Cynosure has a new machine for the American Academy of Dermatology’s 67th Annual Meeting in San Francisco – Elite MPX for its Smartlipo MPX laser lipolysis workstation.

Through the company’s patented MultiPlex(TM) technology, Elite MPX combines two wavelengths — 755nm Alexandrite and 1064 nmNd:YAG – along with Xenon Pulsed Light (XPL2) technology to create one of the industry’s most powerful workstations for vascular treatment, hair removal and skin rejuvenation. In addition, Cynosure is introducing two new intelligent delivery systems for the Smartlipo MPX workstation for laser lipolysis: SmartSense with ThermaGuide and ThermaView, the world’s first subcutaneous temperature sensing technology and thermal imaging system for Laser Body Contouring.

Elite MPX incorporates Cynosure’s proprietary MultiPlex technology, which sequentially fires two wavelengths for more effective treatments than single-wavelength systems. A completely new software system runs the graphically enhanced Graphic User Interface, which makes its operation simple and easy.

The workstation also features a built-in Zimmer SmartCool(R) skin cooling system that is exclusive to Cynosure. Rather than requiring a separate SmartCool device, Zimmer technology is integrated into a single compact module, saving precious office space and reducing treatment time. In addition, the Elite MPX includes eight different spot sizes, including an 18mm spot size that results in 44% more treatment area per pulse than standard spot sizes.

“Cynosure’s Elite MPX is a powerful and versatile system that enables clinicians to customize treatments for a broad range of skin types and conditions, including sun-damaged skin, pigmented lesions, dyschromia and rosacea,” said Emil Tanghetti, M.D., Clinical Professor of Dermatology at the University of California, Davis and Director of The Center for Dermatology and Laser Surgery, Sacramento, California. “As practitioners, we are seeing a growing cultural diversity within our patient base, and I expect the Elite MPX will provide benefits across the spectrum of applications for these patients.”

According to InMedica, the worldwide demand for hair removal, pigmented lesion removal and vascular lesion removal is expected to increase from $650 million in 2007 to $750 million by 2010.

SmartSense with ThermaGuideis equipped with a thermal sensing cannula for measuring temperatures in the subcutaneous areas of the body. This technology allows the practitioner to set temperature thresholds to achieve targeted and controlled energy delivery for a safe and optimal clinical endpoint.

The ThermaView thermal camera system measures skin surface temperature and provides a visual map of temperatures within the treatment area in order to provide a homogeneous delivery of thermal energy. This intelligence is integrated into the Smartlipo MPX system. As a result, thermal energy is delivered to a targeted temperature setting, helping to ensure the safe and effective treatment of the superficial layer of the surface area.

LaserOffers.com comment

Many people will call these advances bells and whistles. We disagree. Cynosure has come up with a lot of real technological advances rolling out this system. High capacity, large volume clinics will benefit from it, if they can afford it. All it takes to get your money back is a few hundred patients a month. Every month.

Introduction

Advances in nonablative skin rejuvenation technologies have sparked a renewed interest in the cosmetic treatment of aging skin. More options exist now than ever before to reverse cutaneous changes caused by long-term exposure to sunlight. Although Caucasian skin is more prone to ultraviolet light injury, ethnic skin (typically classified as types IV to VI) also exhibits characteristic photoaging changes. Widespread belief that inevitable or irreversible textural changes or dyspigmentation occurs following laser or light-based treatments, has been challenged in recent years by new classes of devices capable of protecting the epidermis from injury during treatment. Ethnic skin represents the majority of the world’s population and yet few research studies have targeted the safety and efficacy of cosmetic skin procedures in ethnic skin. This article highlights newer advances in nonablative ethnic skin rejuvenation and evaluates their safety and efficacy.

Defining Ethnic Skin

In addition to grouping people of ethnic descent into classic Fitzpatrick categories of IV to VI to describe their propensity for sun reactivity, it is useful to describe how ethnic features and groups relate to one another. People of ethnic skin comprise the majority of the world’s population. These include Asians, who can be subdivided into East Asians (Chinese, Japanese, Koreans), Southeast Asians (Indonesians, Malaysians, Singaporeans, Thais, Cambodians, Vietnamese), and South Asians (Bangladeshis, Indians, Pakistanis, Sri Lankans). Those from East Asia tend to have lighter skin color, although Koreans are generally more brown-skinned than the Chinese or Japanese. Southeast Asians have brown skin color while East Asians and Southeast Asians have a Mongoloid ethnic background. South Asians are of Caucasian ethnic background but have brown to dark brown skin.

