Botulinum toxin injection for treatment of facial wrinkles is the most frequently performed cosmetic procedure most countries, and it is one of the most common entry procedures for clinicians seeking to incorporate aesthetic treatments into their practice. Wrinkles are formed by dermal atrophy and repetitive contraction of underlying facial musculature. Botulinum toxin is a potent neurotoxin that inhibits release of acetylcholine at the neuromuscular junction. Injection of small quantities of botulinum toxin into specific overactive muscles causes localized muscle relaxation that smooths the overlying skin and reduces wrinkles. Botulinum toxin effects take about two weeks to fully develop and last 4 to 6 months on average . Dynamic wrinkles, seen during muscle contraction, yield more dramatic results than static wrinkles, which are visible at rest. Botulinum toxin injection is contraindicated in persons with keloidal scarring, neuromuscular disorders (e.g., myasthenia gravis), allergies to constituents of botulinum toxin products, and body dysmorphic disorder. Minor bruising can occur with botulinum toxin injection. Temporary blepharoptosis and eyebrow ptosis are rare complications that are technique-dependent; incidence declines as injector skill improves.
Mechanism of Action
Botulinum toxin is a potent neurotoxin protein derived from the Clostridium botulinum bacterium. It exerts its effect at the neuromuscular junction by inhibiting the release of acetylcholine, which causes temporary chemical denervation.
Indications
Botulinum toxin has been used for more than 20 years to treat a variety of conditions including blepharospasm, strabismus, cervical dystonia, migraines, hyperhidrosis, and muscle spasticity. Botulinum toxin was first approved by the U.S. Food and Drug Administration (FDA) for cosmetic use in 2002 as Botox to treat glabellar complex muscles that form frown lines and in 2013 to treat lateral orbicularis oculi muscles that form crow’s feet; it is used off-label for all other cosmetic facial indications. It has become the treatment of choice for wrinkles occurring in the upper one-third of the face (i.e., frown lines, horizontal forehead lines, and crow’s feet). It is also used in the lower two-thirds of the face, but this is more technically challenging and is an advanced application.
Patient Selection
Patients with dynamic wrinkles demonstrate the most dramatic improvements from botulinum toxin injection and are ideal candidates for treatment. Patients with static wrinkles that are visible at rest are also candidates, but results are slower and patients may require two or three consecutive botulinum toxin treatments for significant improvements. Deep static lines may not fully respond to botulinum toxin injection alone and may require combination treatment with dermal fillers or other cosmetic procedures to achieve optimal results. Setting realistic expectations at the time of consultation is important for patient satisfaction and success with botulinum toxin treatments. Contraindications to botulinum toxin injection include keloidal scarring, neuromuscular disorders (e.g., myasthenia gravis), allergy to constituents of botulinum toxin product, unrealistic expectations, and body dysmorphic disorder
Copyright © Rebecca Small, MD.
Reprinted from Small R, Hoang D. A Practical Guide to Botulinum Toxin Procedures. Philadelphia, Pa.: Lippincott Williams & Wilkins; 2012.
Copyright © Rebecca Small, MD.
Reprinted from Small R, Hoang D. A Practical Guide to Botulinum Toxin Procedures. Philadelphia, Pa.: Lippincott Williams & Wilkins; 2012.
Aftercare
Patients are advised to avoid lying supine following treatment for four hours. They are also advised to avoid massaging or applying heat to the treatment area, and to avoid activities that cause flushing (such as exercising heavily, consuming alcohol, and hot tub use) on the day of treatment. These aftercare practices are used to reduce potential spread of the toxin, however; they are not supported by randomized controlled trials.
Results and Follow-Up
Partial reduction in function of the targeted glabellar complex muscles is seen by the third day after botulinum toxin injection, with maximal reduction visible two weeks after injection. Return of muscle function is gradual, typically four to six months after treatment. Subsequent treatment is advised when muscle contraction is visible in the treatment area before facial lines return to their pretreatment appearance. After multiple treatments, botulinum toxin effects may be prolonged and, for some patients, treatment intervals can be extended beyond 4 to 6 months.