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Botulinum Toxins for Facial Wrinkles: Beyond Glabellar Lines


Authors: Steven H. Dayan, MD and Corey S. Maas, MD

Manuscript developed by IntraMed Educational Group

Draft Date: November 2, 2006

[Data source: published literature; authors]

Botulinum toxins for facial wrinkles: beyond glabellar lines

Steven H. Dayan, MDa and Corey S. Maas, MDb,c

a. Clinical Assistant Professor, Department of Dermatology, University of Illinois; Chicago, Illinois

b. The Maas Clinic San Francisco; and cDepartment of Otolaryngology-Head and Neck Surgery, Division of Facial Plastic Surgery, University of California, San Francisco

a. Corresponding author for proof and reprints:

Steven H. Dayan, MD
Department of Dermatology,
University of Illinois
845 N. Michigan Ave, Suite 923
Chicago IL 60611
(312) 335-2070
(312) 335-2074 (fax)
sdayan@drdayan.com (email)

b. Coauthor address:

Corey S. Maas, MD
2400 Clay Street
San Francisco, CA 94115
(415) 567-7000
(415) 567-7011 (fax)
drmaas@drmaas.com (email)

<>

Dr. Steven H. Dayan is a national education faculty member of Allergan, Inc. He has received research grants from Allergan, Inc., and Medicis Pharmaceutical Corporation.

<< Statement of Financial Disclosures/Funding Sources Needed for Dr. Maas>>

Synopsis

Botulinum toxin type A (BTX-A) has been utilized for years with excellent results for upper facial cosmetic applications. Because of this success, the use of BTX-A for facial aesthetics has expanded to the lower facial and neck regions. BTX-A, especially when used in combination with fillers, has generally proven to be safe and efficacious in these areas. For optimal results, however, a number of issues must be taken into consideration, including dosing differences versus upper facial applications, the specific type of botulinum toxin utilized, and the importance of precise placement and injection technique. In this article, we present our experience with BTX-A in the lower face and neck, and compare and contrast our current practices with those reported by others.

[Article]

Botulinum toxin type A (BTX-A) has been successfully utilized for many years for a variety of cosmetic indications. Its use for upper facial rhytids and dynamic line applications (most commonly for the treatment of glabellar lines, horizontal forehead lines, and crow’s-feet) is particularly widespread [1,2]. The use of BTX-A in the lower face initially was considered “controversial” as results were thought to be unpredictable [3]. However, the demarcation between the upper and lower face was somewhat arbitrary and subjective, and the utility of this product for a number of lower facial and neck applications is becoming clear [3].

Although most of our use of BTX-A is still in the upper facial region, in our practices it also is used in the lower face and neck. The literature, however, remains sparse, with most published accounts of the use of BTX-A in the lower facial and neck regions reporting individual clinician experience, not rigorous scientific studies. Here, we synthesize and comment on this literature, and compare and contrast what has been reported with our observations and current practices.

Available botulinum toxin products

There are several brands of BTX-A available and used for aesthetic purposes around the world. BOTOX (also known under the names BOTOX Cosmetic, Vistabel, and Vistabex; Allergan, Inc., Irvine, Calif.) is the most well-known brand of BTX-A, is used worldwide, and is the only brand available in the United States. Dysport (Ipsen Limited, Slough, United Kingdom) is available in some European, Asian, and South American countries, but is not approved or available in the United States and Canada. Xeomin (Merz Pharmaceuticals Frankfurt, Germany) is approved for use in Germany for noncosmetic indications. Several brands of BTX-A are manufactured in other areas of the world but are neither approved nor commercially available in North America.

The vast majority of literature and experience pertaining to the cosmetic use of BTX-A involves BOTOX. This is especially true with lower facial and neck applications, with only one known study [4] reporting experience with Dysport (mandibular contouring). There are differences between BOTOX and Dysport that affect dosing (more units of Dysport are needed to produce the same effect as BOTOX), and thus they cannot be used interchangeably, nor can results with one product be extrapolated to another. Recently published consensus recommendations for the utilization of BTX-A discuss the use of BOTOX only [5]. In this article, all discussions of BTX-A, unless otherwise specified, refer to BOTOX.

