Laser update: Fractionated devices, wavelength combinations drive surgery segment

Washington - Over the next five years, fractionated lasers and combined-wavelength treatments will continue to lead growth in the dermatologic laser surgery segment, according to a leading dermatologic laser surgeon.

"Today, we treat a variety of dermatologic conditions, ranging from vascular and pigmented lesions to unwanted tattoos, hair, scars and wrinkles," says Tina S. Alster, M.D., director, Washington Institute of Dermatologic Laser Surgery.

History

Dermatologic laser treatments have come a long way from their origins, she says. "Before the advent of lasers built on the theory of selective photothermolysis, we applied a variety of continuous wave (not pulsed) systems, such as the argon (488, 514 nm), the CO2 (10,600 nm) and the Nd:YAG (1,064 nm) lasers to destroy lesions in the skin, which often led to scarring due to excessive heating of the tissue."

Conversely, she says the pulsed-dye laser (PDL; 585 nm to 600 nm) - the first laser designed using the principles of selective photothermolysis - allowed physicians to treat vascular lesions safely and effectively.

The PDL system typically emits pulse durations shorter than 1.5 milliseconds, along with dynamic cooling to protect the epidermis, while laser energy is concomitantly delivered to the dermal microvessels.

Benefits of PDLs

With PDLs, "We can treat port-wine stains, perinasal telangiectasias, hemangiomas and poikiloderma," Dr. Alster says.

"More recent PDL systems have even longer pulse durations, so that larger telangiectasias, such as those seen in the perinasal area and lower extremities, can be adequately treated.

"Companies also are designing PDL systems that concomitantly deliver longer wavelengths (1,064 nm Nd:YAG) for improved treatment of deeper vessels (Cynosure, Cynergy)," Dr. Alster says.

These advances improve dermatologists' ability to treat leg veins and recalcitrant port-wine stains, she says.

Pigmented lesions

For pigmented lesions and tattoos, "We've been using Q-switched (nanosecond pulsed) pigment-specific lasers such as the ruby (694 nm), alexandrite (755 nm) and Nd:YAG (532 nm/1,064 nm)," Dr. Alster says.

Applications for these lasers include treatment of nevi of Ota, café-au-lait spots and melanocytic nevi, as well as minocycline-induced pigmentation (Alster TS, Gupta SN. Dermatol Surg. 2004;30:1201-1204) and exogenous ochronosis (Bellew SG, Alster TS. Dermatol Surg. 2004;30:555-558).

Tattoos

A variety of tattoos - from professional to amateur to cosmetic to medicinal - can be eradicated with these laser systems, Dr. Alster says.

However, "A significant problem with laser treatment of cosmetic (e.g., eyeliner, lip liner) tattoos is the risk of tattoo ink darkening due to the chemical reduction of iron or titanium oxide pigments.

"Should this unfortunate event occur, it is best managed by CO2 laser vaporization," she says.

Cafe-au-lait macules

Cafe-au-lait macules also are very difficult to remove, because they contain giant melanosomes, which are programmed to produce pigment.

"Often a satisfactory clinical response is obtained after laser treatment," Dr. Alster says, "but after subsequent exposure to sunlight, these lesions recur fairly regularly."

Improving performance

To improve lasers' performance for pigmented lesions and tattoos, dermatologists have begun adding pre-treatment photosensitizers (for pigmented lesions), while a newer form of tattoo ink (made by Freedom-2) contains biodegradable dye encapsulated in biocompatible polymer beads that rupture when exposed to laser radiation.

"So, instead of requiring multiple (often 10 or more) laser treatments in order to significantly fade or eliminate a tattoo," Dr. Alster says, "you might only need one or two treatments. It would be nice to see this ink in mandatory use in tattoo parlors in the future."

Hair removal

Pigment-specific lasers also work for hair removal, which Dr. Alster says requires pulse durations in the millisecond range (versus the nanosecond range used with pigmented lesions).

For patients with unwanted dark hair, she says a series of three monthly treatments typically provides a 50 percent to 80 percent permanent reduction.

