• Primary goal: Reduction of wrinkles, folds, and furrows due to muscular pull
• Secondary goals: Treatment of brow, eyelid, and facial asymmetries
• Special anatomy: None
• Anesthesia: Local anesthesia is unnecessary and may even interfere with best localization of the areas requiring treatment. Injection is painless or nearly so.
• Operative technique: Botulinum toxin treatment is a non-surgical procedure. Tiny amounts of a potent neurotoxin are injected through a fine needle either into or just above multiple areas of muscle whose pull is responsible for the generation of many facial wrinkles and folds. The intent is to partially paralyze the action of the muscle and thereby relieve its creasing of overlying skin.
• Variations: Beyond it effect on wrinkles, the toxin may be employed for any number of other creative purposes on the face, such as addressing imbalances in eyebrow shape or symmetry, smoothing "lipstick lines" above the upper lip, and so on.
• Advantages: Chemodenervation provides a safe and effective method for softening wrinkles associated with "hyperkinetic" muscular pull, such as crow's feet, forehead creases, as well as larger furrows, such as "frown lines" between the eyebrows.
• Limitations: The beneficial effect from chemodenervation is temporary, lasting from two to six months. Repeated treatments are necessary. Some patients develop a resistance to botulinum toxin and may require higher doses or more frequent injections. Wrinkles, lines, and depressions not related to muscular pull (such as those caused by scars or tissue loss) benefit more from other "skin rejuvenation" techniques, such as the use of tissue fillers (see Chapter 24: Collagen).
• Care and recovery: No special post-treatment care in required. Most commonly, the toxin takes effect between 1-4 days following injection.
• Risks and complications: Uncommon and transient. Injection of excessive amounts of toxin may result in more muscle weakness than intended and cause the eyelid or brow to droop as if paralyzed. As the effect of the toxin disappears, the muscles regain normal function. The injections may also cause superficial or deeper bruising.
In year 2002 and to great fanfare, the FDA approved botunlinum toxin for use in treating furrows between the eyebrows. Contrary to popular opinion, however, the FDA has not as yet approved usage in the periorbital (around the eye) region or on crowsfeet; such treatments are still considered "off-label".
• Comments: While the benefits of chemodenervation are appealing, many initially-satisfied patients grow weary of repeated visits (and recurring costs) and discontinue treatment.