Another type of botulinum toxin-botulinum toxin type B (BTX-B)-is also available under the brand name Myobloc (Solstice Neurosciences, South San Francisco, Calif.). BTX-B differs from BTX-A in a number of important ways, eg, it appears to have a faster onset of action, a shorter duration of action, and an association with more pain during injection [6-8]. We are not aware of any studies that have evaluated the effects of BTX-B in terms of its cosmetic use in the lower face and neck.

The favorable results obtained with the cosmetic use of BOTOX-both in the lower face and general facial area-stem from its ability to act directly at the site of injection to produce a natural and relaxed look, minimizing dynamic wrinkles while retaining the patient’s ability to express emotion. This is due in part to its minimal migration from the site of injection to other tissues [9,10] where it could cause unwanted muscle weakening.

Treatment recommendations for specific anatomical sites

Perioral lip line

Chemodenervation of lip rhytids is the BTX-A procedure performed most commonly in the lower face, and meticulous injections in the right patients can produce optimal results [3,11]. Muscles treated include the orbicularis oris (primarily), depressor anguli oris (DAO), and mentalis (Fig. 1) [12]. It is unusual for a patient to request BTX-A treatment of the perioral lip line; rather, patients require information regarding treatment options, such as the risks and benefits of BTX-A, for this indication. Approximately 90% of the time, we administer BTX-A in this area in combination with dermal fillers (soft tissue augmentation).

In the literature and as seen in our practices, BTX-A treatment of the perioral lip line is not offered to individuals whose lives may be significantly affected by a potential compromise in oral competency (eg, singers, musicians, scuba divers, etc.) [1, 5,12-14]. As with any BTX-A procedure, patients may have unrealistic expectations and should be counseled regarding the potential benefits and optimal results [5,12]. We advise patients in advance about the possibility of adverse effects (AEs), especially those related to speech. Occasionally, patients receiving BTX-A in the perioral lip line will feel a little awkward with their lip motions for up to 2 weeks after treatment; for example, they might have to concentrate while speaking or drinking through a straw [3,13,14].

In terms of dosing, optimal results generally are obtained with 4 to 8 U (rarely going as high as 10 U) in the upper lip and 4 to 6 U (sometimes going as high as 8 U) in the lower lip. This is consistent with what others have found, where the total recommended starting doses for the upper lip and lower lip are 2 to 8 U and 2 to 6 U, respectively. (It should be noted that some practitioners recommend injecting the upper lip only, as treatment of the lower lip is thought by some to be associated with more AEs) [1-3,11-15]. It is recommended that the specific dose be determined based on muscle mass and the degree of weakening desired [3].

Injections at 4 to 5 evenly spaced points on the upper lip, and 4 to 5 evenly spaced points on the lower lip provide good results (see Fig. 1). Recommendations in the literature vary from 2 to 11 sites per lip, with 4 to 6 sites most commonly advised [1,2,11-15] and at least one physician suggesting a threading technique [3]. We tend to utilize ~1 U per injection (the literature recommends 0.5 to 2 U) [1-3,5,11-13,15]. Although we both sometimes inject a little bit at the midpoint, others advise against it [3,11,12,14].

When performing the injections, we stay close to the vermilion border (recommendations in the literature range from “just above” to 5 mm above the vermilion border) [3,11,12,14]. Along with others, we advise injecting superficially immediately over the vermilion [2,5,12].

In general, results with BTX-A treatment of the perioral lip line are not as dramatic as those seen in the upper face; however, patients who are particularly interested in improving this anatomical area are generally very appreciative of the results from this procedure. This concurs with a report in a “small series” of patients (number not provided) showing that although minimal improvement was seen by the treating clinician, all patients were satisfied with the results [1]. Also of relevance are findings of a retrospective study indicating that satisfaction levels were “uniformly high” in patients treated in the upper face and the mouth and/or neck areas (n=35) as compared with satisfaction levels for those treated in the upper face only (n=56) [15].

