Myomodulation PDF

D MYOMODULATION Mauricio de Maio and Izolda Heydenrych The definition of modulation is the exertion of a modi- aspect. The first publication on myomodulation high- fying or controlling influence on something. lighted the ability...

D MYOMODULATION Mauricio de Maio and Izolda Heydenrych The definition of modulation is the exertion of a modi- aspect. The first publication on myomodulation high- fying or controlling influence on something. lighted the ability of injectable fillers to influence facial muscle action in a reproducible manner by address- Clinical observation over the past two decades ing the muscle imbalance resulting from structural has shown that injectable fillers may, in addition to deficiencies with and without substantial volume loss addressing volume loss, also profoundly influence. The evolution of innovative treatment paradigms muscle dynamics. With aging, structural deficiencies is offering new treatment methods—and hope—for in either bone or fat pads may precipitate abnormal patients with facial palsy. muscle movement. As the indications for facial inject- able fillers have evolved from the mere treatment of lines and folds, through three-dimensional facial volu- mizing, to the current sophisticated paradigm of mod- TERMINOLOGY ifying muscle movement by the use of hyaluronic acid (HA) fillers, it has become possible to consciously complement the mechanism of neurotoxins by the The succinct new language of the MD Codes, also use of HA fillers. encompassing MD ASA and MD DYNA Codes, was conceived in order to refine and standardize Despite a paucity of literature detailing scientifically description of both facial assessment and technique, measurable muscle strength, case studies offer irre- and constitutes an invaluable teaching tool. It is futable evidence of the potential clinical impact of important to understand that these points should be injectable fillers on muscle function in both the pres- applied according to clinical indication and expertise ence and absence of volume deficiency. It is clear and, as such, constitute a set of accurately defined that various factors may be instrumental in either placement points rather than a rigid prescriptive facilitating or reducing muscle movement, making method. this a fascinating field for ongoing study [1,2]. The MD Codes divide the face into structural units The treatment of facial palsy and asymmetry is com- and depict target structures, injection technique, plex and mandates insightful, detailed mastery of both product choice, and danger areas in a detailed and anatomy and technique in order to achieve reproduc- standardized manner through the use of symbols. ible results. Developing expertise in this field often Placement points and symbols are briefly illustrated requires many years of experience, making consistent in order to facilitate the methodology later in this and reproducible transfer of knowledge a challenging chapter (Figures D.1, D.2 and Table D.1). 17  Myomodulation Figure D.1 Illustration of the MD Codes placement and terminology. Figure D.2 Example of level of injection and danger zones: five-point cheek reshape. 18  Mechanisms Table D.1 The Five-Point Cheek Reshape: Injection Areas and Effects Code Injection Area Effect of Injection Aim Ck1 Zygomatic arch Lifts the cheek Bone structure and lateral Gives support to eyebrow and lower eyelid suborbicularis oculi fat (SOOF) Ck2 Zygomatic eminence Provides projection of the cheek and Bone structure and lateral SOOF shortening of the palpebral-malar sulcus Ck3 Anteromedial Improves the medial lid-cheek junction and Bone structure, deep malar fat cheek-midcheek softens the tear trough pad; medial SOOF Ck4 Lateral lower cheek/parotid Addresses the sunken area at the parotid Subcutaneous area level and volume loss; lifts the jawline Ck5 Submalar Addresses the sunken area and improves Subcutaneous volume loss in the submalar area The choice of injection device should be based on Table D.3 Details of Injection Delivery individual experience and preference (Tables D.2 Very small droplet of injectable and D.3). Microaliquot (0.01–0.05 mL per point) Static injection of a small amount The targeted structures are specified as: Aliquot of injectable (0.1–0.2 mL) Dermal Static injection of injectable Small