| boTulInum ToxIn A | arTICle In younger patients with taut
skin and no compensatory brow lifting, brow ptosis often can occur medially when there is an overzealous injection of onabotulinumtoxina in the center of the forehead.
Figure 12 (A)Typical injection points and amount of units for a man who works outdoors and has strong depressors and levators of the brow and forehead causing very deep lines. Before treatment with onabotulinum- toxinA injections. (B) Same patient 2 weeks after the initial onabotulinum- toxinA treatment and before an additional 6 U of onabotulinumtoxinA. Note elevated lateral eyebrows and where additional 3 U of onabotulinumtoxinA were injected on each side to lower the lateral tail of the eyebrows in this man who usually has straight eyebrows. (C) Same patient having a touch-up injection of 3 U of onabotulinumtoxinA 2 weeks after his initial onabotulinumtoxinA treatment. (D) Same patient 5 weeks after the initial onabotulinumtoxinA treatment and 3 weeks after a touch-up treatment (note the flatter less arched lateral brows)
subsequent treatment session. Therefore, after the first 2 – 3 years of treatment sessions regularly scheduled every 3–5 months, some patients may prefer to return for their next retreatment on an as-needed basis.
Specific side effects Ptosis of the upper eyelid is the most significant complication seen when injecting onabotulinumtoxinA in and around the glabella (9-10). It is felt by some that blepharoptosis is caused by the migration of injected onabotulinumtoxinA through the orbital septum, weakening the levator palpebrae superioris. This is found to occur more frequently when large volumes of highly diluted onabotulinumtoxinA are injected deeply and low, close to the bony supraorbital margin at the midpupillary line. occasionally at this location some actual muscle fibers of the levator palpebrae superioris extend anteriorly into the levator aponeurosis, allowing for easy access of the onabotulinumtoxinA that has diffused through the barrier of the orbital septum to weaken some of the muscle fibers of the upper eyelid levator, and produce ptosis of the upper eyelid. blepharoptosis, when it occurs, is seen as a 1–2 mm or
more drop in the upper eyelid, obscuring the upper border of the iris. Ptosis can appear up to 7–10 days after a onabotulinumtoxinA injection and usually can last 2–4 weeks or even longer(4,6,9-10). blepharoptosis also can be induced secondarily when
the lower fibers of the frontalis are weakened, producing a drop in the height of the brow. The weight of the ptotic brow then impinges upon the upper eyelid and causes it to droop, narrowing the vertical palpebral aperture. This seems to occur more frequently in older patients who possess dermatochalasis of the skin of the eyelids and brow. In order to compensate for a heavy, lax brow, some individuals, regardless of age, involuntarily use the lower fibers of their frontalis to lift the soft tissue of the brow, which also maintains their upper eyelids in a raised position(16). When this compensatory action of the
prime-journal.com | March 2011
Figure 13 (A) The ‘medial brow dip’ of the central glabella and eyebrows of this 40-year-old occurred after onabotulinum- toxinA injections because the lower central frontalis was overly treated. Patient is frowning before and after onabotulinumtoxinA. Note the fullness of the medial brow skin after treatment. (B) The “medial brow dip” of the central glabella of this 45-year-old patient was avoided after onabotulinum- toxinA injections because the central frontalis was not treated
frontalis is weakened by onabotulinumtoxinA, a secondary blepharoptosis is created(39). In younger patients with taught skin and no
compensatory brow lifting, brow ptosis often can occur medially when there is an overzealous injection of onabotulinumtoxinA in the center of the forehead. medial brow ptosis is exhibited by the medial head of the eyebrows appearing excessively lower than the lateral tail of the eyebrows. A bulge of skin in the center of the glabella also can accompany the “medial dip” of the eyebrows. lagophthalmos or incomplete eyelid closure is another
potential complication that can occur particularly when overzealous injections of onabotulinumtoxinA are given in the periorbital area. lagophthalmos results when there is a loss of the normal sphincteric function of the orbicularis oculi, and the upper eyelid does not close and approximate firmly against the lower eyelid. loss of the sphincteric function of the orbicularis oculi either with involuntary blinking or with deliberate forced eye
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