Results last about 10 weeks. Duration of effect may be shorter when treating the perioral lip line versus other lower facial areas due to the comparatively lower doses utilized [12]. Most patients tolerate BTX-A treatment of the perioral lip line well, although there is potential for dysarthria and/or drooling (usually associated with treating the corners of the lips) with higher doses [2,12,14]. The literature also reports rare cases of lip asymmetry and problems with articulation/elocution, suction, eating, brushing teeth, using a straw, whistling, and/or proprioception [2,5,12,14,16], and recommends that special care be taken with elderly females with severe rhytids and minimal muscle mass [3].

Oral commissures

The oral commissures are another popular area for BTX-A treatment in the lower face; indeed, this is a region patients typically present for improvement [11]. In addition, at least one physician has pointed to this area as having the lowest risk and highest patient acceptance of all the lower facial treatment sites [3]. The muscle involved here is the DAO (Fig. 2) [5]. As with the perioral lip line, oral commissures should not be treated in patients for whom possible compromise of oral competency would be debilitating (eg, singers, musicians, scuba divers, etc.) [5].

We have obtained good results with BTX-A 5 U/side as the standard starting dose for the treatment of oral commissures, which is slightly higher than the 2 to 4 U/side recommended by others in the literature [2,5,13,14]. We tend to administer 1 injection per side (others have suggested 1 U [2,5,14] or 2 U [3]). Injections can be made directly into the DAO muscle located on the mandibular body (see Fig. 2). A number of specific techniques have been recommended, with care taken not to inject too closely to the mouth or into the mental fold, or in a manner that will cause interaction with the orbicularis oris [5]; an injection 1 cm lateral and 1 cm inferior to the angle of the mouth [2]; an injection into the DAO belly at the level of the mandible (with caution taken not to inject medially into the depressor labii muscles) [14]; and an injection at the midpoint of the DAO with a second injection midway between the first injection and the caudal border of the mandible (taking care to avoid the DAO apex) [3].

We find efficacy and patient satisfaction to be high when treating the oral commissures in combination with a dermal filler. Patients can expect the BOTOX effects to last 10 to 12 weeks. Indeed, one author has commented that the treatment of oral commissures is associated with the highest patient satisfaction rate of all lower facial BTX-A applications.3

Potential complications associated with this procedure are often the result of injections that are not precisely placed. If injections are made too medially, there can be a flattening of the contour of the lower lip when the patient attempts to form an “O” (affecting the depressor labii inferioris); if injections are made too high, there can be problems with speech and suction [5,16]. Flaccid cheeks, an incompetent mouth, and an asymmetric smile can also occur [2,5]. In our practices, we have seen asymmetry following injections in this region. However any asymmetry that may occur is usually short-lived and resolves within 2 weeks with persistence of the beneficial effects. Similarly, lower lip weakness is a rare complication that also is short-lived.

Nasolabial folds

Treating the nasolabial folds is predominantly accomplished with dermal fillers. Indeed, there is debate on the utilization of BTX-A in this area [3], with a number of practitioners recommending that this treatment modality not be utilized for this application [2,14,16].

Some physicians, however, have had success using BTX-A to treat nasolabial folds [3,5,17]. According to these reports, patient selection is absolutely crucial [3,5,17], with a few recommending that the procedure only be performed in those patients with naturally short upper lips [5]. Another practitioner offers BTX-A injections only to those with “canine” smile patterns (strong raising of the medial portion of the upper lip), and not to patients with “Mona Lisa” smiles (commissures raised to the highest point in the smile), or “full-denture” (simultaneous contraction of all upper lip elevators and lower lip depressors) smiles [3,17].

In general, it is recommended that patients be carefully analyzed in terms of animation and smile patterns before recommending BTX-A therapy [17] and advised that changes to their smile may be seen.

