Your editor recently spent his Saturday in a DFW airport hotel conference room in the company of a group of cadavers, learning how to avoid and treat cosmetic complications of onabotulinumtoxinA (BotoxA) administered for prevention/suppression of chronic migraine. Not precisely his idea of the perfect way to spend a Saturday but nevertheless productive.

The training session was supervised by Dr. Andy Blumenfeld, an old friend and colleague who is director of the Headache Center of Southern California. It was Dr. Blumenfeld who first Instructed me in the administration of BotoxA for chronic migraine over 20 years ago. I subsequently have treated thousands of patients with BotoxA and have conducted a fair amount of clinical research involving BotoxA and chronic migraine, but even after all these years I still find I can learn something new from Dr. B (see this issues “Migraine Tip of the Month”.

BotoxA is a remarkably “clean” therapy for suppressing chronic migraine. Over the 20+ years I have been administering the neurotoxin, about the only side effect I have encountered is ptosis (eyelid droop) which in my population of patients complicates less than 1% of treatments but in clinical trials involving Botox for chronic migraine was reported to occur in as many as 4% of patients receiving Botox. Ptosis can be quite mild and is inevitably transient, reversing as the BotoxA effect wears off over a period of weeks, but it can be distressing for patients nonetheless.

The ptosis most commonly associated with BotoxA therapy is “brow ptosis”, occurring when Botox is injected into the frontalis muscle that acts to elevate the eyebrow (see Figure 1). If the frontalis injections are made too low in the forehead or the neurotoxin diffuses down to the lower portions of the muscle even when injected high, the muscle loses its tone and “slumps”. This causes asymmetry of the brows and excess tissue overhanging the eye. The brow ptosis may involve only the medial portion of the brow or the entire brow, medial and lateral. Notice in Figure 2 that especially with the complete brow ptosis the left eyebrow clearly sits lower than the right…especially when the frontalis muscle is voluntarily contracted in the attempt to raise the eyebrows.

To avoid producing brow ptosis your injector/provider will take pains to inject the frontalis muscle high in the forehead and well away from the eyebrows. He/she also will also take particular care in injecting the corrugator muscles that depress the brows when you squint or frown (Figure 3), using a technique that minimizes the chance of BotoxA extending beyond the corrugator and into the lower portion of the frontalis muscle.

“Lid ptosis” is more cosmetically prominent and, happily, far less common. Compare the complete left brow ptosis in Figure 2 with the left lid ptosis in Figure 4. Notice how in lid ptosis the eyebrow elevates normally with contraction of the frontalis muscle while the lid remains “drooped”.  Although it long has been thought that lid ptosis resulted from diffusion of Botox inferiorly to paralyze the small muscles that elevate the eyelid, those muscles in fact are anatomically protected from downward diffusion of Botox. It now appears that in many cases what is believed to be a Botox-induced lid ptosis may in fact represent pre-existing and clinically mild lid ptosis made more apparent by Botox-induced brow ptosis (see paragraph below for more on this). To assist in differentiating lid and brow ptosis and specifically to determine whether some degree of pre-treatment ptosis may exist, we routinely obtain pre-treatment photographs to have available for comparison if treatment-related ptosis should occur. On those occasions when Botox does produce lid ptosis, there are eyedrops (apraclonidine) available that can serve at least partially to offset the ptosis.

Even when Botox is administered according to the paradigm proven to be effective for treating chronic migraine and recommended by the FDA,  patients can be left with what some call the “Jack Nicholson effect” (I prefer to take a more positive approach and refer to it as the “Nicole Kidman effect”). This occurs because BotoxA partially paralyzes the muscle that elevates the medial portion of the eyebrow but allows the lateral portion to elevate as per normal. This can result in a transient facial appearance that some dislike intensely, some simply ignore and could care less, and a few actually find pleasing. if you fall in the first group, you can request that your provider/injector inject an additional small amount of Botox a bit more laterally in the muscle that elevates the eyebrow, taking care not to inject too low or too much (which can result in brow ptosis). With this result, neither eyebrow will elevate as high as it normally does, but the two brows will elevate symmetrically. A somewhat different technique can be cosmetically effective if there is prominent asymmetry of brow elevation, with one elevating normally and the other lagging behind. 

In contrast to the “perfect” eyes, brows and lids in the photograph that introduces this article, many of us have subtle, naturally occurring asymmetry of our eyebrows, our eyelids or both. If, say, you have a naturally arched left eyebrow, administration of Botox potentially may accentuate that asymmetry between the two brows or reduce it, depending upon where and how Botox is administered to the frontalis muscle. If one of your upper eyelids naturally covers a bit more of the eye than the other, a Botox-induced brow ptosis may combine with the slight pre-existing ptosis to mimic a lid ptosis.

All this said, BotoxA is a safe, effective and well-tolerated therapy for suppressing chronic migraine. Side effects associated with its use are rare, but to avoid cosmetic side effects in particular it is advisable to receive your treatments from a skilled injector experienced in performing the procedure.

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