Chemodenervation, using botulinum neurotoxin-A, prolongs the lasting effects of hyaluronic acid (HA) fillers by reducing muscle activity in the treated area, according to a new study.
Aesthetic physicians have been known to use HA fillers in combination with Botox (Allergan) to temporarily reduce muscle activity and prolong filler life. Turkish researchers used an animal model to more objectively demonstrate the approach.
They injected a small amount of HA filler under rabbits’ skin, in the front of each ear (to mimic the glabellar region in humans). Researchers used HA filler, alone, on one side, and HA filler combined with Botox on the other.
After three months, the researchers compared the amount of filler remaining on the two sides by using MRI scans. The follow-up scans confirmed that Botox slowed filler degradation by 42% compared to the non-Botox side. The difference was both visible on photographs and measurable.
According to the study’s abstract: “Average initial volumes of filler only and filler combined with botulinum neurotoxin type A were 0.61 cm3 on both sides, and there was no difference between initial volumes of the two sides…. At the end of three months, average degraded volumes of filler only and filler combined with botulinum neurotoxin were 0.33 cm3 and 0.19 cm3, respectively, and the degradation difference was significant between the two groups…. End volumes for the filler-only and the filler combined with botulinum neurotoxin sides were 0.28 cm3 and 0.42 cm3, respectively, and end volumes between the two sides were also statistically significant….”
What It Means to Your Practice
Kavitha K. Reddy, M.D., director of the Cosmetic and Laser Center at Boston University Medical Center, says the study provides needed data on factors affecting filler degradation in-vivo, but studies still need to be performed on humans.
“The study is of interest because it highlights the potential clinical significance of muscle movement in promoting filler degradation and in reducing the duration of filler effect,” Dr. Reddy tells Cosmetic Surgery Times. “It’s important to note this study was done in rabbits, not in humans, so that the benefit of combining botulinum and filler specifically to improve filler longevity in human patients has not yet been verified.”
While it’s promising to consider using Botox and HA fillers together in certain areas, such as the forehead, to maintain the filler effect, the number of areas where paralysis is desirable is limited, according to Dr. Reddy.
“… for example, we would not want to paralyze the cheeks, lips or other areas that are more commonly treated when using fillers. In addition, the glabella is often a site avoided during filler treatment due to risks of ischemia, and some physicians also choose to avoid the temples to reduce potential complications. Therefore, the clinical utility of this finding remains somewhat limited,” she says.
Dr. Reddy says she combines fillers and neurotoxins; however, the filler is often in an area that is separate from the area receiving neurotoxin.
“In cases where we use Botox to reduce forehead lines as well as add superficial filler to erase these lines, the filler may last longer with the combination technique,” Dr. Reddy says. “I would recommend the combination to patients in such a case so that they not only address the underlying cause of their forehead wrinkles, but also potentially increase the duration of their filler results, thereby, more optimally treating their forehead wrinkles.”
New York City plastic surgeon Scot Bradley Glasberg, M.D., past president of the American Society of Plastic Surgeons, tells Cosmetic Surgery Times that he typically combines Botox and fillers, but usually not in the same area unless for a very deep rhytid.
“In general, the face is more dynamic… and hence, things tend to absorb quicker,” Dr. Glasberg says. “Fat injections are the classic example that we see tending to absorb quicker in the face than other parts of the body, such as the breast or the buttocks. [This is an] interesting study. It makes sense that areas that tend to stay more static from Botox would hold onto fillers for a longer period of time. It will be interesting when someone performs a similar study in humans on a clinical basis to see if the difference is really significant.”
NEXT: Practical Application
Another New York City plastic surgeon, David Shafer, M.D., says the new study gives objective evidence to observations that plastic surgeons see every day in clinical practice.
“Combination treatment (chemodenervation with Botox plus hyaluronic acid fillers, such as Juvéderm or Restylane) tends to give a prolonged and enhanced effect when compared to filler alone,” Dr. Shafer says. “This method of study allows for direct comparison and control in the same model. Translation to clinical practice is straightforward as both products are commonly used in combination already.”
Dr. Shafer says that in his practice, combination therapy with Botox and dermal filler is the number one treatment after each therapy alone.
“The most common area is the glabella where Botox Cosmetic is used to treat dynamic wrinkles and dermal filler is used to treat resistant static and deep wrinkles in this zone,” he says. “A secondary area is the crow’s feet lateral to the eyes when treating a combination of dynamic and static wrinkles. This method of treatment offers not only an effective treatment but an enhanced result. An area where this combination treatment is not recommended includes primarily the lips where risk of paralysis of the orbicularis oris muscle outweighs any benefits of prolonged duration.”