Those recommending this procedure advise that relatively small doses be utilized, with different clinicians reporting somewhat different dosing ranges. Some physicians have advised that 1 U per side (2 U total) be utilized for the treatment of nasolabial folds [5,13]. In a report of his experience with over 1000 nasolabial fold injections, Kane details the evolution of his dosing preferences, first injecting this area with 5 U/side (10 U total), then shifting to 2.5 to 8.5 U/side (5 to 17 U total), with most patients in the 3.75 to 5 U/side (7.5 to 10 U total) range [17]. Doses were determined by the pattern and degree (strength) of the patient’s smile [17]. With subsequent experience, Kane revised his dosing slightly to ranges between 3.75 and 15 U (total dose), with most patients falling within the 5 to 7.5 U (total dose) range [3]. His injections for this indication are at the nasomaxillary junction, just superior lateral to the ala.

Recommendations for injection locations vary slightly and include the “lip elevator complex in the nasolabial fold” [5] and the levator labii superioris alaeque nasi muscle [3,17]. One injection per side is advised [5].

Duration of effect with BTX-A for the treatment of nasolabial folds has been reported to be up to 6 months [5]. Interestingly, patient satisfaction has been reported to have shifted with an advancing understanding of patient selection. Kane found that 16 of 25 patients analyzed (64%) were satisfied with the procedure results [3]. Analysis of these patients indicated that all of those who were dissatisfied had a “Mona Lisa” smile pattern, and because of this, Kane has been since offering the procedure only to patients with a “canine” smile pattern. This has led to an increase in patient satisfaction with the majority now being pleased with their results (concrete numbers not provided) [17].

Patients with “gummy smiles,” or smiles in which all the incisors and some of the gingival show, have been reported in the literature to generally also have deep nasolabial folds and to be good candidates for BTX-A [17]. We occasionally administer BTX-A for the correction of a “gummy smile,” using 2 to 3 U and injecting once just below the nose to elongate the upper lip. Higher doses and a different administration pattern (5 to 7.5 U/side, with the physician noting that “gummy smile” patients often have an asymmetrical smile and require different dosing on each side) also have been reported with good results [17]. Indeed, according to Kane, patients with a “gummy smile” have the highest satisfaction rates of all patients treated for nasolabial folds [17]. Dayan and Kempiners [18] have reported on the efficacy of BTX-A for reducing dynamic nasal tip ptosis associated with a short curling upper lip and a snarl-like smile. Injections of 5 U BTX-A into each depressor septi nasi and 3 U into each levator labii superioris alaeque nasi muscle resulted in a less ptotic nasal tip at maximal smile, a lengthening of the upper lip, a less snarled appearance, and a more horizontal base position.

Chin

BTX-A can be utilized to correct a dimpled chin, another popularly treated area.11 The muscle involved is the mentalis (Fig. 3). According to the literature, the ideal patient for this procedure is one in whom a dimpled chin is observed when saying certain sounds and/or with the mouth closed and at rest [3].

In a recent double-blind, placebo-controlled study, Beer et al. reported on the efficacy of BTX-A in 20 patients with chin rhytids [19]. Patients received 5 U BTX-A in one side of the mentalis (into the belly at its midpoint) and saline in the other. Both physicians and patients were able to discern, at rest and with full contraction and across all time points (from 2 to 12 weeks postinjection), which side of the chin was treated with BTX-A and which was treated with saline. These findings were statistically significant [19]. Based on results of this study, 5 U is a good starting dose of BTX-A in the chin. This is consistent with other reports in the literature, with most clinicians advising a starting dose of 4 to 6 U and indicating that 5 to 10 U is generally considered adequate, although some practitioners go as high as 12.5 U [2,3,5,12-14]. When treating the chin, we use between 5 and 10 U of BTX-A, with most patients receiving 6 to 8 U.

When injecting the chin, 2 injection points are recommended, with care taken not to inject too laterally (see Fig.3), although some clinicians advise using just 1 injection site [2,5,11-14]. If 1 injection is given, practitioners are advised to inject once in the midline mass of the muscle at the prominence of the chin [2,5,11-14], “at least 1 cm inferior to the mental sulcui” [2] and “as far from the lower lip (near the symphysis) as possible” [11]. If 2 injections are given, it is advised that they be symmetrical lateral injections each 5 mm lateral to the median cleft of the chin, with care not to go lateral of these sites [2,5,11-14].

