Aesth. Plast. Surg. 19:183-191, 1995 Aest]aeuc _ t'lastlc Surgery © 1995 Springer-Verlag New York Inc. Mimetic Modulation for Problem Creases of the Face Wolfgang Miihlbauer, M.D., Jeffrey Fairley, M.D., and Jan van Wingerden, M.D. Munich, Germany and Pretoria, Republic of South Africa Abstract. Problem creases of the face such as frontal lines and frown lines, crow's feet, deep nasolabial and perioral folds, and cervical bands may be caused by the aging process, excessive exposure to the sun, disease, or genetic disposition. The condition may become aggravated by habitual hyperkinesia of certain mimetic muscles like the frontalis, corrugators, orbicularis oculi, levatores labii superiotis, zygomatici, and the platysma. The diagnosis is established clinically by electromyography and selective muscle and nerve blocks. In these cases we advocate regulation of the mimetic hyperkinesia through selective myotomy, myectomy, and neurotomy of the responsible mimetic muscles (mimetic modulation). These procedures may be performed exclusively or in combination with a blepharoplasty, rhytidectomy, or other procedure. Our experience with 60 patients over the past five years (medium = 3.5 years) is presented. Problems and complications such as paresthesia and hypesthesia, partial paresis and asymmetry, incomplete correction, and recurrences are discussed. We believe that mimetic modulation is a valuable concept in treating problem creases and thereby improves the results of the aesthetic surgery of the face. yield unsatisfactory results. Problem creases such as forehead and frown lines, crow's feet, deep nasolabial folds, and vertical bands of the neck are hardly improved or recur quickly to the chagrin of the patient and the surgeon alike. A closer look at these cases, using neurological and selective EMG examinations of the muscles of facial expression, revealed the amazing finding of habitual hyperkinesia of the mimetic muscles, which could hardly become relaxed voluntarily. Prolonged hyperkinesia of the frontalis muscles eventually puts furrows in the forehead. Hyperactive corrugator muscles will carve out typical frown lines. The orbicularis oculi muscles will produce crow's feet. The levator labii superioris, levator alae nasi,and the zygomatic muscles deepen nasolabial folds. Hyperkinesia of the orbicularis oris muscle is at least in part responsible for the typical perioral wrinkles as is the hyperactive platysma muscle responsible for the vertical bands of the neck [2, 3, 6, 7] (Figs. 1-3 ). Key words: Facial creases Mimetic modulation--Myoneurotomy Mimetic Modulation Facial rhytides are usually the result of aging, excessive exposure to sunlight, disease, or genetic disposition. They are treated by a variety of methods such as injections, implants, dermabrasion, rhytidectomy, and blepharoplasty, with generally good results. In a number of cases, however, the conventional treatment may Correspondence to Wolfgang Miihlbauer, M.D., Abteilung f'tir Plastische, Wiederherstellende und Handchirurgie, Zentrum ftir Schwerbrandvedetzte, Klinikum Bogenhausen, Englschalkinger Str. 77, 81925 Miinchen, Germany In view of these observations, selective myotomy, myectomy, or neurotomy of the hyperkinetic facial muscles--well known as treatment for blepharospasms and facial spasms---should be a causative approach to reduce and thereby modulate the mimetic hyperactivity and smooth those recalcitrant creases. This operative mimetic modulation may be performed as a singular procedure or in combination with a rhytidectomy or blepharoplasty as an adjuvant therapy [4, 5]. During the past five years (medium followup period was 3.5 years) 60 patients were treated with mimetic modulation for purely aesthetic indications. We report on the details of the various procedures and present typical examples with long-term results. Mimetic Modulation for Problem Creases Fig. 1. (A) Anatomy of the mimetic muscles (from J. SobottaJH. Becher: Atlas der deskriptiven Anatomie des Menschen (1. Teil). Miinchen: Urban & Schwarzenberg, 1967, p 288. (B) Anatomy of motor and sensory nerves of the face (from J. Sobotta/H. Becher: Atlas der deskriptiven Anatomie des Menschen (3. Teil). Miinchen: Urban & Schwarzenberg, 1973, p 205) Fig. 2. (A) Hypertrophy of the corrugator muscles: cadaver dissection. Exposure through coronal