Photorejuvenation

Photorejuvenation is defined as the use of visible or infrared light energy sources to reverse the process of sun-induced or environmental damage to the skin. [1] Visible disruption to the overlying epidermis should not occur while trying to accomplish this in a nonablative manner. The primary objective of nonablative rejuvenation is to improve aesthetic concerns characteristic of photoaged skin, including the appearance of dyspigmentation, static fine wrinkles, coarse texture, prominent pores, and telangiectasias. In contrast, chronological skin aging results in thin skin with reduced elasticity that retains normal skin pigmentation and texture. [2] A secondary objective includes the recontouring of mild surface irregularities via subsequent dermal collagen remodeling.

In general, all races are susceptible to photoaging. [3] However, it is clear that photoaging is delayed and less severe in patients with Fitzpatrick’s skin phototypes IV to VI. This is due to the photoprotective role of melanin. [4],[5] Published studies on photoaging in black skin have been limited to African Americans. Photoaging is more prominent in lighter-complexioned African American individuals. In addition, photoaging may not be apparent until the fifth or sixth decade of life. Clinically, the features of photoaging in African Americans can include fine wrinkling, mottled pigmentation, and dermatosis papulosa nigra. African Americans also tend to manifest signs of skin laxity with aging. This is most evident in the nasolabial folds and jaws. [6] Most studies on the treatment of photorejuvenation in ethnic skin utilize nonablative technologies that will be discussed in this paper.

Fractional devices

Fractional photothermolysis (Fraxel SR, Reliant Lasers, Palo Alto, CA, USA) is a novel nonablative erbium:glass (1500 nm) laser treatment for facial rejuvenation. [7] It is also used for the treatment of melasma and acneiform scarring. [8] Fractional photothermolysis is performed with a midinfrared laser, which creates microscopic columns of thermal injury. These zones of thermal injury, termed microthermal zones (MTZs), have a diameter that is energy-dependent and ranges from 100 to 160 μm. The depth of penetration ranges from 300 to 700 μm at the energies commonly used for facial rejuvenation (8-12 mJ/MTZ).[9] Relative epidermal and follicular structure sparing are responsible for rapid recovery without prolonged downtime. Melanin is not at risk of selective, targeted destruction; therefore, fractional resurfacing has been used successfully in patients with skin of color. Kono et al . [10] have described the use of the Fraxel in 35 type IV and V Asian patients and concluded that increased density was more likely to produce swelling, redness, and hyperpigmentation when compared to increased energy. In this study, the authors concluded that patient satisfaction is significantly higher when their skin is treated with high fluences than when treated with high densities. They concluded that fractional photorejuvenation can be safe and effective in darker ethnic skin types. [10]

Prior studies using fractional photothermolysis have demonstrated its effectiveness in the treatment of photodamaged skin; however, only preliminary results have been reported regarding its use for scars. Given the rapid healing associated with this procedure and its known effect on collagen remodeling, this study was designed to prospectively evaluate the use of fractional photothermolysis in the treatment of atrophic scars. Fifty-three patients (skin phototypes I-V) with mild-to-moderate atrophic facial acne scars received monthly treatment with a 1550 nm erbium-doped fiber laser (Fraxel, Reliant Technologies Inc., San Diego, CA). Clinical response to the treatment was determined by two independent assessors at each treatment visit and six months after the final treatment session, by using a quartile grading scale. Side effects and patient satisfaction were monitored at each follow-up visit. Ninety-one per cent of the patients had at least 25-50% improvement after a single treatment, whereas 87% of the patients receiving three treatments demonstrated at least 51-75% improvement in the appearance of their scars. Moreover, age, sex, and skin phototype also did not significantly affect the observed clinical responses. Hence, it was concluded that fraxel procedures were effective in acne scar treatment for skin of color. [11]

