This was a study out of the Plastic and Reconstructive Surgery Journal in October 2015. The title, (hold onto your hats, it’s a long one), “Cohesivity of Hyaluronic Acid Fillers; Development and Clinical Implications of a novel Assay, Pilot Validation with a Five Point Grading Scale, and Evaluation of Six US FDA approved fillers.”
Why:
HA fillers are used widely to do soft tissue augmentation in the cheek, lips, and other areas of the face. There are different brands made by different manufacturers. They wanted to bring some science to comparing these fillers. Cohesivity maintains the gel integrity and tissue support. It is defined as ” the capacity of a material not to dissociate, because of the affinity of its molecules for each other.” They made a new assay to evaluate these fillers.
How:
They extruded the HA gel into sterile water. They then used a new Cohesivity Scale to assess the fillers. They call this scale the “Gavard Sundaram Cohesivity Scale.”
Results:
They found the scale was repeatable and consistent. (A good thing to show it is a good assay.) They found the fillers showed significant differences.
- HIGH COHESIVE: Belotero Balance
- MEDIUM HIGH COHESIVE: Juvederm Ultra and Juvederm Ultra Plus
- LOW MEDIUM COHESIVE: Juvederm Voluma
- LOW: Restylane and Perlane (now Restylane Lyft)
What does this mean?
They state this is evidence in the lab, and a correlation needs to be made to how these act in patients. There are other factors of HA fillers which were not addressed, primarily elasticity (also called G prime, which some feel is the ability of the HA filler to apply force to push out the wrinkles) and viscosity.
My thoughts?
HA fillers are one I see a lot of variation between people. In my Palo Alto office, I use primarily Juvederm, Restylane, Perlane (Restylane Lyft), and Voluma. (I also use non HA fillers like Sculptra and fat transfer.) For some one brand is better than the other, but it is not consistent which brand is “best.”
This study done in the lab does not take into account the actual person’s body and their reaction to a foreign substance. I think we will find when people’s bodies recognize something as foreign- an invader -they break it down faster. All these fillers have components in the gel which our bodies recognize. Different manufacturers use different things.
Soft tissue fillers also have other qualities as well. How moldable? How smooth? At what depth are you injecting? . It isn’t all about how cohesive they are. The authors recognize the limitations in their conclusion. They also discuss how there are more filler choices available in Europe, with brands having different filler make up when it is aimed at the deep tissue to volumize, rather than the fine lines in the skin itself.
It is great to have an objective measurement to help stratify fillers in one parameter, but I don’t see this study changing how I advise on fillers yet. After doing fillers on hundreds of women for years, I think cohesivity is one piece to a complex larger puzzle.