Treatment of Skin With Intense Pulsed Light Sources

SUMMARY AND KEY FEATURES

• Intense pulsed light (IPL) devices are highly versatile and can be used for a wide range of esthetic and medical conditions.

• IPL platforms use high-output flash-lamps to produce polychromatic, noncollimated, incoherent (nonlaser) light, with wavelengths ranging from 500 to 1400 nm.

• Benign pigmented lesions, dyschromia, unwanted hair, telangiectasias, facial redness, flushing, Poikiloderma of Civatte, precancerous lesions, and acne can all be effectively treated with IPL.

• While treatment parameters can be adjusted to improve the safety profile of IPL in darker skin types (IV–VI), complications in this patient demographic are not uncommon. IPL should be used with extreme caution in darker skin types and in tanned skin.

• Not all IPL devices are created equally. Differences in the design and optics are significant, translating into huge ranges in efficacy. The device quality seems to correlate almost directly with the price point.

• With thorough understanding of light-tissue interactions and the wide selection of device parameters, experienced practitioners can take advantage of the considerable versatility of high-quality IPL devices.

Introduction

Intense pulsed light (IPL) treatment is one of the most popular, noninvasive skin procedures performed. IPL devices use filtered, high-intensity, pulsed, nonlaser light of varying wavelengths to treat both esthetic and medical conditions. Current IPL devices contain sophisticated, interchangeable light filters, which allow for versatility and a wide range of treatment options. With appropriate patient selection and practitioner experience, IPL can be highly effective, providing excellent results, typically with little downtime. Inappropriate patient selection, incorrect treatment parameters, or poor technique, however, can lead to significant adverse events. This chapter will provide a brief review of the history and science of IPL, then focus on clinical applications, treatment parameters and technique. In addition, we will share some of our personal treatment pearls, gleaned through years of experience with IPL devices.

History

In 1992, Dr. Shimon Eckhouse, an aerospace engineer from Israel, conceived the idea of applying a flash-lamp therapeutically to treat leg veins, which was a significant departure from the device’s original use as a paint vaporizer for fighter jets. At the time, pulsed-dye lasers, with short pulse durations, were engaged for this purpose, with unsatisfactory results and a high rate of complications. Dr. Eckhouse hypothesized that large vessels could be more uniformly treated with broad-band light, given that shorter, more readily-absorbed wavelengths could heat the superficial part of the vessel, while longer, less-readily absorbed wavelengths would penetrate further to heat the deeper portions of the vessel. Additionally, he theorized that a broad range of wavelengths would more effectively target both oxygenated and deoxygenated hemoglobin. Dr. Eckhouse enlisted the help of Dr. Mitchel Goldman and Dr. Richard Fitzpatrick, and together they developed a prototype IPL device. By 1994, the first commercially available IPL platform, PhotoDerm VL (Lumenis Ltd., Yokneam, Israel), gained FDA approval. Some early IPL devices struggled with efficacy, reproducibility and usability, which contributed to a somewhat controversial reputation in the laser community. By late 1990s and early 2000s, however, newer models addressed many of the initial concerns, and IPL gained popularity for the treatment of epidermal pigmented lesions, vascular lesions and unwanted hair. IPL was also found to be effective for the treatment of acne, and precancerous skin lesions. Over the past 2 decades, further technological developments have allowed for the expansion of treatment indications, decreased the risk of side-effects, and increased the ease of operation. They remain highly operator-dependent procedures, and though often delegated to support staff, the best results are in the hands of experienced, committed clinicians.

Intense Pulsed Light Terminology

The following terms and concepts are important in understanding the science behind IPL devices.

• Intense pulsed light: IPL is polychromatic, noncollimated, incoherent light, with wavelengths ranging from 500 to 1400 nm. This is in contrast to laser light, which is a single wavelength, highly-directional, and coherent in nature.

• Flash-lamp: Flash-lamps are pulsed sources of light, which consist of glass tubing with electrodes at either end. The glass tubing is filled with a gas, typically xenon or krypton. When a power supply triggers an electrical discharge between the two electrodes, the gas ionizes. The ionized gas produces a short burst of high-intensity, broad-band light. IPL devices directly emit this broad-band light. Some lasers also use flash-lamps, but in a different manner; instead of directly emitting the broad-band light, lasers use this light to optically excite the laser medium.

• Selective photothermolysis: Similar to lasers, IPL utilizes the principle of selective photothermolysis, in which there is selective heating of target chromophores with preservation of surrounding tissue. The target chromophores of IPL are primarily melanin, oxyhemoglobin, deoxyhemoglobin and methemoglobin, which have broad, overlapping absorption spectra; the polychromatic nature of IPL thus allows for the treatment of both vascular and pigmented lesions with a single light exposure.