bolus (0.1–0.3 mL) Mucosal Subcutaneous Anterograde or retrograde Linear Fat pads Supraperiosteal Multiple linear injections via a Fanning single-entry site creating a fan-like MD DYNA Codes detail the muscles implicated in pattern with needles or cannulae facial muscle excursion and suggest specified place- ment sites for both neuromodulator and/or HA filler. to reflect critically on the desired effects of placement Accurate knowledge of muscle origin and insertion is above, below, or within muscles and to define a strat- essential, as is knowledge of the muscular anatomi- egy encompassing placement, product choice, and cal plane. Insightful knowledge of functional groups method of delivery before embarking on treatment and muscle synergism/antagonism is vital in plan- (Figures D.3 and D.4). ning product placement; the injector is encouraged Table D.2 Considerations in the Choice of Injection MECHANISMS Device May minimize risk of intravascular injury and The factors influencing the effect fillers may exert bruising Recommended for use in danger zone areas on muscle action (mechanical myomodulation) (see Cannula Figure D.5) include: May be preferred for fine, controlled injections Ideal for bolus at the supraperiosteal level Functional muscle groups Agonist and antagonist pairs Tissue resistance Needle Volume loss 19  Myomodulation Figure D.3 The MD DYNA Codes detailing the specific muscles implicated in facial muscle excursion. Figure D.4 The MD DYNA Codes differentiating chemical and mechanical myomodulation. Superficial muscolar aponeurotic system (SMAS) Factors potentially facilitating muscle strength expansion include: Factors potentially inhibiting muscle strength include: Injecting beneath a muscle to create a “pulley effect” Adding tissue resistance above the muscle Increasing tensile strength by stretching the Injecting directly into the muscle to create a mus- muscle cular block SMAS expansion 20  Mechanisms Figure D.5 Mechanisms of myomodulation. Figure D.6 Language of the MD DYNA Codes specifying placement relative to muscle, angle of injection device relative to skin and proposed mechanism of action: M, muscle. 21  Myomodulation The MD DYNA Codes specify both the placement for Skin the desired mechanism (above, below, or in the mus- Subcutaneous fat cle) and required technical details (angle of needle or Orbicularis oculi cannula to the skin) (Figure D.6). SOOF Levators of upper lip Deep malar fat pad Bone FUNCTIONAL ANATOMY Functional Muscle Groups It is important to know the origins and insertions of the facial muscles (see Tables D.4–D.6). Agonist and antagonist groups function synergis- tically, with levators and depressors working in The skull insertion points are shown in Figure D.7. opposition for normal, balanced facial expression (Figures D.8 and D.9). Levator strength generally It is imperative that the injector have knowledge of predominates in youth, thus maintaining the position anatomical layers and an understanding of the differ- of soft tissue structures and counteracting down- ential effect of injecting above or below a muscle. This ward gravitational pull and depressor antagonists. is especially important in the midface, where incor- In youth, this balance may be disrupted by underly- rect placement may negatively impact animation and ing structural deficiencies, while loss of bone and/ upper-lip length. The layers of the midface comprise: or soft tissue become an increasing problem during Table D.4 Muscles of the Upper Face Muscle Origin Insertion Function Temporalis Temporal lines on the parietal bone Coronoid process of the Functions to elevate and retract the of skull and the superior temporal mandible mandible surface of the sphenoid bone Elevators Frontalis Galea aponeurotica along the Superciliary skin, where it Inferior: elevates the brow coronal suture interdigitates with the brow Superior: causes descent of anterior depressors hairline Depressors Procerus Periosteum of the nasal bone near Glabellar or mid-forehead Depressor of brow with two contraction the medial palpebral ligament dermis; merges with patterns frontalis 1: Lowers lateral end of brow 2: Produces lateral eyelid crow’s feet Depressor Nasal portion of the frontal bone Dermis beneath medial Moving and depressing brow supercilii head of brow