Modulating Expression

Physicians share their techniques for obtaining better longevity and more natural-looking results with botulinum toxins.
Improving longevity and outcomes with neurotoxins

For the JDD study, he and his coauthors doubled the recommended dose of Dysport, injecting 120 units into the glabella of patients with moderate and severe frown lines. With this dose, they were able to double the duration of the toxin.

“The reason people are hesitant to use a larger dose is because they are fearful that the product will spread to the upper eyelids or into the upper forehead,” says Dr. Joseph. “What I did in my trial was double the dose of toxin and reduce the volume of fluid that I used to deliver it to half of what they used in the clinical trials.”
He calls this the big dog/short leash theory. “If you want to walk a mastiff across a park full of people and dogs, are you going to use a 2-foot leash or a 40-foot leash? You’re going to use the 2-foot leash,” he explains. “The big dog is the big dose and the short leash is the small amount of fluid I’m going to use to actually inject that product into the patient. This controls the field of effect. I deliver a large amount of the neuromodulator right into the muscle, but it’s so concentrated that it can’t spread and create adverse events. All I have to do is double the dose, cut the volume in half and I get a better result that lasts longer.”

Dr. Joseph’s study is one of the first to follow patients with this type of dosing, but longer effects also have been seen in male patients who require a larger dose of toxin to achieve their desired outcomes, notes Joel L. Cohen, MD, of AboutSkin Dermatology and DermSurgery in Greenwood Village, Colorado. “That can be appealing for some people, but also we need to back up and think about what looks natural,” he says. “If we completely annihilate a muscle, that doesn’t always look appropriate.”

In his clinical practice, Dr. Joseph is most likely to use a higher, more concentrated dose in the glabella and crow’s feet, where the goal is to inactivate a significant portion of the muscle. He pulls back on his dosing in more complicated areas, like the forehead. “This is one area you don’t want completely frozen. You need some expression,” he says. “Of these three key areas—glabella, crow’s feet, forehead—the forehead is the hardest treatment area to get right and it has the highest rate of adverse events. You are not going to push hard in an area that is really tricky and does need motion.”

Achieving More Natural Results

As the injection areas for neuromodulators have expanded, so have dosing techniques. The goal is to balance a desire for longevity with the goal of providing more natural-looking results. “On the forehead, I like to underdose to preserve movement, even though I know a higher dose will last longer,” says Dr. Cohen. “This allows the muscle to still function but be softened, and it preserves brow positioning as well.”

He often uses only 7 units of Botox or Xeomin—or 15 units of Dysport—in the forehead and tells patients that the results will last seven to eight weeks. “It looks good and maintains that movement that I want,” says Dr. Cohen. “I don’t want to use a high dose to get them to the typical three or four months that we get in the glabella and crow’s feet, and I certainly don’t want to use a super high dose in the forehead, which some people prefer to do in the glabella to knock out more of the muscle or extend the timeframe.”

Dr. Wilson has also adapted his injection technique—using lower doses in the frontalis and higher doses in the glabella and crow’s feet. “I’ve seen a lot of patients who were overtreated in the frontalis, and it gives them a heavy brow,” he says. “The trend in treatment is to do less on the frontalis to allow more brow elevation, and do more in the crow’s feet.”

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