forehead flap. (B) Hypertrophy of the corrugator muscle: histological section (H.E. stain, magnification × 250) .A. .. i L i i i Irn ~ L : ! ! i i iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii iiiiiiiiiiiiiiiiiiii ii i ii i iii i¸ ii ii ii ¸ I I l I m~ I I I Fig. 3. (A) Electromyography of a normal corrugator muscle at rest (left) and during frowning (right). (B) Electromyographical tracing of a hyperkinetic corrugator muscle at rest (left) and on frowning (right). Hyperactive muscle spikes, no complete relaxation possible. W. Miihlbauer et al. 185 Fig. 4. (A) Representation of various myotomies described herein, drawn over the original figure shown in Figure 1A. (B) Sites of the neurotomies described herein, drawn over the original anatomy shown in Figure lB, _ _ JB I 1 I I I I _ I I__ Im= Jn~ ~ j I I _ _ l ~ J I 1 I Fig. 5. (A) Electromyography of a hyperkinetic corrugator muscle at rest (left) and when frowning (right) before partial myectomy and neurotomy. Hyperactive muscle spikes, no complete relaxation possible. (B) Electromyography of a hyperkinetic corrugator muscle at rest (left) and on frowning (right) one year after partial myectomy and neurotomy. Minimal electrical activity at rest. Reduced activity on frowning. No signs of denervation Operative P r o c e d u r e s During the preoperative examination the main vectors of the mimetic muscle contractions are marked with a marking pen with the patient in an upright position, with the face at rest and animated. The procedures are performed with the patient awake but under intravenous sedation and sensory nerve blocks with some superficial subcutaneous local anesthesia [0.5% xylocaine with vasopressin (POR---8 Sandoz: 3 units in 50 cc of local anesthetic)]. The muscle fibers must not be infiltrated nor the facial nerve branches blocked. A nerve stimulator is used intraoperatively to find and stimulate the fine branches of the facial nerves that go to the various muscles. The responsible facial muscles are either dissected or partially resected under constant control with the patient awake and cooperating. Myotomy and myectomy are sufficient procedures for treating mild forms of mimetic hyperkinesia. For a good and long-lasting result, we usually perform a selective neurotomy the extent of which depends on the severity of the problem. The resulting effect becomes more pronounced as one transects the nerve fibers closer to the main branches. Both severed nerve ends are resected and coagulated to prevent spontaneous reinnervation. In most instances a symmetrical approach is mandatory (Figs. 4A, B, 5A, B). H o r i z o n t a l F o r e h e a d Lines Deep horizontal lines develop in the forehead as a consequence of hyperkinesia of the frontalis muscles. Ordinarily two to three horizontal myotomies of the 186 Mimetic Modulation for Problem Creases Fig. 6. (A) Intraoperative view of partial myotomy and neurotomy of the frontalis muscle during a coronal, subperiostial forehead lift. One temporofrontal branch of the facial nerve is lifted with a nerve hook (arrow) at the site of the neurotomy (right side of forehead and temporal region). (B) Deep horizontal forehead lines in a 50-year-old man preoperatively. (C) The patient six months after mimetic modulation (see A) frontalis muscles parallel to the main furrows performed during a frontal lift yield a pleasing result with enough muscle action preserved. The trigeminal nerve branches running directly over the external muscle fascia must be spared. At the same time, through this access path or using endoscopy, a near total myectomy of the corrugator muscles is done to erase any vertical skin creases. If the patient does not want a coronal incision, however, we advocate a partial neurotomy of the temporofrontal branches of the facial nerve to the frontalis muscles to smooth or even erase the horizontal lines. With the help of a nerve stimulator, one may differentiate usually two to three terminal branches of the main temporofrontal branch of the facial nerve between the temporal hairline and the eyebrow. These branches may be approached directly through a small skin incision under the deep layer of the temporofrontalis fascia or under a temporal skin flap in the course of a facelift procedure. One terminal nerve branch-usually the uppermost--must be preserved for