The Gavard-Sundaram cohesivity scale, a new visual scale illustrating five principal patterns of Hyaluronic acid filler gel behavior—from fully dispersed to fully cohesive—may help plastic surgeons make better dermal filler choices for their patients.
Juvéderm Voluma or Belotero?
Restylane or Perlane?
With so many Hyaluronic acid (HA)-based fillers to choose from, how can you make the best decision on which to use? A new, validated method for providing standard ratings of cohesivity for currently available HA gel fillers may help guide the decision-making process.
Up until now, plastic surgeons have tried to match their individual properties to the purposes for which they will be used, but there’s a lack of scientific data to support this matching process, including the rheologic properties of the various available products. One key property is cohesivity, defined as the capacity of a material not to dissociate.
Researchers led by Hema Sundaram, MD, a dermatologist in Rockville, Md, and Samuel Gavard Molliard, a scientist in Geneva, Switzerland, developed a standard test for comparing the cohesivity of HA dermal fillers. In the pilot study, samples of each filler gel were dyed, then squeezed into water and stirred using automated technology. A panel of plastic surgeons and dermatologists experienced in using HA fillers then rated each sample’s cohesivity on an original five-point scale, known as the Gavard-Sundaram scale.
On testing of six US Food and Drug Administration (FDA)-approved fillers, cohesivity scores varied across the full range of the scale: from “fully dispersed” to “fully cohesive.” Specifically, cohesivity was rated high for one product, medium to high for three, low to medium for one, and low for one.
The new findings appear in the October issue of Plastic and Reconstructive Surgery®.
This doesn’t mean that products with higher cohesivity scores are always the best. Rather, the goal of the ranking system is to “provide a scientific rationale for the intuitive selection of different products for specific clinical objectives,” the study authors write. For example, fillers with higher cohesivity may be a better choice for more superficial placement, or placement in mobile areas such as around the mouth or eyes. Products with lower cohesivity may be effective for use as “deep volumizers.”
“This new, reproducible cohesivity assay may have value together with elasticity (G’) and viscosity measurements to understand and leverage distinct tissue-distribution patterns and clinical behaviors of different Hyaluronic acid products,” they write. “When integrated with general patient considerations, specific ones pertaining to the target tissues, and the direct influence of injection depth and implantation patterns, rheologic tailoring can facilitate the achievement of clinical objectives.”
The researchers believe that this information will be increasingly useful as new FDA approvals increase the availability and variety of filler products, and American practitioners transition to the use of full-product families. “Complete Hyaluronic acid filler families, available in Europe and elsewhere, include products for deep volumization, midlevel implantation, and superficial placement; and sometimes one or two additional products for specific applications such as lip or tear trough injection,” they write.
“Partial product families are currently available in the United States; for instance, the deep volumizer, Juvéderm Voluma, without its midlevel and superficial partners (Volift and Volbella); and the superficial/midlevel product, Belotero Balance, without its accompanying deep volumizer, midlevel and superficial partners (Belotero Volume, Intense and Soft, respectively). The Restylane/Emervel and Teosyal families also have several products that are not available yet in the United States,” they write. “Each product within a family is engineered differently and intended for different clinical purposes.”
What’s the name of eye trough filler with high cohesivity that will drop into cheeks?