• Pulse duration: Pulse duration represents the length of time over which the light energy is delivered and the duration the tissue is exposed to the light beam. The pulse duration of IPL systems can be set between 0.2 and 100 milliseconds, depending on the device. Pulse duration is guided by thermal relaxation time and thus the size of the target chromophore. Pulse duration is usually set to be shorter than the thermal relaxation time of the target chromophore, to minimize damage to surrounding structures.

• Multiple sequential pulsing and pulse delay: Depending on the IPL device, light can be delivered either as a single-pulse, or as a double- or triple-pulse, separated by short pulse delays in the millisecond range. “Multiple sequential pulsing” is the term used to describe the use of double- or triple-pulses. In theory, and practice, “multiple sequential pulsing” allows for a gentler treatment, given high fluences can be divided into multiple, shorter pulses of lower fluences. “Multiple sequential pulsing” also permits successive heating of large vessels, while still allowing adequate cooling of the epidermis. Some IPL devices also allow adjustment of the pulse duration of each individual pulse and the length of the pulse delay between the pulses. When more epidermal protection is needed, as in the case of tanned skin or darker skin, the pulse delay can be elongated to provide more time for enhanced protection through various means.

• Spectral shift: IPL devices experience a phenomenon known as spectral shift , in which a decrease in power causes a relative increase in the amount of energy density emitted at longer wavelengths. Specifically, for a set fluence, when coupled with a longer pulse duration and the accompanying decrease in power, the relative amount of energy density emitted in the longer wavelengths increases, with a relative decrease at the shorter wavelengths when compared to the same fluence at a shorter pulse duration. The spectral shift phenomenon enhances the effectiveness of IPL devices in treating deeper, darker, and larger vessels, which respond well to longer wavelengths.

Equipment

There are multiple commercially available IPL devices. This section will provide a broad overview of some of the common components of IPL devices.

• Cut-off filters and absorption filters: Many IPL devices utilize interchangeable, optically-coated, quartz filters, called “cut-off filters.” These filters narrow the range of the wavelengths emitted in order to optimize absorption by the desired chromophores. There is a wide range of available cut-off filters, including 515, 550, 560, 590, 615, 645, 690, and 755 nm; filters typically work by blocking the emission of wavelengths of light shorter than the set limit. The Palomar Icon’s MaxG hand-piece (Cynosure, Westford, MA) is entirely unique in that it incorporates an absorption filter to allow for dual-spectral output, with two different wavelength ranges, specifically 500–670 nm and 870–1400 nm. This filter absorbs the majority of the wavelengths between 670 and 870 nm, but allows for emission of flanking wavelengths. It is this optimization of the spectral emission that distinguishes this device, and is one of the rationales for its enhanced results. It is known as an OPL, an “Optimized Pulsed Light,” for this reason. The BBL (Broad Band light) HERO (High-Energy Rapid Output) device (Sciton, Palo Alto, CA) has seven separate cut-off filters including the 420 nm narrow band blue light filter, the 515, 560, 590, 640, 690 and 800 nm filters. Notably, the BBL is also unique in that it can be used both for facial and nonfacial photodamage of the neck, chest, arms, etc. ( Fig. 5.1 ). This device delivers hundreds of low-energy pulses within minutes in a sweeping motion reducing the risk of stamping burns and “zebra stripes” in these high risk areas. The M22 (Lumenis, San Jose, CA) has nine filters including the 515, 560, 590, 615, 640, 695 nm, as well as the “vascular” and “acne” filters. The acne filter is a novel dual-band notch filter delivering wavelengths of 400–600 nm and 800–1200 nm simultaneously that has shown significant promise in clearance of acne. The vascular filter is a dual band notch filter delivering 530–650 nm and 900–1200 nm wavelengths simultaneously designed to targe fine telangiectasias. Most IPL devices (excluding the Palomar Icon) utilize water surrounding the flash-lamp to prevent emission of wavelengths greater than 900 nm.