532 nm Laser

Although not a prominent feature of ethnic skin, treatment of the pigmented and telangiectatic component of photoaging has been reported in ethnic skin. [12],[13] Rashid and colleagues reported the use of a quasicontinuous wave 532 nm laser in the treatment of lentigines in type IV skin patients. [13] They showed 50% improvement in lesion clearance, with a 10% incidence of hyperpigmentation and 25% incidence of hypopigmentation after multiple treatments. These side effects abated after two to six months. Lee reported 150 patients with skin types I to V who were treated in multiple sessions with 532 nm (4 mm spot, 6-15 J/cm 2 , 30-50 millisecond pulse duration), 1064 nm (10 mm spot, 24-30 J/cm 2 , 30-65 millisecond pulse duration), or a combination of both. [11] Sapphire-tipped contact cooling was utilized. Improvement in erythema, texture, pigmentation, and rhytids was reported in both study arms but was highest in the combination group. An incidence of 5% postinflammatory hyperpigmentation was reported in patients with types III and IV skin treated with the 532 nm laser alone, which resolved after 4-6 weeks. [12] The use of conservative settings to achieve the desired results is prudent. Following these guidelines, the clinician is most likely to achieve a favorable result with the least unwanted side effects. Test spots are necessary to assess the initial patient response and decrease the risk of hypopigmentation, which is often very difficult to treat.

1064 nm Laser

Long-pulsed and Q-switched 1064 nm lasers target melanin as well as hemoglobin and water. Although safer for darker skin, there is a diffuse heating of dermal tissue owing to the deep, penetrating nature of 1064 nm with a typical dispersion depth of 5-10 mm. [1] One study has shown evidence of improvement with a Q-switched 1064 nm laser for nonablative treatment in type IV skin. [13] Sun-damaged 4 cm × 4 cm areas of infraauricular skin were exposed to a 1064 nm Q-switched Nd:YAG laser at a fluence of 7 J/cm 2 and a 3 mm spot size. Two laser passes with a 10-20% overlap, were used on all subjects in an attempt to promote petechiae as the visible end point. Petrolatum dressings were applied for a week after treatment. Three millimeter punch biopsy specimens were taken from each subject before treatment. Photographs were taken of the biopsy sites. Three months after the last treatment, another biopsy specimen was taken from a different previously treated area. Histological specimens were evaluated blindly by a board-certified dermatopathologist. Four out of six skin biopsy specimens obtained three months after the last laser treatment, showed mild fibrosis with histological improvement in pretreatment solar elastosis. There was a mildly thickened, upper papillary collagen zone, with an improvement in the organization of collagen fibrils. The remaining two specimens showed no changes. Clinically, none of the treated, nonbiopsied areas showed any evidence of pigmentary changes or scarring. [13]

Another study utilized the 1064nm Nd:YAG (Laser genesis) for the rejuvenation of facial skin of types I-V. Patients’ and masked physician assessment demonstrated overall improvement. Specific improvement was also demonstrated in coarse wrinkles and skin laxity. No adverse events were noted in this study. [14] Studies have all confirmed the effectiveness and low risk of complication associated with Nd:YAG for rejuvenation in skin of color.

Intense Pulsed Light

Another device for photorejuvenation of ethnic skin is Intense Pulsed Light (IPL). IPL is produced by a noncoherent flashlamp-pumped light source that is capable of emitting light from 500 to 1200 nm. [15] The use of cutoff filters allows the elimination of some of the shorter wavelengths of the visible light spectrum to limit melanin absorption. Different pulse widths can be chosen so that appropriate parameters match the thermal relaxation times of the targets. [16] Cooling of the epidermis is achieved with contact cooling in the device head or with external cooling devices.

Negishi and colleagues were among the first to investigate the use of IPL in types IV and V Japanese patients using pulsed light devices. They applied a thin layer of ice-cold gel and they utilized a 550 nm cutoff filter. Settings were 28 to 32 J/cm 2 and 2.5-4.0 and 4.0-5.0 millisecond pulse durations. Excellent results were reported in 73 out of 97 patients. [17],[18] No evidence of dyspigmentation was reported in either series. Negishi and colleagues have also employed UV photography to identify and treat subclinical epidermal hyperpigmentation with IPL in skin of color. [19] Although IPL has been utilized with success in skin of color, treatment of such patients should utilize conservative settings to achieve a favorable result with the least unwanted side effects.