The literature is divided in terms of the depth of injection, with some suggesting the mentalis should be treated with a deep injection [11] and others recommending injection of the superficial mentalis in order to leave the deep mentalis fully functional [3]. From a practical standpoint, the depth of the injection is not terribly important, as long as the injection is intramuscular.

Duration of effect when treating the chin has been reported to be from 3 to 4 months to up to 6 months [12,19] with maximal improvement in one study occurring 4 weeks postinjection [19]. In terms of patient satisfaction, the study by Beer et al. [19] reported that only 11 of 20 patients (55%) were satisfied with their results. The study investigators suggest that this somewhat low rate of patient satisfaction had to do more with the asymmetrical appearance associated with the split-chin study design than dissatisfaction with the improvement on the treated side [19].

Placing injections too high when treating the chin area with BTX-A can lead to complications like drooling and/or a drooping mouth [12,14,16]. Overinjection should also be avoided in this area as it can lead to complications ranging from lower incisor show to oral incompetence [2,3]. In addition, care should be taken when treating patients with extremely dimpled chins, as these patients may have a hypertrophic mentalis muscle and-although they appear to be the ones who will benefit most-are the population most affected by complications (oftentimes oral incompetence) [3,12].

Platysmal bands

The platysma is another popular area where BTX-A treatment can be successfully used in the lower face and neck (Fig. 4) [5,12,13,20,21].

Patient selection is especially important when considering BTX-A treatment of the platysmal bands, although there is some variation in the literature as to what constitutes an appropriate patient [5,12,20,21]. At least one clinician suggests that this procedure is appropriate for older patients who are not good candidates for surgery or who have had neck rejuvenation surgery and younger patients with strong bands who are not yet candidates for surgery [20,21]. Others recommend that only patients with obvious platsymal bands, those who have retained their skin elasticity, and those with minimal descent of submental fat should be treated [5,12].

Patient populations to avoid include those with necks with jowl formation and/or bone resorption [5,12] and those with excess skin in the neck area [20]. In our experience, BTX-A seems to work best as an adjunct to surgery in order to reduce persistent, residual banding that often becomes apparent following the face-lifting procedure [5]. Prior to the administration of BTX-A injections, patients should be made aware that variable results are seen in the neck, that treatment with BTX-A is not a substitute for long-term surgical results, and that BTX-A will have no effect on skin laxity or fat deposits [12]. It is, however, an excellent alternative for patients unwilling or unable to undergo platysmaplasty or face- or neck-lifting surgery.

In general, it appears that the neck requires higher doses of BTX-A than the lower face [2,16]. However, platysmal band dosing recommendations vary greatly in the literature, ranging from 2 to 40+ U/band [2,5,12-16,20,21]. We typically use 10 U per band. Some physicians recommend that the amount of BTX-A injected should be dependent on the thickness of the band, with thicker bands receiving more product [2,20].

Many clinicians prefer to use a lower dose and have the patient come back for touch-ups rather than use too high a dose initially, which could potentially result in dysphagia [5,14]. Again, however, what is considered an acceptable total dose limit varies widely, from 50 U [14,16] to 100 U [5] to 250 U [2,22]. Several physicians report that up to 200 to 250 U have been used per treatment session without issue (although 50 to 100 U doses were more common) [2,22].

Most clinicians report treating each band at 3 to 5 sites, with injections administered at 1 to 1.5 cm intervals from the jaw line to the lower neck [2,5,12,20,22]. One physician suggests more sites (3 to 8 per band) [14]; another recommends a wider spacing (4 cm between injection sites) [13]. In our practices, we use a slightly different technique, injecting the central third of the band at the cervical mental angle 1 to 2 or 2 to 4 times; in other words, not trying to treat the whole band up and down, but rather to recreate the cervical mental angle for the patient (see Fig. 4). Injections should be delivered into the belly of the muscle [2,12], with great care taken to inject into the platsymal muscle and not beneath it (eg, the strap muscles must be avoided); grasping and holding each band can be helpful [2,12,16,22].

