WP Chung O T in Facial Aesthetic Surgery_9781496349231

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Chapter 1 Injection of Botulinum Toxin to the Glabellar Region

PATIENT HISTORY AND PHYSICAL FINDINGS ■■ It is important to evaluate the eyebrow and eyelid margin position prior to any injection of botulinum toxin in the periorbital region. ■■ The position of the eyebrow is related to the relative con- traction of the brow elevator (the frontalis muscle) vs the brow depressors (the CS and procerus muscles medially and the orbicularis oculi muscle laterally). ■■ In patients who are brow depressor dominant, the brow will assume a relatively inferior position and appear ptotic; chemodenervation will elevate the brow and enhance peri- orbital appearance. ■■ The position of the upper eyelid margin in relation to the globe is also important to evaluate prior to any botulinum toxin injection in the periorbital region. The amount of pto- sis is related to the amount of globe coverage by the upper eyelid. ■■ The distance from the superior to the inferior limbus of the globe is 11 mm in most adults with the upper eyelid typi- cally covering the superior limbus by 1 mm. If the upper eyelid position is inferior to this level, the lid is considered ptotic. ■■ It is important to diagnose any upper eyelid ptosis preinjec- tion as any injection into the periorbital musculature will affect brow position and injection into the frontalis muscle in patients with eyelid ptosis may cause a decrease in the visual field. ■■ Any asymmetries in eyebrow and/or upper eyelid posi- tion should be noted, documented, and discussed with the patient before injection of botulinum toxin. ■■ Hypercontraction of the corrugator muscles produces an angry, scowling appearance. Muscular contraction depresses the medial clubhead of the brow and causes a vertical fold that appears at right angles to the muscular axis. ■ Injection of Botulinum Toxin Into the Glabellar Region ■■ Topical anesthetic cream, commonly containing lido- caine, is applied and left in place for a minimum of 15 to 20 minutes and sometimes longer for maximal anesthetic effect. ■■ Botox is reconstituted into sterile injectable saline to the concentration of 2.5 to 4 units/0.1 mL. This is drawn up into a 1-cc syringe, and a 30-gauge short Luer Lock needle is prepared for injection. ■■ To avoid any spread of toxin into the extraocular mus- cles, or the upper eyelid retractors (levator aponeurosis and Müller muscle), the needle is usually directed away from the globe.

■ The brow clubhead is moved both medially and inferiorly with contraction of the corrugator. This is important in patients who have cosmetically removed medial brow hairs, as injection of botulinum toxin will cause elevation and lat- eralization of the brow clubhead. ■ Hypercontraction of the procerus muscle draws the medial brow inferiorly and causes a horizontal furrow at the root of the nose. ■ Injection of botulinum toxin of the procerus causes eleva- tion of the medial brow and lessens the horizontal deep rhy- tid at the nasal root. ■ Patients should be screened for neuromuscular disorders including amyotrophic lateral sclerosis, myasthenia gravis, and Eaton-Lambert syndrome because these are contraindi- cations for the use of the product. ■ Use in pregnant or nursing mothers is not advised, though no studies have shown teratogenic damage to fetus or adverse effects to breast-feeding infants. ■ Patient medications should be screened for aminoglycoside antibiotics because these affect the pharmacokinetics of the toxin and can potentiate the effects. ■ The patient is examined in an upright position along with full facial analysis. The treatment position is surgeon prefer- ence, upright, slightly recumbent, or supine. Approach ■ Delivery of the product is performed uniformly with percu- taneous injection. Positioning SURGICAL MANAGEMENT Preoperative Planning

T E C H N I Q U E S

■ Injection of the glabellar muscles should be performed with a no. 30- to no. 32-gauge needle. ■ Approximately 20 to 25 units of botulinum toxin (or equivalent) are typically sufficient to treat the glabellar musculature including both the CS and procerus. This is usually distributed in a V-shaped pattern with the apex at the nasal root. ■ The medial corrugator/depressor (clubhead) injection should be deep (just superficial to bone), and the tail of the muscle should be injected closer to the skin with the needle tangential to the skin. ■ Injection of toxin into the procerus should be at moder- ate depth over the midline of the nasal root, with the needle being placed perpendicular to the skin at the nasion.

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