While it may not be clear from the title, everyone has their preference of how they like their favorite things. James Bond likes his martini’s shaken, not stirred. And similarly, or not so similarly, plastic surgeons administer botulinum toxin (BOTOX®, Xeomin® or Dysport®) based on their preference – area vs volume.
Since botulinum toxin is used to treat wrinkles in the forehead, in between the eyebrows (the “11’s”) or around the eyes (the “crows feet”), doctors may inject based on volume or the area of treatment. For example, they may charge by the unit ($8-$16 per unit) and inject 20 units into the forehead or they may just charge a flat fee for an area ($200 for the area in between the eyebrows). While Botox works regardless of the bookkeeping method the doctor chooses, I do think there are advantages of injecting based on units rather than area. First off, the patient knows exactly what they’re getting. If the patient goes to one doctor and he/she injects some unknown amount into their forehead because that particular doctor injects based on area, not dosage, and the patient feels their forehead is too “frozen” after the treatment, then it’s hard to give the doctor feedback the next time they go back. You can tell them you want less injected this time around but what is considered “less” if you’re not sure how much they injected the last time. On the other hand, if they injected 40 units into the forehead, then you can go back and say, “I want less than 40 units” so my forehead isn’t as frozen.
By describing Botox as units, it’s easier for the patient, and in my opinion, the doctor to adjust dosages in the future. Treating by area leaves a nebulous, or feeling of the unknown for the patient. I think an analogous example would be if your tires on your car specified that you should fill up your tire “full” vs fill it up to 35 PSI.
Plus, in this new world of evidenced based medicine or finding the most appropriate CarePath, accuracy and knowing the exact dosage is sort of important! I don’t really know why some doctors choose one bookkeeping method over another and it may be something as simple as that’s the way their mentors did it in their fellowship. But it’s important for you, the patient, to ask your doctor how much they injected. Even if they inject/bill based on area, you can still ask how much they’re injecting so you can objectively assess if you need more or less when the Botox wears off in 3 to 6 months (and if they don’t know how much they injected when you ask, that’s a red flag!). This kind of feedback is very helpful for me as a board certified plastic surgeon and hopefully your plastic surgeon will feel the same way.