But for light/vellus hair, she says, "Lasers have not been that successful. Perhaps it’s because we shouldn't be using lasers at all, but, instead, radiofrequency or some other heating device, or we should use lasers in combination with other products that enhance the visibility of the hair (e.g., Meladine, Creative Technologies)," Dr. Alster says.

Scar revision

Regarding scar revision, Dr. Alster says, "I like the 585 nm PDL for hypertrophic scars."

Not surprisingly, she says, the PDL, which is vascular-specific, would be expected to remove the erythema in these scars.

"But what's unexpected - and is seen routinely - is a reduction in scar bulk (flattening), improvement of skin texture and alleviation of symptoms (pruritis, dysesthesia) after a couple of treatments delivered at six- to eight-week intervals (Alster TS, Zaulyanov L. Dermatol Surg. 2007;33:131-140)," Dr. Alster says.

Laser skin resurfacing

Laser skin resurfacing using ablative CO2 or erbium:YAG systems, on the other hand, is best used for improvement of atrophic scars and photodamaged skin, Dr. Alster says.

These systems vaporize the epidermis and upper dermis, causing controlled dermal necrosis. But because of the relative lack of pilosebaceous units in non-facial areas (such as the neck, chest or dorsal hands), which are crucial for expedient re-epithelialization, Dr. Alster says these lasers' utility off the face was limited.

Another drawback was that, although ablative resurfacing achieved impressive results with a single treatment, "It took several months to resolve all the postoperative erythema and dyspigmentation," she says.

Nonablative technology

Because of such side effects, Dr. Alster says, "Laser skin resurfacing treatments trended to nonablative technology."

The nonablative lasers create no external wounding, but rather controlled heating of dermal elements such that after three to five successive monthly treatments, "Patients would exhibit significant tightening and collagen remodeling within the treatment areas. In such a way, it was possible to safely treat in non-facial areas as well,"Dr. Alster says.

However, Dr. Alster says these lasers' results developed too slowly.

"It was like watching your hair grow,"she says.

Overcoming drawbacks

To overcome these drawbacks, manufacturers began introducing fractionated lasers and other devices that seek to combine the best of ablative and nonablative technologies.

Among nonablative resurfacing technologies, Dr. Alster says fractional resurfacing (Fraxel, Solta Medical) and plasma skin regeneration provide excellent efficacy on facial and non-facial areas.

Non-facial areas in which plasma skin resurfacing has shown efficacy include the neck, chest and hands (Alster TS, Konda S. Dermatol Surg. 2007;33:1315-1321), Dr. Alster says.

"Strictly speaking, fractional and plasma resurfacing technologies don't vaporize tissue, but they do achieve desquamation," she says. "They also provide superficial and deep dermal coagulation and collagen contraction."

Along with photodamage, Dr. Alster says fractional resurfacing can effectively address striae and atrophic scarring. However, a typical Fraxel series requires at least three treatments, she says.

Taking it ’up a notch’

To give patients faster results, Dr. Alster says, "Laser manufacturers have taken it up a notch and are fractionating their CO2 and erbium systems."

Such lasers require only a single treatment session, she says.

"There is some postoperative recovery, but not as much as with the ’old-fashioned- CO2 or erbium lasers.

"What's nice is that because these lasers are fractionated, we can use them safely on non-facial areas (Alexiades MR, Dover JS, Arndt KA. J Am Acad Dermatol. 2008;58:719-737)," Dr. Alster says.

ractionated CO2 lasers include the Active FX (Lumenis) and the re:pair (Reliant). The ProFractional (Sciton) operates at 2,940 nm (Er:YAG).

Combining treatments

"The least effective skin resurfacing lasers - the nonablative systems - have the fewest side effects. Ablative lasers may be the most clinically effective, but they carry the highest risks," Dr. Alster says.

"The latest trend is to deliver treatment between those two extremes - typically with plasma technology, fractionated CO2 or erbium systems, or the Fraxel laser," she says. DT

Disclosures: Dr. Alster reports no relevant financial interests.