Selective Ablation

Achieving optimal outcomes with fractional ablative lasers.

Selective Ablation

Fractional laser delivery has expanded the option of ablative laser resurfacing to a much broader base of patients. Providers can prescribe treatments based on specific concerns, skin types and even individual downtime requirements. But in order to achieve the safest and most effective treatments, you need to know your individual devices well and keep a close eye on both clinical endpoints and patient selection. “Perform a physical exam to make sure the patient is healthy and doesn’t have any conditions that would interfere with the healing process,” says Michael H. Gold, MD, medical director of Gold Skin Care Center in Nashville, Tennessee.

Ideally, candidates for this procedure will have Fitzpatrick skin types I-III. Patients with darker IV and V skin types can be treated, but require less aggressive settings because they are at much higher risk of pigmentary alteration, says Rachel Nazarian, MD, FAAD, of Schweiger Dermatology Group in New York City and assistant clinical professor at Mount Sinai Hospital.

Contraindications

You should not perform fractional ablative laser treatments on patients with a history of keloid formation, facial radiation or infectious conditions, including a con­current presence of molluscum contagiosum, verrucae or herpes labialis. “These patients are contraindicated due to risk of dissemination to treatment sites and wors­ening of their condition, which increases the risk of scarring,” says Dr. Nazarian.

You must also exclude patients with very thin skin and those with underlying medical conditions that impede wound healing, such as connective tissue disorders or diabetes, says Vic Narurkar, MD, FAAD, director and founder of Bay Area Laser Institute in San Francisco.

Isotretinoin (Accutane) therapy, which also impedes wound healing, has been associated with hypertrophic scarring and keloid formation following laser resurfac­ing, says Macrene Alexiades, MD, PhD, FAAD, associate clinical professor at Yale University in New Haven, Connecticut.

Other patients at high risk of adverse events include:

  • Those with prior scars or hypopigmentation, which may become worse with ablative resurfacing;
  • Those who are pregnant or breastfeeding, because post-inflammatory hyperpigmentation (PIH) is common under these circumstances;
  • Those who have had silicone injections, which can cause adverse outcomes following this procedure;
  • Those with active infections, which could worsen following resurfacing;
  • Those with koebnerize (such as psoriasis or vitiligo), as traumatized and injured skin may induce flaring of the disease;
  • Smokers, who have impaired wound healing secondary to decreased oxygen concentration in the skin.

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Pretreatment Considerations

Pre-existing skin conditions, such as active acne, must be controlled prior to beginning treatment, says Dr. Alexiades. If a patient has melasma, which may be exacerbated by laser treatment, she prescribes a bleaching cream such as Tri-Luma (Galderma). She also prescribes antiviral drug famciclovir 250mg twice a day starting the day before treatment and continuing for five days afterward. If a patient has a history of facial staph or strep infections, Dr. Alexiades prescribes oral antibacterial antibiotic dicloxacillin 250mg-500mg four times a day for five days starting one day prior to treatment.

To reduce the risk of PIH in all patients, Girish “Gilly” Munavalli, MD, MHS, FACMS, medical director of Dermatology, Laser & Vein Specialists of the Carolinas in Charlotte, North Carolina, counsels sun avoidance for four to six weeks prior to the procedure. He also recommends a regimen consisting of antibiotics, antivirals and antifungals delivered immediately prior to, during and after the procedure. He typically prescribes Doryx (doxycycline, Mayne Pharma), Sitavig (acyclovir, Cipher) and Diflucan (fluconazole, Pfizer). “Although there is no solid proof of pretreatment with hydroquinone to prevent rebound hyperpigmentation, I oftentimes advise it,” he adds, noting that he typically starts patients on retinoid and growth factor creams two months before a procedure in order to rev up the skin for healing as well.

Dr. Nazarian prescribes prophylactic antibiotics to prevent postoperative impetiginization and bacterial infection of the treated area as follows: Beginning one day before the procedure, she recommends taking either Keflex (cephalexin, Pragma Pharmaceuticals) 500mg or cefdinir 300mg by mouth twice daily for 10 days.