Corrugator Medially and deep along Interdigitating with frontal Approximation and depression of supercilii nasofrontal suture/supraorbital muscle and inserting in the brows; creating vertical glabellar lines ridge of frontal bone midbrow skin Orbicularis Medial orbital margin, medial Preseptal segment inserts Thick orbital part closes eyelids tightly; oculi palpebral ligament, anterior into dermis of upper eyelid thin palpebral part closes eyelids lacrimal crest and brow lightly 22  Functional Anatomy Table D.5 Muscles of the Midface Muscle Origin Insertion Function Levator labii superioris Upper frontal process of maxilla, Skin of lateral nostril and Dilates nostril, elevates and alaeque nasi (LLSAN) medial infraorbital margin upper lip inverts upper lip “Elvis muscle” Levator labii superioris Broad sheet, medial infraorbital Skin and muscle of Elevates upper lip margin; extending from side of upper lip nose to zygomatic bone Zygomaticus minor Lateral part of zygomatic bone Skin of lateral upper lip; Pulls the upper lip backward, medial to zygomaticus major extends to nasolabial upward, and outward sulcus Aids in deepening and elevating the nasolabial sulcus Zygomaticus major Temporal process, anterior Temporal process, Elevates and draws angle of zygomatic bone anterior zygomatic bone mouth laterally Risorius Pre-parotid fascia Modiolus Draws back corner of mouth Table D.6 Muscles of the Lower Face Muscle Origin Insertion Function Depressor labii Line of mandible between mentonian Orbicularis muscle and skin Depresses lower lip inferioris symphysis and mental foramen of lower lip Depressor anguli Oblique line of the mandible and Modiolus Depresses corners of mouth oris mandibular tubercle Mentalis Upper mentonian symphysis and mental Orbicularis oris and skin of Elevates and projects lip fat compartments lower lip outward Platysma Deep fascia of upper thorax Lower border of mandible Depression of mandible Orbicularis oculi: Corrugator supracilii Upper Middle Procerus Lower Temporalis LLSAN LLS Zygomaticus major Zygomaticus minor Levator anguli oris Depressor septi nasi Temporalis Buccinator Platysma Masseter Depressor anguli oris Depressor labii inferioris Mentalis Figure D.7 Points of muscle insertion on the skull. 23  Myomodulation Figure D.8 Midface levators and synergists. Figure D.9 Lower face depressors. the aging process. With the loss of levator strength, The Periorbital Area depressors are more likely to predominate. As with muscles elsewhere in the face, the perior- bital muscles are connected by the SMAS. Lending Factors Influencing the Angle support to one periorbital area—for example, on the of the Mouth/Smile temporal bone beneath the orbicularis oculi—may therefore impact both adjacent and distant areas, In youth, the zygomaticus major plays a critical role thus impacting brow position and horizontal frontalis in tilting the angle of the mouth when smiling. When lines. zygomaticus major lifting power is reduced due to a lack of underlying structural support, the relative role In addition, orbicularis oculi and levator palpebrae of the risorius muscle increases, producing a more superioris function as antagonists. Supporting a horizontal smile. On further diminution of zygomati- weakening orbicularis oculi—for example, by placing cus major lifting capacity, the depressor anguli oris volume on the temporal bone or lateral zygoma— (DAO) predominates with a resultant “DAO smile” may effect improved upper eyelid function, improve (downturned angles of the mouth; Figure D.10). The lateral scleral show, and reduce compensatory fron- lack of tissue resistance leading to a DAO smile may talis action. Lateral cheek support may also facilitate be age-related or secondary to structural deficiency eye closure, thus serving great practical purpose in in youth. facial palsy patients. 