Light-emitting diode (LED)

Apart from the light- and laser-based devices described above, three newly described nonablative technologies have been used for treatment in ethnic skin types. Light Emitting Diodes (LEDs) represent the latest advancement in visible spectrum, monochromatic light therapy for photoaged skin. Typically, LEDs in devices are arrayed in panels, and each emits visible light in a ±10-20 nm band around the dominant emitted wavelength. Energy output is less than 25 W, representing a fluence of about 0.1 J/cm 2 . The Gentlewaves LED device (Light Biosciences, Virginia Beach, VA, USA) recently received approval from the US Food and Drug Administration for the treatment of periorbital wrinkling. [20] In brief, this device is thought to act by targeted stimulation of fibroblastic mitochondrial metabolic activity, concomitant upregulation of procollagen, and downregulation of matrix metalloproteinase I. [21],[22]

Radiofrequency (RF)

Radiofrequency (RF) is an electromagnetic radiation in the frequency range of 3 kHz to 300 GHz. The primary effects of RF energy on living tissue are considered to be thermal. The main goal of these new frequency-based devices is to heat specific layers of the skin. Directed use of RF can induce dermal heating and cause collagen degeneration. Wound healing mechanisms promote the remodeling of collagen and wound contraction, which ultimately enhances the appearance of mild to moderate skin laxity. Preliminary studies with one device (Thermacool, Thermage Inc, Hayward, CA, USA) have reported efficacy in the treatment of laxity involving the periorbital area and jowls. [23] As RF energy is not dependent on specific chromophore interaction, epidermal melanin is not at risk of destruction and treatment of all skin types is possible.

Kushikata et al. [24] reported the use of RF in a series of 85 Asian patients of dark skin types and concluded that RF treatment was very satisfactory for skin tightening in Asian facial skin. RF appears to be a promising means of photorejuvenation in ethnic skin.

Infrared Tightening

Improvement of facial and cervical skin laxity has been difficult to achieve without surgical procedures. A device called the Titan (Cutera, Inc., Brisbane, California) uses infrared (IR) light to volumetrically heat the dermis. It is designed to thermally induce collagen contraction with subsequent collagen remodeling and neocollagen synthesis. The epidermis is protected via pre-, parallel, and posttreatment cooling. No anesthesia is necessary as there is minimal to no discomfort during the procedure. Improvements in skin laxity and facial and neck contours have been achieved with this device, although results can vary. This variation may be caused by patient variability and differences in technique. [25]

Few studies have addressed the efficacy and safety of infrared use in darker skin, however Chua et al. investigated the use of IR on 21 patients of Fitzpatrick skin types IV and V. Eighty-six per cent of the patients had improvement as measured by the physician’s assessment at their six months’ follow-up visit. Hence, Chau et al. concluded that direct application of infrared light with epidermal cooling is effective in achieving gradual, mild-to-moderate clinical improvement in the treatment of facial and neck skin laxity. The procedure is associated with minimal downtime and is safe for use in darker skin types IV and V. [26]

Plasma skin regeneration (PSR) technology

Plasma is the fourth state of matter acquired by ionizing a gas. One example of this is the light we see with lightning. The electricity (energy) discharged from the clouds to the earth heats up the air (gas) and converts it into plasma. [27] A basic understanding of skin structure is required to understand how PSR works. Briefly, skin consists of three layers: the epidermis (uppermost layer), dermis (middle layer) and subcutis (lower fat layer). The epidermis contains pigment-producing cells called melanocytes, which are responsible for skin coloring. The dermis is made up of collagen and elastin fibres that provide skin with strength, toughness, elasticity and pliability. The appearance and characteristics of skin change as the body ages. The epidermis becomes thinner so that blemishes become more visible, and collagen in the dermis is gradually lost, which contributes to the formation of facial lines, sagging skin and wrinkles. [28]