The duration of effect for BTX-A in this area has been reported to range from 3 to 6 months [2,12,22]. It also has been reported that the effects last longer with each subsequent injection [22].

Patients receiving BTX-A injections into the platysmal bands have been described as “uniformly satisfied” [22]. Kane summarized his experience with 44 patient-injections, finding that “most” of the patients were “very happy” with the results, and all patients had at least a small subjective improvement following administration, with results growing more positive as doses increased (5 to 20 U per band were utilized) [20]. Younger patients, and those who had undergone prior surgery, had the best subjective results, and all patients had better response during animation versus repose [20]. In addition, in the previously mentioned retrospective study looking at patient satisfaction following BTX-A administration, satisfaction levels were “uniformly high” both for those treated in the upper face and the mouth and/or neck areas (n=35), as compared with those treated in the upper face only (n=56) [15].

Dysphagia, dysphonia, and neck weakness (weakness of the neck flexors, eg, while doing sit-ups or lifting the head off the pillow) are all potential complications when treating the platysmal bands with BTX-A [2,5,12,13,16,22]. In one analysis of 1500 patients, 15 patients (1%) had neck weakness and only 1 patient (0.067%) had clinically significant dysphagia [23]. As previously mentioned, dysphagia is associated with higher total doses; thus such doses must be used with caution [5]. In our experience, with proper dosing and attention to technique, these AEs are quite rare.

Another neck area in which some of the literature reports successful outcomes with BTX-A is the treatment of horizontal “necklace” lines [5,12,21]. However, we and some others have not had much success in this area [13]. A total of 15 to 20 U has been recommended for the treatment of “necklace” lines [5], with injections placed just above and below the horizontal lines [21], or small doses administered over multiple deep dermal sites (“dancing” along the lines) [5]. Kane and others are seldom using this technique due to inconsistencies or nominal results, despite their extensive experience (conversation between Michael Kane, MD and Corey Maas, MD, 2006).

Asymmetry/facial nerve paralysis

Carruthers et al. have reported that patients with hemifacial spasms (repeated clonic and tonic facial movements that draw the face over to the hyperfunctional side), hypofunctional issues, asymmetrical jaw movements, an off-centered mouth, and marginal mandibular nerve injuries are candidates for BTX-A injections [5]. A number of different muscles can be involved, including the zygomaticus, risorius, orbicularis, masseter, internal pterygoid, and/or the DAO [3,5].

Treatment of facial paralysis with BTX-A is highly variable and depends on the degree of deformity [24]. Therefore, there is not one uniform method of injection, nor are doses established to a “one size fits all” framework. In general, the opposing hyperfunctional muscle is treated to further create symmetry. The dose placed into the muscle is dependent on the size of the muscle and the force with which it is contracting. In general, doses can range from 5 to 35 U, with larger muscles requiring more BTX-A.

A dose of 10 to 15 U has been successful in relaxing a hyperfunctioning jaw [5]. For problems related to hypofunctioning, 1 to 2 U in the zygomaticus, risorius, and/or orbicularis muscle has been recommended [5]. <>

Masseter reduction

Success has been reported with the use of BTX-A in patients where correction of masseter muscle hypertrophy is desired for aesthetic (facial contouring) reasons (Fig. 5) [4,5,13,25,26]. Generally, masseter reduction is requested by those of Asian ethnicity, in particular the Korean population. Patients in whom this procedure is performed must have muscular hypertrophy as the underlying cause of facial widening, not a mandibular bony prominence [25].

We utilize BTX-A doses ranging from 10 to 25 U/side. The literature reports somewhat higher doses, ranging from an average of 25 to 30 U/side [5,13,25,26] to an average of 100 U/side [5] to 200 to 300 U/side [5], with some authors noting a trend towards more dramatic and longer-lasting results with higher injection amounts [5]. Results from a recent prospective dose-ranging study (N=22) analyzing the impact of 10, 20, or 30 U BTX-A per masseter-to our knowledge the only published BTX-A dosing study involving a lower facial application-indicate that doses should be above 20 U/side [26]. Finally, in a paper reporting the use of Dysport (not BOTOX) for a lower facial application, results were seen with doses of 100 to 140 U/side [4].