the desired modulated animation. A preoperative nerve block helps to evaluate the prospective effect. One should avoid cutting the main temporofrontal branch over the zygomatic arch for it will make the eyebrows droop and the forehead immobile. A totally paralyzed forehead is exceptable only in patients with unilateral facial palsy to balance the facial expression (Fig. 6A-C). Frown Lines Permanent, deep frown lines are a consequence of chronic hyperactivity of the corrugator muscles, which originate at the frontonasal suture line and insert in the forehead skin above the eyebrows. The corrugator muscle is innervated primarily by a distinct branch of the facial nerve, which separates from the frontotemporal branches to the frontalis muscle near the lateral end of the eyebrows. There are several ways to flatten or even erase the frown lines. A partial myectomy of the deep medial portion of the muscle at its origin through a small incision in the medial eyebrow is advisable only for minor wrinkles. Deeper furrows resulting from true muscle hypertrophy need a subtotal excision and a selective neurotomy of the above-described branch of the facial nerve through a separate stab incision at the lateral end of the eyebrows. This nerve branch may be stimulated percutaneously and then dissected under loupe magnification deep to the orbicularis oculi muscle at its lateral circumference. The myectomy may also be performed through an upper-eyelid incision during a blepharoplasty, and the neurotomy under the temporal flap during the course of a facelift. A coronal facelift provides the best exposure. When one resects the medial portion of the corrugator muscle, the crossing supratrochlear and medial frontalis neurovascular bundles must carefully be dissected out and preserved (Fig. 7A-F). Crow's Feet Crow's feet form as radiating wrinkles around the lateral canthus and the lower eyelid perpendicular to the contraction of the orbicularis oculi muscle. Crow's feet may be an attractive sign of smiling, but when permanently engraved, even in repose, they are disliked by some individuals. The major cause of crow's feet is longstanding hyperkinesia of the eyelid sphincter muscle as a result of trying to protect the eyes from W. Miihlbauer et al. 187 Fig. 7. (A) Intraoperative view after partial myectomy of the right corrugator through an upper blepharoplasty approach. (B) Intraoperative exposure of the rami frontotemporales of the facial nerve during a facelift with the branch to the corrugator muscle isolated with a nerve hook before separation and coagulation. The various nerve branches have been defined intraoperatively with the help of a nerve stimulator. (C) Deep frown lines in a 51-year-old woman with hyperkinetic corrugator muscles at rest before treatment. (D) Forehead at rest three years after mimetic modulation (see A and B), upper blepharoplasty, and temporal rhytidectomy. (E) Aggravated vertical creases on frowning before treatment. (F) Minimal glabellar lines on frowning three years after mimetic modulation (see A and B), upper blepharoplasty, and temporal rhytidectomy sun glare and wind or from squinting instead of wearing corrective eyeglasses. Correction is best achieved with a pie-shaped segmental myectomy of the orbicularis oculi muscle at the lateral comer of the eyelid done during a blepharoplasty. The cut muscle edges must be spread apart and sutured in place to prevent a spontaneous reunion of the interrupted muscle ring. One should coagulate and transsect at least two small nerve fibers to the orbicularis muscle deep to this resected segment; the nerve fibers derive from the main zygomatic branch of the facial nerve. Permanent peretic lagophthalmus is not likely to occur because enough nerve fibers to the orbicularis coming from below and above remain. The same myectomy and neurotomy may be performed without a blepharoplasty during a facelift. The tempo- 188 Mimetic Modulation for Problem Creases Fig. 8. (A) Intraoperativeview of segmental myectomyof the orbicularis oculi muscle at the lateral canthus. (B) Intraoperative view of facial nerve branches to the orbicularis oculi muscle elevated by a hook at the site of a neurotomy over the right zygoma through a facelift exposure. White rod demonstrates the level of the neurotomy. (C) Excessive crow's feet on smiling and