Botulinum Toxin

21 Botulinum Toxin

Treatment of facial lines and wrinkles (also called rhytids) with botulinum toxin has become the most frequently performed cosmetic procedure in the United States, according to statistics from the American Society for Aesthetic Plastic Surgery.1 It is also one of the most common entry procedures for health care professionals seeking to incorporate aesthetic procedures into their practice.2

As we age, the skin naturally thins, and repetitive contraction of the underlying facial musculature causes visible lines and wrinkles. Initially, these lines are seen only during facial expression with frowning, laughing, or smiling and are referred to as dynamic lines. Over time, however, dynamic lines may become etched into the skin, resulting in permanent or static lines. Botulinum toxin reduces unwanted dynamic lines, and to a lesser degree static lines, by relaxing hyperdynamic facial muscles and smoothing the overlying skin.

Botulinum toxin is a potent neurotoxin protein derived from the Clostridium botulinum bacterium. It reduces muscular contraction through inhibiting release of acetylcholine at the neuromuscular junction. Injection of small quantities of botulinum toxin into specifically targeted muscles causes localized, temporary chemical denervation with resultant muscle relaxation.3

Botulinum toxin has been used for more than 20 years to treat a variety of clinical conditions such as blepharospasm, strabismus, cervical dystonia, hyperhidrosis, migraines, and muscle spasticity.46 Botulinum toxin is used in numerous facial aesthetic areas. However, treatment of the glabellar complex,7 frontalis8 and orbicularis oculi muscles,9 which contribute to formation of frown lines, horizontal forehead lines, and crow’s feet, respectively, offers the most predictable results, greatest efficacy, and fewest side effects.10,11 Botulinum toxin treatment of hyperdynamic muscles in the upper one-third of the face are a core aesthetic procedure for providers interested in incorporating aesthetic care into office practice.12


A thorough understanding of facial anatomy in the treatment areas is essential prior to performing botulinum toxin procedures (Figure 21-1). The muscles of facial expression are unique because, unlike most muscles, which have bony attachments, they have soft tissue attachments to the skin through the superficial muscular aponeurotic system. When a muscle contracts, the overlying skin moves with it and wrinkles are formed perpendicular to the direction of the muscle contraction. Figure 21-2 shows lines and wrinkles in the upper one-third of the face and the corresponding underlying musculature.

Glabellar wrinkles, or frown lines, are vertical lines that occur between the medial aspects of the eyebrows. The muscles that contribute to formation of frown lines are the glabellar complex depressor muscles, which pull the brows medially and inferiorly and include the corrugator supercilii, procerus, depressor supercilii, and medial orbicularis oculi (Figures 21-1, 21-2 and 21-3).

Horizontal forehead lines result from contraction of the broad frontalis muscle, which spans the forehead between the temporal fusion lines (see Figures 21-1, 21-2 and 21-3). The muscle fibers are vertically oriented and contraction of this levator muscle raises the eyebrows. The inferior 2-cm portion has the most marked effect on eyebrow height and shape. The goal of treatment in this area is to partially inhibit activity of the frontalis muscle to reduce horizontal forehead lines while maintaining a desirable eyebrow shape and height.

Periorbital wrinkles, commonly known as crow’s feet, result from contraction of the lateral portion of the orbicularis oculi, a thin, superficial muscle that encircles the eye (see Figures 21-1, 21-2 and 21-3). Contraction of the palpebral portion of the orbicularis oculi muscle results in closure of the eyelid. The goal of treatment in this area is to focally inhibit the lateral orbicularis oculi to reduce crow’s feet without excessive orbicularis oculi muscle relaxation.

Many of the muscles of facial expression interdigitate with one another and, while providing treatment with botulinum toxin to one area in isolation will often provide adequate wrinkle reduction results, in some cases an adjacent muscle group may require concomitant treatment to achieve the desired results. For example, the glabellar complex muscles interdigitate to a greater or lesser degree with the frontalis muscle, and treatment of the frontalis in addition to treatment of the glabellar complex muscles may be required to smooth frown lines in some cases14.

Mar 12, 2016 | Posted by in General Surgery | Comments Off on Botulinum Toxin

Full access? Get Clinical Tree

Get Clinical Tree app for offline access