Treatment plans vary based on each patient's requirements. For optimum penetration of the topical ALA, cleanse the skin with alcohol or acetone followed by a gentle soap cleanser. Microdermabrasion prior to AIA incubation is excellent as well. The ALA is applied using a brush or a sponge applicator to the clean, dry skin ofthe entire treatment area. Some clinicians place their patients in a dimly lit room (to avoid photoactivation of the ALA) for 30 minutes to 3 hours depending on the practitioner's discretion. The ALA is not washed off prior to light acti- vation Proper eye protection is selected based on the laser or light source to be used A11 treatment areas are covered using one pass of the light source, or multiple passes based on endpoint and parameters and patient tolerance. Ideally, the ALA is completely photobleached by the treatment but there may be residual ALA that can lead to photosen- sitivity in sunlight for 24 hours postoperatively. Gently wash the treatment area and apply nonirritating sunscreen to the treatment area before the patient leaves the office.
Ifthe patient has experienced pain, cool packs and topical steroids may be applied judiciously.