Botulinum and the brow

Dr. Lamb

The extent that brows descend after botulinum toxin injections is greatly influenced by the amount of frontalis weakening, according to a small study by German researchers published May 2019 in the Aesthetic Surgery Journal.

German researchers used three-dimensional (3D) technology to evaluate eyebrow position after treatment with abobotulinumtoxinA (Azzalure, Galderma). They studied two groups of adult women: one group received glabella-only injections; the other received glabella plus frontalis muscle injections. Researchers measured brow position pre-injection and at 2 weeks, 3 months and 6 months post injection.

While 37 women enrolled in the study, results are based on 9 glabella-only and 20 glabella-frontalis patients. Eight patients were excluded because of faulty 3D modeling or they were lost to follow up.

The authors reported no clear trend in brow position change in the glabella-only group, but they found a significant change in the glabella-frontalis group. Those patients’ brows descended notably across the entire brow length after 2 weeks, according to the study. The brow descent among women in the glabella-frontalis group diminished after three months but was still significant and moved medially.

Interestingly, patient age didn’t seem to be a factor in whether brow position changed post treatment.

Angela J. Lamb, M.D., associate professor of dermatology Icahn School of Medicine at Mount Sinai, who isn’t an author on the study, tells Dermatology Times that she agrees with the study’s findings.

“The science behind why botulinum works makes this feasible. It paralyzes the muscles. It makes sense that brow position would change,” Dr. Lamb says.

A descending brow post treatment with botulinum toxin is a common patient complaint, according to Dr. Lamb.

“I try to stay very high when I inject to avoid this, but it happens even to the best of injectors,” she says. “[Injecting high] can mean that sometimes the wrinkles lower on the forehead are still visible, so I have to do a lot of coaching about the balance between removing the wrinkles and risk of dropping the brow.”

Clinicians should evaluate the anatomy of individual patients and ask about results with previous botulinum toxin injections, according to the authors.

It is important to examine patients by monitoring the dynamic behavior of their brows in different situations.

“Patients who require frontalis activity to assure straight and unhindered forward gaze might be better served with a surgical forehead-lifting technique,” the authors write. “If they insist on botulinum toxin treatment, it is safest to start injecting the medial frontalis relatively high above the brows and use only 2 to 3 injection points per side in a V-shaped manner and reschedule after 2 to 4 weeks for possible touchups.”

More research with 3D image analysis is needed to confirm these findings, according to the study.

Disclosures:

The authors report no relevant conflicts. Galderma supplied the botulinum toxin for the study.

References:

Schlager S, Kostunov J, Henn D, Stark BG, Iblher N. A 3D Morphometrical Evaluation of Brow Position After Standardized Botulinum Toxin A Treatment of the Forehead and Glabella. Aesthet Surg J. 2019;39(5):553-564.