The vertical frontalis muscle is responsible for the formation of the horizontal forehead lines (HFL). Dysport can be used off-label to smooth these wrinkles. The frontalis muscle inserts into the periocular muscles such as the procerus, corrugator supercilii, orbicularis oculi, and depressor supercilii. Superiorly, the frontalis inserts into the galea of the scalp. Often, muscle fiber will be absent in the midline of the forehead. The fibers of the frontalis muscles are oriented vertically, while the wrinkles from the frontalis mucles form horizontally.
While standing directly in front of the patient, ask your patient to forcefully raise the eyebrows up and visualize the lines. Note the points of maximal contraction, brow asymmetry and ptosis and discuss this with your patient. The goal for the treatment is to soften the lines without causing brow ptosis or eliminating all expression. A conservative approach is recommended, as many patients do not want a ‘frozen face’ or a droopy, heavy eyebrow. The frontal process of the zygomatic bone fuses with the frontal bone and creates a palpable ridge that an injector can feel bilaterally on the lateral forehead. Draw a line here as frontalis rarely extend laterally to this palpable ridge. Test this assumption by asking your patients to lift their eyebrow while palpating outside of this boney ridge. You will likely feel the frontalis muscle only medial to this boney ridge.
Technique and injection points vary depending on the patient. Frontalis muscle shape will vary from tall, short, narrow, wide, or V-shape. Please see the figure for possible different forehead injection patterns. Also, it is important to note that a higher injection point above the mid brow is recommended to avoid flattening an arched feminine eyebrow in women. It is recommended that you inject at least 2 cm above the eyebrow (or upper 2/3 of the forehead) to minimize brow ptosis.
This also maintains a more natural appearance. Consensus recommendation by a panel of experts has suggested 4 to 6 total injection sites. The injections are subcutaneous, roughly 2 cm apart. Typical recommendation is to inject the minimal amount of dosage, 5 units of Dysport per injection site, with close follow up in2 weeks.
Many use a V-shaped configuration for injections in women to create an arched eyebrow. This should be avoided in patients who do not desire this look, such as some male patients. If your patient experiences an undesired arched eyebrow, then this can be corrected with a small dose of additional toxin (4 – 5 units) 1–2 cm superior to the apex of the arched eyebrow.
Adverse events include injection site pain, bruising and swelling, headache, eyebrow ptosis, and eyelid ptosis. Patients with advanced age (over 60), mild brow ptosis at baseline and hyperfunctional eyebrow (patients who use their frontalis muscle to open their eyes) should be treated with caution. Treatment of the glabellar muscles will minimize the eyebrow ptosis.
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