Dermal sculpting, using a solid-state, pulsed neodymium:YAG laser with a fluence of 1.32 micrometers, can improve mild to moderate facial rhytids without epidermal ablation, Tina Alster, M.D., said.

Because the epidermis is left intact, the week-long re-epithelialization period is avoided and patients experience no down time, Dr. Alster said at the annual meeting of the American Society for Laser Medicine and Surgery.

Cryogen cooling of the cutaneous surface and the laser's ability to selectively target subepidermal tissue combine to protect the epidermis, she said. The laser energy is thus directed to deeper tissue, where it produces thermal damage that stimulates gradual formation of new collagen.

"What's nice about this is that people can literally go straight back to work or their regular activities with no side effects," said Dr. Alster, director, Washington Institute of Dermatologic Laser Surgery, clinical assistant professor of dermatology, Georgetown University Medical Center.

She treated periorbital and/or perioral wrinkles in 10 women and two men using the Nd:YAG laser (Laser Aesthetics, Auburn, Calif.). Topical anesthesia (Elamax), applied 15 to 20 minutes before the procedure, was more than adequate, she said.

The treatment consisted of two consecutive passes over the target area, with the laser set at 33 to 35J/cm2 and a 200ms pulse duration. Each pulse was preceded by a 20 to 30ms burst of cryogen spray with a 30 to 40ms delay before the later pulse. A built-in temperature probe gave instant readings that allowed the surgeon to heat the cutaneous surface to between 44 and 48 degrees Celsius. "This is what we wanted," Dr. Alster said, "because we knew that the dermis would be about 20 degrees warmer. So we had enough heat to induce collagen tightening, but no so much that we would burn the tissue nonselectively."

Three such treatments were applied two weeks apart over a six-week period. Patients were examined for clinical efficacy and side effects at half a week and one, two, four, 12 and 26 weeks postoperatively, she said.

Gradual Improvement Noted

"What we found was that there was a minimal clinical improvement seen immediately after the treatment, but there was also a progressive improvement of skin texture and degree of wrinkling throughout the 26-week postoperative period," Dr. Alster said. Side effects were limited to mild, transient erythema in three patients that resolved within hours, she said.

Biopsies were taken from a preauricular test area before and immediately after laser application and again at the end of the six-month follow-up period.

"Histologic changes were slight, but there was a mild increase in the collagen content observed at the end of the study," she said. "So we were able to conclude from this study that the solid-state pulsed Nd:YAG laser, emitting at 1.32 micrometers, provides gradual clinical and histologic improvement of facial rhytids with minimal side effects."

Dr. Alster tells patients not to expect immediate improvement. The suspected mechanism of action - dermal heating induces fibroblasts to begin producing new collagen - takes several months to fully take effect. An initial clinical improvement was generally noted but may have been due at least partially to subclinical edema, she said. "It's typical that after any type of skin injury, there is a minimum of a six-month repair process," she said.

The biggest improvement after the first month was seen between the 12-week and the 26-week follow-up exams, Dr. Alster said, noting that remodeling changes are difficult to quantify after any such procedure.

In each case the patient and two clinicians (one blinded) evaluated rhytid improvement based on the following scale: worsening, no improvement, slight improvement, and marked improvement.

After 26 weeks most patients saw "improvement" and two saw marked improvement. Only one patient thought there was no improvement, and none saw worsening. The investigators' judgements matched those of the patients in general, although they tended to see slightly more improvement. For example, the clinicians saw marked improvement in three patients.

Optimal Regimen Undetermined

Because of the newness of the particular laser modality, some questions remain to be answered by further studies, Dr. Alster said.

"We do not know how many treatments are optimal, or the exact timing between the treatments to optimize the effect. We are making sure that we are delivering safe energies and giving enough time for recovery without overtreating the skin," she said. She noted, however, that she is comfortable with the fluences and the cryogen settings.

Appropriate selection and education of patients is essential, as with any cosmetic procedure, Dr. Alster said.

"If somebody presents with marked facial wrinkling requiring extensive collagen tightening and who in addition may need removal or rejuvenation of the epidermis because of the presence of numerous lentigines, the Nd:YAG treatment is not a good choice unless a chemical peel is also planned," she said.

A chemical peel may be a good complement to treatment with the 1.32 micrometer pulsed Nd:YAG, but she would not recommend they be done together.

"I prefer to do peels first, in order to even out the skin tone as much as possible, and then perform the dermal tightening procedure a minimum of two weeks later," she said. "You also get an idea of how compliant somebody is with a program and how his or her skin responds to a topical regimen."

Maintenance with Nd:YAG

Maintenance therapy may turn out to be an important application of this procedure, Dr. Alster said, especially in patients who have been through a major resurfacing procedure with a carbon dioxide or erbium laser, or those who have undergone a TCA peel.

"There's no down time. We've already rejuvenated the outer layer of their skin, and they already have tightening, so it's a matter of maintaining that and maybe even improving on it," she said.

The problem is that it often can be difficult to convince American patients that this is the best approach, except in certain pockets of the country where people are well-educated about cosmetic procedures and maintenance regimens.

"Many people want everything done at once, and if they've already been through a CO2 laser resurfacing procedure, they're not really going to be keen on doing anything else," she said. "But I think it's kind of silly to think of aesthetic enhancement as a one-shot deal; maintenance is important."

The controlled dermal heating possible with the Nd:YAG laser makes it a candidate for other types of procedures as well, Dr. Alster said. Potential applications might include treatment of atrophic or hypertrophic scars and striae on various parts of the body, especially delicate tissue areas.

Dr. Alster has no financial interest in the Nd:YAG laser or its manufacturer. Laser Aesthetics loaned the equipment used during the course of the study.