To date, there are five anti-aging treatment regimens – PSR 1, PSR 2, PSR 3, PSR 2/3 combination and a fifth newly FDA approved one. A particular regimen is chosen according to the severity of the problem being treated and the recovery time available. The fifth treatment is a new FDA-approved, anti-aging procedure for treating nonfacial areas of the body. All protocols could be used for lines; however, higher energy treatments are needed for skin tightening. Studies have shown that the thermal energy at 1.0 and 2.0 J was limited to the epidermis and dermoepidermal junction. At 3.0 and 4.0 J, the thermal injury reached the papillary dermis. PSR 1 protocol uses a low-energy treatment spaced three weeks apart. PSR 2 uses a single high pass 3.0-4.0 J energy treatment with a recovery time of 5-7 days. PSR 3 uses two high-energy passes (3.0-4.0 J) with a recovery period of 6-10 days. A fourth protocol uses a combination of PSR 2 and PSR 3 and the fifth one uses very low energy (0.5 J) in a series of three treatments at three-week intervals. [29] Few studies have been carried out on subjects so far; however, Kilmer, [30] Poter, [31] Benstein [32] and Bogle [33] have all demonstrated the low risk and efficacy of using such technology in all skin types.

Summary

In conclusion, laser procedures in darker skinned patients are challenging but can be successfully achieved if certain treatment guidelines are followed. Discussion of risks and patients’ expectations are essential in treating the darker-skinned patient population. Pre- and postlaser cooling can be helpful to minimize side effects and improve patients’ comfort. This is especially true with laser hair removal. Photorejuvenation can be successfully achieved with low risk when appropriate settings are used. Fractional technology has increased treatment options for rhytides and atrophic scars. Although there are few studies on LED treatments in skin of color, this type of treatment can be used either as a primary or adjunctive treatment modality with apparently low risk. The 532 nm laser has proved to be risky in skin of color and conservative guidelines should be followed when using it. On the other hand, the 1064 nm laser may offer greater safety when treating ethnic skin albeit still risky in type VI skin. The IPL is a safe option for treating skin of color although it is advisable to limit its use for skin types V and VI. Finally, radiofrequency and newer tightening technologies are safe and highly reliable to use for ethnic skin. However, it is prudent to use conservative settings to achieve the desired results when treating darker skinned patients. The clinician is most likely to achieve a favorable result with the least unwanted side effects if these guidelines are followed.