24  Functional Anatomy Figure D.10 Smile patterns as mediated by the relative balance of elevators and depressors. Blue circle, modiolus. Indirect effects of treating the lateral zygoma (Ck1,2) The Perioral Area include: Adding tissue resistance over the mentalis muscle Shortening the lid–cheek junction (C1) inhibits upward rotation of the chin, increases Improving the intercanthal angle vertical height and may also influence lower-lip ever- Normalizing the position of the brow sion, as illustrated in a recent study detailing reduc- Enlarging eye size tion in size of thick Asian lips by adding volume to Improving horizontal forehead lines the chin area. Adding resistance over the DAO Improving the nasolabial fold inhibits its downward traction, while layering prod- Improving the jawline uct over the orbicularis oris and DAO are invaluable See also Figure D.11. methods for balancing the perioral region in facial Figure D.11 The indirect effect of filler placement in the deep temporal region (T1), lateral zygoma (Ck1), and lateral cheek (Ck4) on adjacent and distant muscles. Note the improvement in upper eyelid function and the reduction in forehead lines. No botulinum toxin was used. (Left) Before; (right) after. 25  Myomodulation Figure D.12 Improvement of upper lip rhytides after layering HA over the DAO and orbicularis oris. (Left) Before; (right) after. palsy patients where asymmetry on smiling and pho- HOW I DO IT nation may drastically reduce quality of life. Adding resistance over the orbicularis oculi may inhibit upper lip rhytides (Figure D.12). For chin wrinkling/expressing disappointment, see Figure D.13. The upper lip levators function as a synergistic group. For gummy smile, see Figures D.14–D.16. Strengthening zygomaticus major and minor function by adding support in the lateral cheek (Ck1,2) may For perioral lines, see Figure D.17. thus indirectly improve a gummy smile by inducing relaxation of the LLSAN. For the treatment of facial palsy with toxins: Document meticulously with photographs and vid- When treating the upper cutaneous lip (Lp8), also eos both at rest and in animation. treat Lp1 where indicated to provide deep support and Assess for underlying residual facial nerve func- prevent undue flattening of the vermilion lip. tion on the palsy side, e.g., platysma, zygomaticus major. When balancing a “joker’s smile” (overactive zygo- Treat the hyperdynamic side of the face with toxins maticus major): in order to counter the Hering-Breuer reflex; pro- ceed conservatively in the perioral area to mini- Treat Ck4 to stretch the risorius, thus improving its mize functional discomfort. tensile strength. Follow up at 2 weeks for possible top-up with toxins. Place Ck1 points posterior to the bony suture, Caution that phonation and chewing may initially facilitating less strengthening of the zygomaticus be affected and warn against inadvertent lip biting major. and drooling. 26  How I Do It Figure D.13 (a) Codes; (b) technique. Figure D.14 Codes for gummy smile. Encourage chewing on the weaker side in an Fillers may be used to rebalance the face in cases of attempt to recruit muscle strength. facial palsy, thus contributing significantly to quality Myomodulation with fillers may be attempted at of life. Figure D.19 illustrates salient clinical observa- 1 month after toxin treatment. See also Figure D.18. tions over a 6-month period before and after a single 27  Myomodulation Figure D.15 Muscle vectors to consider when treating a gummy smile. Figure D.16 Treatment Codes for addressing a gummy smile. 28  Complications Figure D.17 Codes and ­technique for ­perioral lines. treatment with fillers based on myomodulation prin- ciples. Note that no toxins were used. The main details before treatment are shown in Table D.7. Treatment was according to the principles of ­myomodulation (Figure D.20). The main details after treatment are shown in Table D.8. COMPLICATIONS Injecting filler above the upper-lip levators may lead to an undue lengthening of the upper lip, especially in patients with structural deficiencies Figure D.18 Potential botulinum toxin treatment areas in facial palsy. and a lengthened upper lip at baseline. 29  Myomodulation Figure D.19 The evolution of facial symmetry and muscle function upon smiling during the 6 months following treat- ment with mechanical myomodulation in a patient with facial asymmetry post-surgery for an acoustic neuroma. Table D.7 Clinical Details of Patient’s Left and Right (Palsy) Sides Before Treatment Left Side Right Side (Palsy Side) Deviation of mouth/oral commissure to L Scleral show as patient tries to close eyes Prominent nasolabial fold Excessive activation of orbicularis oris and platysma activity on Narrower eye attempting to close eyes Some platysma activity on smiling, signaling residual VII activity Injecting below the upper-lip levators may levators) may initially influence speech; it is pru- increase muscle action, aggravating a gummy dent to warn patients beforehand. smile. Large volumes placed above the upper-lip levators Injecting over the muscles of phonation (DAO, may lengthen the upper lip or induce an unnatural depressor labii inferioris, mentalis, and upper-lip smile. 