All patients at the Bay Area Laser Institute are pretreated with antiviral prophylaxis to prevent a herpes simplex virus (HSV) flare-up. For patients without a history of HSV, Dr. Narurkar prescribes a prophylactic dose of Valtrex (valacyclovir, GlaxoSmithKline) 2g taken once in the morning and once in the evening the day before laser resurfacing. For patients with a history of recurrent HSV, he also prescribes Valtrex 500mg twice daily for one week after treatment.

Determining Treatment Settings

Fractional laser systems allow you to customize procedures by varying the energy and density settings. While these settings do vary by manufacturer—“Density and energy levels are more device-dependent than anything else,” says Dr. Gold—there are some basic guidelines as well as clinical endpoints that can help you determine the right combination.

Dr. Nazarian uses a 2490nm Er:YAG laser for pa­tients requiring superficial resurfacing and notes that a thermal damage zone of 50µ or more is needed for photocoagulation.
For perioral rhytides, she performs multiple passes at 150µ ablation, followed by one pass at 30µ ablation limited to areas of residual lines until pinpoint bleeding is visualized. For periorbital lines, she has seen improvement with a single treatment of 80µ ablation and 50µ coagulation. Patients with lax lower eyelids, subciliary lower blepharoplasty or sclera are at higher risk for ectropion and should be treated at a lower fluence or density.

Dr. Alexiades determines the energy level and density based on the degree of rhytides and solar damage. For severe cases, she employs the highest fluence and high densities with at least one pass to the most affected areas. If a patient is a slow healer or has sensitive skin, she’ll employ lower fluences and lower densities. She also considers recovery time. “For patients who must return to work or social activities within a certain timeframe, I may use lower settings with the understanding that I’ll repeat the treatment to attain the desired outcome,” she says.

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In the majority of cases, Dr. Alexiades performs only one pass with the fractional CO2 laser. “But if the rhytides are severe, I administer a second pass. I am always on the lookout for any signs of charring, which include yellowish-brown debris,” she says. If she sees such signs, she re­­frains from further passes or decreases the settings—in particular the dwell time that correlates with thermal injury. She notes that if the microzones of ablation are too superficial, the white color will not be opaque; this indicates that you need to use a higher fluence. In addition, she looks for immediate contraction—a sign that the proper power is employed—and titrates accordingly.

For Dr. Nazarian, clinical endpoints include pinpoint bleeding or coagulation, depending on the settings and laser used. Because CO2 lasers cause more significant coagulation, these procedures result in a relatively bloodless field, while Er:YAG is a more bloody procedure.

In order to maximize collagen stimulation, Dr. Munavalli uses both Er:YAG and CO2 lasers, shifting between fully confluent and fractional, and deep and superficial depending on the targets (e.g., marked elastosis, etched-in lines and wrinkles, and epidermal lesions such as macular seborrheic keratosis and scars). “In general, I like to perform erbium in multiple passes to achieve the precise depth of ablation with a low number of CO2 passes to achieve ablation plus coagulation,” he says.

Dr. Narurkar varies his settings based on the severity of photodamage and the areas of the face being treated. “I use the most aggressive settings around the perioral area and for thick hypertrophic scars,” he says. “I generally avoid treating non-facial skin, such as the neck and chest, due to the higher risk of scarring.”

Areas of Concern

Some areas of the face and body carry a higher risk of scarring and adverse events than others and should be treated more cautiously, both with decreased energy settings and limitations on the number of passes. “The vermilion border and periorbital area may be restricted to one pass due to their delicate nature,” says Dr. Nazarian. “Non-facial rhytides, including those on the neck and chest, should be treated with great care or avoided completely as decreased adnexal structures and vascularity increase the risk for scarring and pigmentary alteration as compared to facial skin.”

The neck and chest are hot spots for adverse events, such as hypertrophic scarring. “If this occurs, fluences that were too high and too many passes were employed,” says Dr. Alexiades, adding that she has safely and effectively treated these areas by adjusting the density so that the collateral columns of thermal injury do not overlap between microthermal columns. She also employs conservative fluences when working off the face.