1. Weiss RA, McDaniel DH, Geronemus RG. Review of nonablative photorejuvenation: Reversal of the aging effects of the sun and environmental damage using laser and light sources. Semin Cutan Med Surg 2003;22:93-106.
2. Kim KH, Geronemus RG. Nonablative laser and light therapies for skin rejuvenation. Arch Facial Plast Surg 2004;26:186-95.
3. Griffiths CE, Goldfarb MT, Finkel LJ, Roulia V, Bonawitz M, Hamilton TA, et al. Topical tretinoin (retinoic acid) treatment of hyperpigmented lesions associated with photoaging in Chinese and Japanese patients: a vehicle-controlled trial. J Am Acad Dermatol 1994;30:76-84. [PUBMED]
4. Kligman AM. Solar elastosis in relation to pigmentation. In : Fitzpatrick TB, Pathak MA, editors. Sunlight and man. Toyko: University of Toyko Press; 1974. p. 157-63.
5. Pathak MA. The role of natural photoprotective agents in human skin. In : Fitzpatrick TB, Pathak MA, editors. Sunlight and man. Tokyo: University of Tokyo Press; 1974.
6. Matory WE. Skin care. In : Matory WE, editor. Ethinic considerations in facial aesthetic surgery. Philadelphia: Lippincott; 1998. p. 100.
7. 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;34:426-38. [PUBMED]
8. Fisher GH, Geronemus RG Short-term side effects of fractional photothermolysis. Dermatol Surg 2005;31:1245-9.
9. Fitzpatrick R, Geronemus R, Goldberg D, Kaminer M, Kilmer S, Ruiz-Esparza J. Multicenter study of noninvasive radiofrequency for periorbital tissue tightening. Lasers Surg Med 2003;33:232-42. [PUBMED]
10. Kono T, Chan HH, Groff WF, Manstein D, Sakurai H, Takeuchi M, et al. Prospective direct comparison study of fractional resurfacing using different fluences and densities for skin rejuvenation in Asians. Lasers Surg Med 2007;39:311-4. [PUBMED]
11. Alster TS, Tanzi EL, Lazarus M. The use of fractional laser photothermolysis for the treatment of atrophic scars. Dermatol Surg 2007;33:295-9. [PUBMED]
12. Lee MW Combination 532-nm and 1064-nm lasers for noninvasive skin rejuvenation and toning. Arch Dermatol 2003;139:1265-76.
13. Rashid T, Hussain I, Haider M, Haroon TS. Laser therapy of freckles and lentigines with quasi-continuous, frequency-doubled, Nd:YAG (532 nm) laser in Fitzpatrick type IV: A 24-month follow-up. J Cosmet Laser Ther 2002;4:81-5. [PUBMED]
14. Dyan SH, Vartanian AJ, Menaker G, Mobley SR, Dayan AN, Nonablative laser resurfacing using the long-pulse (1064-nm) Nd:YAG laser. Arch Fac Plast Surg 2003;5:310-5.
15. Goldberg DJ, Silapunt S. Histologic evaluation of a Q-switched Nd:YAG laser in the nonablative treatment of wrinkles. Dermatol Surg 2001;27:744-6. [PUBMED]
16. Chan HH. Photoaging in Asian. In : Rigel DS, Weiss RA, Lim HW, et al , editors. Photoaging. New York: Marcel Dekker; 2004. p. 343-64.
17. Negishi K, Tezuka Y, Kushikata N, Wakamatsu S. Photorejuvenation for Asian by intense pulsed light. Dermatol Surg 2001;27:627-31. [PUBMED]
18. Negishi K, Wakamtsu D, Kushikata N, Tezuka Y, Kotani Y, Shiba K. Full face photorejuvenation of damaged skin by intense pulsed light with integrated contact cooling: Initial experiences in Asian patients. Lasers Surg Med 2002;30:298-305.
19. Negishi K, Kushikata N, Tezuka Y, Takeuchi K, Miyamoto E, Wakamatsu S. Study of the incidence and nature of “very subtle epidermal melasma” in relation to intense pulsed light treatment. Dermatol Surg 2004;30:881-6. [PUBMED]
20. Gentlewave approval FDA Gentlewave FDA approval. 2005. Cosmetic surgery-news. Available from: http://www.cosmeticsurgery-news.com/article2357.html.
21. Weiss RA, Weiss MA, Geronemus RG, McDaniel DH. A novel non-thermal non-ablative full panel led photomodulation device for reversal of photoaging: Digital microscopic and clinical results in various types. J Drugs Dermatol 2004;03:605-10.
22. Weiss RA, McDaniel DH, Geronemus RG, Weiss MA. Clinical trial of a novel non-thermal LED array for reversal of photoaging: Clinical, histologic, and surface profilometric results. Lasers Surg Med 2005;36:85-91. [PUBMED]
23. Hsu TS, Kaminer MS. The use of nonablative radiofrequency technology to tighten the lower face and neck. Semin Cutan Med Surg 2003;22:115-23. [PUBMED]
24. Kushikata N, Negishi K, Tezuka Y, Takeuchi K, Wakamatsu S. Non-ablative skin tightening with radiofrequency in Asian skin. Lasers Surg Med 2005;36:92-7. [PUBMED]
25. Bunin LS, Carniol BJ. Cervical facial skin tightening with an infrared device. Fac Plast Surg Clin North Am 2007;15:179-84.
26. Chua SH, Ang P, Khoo LS, Goh CL. Nonablative infrared skin tightening in Type IV to V Asian skin: A prospective clinical study. Dermatol Surg 2007;33:146-51.
27. Penny K, Sibbons P, Andrews P, Southgate A. A histopathologic assessment of the effects of hydration on the absorption of plasma skin regeneration energy (PSR) in an animal model. Lasers Surg Med 2005;36:23.
28. Bogle MA, Plasma skin regeneration technology. Skin Ther Lett 2006;11:7-9.
29. Tremblay JF, Moy R. Treatment of post-auricular skin using a novel plasma resurfacing system: An in vivo clinical and histologic study. Lasers Surg Med 2004;34:25.
30. Kilmer S, Fitzpatrick R, Bernstein E, Brown D. Long term follow-up on the use of plasma skin regeneration (PSR) in full facial rejuvenation procedures. Lasers Surg Med 2005;36:22.
31. Potter M, Harrison R, Ramsden A, Andrews P, Gault D. Facial acne and fine lines: Transforming patient outcomes with plasma skin resurfacing. Lasers Surg Med 2005;36:23.
32. Bernstein EF. Very low energy plasma skin resurfacing treatments improve photodamage. Lasers Surg Med 2007;39:17.
33. Bogle MA, Arndt KA, Dover JS. Evaluation of plasma skin resurfacing technology in low fluence full-facial rejuvenation. Arch Dermatol 2007;143:168-74.

