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September 26, 2011 (Denver, Colorado) — The developer of an investigational thread-like solidified hyaluronic acid (HA) product that can be slipped under narrow facial wrinkles claims that it might one day simplify procedures for cosmetic surgeons who struggle to keep gel-based fillers within their intended boundaries.
Research presented here at Plastic Surgery 2011: American Society of Plastic Surgeons (ASPS) Annual Meeting demonstrates that solid-state HA is effective for treating crow's feet, transverse forehead wrinkles, and other facial wrinkles.
Lead investigator Geoffrey Gurtner, MD, professor of surgery at Stanford University School of Medicine in Palo Alto, California, told meeting attendees that it allows for instant procedural reversibility — an advantage not possible with injectables.
"Gel fillers usually follow the path of least resistance," Dr. Gurtner said. "Since wrinkles and folds are lines, it would be nice if we could put a cylinder underneath them to essentially buttress them. We think the solid-state HA is a new class of products that can improve predictability and precision in filling techniques."
Dr. Gurtner is founder of the TauTona Group, the California company that is developing the product. He and Stanford surgeon Mike Longaker, MD, recently collaborated on a single-center prospective 31-patient study of solid-state HA. Participating physicians reported that the HA strings resulted in greater predictability, greater ease of use, and quicker application than traditional fillers.
Solid HA threads were able to hydrate back to a gel state within a few hours, facilitating the effective treatment of tear troughs, nasolabial folds, and glabellar creases. The product was also effective in the contouring and volumizing of lips.
"We feel it is best suited for some specific areas, but clinical trials are necessary to statistically demonstrate where it is most effective," Dr. Gurtner told Medscape Medical News.
In preclinical studies, the researchers found that existing filler products, such as Juvéderm and Restalyne, can migrate up to 2 cm from the injection site. Solid-state HA does not spread and, if necessary, can be quickly extracted.
"This is a fundamental difference between the thread and the injectables," said Dr. Longaker. "Injectable fillers cannot be controlled in terms of where they go once injected into the body. The HA thread can be placed precisely where the physician desires and it does not appear to migrate. In addition to enhanced precision during placement, the thread avoids potential complications, such as injection into a blood vessel, causing an embolus. This is a concern when placing injectables around the eye."
According to Dr. Gurtner, the worst-case scenario occurs when a gel is mistakenly injected into a vessel and forced upstream, resulting in occlusion and tissue necrosis.
"There are even a few extremely unfortunate documented cases of blindness or a stroke, although the published incidence of such serious complications is less than 1 in 1000," he said. "Solid-state HA should reduce the occurrence of serious complications because it is not injected under pressure; it is threaded in a hair-like suture."
The study revealed that solid HA results in less pain than traditional dermal fillers. This benefit was demonstrated even though HA strands are pulled into place using a straight (Keith) needle as a guide.
Drs. Gurtner and Longaker said the mediation of pain with solid HA is largely attributable to the fact that injected fillers promote an uncomfortable hydrostatic dissection of tissue, whereas the HA thread does not.
Moreover, when correcting nasolabial folds, it is common for physicians to inject a gel numerous times — a "string of pearls" technique — whereas the use of HA allows for fewer needle sticks, Dr. Gurtner said.
Several iterations were necessary to perfect a processing method by which HA could be transformed into a value-added investigational product by means of a very slow extrusion process.
According to Dr. Gurtner, manufacturing costs will allow solid HA to be priced similarly to existing products. However, some physicians might choose to charge premiums if they use it for sophisticated treatment methods that others cannot perform, he noted. For now, plans call for further studies with longer follow-up periods to test for product durability.
According to the ASPS, HA-based products are the most popular fillers used for soft-tissue defects, with more than 1.2 million procedures completed in 2010.
By: Rod Franklin