30  Top 10 Tips Figure D.20 Treatment areas and target muscles. Injection depth is indicated by red (superficial to muscle), yellow (under muscle), or blue (structural injections). Table D.8 Clinical Details of Patient’s Left and Right (Palsy) Sides After Treatment Left Side Right Side Reduction in the upper lateral excursion of the Immediately after treatment zygomaticus major muscle on his left side Better positioning of the oral commissure, upper and lower lips Improved facial symmetry Deeper NLF on R due to increased lever effect on Upper lip levators Oral commissures more balanced Less scleral show Better alignment of the oral commissures One month after treatment Contraction of zygomatic muscles facilitated Less recruitment of platysma At 6 months Closing eye with less recruitment of zygomaticus major Treating NL1 and Lp8 will block levator anguli oris 2. Fillers may either facilitate or reduce muscle (LAO), thus improving a gummy smile, but length- activity, thus differing from botulinum toxin, which ening the upper lip in patients with a long upper lip. promotes a temporary flaccid paralysis. Placement below the upper-lip levators will 3. Always treat the lateral vectors (Ck1, Ck4) first in strengthen muscles, thus elevating and everting order to mitigate the gravitational sagging which the upper lip, but may worsen gummy smile. weakens elevators, thus facilitating depressor action. 4. Work consciously with the concept of synergists TOP 10 TIPS and antagonists. 5. The upper-lip elevators function synergisti- 1. In complex asymmetry, consider using HA fillers cally. Strengthening one muscle (e.g., zygo- as an adjunct to treatment with botulinum toxin. maticus major) may induce relaxation of others 31  Myomodulation (e.g., LAO), thus improving a gummy smile by 2. Swift A & Remington BK. The mathematics treating the lateral cheek vectors first. of facial beauty. In: Jones DH & Swift A, eds. 6. Boluses injected with a needle on bone usually Injectable Fillers: Facial Shaping and Contouring, facilitate muscle movement via a lever or pulley 2nd ed. Wiley: Oxford; 2019, pp. 29–61. effect. 3. De Maio M. J Cosmet Laser Ther. 2003;5:216–7. 7. Fanning with a cannula above muscles in the 4. De Maio M & Bento RF. Plast Reconstr Surg. subcutaneous zone usually reduces muscle 2007;15(7):917–27. movement by stretching fibers and adding tissue 5. Alam M & Tung R. J Am Acad Dermatol. resistance. However, 2018;79(3):423–35. 8. Exceptions to this rule include 6. Hutto JR & Vattoth S. Am J Roentgenol. Muscle block with needle on bone in LLSAN, 2015;204(1):W19–26. e.g., when treating a gummy smile. 7. Sykes JM et al. Plast Reconstr Surg. Increasing tensile strength of risorius when 2015;136(5):204–18. fanning over buccinator. 8. Cotofana S et al. Plast Reconstr Surg. 2015;136(5 9. Be aware of the angle of needle/cannula when Suppl):219S–34S. applying myomodulation principles. 9. Humphrey S et al. Plast Reconstr Surg. In the midface, 2015;136:235–57. A ∼30° cannula angle to skin will lead to 10. Prendergast PM. Anatomy of the face and neck. placement in the SOOF (i.e., superficial to In: Shiffman MA & Di Giuseppe A, eds. Cosmetic upper-lip levators). Surgery: Art and Techniques. Springer: Berlin; A ∼60° cannula angle will facilitate deposi- 2013, pp. 29–45. tion in the deep malar fat pad (i.e., deep to 11. Eskil MT & Benli KS. Comput Vis Image Underst. upper-lip levators). 2014;119:1–14. 10. Respect your learning curve; do not attempt treat- 12. Coleman SR & Grover R. Aesthet Surg J. ment of facial palsy patients unless you are able 2006;26(1S):S4–9. to correct asymmetry in normal patients. This 13. Peng PHL & Peng JH. Adding Volume for holds true particularly for addressing the smile. Reduction of Thick Lips in the Asian Patient. Dermatol Surg. 2018;44(2), pp. 296–298. References 1. De Maio M. Aesthetic Plast Surg. 2018;42(3):​ 798–814. 32