Assessing hyaluronic acid fillers

More than eight years after Restylane was introduced in Europe, a bi-continental research team of British and American dermatologists examined the safety, duration and most common sites of injection of four hyaluronic acid fillers: Restylane Fine Lines, Restylane, Perlane and SubQ. In the United States, Restylane is the only agent of the four approved by the U.S. Food and Drug Administration.

When evaluating the longevity of the agents, the investigators based their results on a smaller group of patients - 139 treatments with either Restylane (41 treatments) or Perlane (98 treatments).

The researchers found that patients returned within about four months for a follow-up treatment with Restylane for the lips, and about 6½ months when Perlane was injected to that area. For the nasolabial folds, the duration for Restylane from the first treatment was about 13 months, and for Perlane, about 15.8 months.

"Because it was a smaller sample size, the duration of Restylane on the nasolabial area should be further examined," Dr. Lowe says. "Generally, our findings are similar to other studies that show Restylane lasts at least eight months, and the duration of Perlane ranges from 12 to 18 months."

Dr. Lowe, who has been studying hyaluronic acid fillers for nearly a decade, adds that, "we suspect that SubQ lasts significantly longer, possibly several years, but we don't know yet until we have more experience with the agent and more studies are conducted."

Side effects evaluated All dermal fillers, even the newer hyaluronic acid agents, are associated with some adverse events. Adverse events associated with dermal fillers may include inflammatory responses, hypersensitivity reactions, nodule formation, granulomas, discoloration and migration.

"Some fillers can cause extensive complications that require corrective intervention. We wanted to examine the degree of side effects associated with these relatively new fillers," Dr. Lowe explains.

Based on other clinical studies, dermatologists should expect some degree of inflammatory response in the form of swelling and erythema when using hyaluronic acid fillers. In fact, this new research confirms this conclusion. Of 430 treatments examined, 65 percent of patients treated with Restylane experienced transient erythema, and 49 percent had edema. Only five treatments, or 1 percent, experienced transient lumping with Restylane. The side effect profile for Perlane was nearly identical to that of Restylane.

More serious complications were rare with both agents. One case of vascular occlusion was associated with the use of Restylane in the glabellar region. No allergic reactions to Restylane were reported in 430 treatments, and only one in 1,139 treatments with Perlane. Because these agents are non-animal products, hyaluronic acid is believed to pose no risk of disease transmission or allergies and is safe to use without hypersensitivity testing.