Picosecond lasers emerging as a go-to for tattoo removal.
SAN DIEGO -- When counseling patients about laser tattoo removal, resist the temptation to promise clearance in a certain number of treatments.
"You will regret it," Mathew M. Avram, MD, JD, said at the annual Masters of Aesthetics Symposium. "If you say, 'this looks like this is going to take 6-8 treatments, this looks very simple to me,' you'll find that you'll have someone who requires 15-18 treatments. Further, partial clearing may be cosmetically inferior than nontreatment."
Laser tattoo removal can be painful and expensive, but it is still better than all other alternatives, said Dr. Avram, who directs the Massachusetts General Hospital dermatology laser and cosmetic center in Boston. Traditionally, tattoos have been treated with Q-switched nanosecond lasers that were developed at Massachusetts General by R. Rox Anderson, MD.
"These target the microscopic tattoo particles located inside dermal phagocytic cells and scattered extracellularly throughout the dermis," Dr. Avram said. The Q-switched laser heats particles to more than 1,000[degrees]C within nanoseconds, or billionths of a second. "It produces extreme heat, cavitation, and cell rupture," he said. "The clinical endpoint is immediate epidermal whitening of tattooed skin." The process causes transdermal elimination; some of it flows into the lymphatic system, while the rest undergoes rephagocytosis by dermal scavenger cells.
Picosecond lasers are even faster than their Q-switched counterparts, delivering high energies in trillionths of a second. "A picosecond is to a second as 1 second is to 37,000 years," Dr. Avram said. Commercially available picosecond (ps) lasers include devices with wavelengths of 532 nm, 755 nm, and 1,064 nm that deliver energy in a range of 300-750 ps. The Nd:YAG lasers work best for red and black ink, while Alexandrite lasers work best for green and blue ink.
In Dr. Avram's experience, piscosecond lasers are generally more effective for tattoo removal than are nanosecond lasers. "There's some nonselective targeting of other pigments, and they're particularly effective for faded tattoos," he said. "Combining nanosecond and picosecond devices provides enhanced results, but picosecond lasers are more expensive."
The clinical endpoint for picosecond lasers is the same as for nanosecond lasers: epidermal whitening. He said he schedules about 8 weeks between treatments. "If you don't inform patients of the expectations, they're going to be very disappointed with you," Dr. Avram said. "You need to tell them that it's going to take a lot of treatments and that it may not clear completely You may be working with them for a year or 2."
The checklist prior to the first treatment with any laser involves assessing the type of tattoo (amateur or professional), the color of the tattoo, patient skin type, and the duration of the tattoo. "You also want to palpate for an existing scar," he said. 'A lot of times, patients don't recognize they have a scar on the treatment site. You don't want to own a complication that has nothing to do with your treatments. Photographing the scar is also important."
Hyperpigmentation or hypopigmentation is a greater concern in darker skin types or tanned individuals than in fairer-skinned patients. "The 1,064-nm Q-switched Nd:YAG laser is the least likely to affect skin pigment," said Dr. Avram. "It's safest for Fitzpatrick skin types IV-VI but it's not very effective for green, blue, and red tattoo ink colors. Some degree of dyspigmentation occurs in most patients regardless of skin type. Much of this is temporary and improves with time, but it may take months to years."
Professional tattoos are the most difficult to treat because they often feature dense and deeply placed tattoo ink and require 6-20 or more treatments to improve, he said. On the other hand, amateur tattoos, traumatic tattoos, and radiation tattoos improve more rapidly and generally require fewer treatment to yield improvement.
"Color is key," Dr. Avram said. "If you have different colors in one tattoo, it is going to be more difficult to clear." Black and dark-blue tattoos respond best to laser, while light blue and green also respond well. Red responds well, but purple can be challenging. "Yellow and orange do not respond well, but they respond partially," he said.
Researchers who conducted a large cohort trial of variables influencing the outcome of tattoos treated by Q-switched lasers found that 47% of tattoos were cleared after 10 treatment sessions, while 75% were cleared after 15 sessions (Arch Dermatol. 2012;148:1364-9). Predictors of poor response included smoking, the presence of colors other than black and red, tattoo size larger than 30 [cm.sup.2], location on the feet or legs, duration greater than 36 months, high color density, and treatment intervals of 8 weeks or less.
Dr. Avram cautioned against taking a "cookbook approach" to treating tattoos and underscored the importance of decreasing the fluence if tissue "splatter" occurs, as this may produce scarring. "The treating clinician should follow the treatment endpoint, not the laser fluences," he said. "Do not use IPL [intense pulsed light therapy] for tattoos; that's inappropriate and you may end up scarring your patient."
Common adverse effects include erythema, blistering, hyper- and hypopigmentation, and scarring. Less common adverse effects include an allergic reaction, darkening of the cosmetic tattoo, an immune reaction, and chrysiasis, a dark-blue pigmentation caused by Q-switched laser treatment in patients with a history of gold-salt ingestion. "Any history of gold ingestion will produce this finding, even if they ingested 40 years ago," he said. "This is very difficult to correct."
The optimal interval between treatments continues to be explored. For example, the R20 method consists of four treatments separated by 20 minutes. The initial study found that this approach led to better outcomes, compared with conventional, single-pass laser treatment (J Am Acad Dermatol. 2012;66:271-7). A companion technology that is playing a role in such repeat treatments is a Food and Drug Administration-approved transparent silicone patch infused with perfluorodecalin that helps reduce scattering and improves efficacy
"It also allows for performing consecutive repeat laser treatments at the same visit," Dr. Avram said. In one study, 11 of 17 patients had more rapid clearance on the side treated with the perfluorodecalin patch, compared with the side that was treated without the patch (Laser Surg Med. 2015;47:613-8).
Dr. Avram disclosed that he has received consulting fees from Allergan, Merz, Sciton, Soliton, and Zalea. He also reported having ownership and/or shareholder interest in Cytrellis, Invasix, and Zalea.
Please Note: Illustration(s) are not available due to copyright restrictions.
Caption: DR. AVRAM