60 Years and Counting: A Celebration of Dermatologic Surgery

Fractionation

The development of fractional photothermolysis was "a milestone in the history of laser technology and cutaneous resurfacing," according to Dr. Nazanin Saedi, a dermatologist in private practice in Chestnut Hill, Mass., and her colleagues.

The technology, noted the study authors, builds on the knowledge gained from early CO₂ and Er:YAG laser treatment experiences, achieving greater optimization of parameters to induce the types of benefits seen with CO₂ resurfacing, but without the significant postoperative morbidity, complications, and discomfort associated with the earlier technologies.

Furthermore, the older therapies destroyed the barrier protection, which "significantly increased the risk of infection throughout the recovery period and required extensive home care. The risk of scarring, delayed-onset permanent hypopigmentation, and demarcation lines was significant even in the hands of an experienced operator," they wrote (Sem. Cut. Med. Surg. 2012;31:105-9).

In an en effort to overcome these problems, what followed was nonablative dermal remodeling (with less than impressive results), and ultimately, the "idea of fractionated laser technology," they continued.

First used in hair transplant surgery, the technology led to development of the 1,550-nm nonablative "Fraxel" laser (now called the Fraxel Re:Store by Solta Medical), which debuted in the literature in 2004. This and other fractional laser technologies are now used to treat photoaging, superficial and deep rhytids, scars (including in patients with darker skin types), and pigmentation.

Both nonablative and ablative fractional resurfacing have proved to be safer than have traditional ablative lasers, Dr. Saedi and her colleagues noted. However, complications can still occur, such as infections (with herpes simplex virus being the most common), acneiform eruptions, prolonged erythema, pigmentary alteration, and scarring (rare, but can also result from infection associated with treatment).

"Counterintuitively, nonablative or ablative fractionated devices at low energies and densities can be useful in the treatment of scarring, including hypertrophic scars" as previously mentioned, they noted.

"While [fractional lasers are] inherently safer due to the pixelated manner of the treatment, complications can be further prevented with attentive surgical technique and judicious use of prophylaxis," they wrote.

The future of fractional laser technology promises to hold exciting developments. For example, since ablative fractional resurfacing creates microscopic vertical holes in tissue, the delivery of topical drugs through these holes is possible. In animal models, the photosensitizer methylaminolevulinic acid has been delivered using this approach, and tests suggest that low density treatment would be sufficient for deep dermal drug delivery.

"Treatment of skin in a porcine model showed enhanced depth of photodynamic therapy following porphyrin application after pretreatment with fractional resurfacing. An in vitro study utilizing low fluence fractionated Erbium:YAG demonstrated upwards of a 125-fold increase in imiquimod delivery," they noted.

Trials in humans are underway to assess the feasibility and safety of enhanced drug delivery using this approach, and there is speculation that ultimately, it could be used for delivery of biologic peptides and vaccines.

Tattoo removal is another promising use for fractional lasers, with early studies demonstrating good results, noted Dr. Saedi and her colleagues, explaining that ablative fractional lasers, when used in conjunction with a Q-switched laser, appear to provide enhanced tattoo removal capabilities.

"With new devices and wavelengths, the applications of this technology continue to grow," they wrote, concluding that "the future remains bright for fractionated laser devices."

Likewise, the future of dermatologic surgery in general remains promising, Dr. Hanke said. "Many new procedures and advances lie ahead."

Neither Dr. Hanke nor Dr. Saedi had disclosures to report. Another author on the article by Dr. Saedi (Dr. Christopher Zachary) reported receiving an honorarium from Solta Medical.