For Dr. Munavalli, being careful around the eyes, most notably the upper and lower eyelids, is critical. “I prefer lower densities and lower energies in these areas; I approach the endpoint slowly and deliberately,” he says. “The nose tends to be more forgiving.” Furthermore, don’t forget to treat the ears, he says, as they also get sun damaged, and feather the ablation into the hairline and jawline to give a blended, professional look.

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Pain Control

Due to the ablative nature of these procedures, all patients will require some form of pain management during treatment. Dr. Nazarian recommends a Zimmer chiller to keep the skin cool during treatment. For multi-pass CO2 treatments, she may employ a nerve block using 1% lidocaine with 1:100,000 epinephrine, administered for supraorbital, supratrochlear, infraorbital or mental blocks. “Radially spacing subcutaneous injections of lidocaine from a single entry site, called ‘fanning,’ helps to deliver greater anesthesia to areas not sufficiently covered by nerve blocks, including the lateral cheeks and lateral forehead,” she says.

For less aggressive treatments, topical anesthetic may be adequate. Dr. Alexiades’ typical protocol is one hour of topical anesthetic, such as EMLA (lidocaine/prilocaine), prior to treatment. “Once I treat each quadrant of the face, I apply cool compresses consisting of ice-water-soaked gauze immediately after each pass,” she says. Following treatment, patients cool with the Zimmer chiller for 15 to 20 minutes.

For Dr. Munavalli, oral anxiolytics and analgesics combined with topical anesthetics are the mainstay for nonablative resurfacing. “These may work for low energy/low density fractional ablative treatments, but they aren’t sufficient for fully ablative resurfacing,” he says, adding that he has used everything from IV conscious sedation to intramuscular (IM) Toradol (ketorolac) and Demerol (meperidine), as well as other IM anxiolytics and IM antihistamines. “Multiple options are helpful since patients’ pain thresholds vary,” he says.

Post-Care Instructions

Following treatment, Dr. Nazarian asks patients to use cold compresses or ice packs to minimize discomfort, erythema and edema. She treats occasional cases of excessive edema with oral steroids. Because of the increased risk of contact dermatitis, she avoids both Aquaphor ointment and topical antibiotics in the postoperative period, and instead prescribes oral antibiotics and antifungals for up to two weeks following treatment.

Dr. Munavalli, however, is a proponent of using bland, inert ointments such as Aquaphor and Vaniply. He recommends them along with a mild cleanser to minimize crusting. They also help form a barrier to environmental elements and promote a hydrated, supple healing environment.

Dr. Narurkar’s patients are counseled to perform dilute vinegar water soaks two to three times a day followed by aggressive emollition with Aquaphor until re-epithelialization of the skin is complete. Afterward, he recommends topicals such as Biafine or ceramide cream until post-laser erythema is resolved. Patients can also use topical antioxidants to promote proper healing.

“Strict sun avoidance is necessary for a full year following treatment for optimal recovery and to reduce the chance of pigmentary alteration,” says Dr. Nazarian. “Instruct patients at length as to their substantial and pivotal part in postoperative care. Treat cases of persistent erythema with serial intense pulsed light (IPL) treatments at two-week intervals until resolution. Acne and milia are minor side effects seen two to three days post-op and can be gently extracted during follow-up.”

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A localized area of non-healing skin several days post-op may signify an infection and must be closely monitored. If infection is suspected, Dr. Nazarian performs a microbiologic culture test to identify the organism and its sensitivity. Edema following treatment is a common complaint; it typically peaks at days two and three. An oral course of prednisone post-resurfacing for five days can help decrease the swelling, which lasts about one week.

“Ablative laser resurfacing is not a cookbook, cookie-cutter procedure,” says Dr. Munavalli. “It requires a fellowship, or extended observational and hands-on training before performing it. Matching patient expectations with realistic results is critical. I tell my most severely photoaged patients, who are good candidates, that I can take 5 to 10 years off of their appearance if they are willing to accept the additional cost, downtime and risk.”

Due to the pain, swelling, crusting and risk of infection, “these patients must be kept close, seen frequently, and reassured constantly that they are on the right track and that the long-term results will be worth the short-term inconvenience,” says Dr. Munavalli.

Karen Appold is a freelance writer based in Pennsylvania.

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