  

• IPL hand-piece: Most IPL devices deliver light to the skin through a large, flat, rectangular, sapphire crystal. This large footprint can be advantageous because it allows for rapid coverage, even distribution, and deeper penetration of light. With the large spot-size, however, it can be challenging to achieve uniform skin contact on contoured surfaces, especially around the nose, and it can create difficulty maneuvering in areas of focal treatment. To address these issues, some companies offer compact IPL tips to effectively treat irregular surfaces and discrete lesions. For example, the BBL Hero device has variable sized spot adapters that fit over the sapphire crystal to customize the device footprint. Alternatively, opaque masking devices can be used to effectively convert a large IPL footprint into a smaller one. A sheet of paper with a small, customized, cut-out is also a low-tech, safe, and easy method to decrease the footprint of a device while still allowing adequate and necessary contact cooling. Many IPL platforms integrate “slide-in” or “snap-on” cut-off filters into the device hand-piece, which allows for a single hand-piece to be used for a variety of treatments. Absorption filters, however, require constant cooling to prevent cracking and, thus, require entirely separate hand-pieces for each spectral range.

• Cooling mechanisms: Epidermal cooling significantly decreases side effects and allows for the use of higher fluences. Most high-quality devices utilize integrated, continuous contact-cooling, which is achieved through circulation of chilled water around the IPL crystal. In addition, cooled gel, such as Humatrix, a microclysmic gel, is used in conjunction with IPL devices to (1) diffuse skin surface heat and (2) enhance the optical transmission of light by decreasing the index of refraction. Added surface cooling with chilling packs can effectively protect the epidermis, applied immediately prepulse and/or posttreatment to minimize or eliminate undesirable issues. Zimmer coolers are another option to quickly and effectively decrease the epidermal temperature, if desired.

• BroadBand Light (BBL): BBL is a marketing term developed by the company Sciton (Palo Alto, CA) to describe their intense-pulsed light devices. The terms “BBL” and “IPL” are sometimes used interchangeably, and have similar meaning.

Patient Selection

To maximize benefits and minimize complications, appropriate patient consultation and selection is essential. The clinician should ensure that the patient’s skin condition, treatment goals, therapeutic objectives, and skin type are appropriate for IPL therapy. Ideal patients are well-informed, with realistic expectations, presenting with any one or a combination of the following esthetic concerns: diffuse redness, flushing, rosacea, angiomas (spider or cherry), telangiectasias, venous lakes, dyschromia, lentigines, actinic keratosis, and unwanted hair. Regions amenable to therapy include most areas of the body, though treatment parameters must be accommodated accordingly, as the skin responds quite differently from area to area. Patients with conditions less amenable to IPL treatment, such as severe rhytids, without pigmentary or vascular concerns, require counseling on alternative options. While treatment parameters can be adjusted to increase the relative safety of IPL in darker skin types—specifically, lower fluences, longer wavelengths, longer pulse durations, longer pulse delays, and enhanced skin chilling, both pre and postprocedure—complications in this patient demographic are all too common. We, therefore, typically reserve the use of IPL for patients with Fitzpatrick skin types I–III, in which results are predictable and reproducible, and we prefer to use specialized lasers and/or other treatment modalities for patients with darker skin. Even for those with lighter skin, the presence of naturally or artificially tanned skin increases the risk of untoward events, and these patients should be advised to postpone treatment until they are no longer tanned. To assist in the tan assessment, we often compare the skin color of the prospective treatment area to that of the inner forearm or inner upper arm, which are good baselines for untanned skin. Additionally, we typically only treat patients between mid-October and early-June to minimize sun exposure, both before and after treatment. We tend not to rely on the melanin reader devices, such as the Skintel, Melanin Reader, (Cynosure, Westford, MA); though accurate, the recommended treatment ranges can be misleading, in that it is exceedingly wide, and can ultimately translate into under- or over-treatment. We prefer to defer to clinical acumen, which is enhanced with consistent and careful patient follow-up. Combined with a detailed patient history, with particular attention to genotypic and phenotypic ethnicity, a thorough physical exam helps to determine appropriate device settings. A critical component to safe and effective treatments, as with any modality, is high vigilance. Close attention to the intended chromophore targets and the energy-tissue interaction is essential. Accommodation of the parameters as the treatment progresses is quite typical, as the initial settings are simply a starting guide, and good clinical judgement is paramount.

Patients seeking improvement of discrete pigmented lesions require special attention. While dermatologists are educated and trained to recognize abnormal moles and pigmented skin cancers, providers less-trained in skin conditions may be unable to distinguish harmful from benign lesions. If there is any doubt, a skin biopsy should be performed prior to IPL treatment. Additionally, while some studies suggest IPL can be effective for the short-term improvement of melasma, relapse is common and the combination of broad-band light and heat have the potential to flare melasma. For these reasons, we typically do not recommend IPL in melasma and opt for other therapeutic modalities. We also avoid IPL in patients with active connective tissue diseases, such as lupus erythematosus given the potential for exacerbation.

Treatment Protocol