squinting in a 38-year-old woman before treatment. (D) Improvementone year after mimetic modulation (see A and B) ral skin flap must be elevated anteriorly to the lateral corner of the eyelid and over the body of the zygoma. The nerve fibers are found with the help of the stimulator placed under the SMAS, entering the orbicularis muscle fibers from underneath (Fig. 8A-D). Nasolabial Folds Besides sagging cheek skin and fat accumulation, deep nasolabial folds may also be the result of hyperkinesia of the zygomatic, levator labii superioris, and levator alae nasi muscles. They originate at the zygoma, the maxilla under the inferior orbital rim, and the lateral part of the frontonasal suture medial to the medial canthus. They then insert and interdigitate with the orbicularis otis muscle between the corner of the mouth and the nostril to form a common musculofibrous raphae, which interconnects closely with the dermis medially to the nasolabial fold. The unbalanced hyperactivity and even grimmacing of a patient with unilateral facial palsy on spontaneous animation is a perfect example of the effect of this muscle group on the nasolabial fold. Tightening of the skin or even a SMAS lift is not going to produce a satisfactory appearance of the nasolabial fold if mimetic hyperkinesia is the major contributing factor. In addition to the facelift procedure, we weaken the muscle action by detaching the bony origin of the zygomatic muscles and the levator labii superioris, resect approximately a 10-ram portion of the muscle, and perform a partial denervation of as many nerve branches as visible near the lateral edge of these muscles. The major zygomatic and buccal branches of the facial nerve must be preserved, however, for normal animation. The levator alae nasi should not be weakened for functional reasons concerning the nasal valve mechanism (Fig. 9A-C). Vertical Bands o f the N e c k Some individuals are capable of activating their platysma muscle in such a way that one or several vertical bands become obvious through the neck skin during animation. Chronic, spasmlike hyperkinesia is partly responsible for this rudimentary panniculus carnosus muscle hypertrophy, which is most pronounced W. Miihlbauer et al. 189 Fig. 9. (A) Intraoperative view of hypertrophic zygomaticus major and minor muscles at their origin on the right zygoma elevated with a rubber sling. The cannula of the nerve stimulator points to a nerve branch of the rr. zygomatici entering the muscle at its origin. The situation before partial myectomy and neurotomy during a SMAS facelift. (B) Deep nasolabial folds due to hyperkinetic zygomatic and levator labii muscles in a 42-year-old woman before treatment. (C) Improvement two years following mimetic modulation (see A) in combination with a SMAS-temporobuccal rhytidectomy Fig. 10. (A) Intraoperative view of an endoscopic myotomy of the platysma muscle. (B) Pronounced vertical bands of the neck due to a hyperkinetic platysma muscle in a 53-year-old woman before treatment. (C) Improvement six months after partial endoscopic myotomies of the hypertrophic platysma bands submentally and supraclavicularly as sole procedure without skin tightening or excision Mimetic Modulation for Problem Creases 190 Table 1. Problems and complications (n = 60 patients) Patients Paresthia or hypesthesia temporary permanent Partial facial paresis temporary permanent Facial asymmetry temporary permanent Incomplete correction Recurrence ferred to combine myectomies with neurotomies for permanent results. Discussion 10 0 2 0 2 0 6 5 along the medial diastasis. These tight muscle bands are diagnosed by observing them when the patient is animated and electromyography is performed. They must not be misinterpreted as folds of redundant neck skin for which simple neck-skin tightening would suffice. Isolated paramedian platysma muscle bands may be approached through a submental incision. A mere transsection at the level of the hyoid bone is likely to reunite. Therefore, we resect a triangle of approximately 3 cm of muscle and close the cephalad portion of the muscle diastasis with sutures. The lateral portion of the platysma muscle is best approached through a necklift exposure and partially transsected. The cephalad muscle fibers are transposed laterally and sutured to the stenocleidomastoid