Goel A. Clinical applications of Q-switched NdYAG laser. Indian J Dermatol Venereol Leprol [serial online] 2008 [cited 2009 Feb 17];74:682-6. Available from: http://www.ijdvl.com/text.asp?2008/74/6/682/45135

Skin hyperpigmentation is usually caused by excess production and/or clumping of the skin pigment ‘melanin’ with the appearance of darker brown or even black spots on skin. Pigmented lesions can be classified either based on location of pigment as epidermal and dermal, or based on causation as nevoid, hereditary, or acquired – drug induced, postinflammatory, hormonal, etc. – and the treatment depends on the underlying cause. Various topical applications, chemical peels, microdermabrasion, etc. have been used with variable benefits. However, lesions like nevus, tattoos, freckles, etc. are not amenable to the above line of treatment.

This resulted in a search for an ideal laser/light system to effectively target the skin melanin without damaging the surrounding skin. Twenty years of improvements in laser dermatology has resulted in current technology which allows selective targeting of melanin, variable spot sizes, different wavelengths, and a variety of effective cooling devices. These developments have made the treatment of cutaneous pigmented lesions safe and efficacious by targeting selected chromophores while minimizing damage to the surrounding tissue. The absorption spectrum of melanin is extremely broad – a property that allows pigmented lesions to be treated with a wide variety of lasers.

If we closely observe the absorption curve of melanin [Figure 1 above] (which is the target chromophore in all pigmented lesions), the graph clearly shows that any laser right from 400-1100 nm plus can hit the melanin. We are also aware that many laser systems function in this visible and the infrared range of the electromagnetic spectrum. Though all these lasers would have some effect on melanin, three wavelength bands are most useful for treating pigmented lesions – green, red, and infrared. It’s not only about the wavelength, it is more about the right pulse duration and at sufficient fluence. Since green and blue light lasers are long pulsed continuous waves, they cause a lot of damage to surrounding skin. However, in the last decade, the Q-switching technique has given birth to Q-switched ruby, Q-switched alexandrite, and in the infrared category, Q-switched Nd:YAG laser.

Clinical Applications

Most pigmentary skin lesions, whether epidermal or dermal, acquired or congenital, can be treated with Q-switched lasers of blue, green, and infrared light. Though the clinical indications of a Q-switched NdYAG laser are numerous, a few are listed below:

Pigmented lesions

While the epidermal lesions respond best to 532 nm (frequency doubled NdYAG) the dermal lesions are better treated with 1064 nm. Q-switched lasers are the gold standard for treatment of tattoos.

Lentigines: usually 1-2 sessions are enough to clear lentigines at 532 nm. However there is a risk of hypo/hyperpigmentation, so avoidance of sun exposure for 4-6 weeks post laser is very important.
Cafe-au lait macules: these again can be treated effectively in 1-2 sessions, but recurrence is common which requires multiple treatments.
Freckles: Response is same as for lentigines. Although very effective, risk of dyspigmentation exists.
Dermal pigmented lesions: Nevus of Ota, Nevus of Ito, mongolian spots, Hori’s nevus, ABNOMs (acquired bilateral nevus of Ota like macules), and other flat pigmented birthmarks respond well at 1064 nm. Multiple sessions are usually required with near-total clearing of the lesion in most cases.

Medium depth nonablative skin resurfacing

Frequency doubled 532 nm Q switched is a well-established technology for treating photoaging. When used at lower fluences with a larger spot size, it is a medium depth laser peel, with less downtime and high patient satisfaction. However, due to the risk of postinflammatory pigmentary changes in Indian skins, it should be used only after a test patch and adequate sun protection advised to the patient.

