Ablative vs Nonablative vs Fractional: Insights From Dr Nazanin Saedi

Nazanin Saedi, MD, a clinical associate professor at Thomas Jefferson University in Philadelphia, PA, discussed how to choose the best laser for resurfacing in a bonus session at the inaugural Dermatology Week 2021.

The standard for early skin rejuvenation approximately thirty years ago was carbon dioxide (CO₂) and erbium-doped yttrium aluminium garnet (Er:YAG) lasers. Both options have impressive results after full epidermal destruction, but the long down time and needed wound care could be a burden. Further, ablative lasers create a noticeable demarcation. Therefore, nonablative methods such as intense pulsed light (IPL) and mid-infrared lasers grew in popularity despite not being nearly as effective.

However, in modern times, fractionated technology is most popular. Fractional photothermolysis (FP) uses higher fluences applied to narrow columns of tissue with untreated areas in between, creating a checkerboard pattern of microscopic wounds. Nonablative FP can be split into two classes: superficial (thulium; 1927nm) vs deep (mid-infrared; 1410nm, 1440nm, 1470nm, 1540nm, 1550nm). Either class can treat many conditions, including textural irregularities, scarring, and melasma.

Dr Saedi stressed that before selecting a laser, dermatologists need to consider a few things. First, the patient should be a good candidate for laser therapy; similarly, a good candidate needs to have realistic outcome expectations. If a patient has herpes simplex virus, Dr Saedi recommended starting an antiviral 1 day prior to and continuing for 7 days following the laser resurfacing appointment. Patients who are on isotretinoin may also undergo laser resurfacing, citing a consensus statement from the American Society for Dermatologic Surgery.

Dr Saedi offered an important pearl: “I like to pretreat with hydroquinone…prior to the treatment in darker skin patients who have a propensity to hyperpigment.”

Parameters to consider before the appointment is the pulse energy and density. Deep processes such as deep rhytids, acne scars, and traumatic scars require higher energy (1470nm, 1540nm, 1550nm). Note, added Dr Saedi, that these deeper conditions can be treated in darker skin types, but the density of the treatment must be decreased to avoid pigmentary issues.

Pigmentary issues, such as dyschromia and melasma, can be treated with more superficial devices. Even actinic keratoses or disseminated superficial actinic porokeratosis may be treated with superficial fractional lasers, though multiple treatments are needed.

Dr Saedi then spoke about fractional CO₂, which when used creates widely spaced zones of thermal coagulation and ablation with sparing of intervening tissue. Fractional CO₂ has an increased safe depth of injury with significant tightening, offering the benefits of ablative with fractional resurfacing. It may also be used for scarring, burns, rhytids, and rhinophyma, but patients should be prepared for the procedure. In addition to starting antibiotics and antivirals the day before the procedure, said Dr Saedi, topical anesthesia (lidocaine 30%) and nerve blocks should be used at the application site and the periphery.

Postinflammatory hyperpigmentation (PIH) can be an adverse effect (AE) following resurfacing procedures. Dr Saedi shared that she pretreats to help prevent PIH by having patients apply Kligman’s formula (hydroquinone 5%, tretinoin 0.1%, and dexamethasone 0.1%) for 1 month prior to nonablative and ablative resurfacing. “Although there is no evidence for it, I do believe it suppresses melanin production both prior to the procedure and after the procedure,” explained Dr Saedi. Patients should also follow strict sun protection.

Another AE can be tattooing after ablative fractional resurfacing. Patients should be informed to come to their procedure with a clean face that is free of makeup. Further, to minimize scarring, dermatologists should avoid bulk heating and lower settings in underprivileged skin (eg, neck, eyelids).

Reference
Saedi N. Laser skin resurfacing. Presented at: Dermatology Week 2021; September 16-19, 2021; virtual.