fascia. However, a platysma muscle strip of 6-8 cm over the mediolateral aspect of the neck must be left intact to prevent the herniation of the submandibular glands. The severe cases where there are multiple platysma bands under thin neck skin, a neurotomy of the ramus colli n.facialis may be considered (Fig. 10A-C). Problems and Complications (Table 1) Temporary parethesia and hypesthesia of the supratrochlear and frontalis branches of the trigeminal nerve are rather common after myectomy of the corrugators. They are the result of manipulation of the nerve fibers during the procedure. Sensitivity usually returns within a few weeks. Partial motor paresis or weakness is also a temporary condition resulting from the numerous interconnections of the facial nerve branches. Obvious asymmetry has occurred in two cases to the great consternation of the patients. It resolved completely within four weeks, however. Incomplete correction was a problem in the beginning when we heavily relied on myectomy alone. The same was true for recurrences. With increasing experience we pre- Hyperkinesia, with the inability to relax certain mimetic muscles of the face, should be looked for as a contributing factor in patients with problem creases. In these individuals relaxation rather than further tightening of certain muscles used in facial expression is indicated. The diagnosis is made clinically using selective electromyography and diagnostic muscle and nerve blocks. These blocks also help to evaluate the eventual operative result preoperatively. We tried botulinum toxin A with only a temporary effect up to three months. This substance was found difficult to use precisely for it tends to dissipate and block neighboring muscle groups that are not the target [1]. Accidentally cutting a facial nerve branch during a facelift procedure is a concern of plastic surgeons. At first glance it seems strange to introduce intentional neurotomies for treating purely aesthetic problems. On the other hand, contralateral selective neurotomy is a well-established procedure for balancing the face of a patient with hemifacial palsy who grimaces involuntarily with the intact half of the face. An amazing amount of nerve fibers must be cut before the mimetic hyperactivity is visibly weakened because the facial nerve fibers have abundant interconnections in the periphery. It is known that they regenerate and form new pathways generously. A complete and rather permanent paralysis may result only if one severs the main branches near or within the parotid gland. The patient should be informed about the possibility of at least temporary facial paresis or asymmetry. The latter is of more concern because it is more obvious. Incomplete corrections and recurrences are going to decrease as we gain experience. Mimetic modulation, either alone or in combination with standard aesthetic surgical procedures, is an additional tool for treating problem facial creases which result from mimetic hyperkinesia. Acknowledgments. We are grateful to Dr. Keiditsch, head of the Pathological Institute, Dr. Hupfer, Department of Neurology, and Mr. Krischock, Department of Medical Illustrations at St~idtisches Krankenhaus Bogenhausen, Mtinchen, for their help and cooperation. References 1. Borodic GE, Cozzolino D: Blepharospasm and its treatment, with emphasis on the use of botulinum toxin. Plast Reconstr Surg 83:546, 1989 W. Mfihlbauer et al. 2. Freilinger G, Gruber H, Happak W, Pechmann U: Surgical anatomy of the mimic muscle system and the facial nerve: importance for reconstructive and aesthetic surgery. Plast Reconstr Surg 80:686, 1987 3. Greden JF, Genero N, Price L: Agitation-increased electromyogram activity in the corrugator muscle region: a possible explanation of the "Omega Sign"? Am J Psychiat 142:348, 1985 4. Jones TW Jr, Waller RR, Samples JR: Myectomy for essential blepharoplasm. Mayo Clin Proc 60:663, 1985 191 5. Miihlbauer W, Lang G: Die FazialislS_hmung als plastisch-chirurgisches Problem. Med Klin 69:1873, 1974 6. Pessa JE, Brown F: Independent effect of various facial mimetic muscles on the nasolabial fold. Aesth Plast Surg 16:167, 1992 7. Tassinary LG, Cacioppo JT, Geen Th R: A psychometric study of surface electrode placements for facial electromyographic recording: I. The brow and cheek muscle regions. Psychophysiology 26:1, 1989