Melasma

High-energy pigmented selective laser, for example, 694 nm, Q-switched ruby laser, 755 nm Q-switched alexandrite laser, 532 nm frequency doubled Q-switched NdYAG laser, and 1064 nm Q-switched NdYAG laser had been studied for treatment of melasma with poor results. Normal skin color was rarely achieved. Epidermal melasma responds better and faster than dermal/mixed melasma. Complete clearing of lesions may be expected in more than 50% of cases of epidermal melasma. Complete clearing of dermal/mixed melasma may be seen in about 30-50% cases, while the remaining cases will show moderate improvement. Postinflammatory hyperpigmentation and rebound melasma are dreaded complications that may occur in the individual with sensitive skin. Lower energy and fewer repetitions are adequate to produce marked improvement. Improvement will need to be maintained by repeated treatments. However, recurrence is common in melasma.

Tattoos

Though Q-switched ruby and Q-switched alexandrite lasers have been earliest lasers for tattoos, Q-switched NdYAG 1064 nm, due to its longer wavelength, higher fluence, and shorter pulse, has emerged as a better laser for the black and dark blue/ black tattoo pigment. The textural changes, scarring, and hypopigmentation of earlier lasers are remarkably low. However for colored pigments, use of multiple wavelengths is mandatory. Response to Q-switched 1064 nm depends on the type of tattoo:

Professional tattoos: Most of such tattoos have even distribution of ink, mainly in subcutaneous tissue. Ink quality is good; hence, 4-6 treatments are usually required.
Amateur tattoos: Usually these are easy to remove, but in some cases, if the ink is at deeper level, a few extra sessions could be required.
Cosmetic tattoos: Cosmetic tattoos like eyebrows, and eye and lip line are mostly made of iron-based inks. This can sometimes oxidize and turn black, so a test patch must be given.

Nonablative skin resurfacing for wrinkles and acne scars

Q-switched NdYAG laser 1064 nm offers a new technology that helps treat scars and wrinkles at their root, deep in the skin. Using laser energy that penetrates deeply without injuring the top layer of skin, the deep dermis is stimulated to produce natural collagen and other vital proteins that make up healthy, youthful skin. Painlessly done in less than 20 minutes, you’ll leave the office with only mild redness that will fade within a few hours. After 3-6 treatments, done at monthly intervals, wrinkles soften and skin gets toned. Hence it is also referred to as laser skin toning. This is a good option for improving acne scars, wrinkles, and stretch marks without complicated procedures and long recovery times.

Laser-assisted hair reduction

Though the long-pulsed lasers are gold standards for the removal of terminal hair, Q-switched laser has been tried with and without topical carbon suspension. Q-switched pulses produce a photomechanical impact on the tissue and also on hair shaft and hair follicle, causing reduction as well as delay in hair growth cycle. Since it is not color dependent, it can be suited for all skin types, even on tanned skins without fear of pigmentary changes.

Vascular lesions

Nd:YAGs have been shown to be effective in treating vascular lesions like telangiectasia, cherry angiomas, and small spider nevi. More than one treatment could be required. However, it can cause purpura which could take up to a week to clear.

Dark lips

Dark lips are a common cosmetic concern in India. Two to four sessions of Q-switched 532 nm is an effective treatment for lip lightening.

The search for an ideal laser for pigmented lesions has been long and continuing. We started with the ruby and carbon dioxide in continuous mode with heavy and bulky lasers systems which were not practical to use. Moreover, the complications/side effects far outweighed the benefits. Today, we stand tall with new Q-switched technology which delivers a flat top beam to utmost perfection and at the same time sparing the surrounding skin. But does that end our quest for ideal laser for pigmented lesions? We still can’t treat melasma effectively. We still have problems like scarring, ghost shadows, etc. with tattoos. We are still apprehensive of using frequency doubled Q-switched laser 532 nm in Indian skins due to fear of hyperpigmentation. Hence, there is definitely still a long learning curve ahead of us to overcome these lacunae in the application of the existing technology to common skin problems. However, in Q-switched technology we certainly have found answers to some of the previously untreatable conditions. Nevertheless, newer future developments overcoming the shortcomings of the existing ones would certainly be welcome.