We both utilize 1 to 3 injection sites per side when treating the masseter muscle (see Fig. 5); others have recommended 1 site [26], 3 to 4 sites (depending on the width of the muscle) [4], or 5 to 6 sites [5] per side. We have the patient bite down, and then we hold the anterior or posterior aspect of the muscle and inject into the bulk of the muscle, usually over the buckled area, not higher or lower. A variety of similar placement recommendations is seen in the literature, including “the inferior masseter border” [25]; “the lower posterior portion of the masseter muscle” [26]; and “the contour line of the mandible” [4].

Masseter reduction is reserved for those with very prominent masseter muscles and large cheeks who are seeking a more sculpted cheek-jaw area. The effects are much more subtle than that of BTX-A applications in the upper third of the face. The goal of BTX-A is to atrophy the masseter muscle, thereby shrinking it. Maximal effect has been documented in the literature as being seen at 1 to 2 months [25], 3 months [4,5], and 4 months [26] postprocedure. Duration of effect has been documented to be 5 months with Dysport [4]; and with BOTOX to be at least 6 months [26], 6 to 7 months [5], and 6 to 8 months [25] postprocedure.

Patient satisfaction has been reported related to the treatment of masseter reduction. One paper cited 19 of 20 patients (95%) being satisfied with their results after receiving 25 U/side initially, with an additional 25 U/side as needed at 1-week intervals [25]. In another, 36 of 45 patients (80%) expressed satisfaction with the results 10 months after 25 to 30 U/side of BTX-A [5]. In another report, 4 of 7 patients (57%) considered their results to be satisfactory after a single 100 U/side (average) BTX-A injection [5]. In the study utilizing Dysport, 268 of 383 patients (70%) were “greatly satisfied” with the results, with another 88 (23%) “generally satisfied” [4]. Time to peak patient satisfaction has been reported as 3 months postinjection [26]. These patient satisfaction outcomes appear peculiar, given that the goal of treatment is muscle mass reduction, which would not be evident in a single treatment. In our experience, although some results may be evident as early as 2 weeks following treatment, the full benefit is usually not evident for 3 to 4 treatment cycles (approximately 1 year). Therefore, maximum patient satisfaction would also only be expected after this length of time.

Although some complications have been suggested following BTX-A treatment of the masseter muscle, such as mastication difficulty, muscle pain, speech difficulties, and awkwardness with smiling [4,5,13], none of our patients experienced any complications following BTX-A treatment of this area.

Considerations for using BTX-A in the lower facial/neck regions

In contrast to BTX-A utilization in the upper facial regions, the lower facial and neck areas are less forgiving of inexact technique and dosing that may lead to AEs (although it is important to remember that most BTX-A adverse effects, while undesirable, are completely reversible). However, with experience, and along with others, we have become aware of a number of factors and techniques that can greatly improve the chances for successful utilization of BTX-A in the lower face and neck.

First, an understanding of the functional anatomy of the lower facial muscles is extremely important for success [16,27,28]. Less-than-ideal outcomes (eg, smile dynamics that are not aesthetically pleasing) are often related to a functional imbalance, with the risk of such outcomes being higher in the lower versus upper face because of the greater complexity of muscle arrangements in the lower facial area [11,29]. Such outcomes, however, are much less likely when functional dynamics are understood and taken into account.

A related consideration when injecting in the lower face is that complications can be minimized by site- and patient-specific dosing [16]. Many lower facial muscles vary greatly in the way they move each individual’s lower face; thus, ideally clinicians are not just memorizing doses and injection points, but are individualizing therapy based on each patient’s unique animation patterns [3].

Second, good technique-most importantly, precisely placed injections-is key to minimizing complications in the lower face and neck [13,16]. Indeed, most BTX-A-related complications are due to poor injection technique [5]. Excellent control is needed for success in the lower face, because unlike the upper face, the lower face cannot tolerate even a few misplaced units, which most commonly affect the smile in an undesirable way [3]. In addition to precise placement, injecting superficially and symmetrically are important in terms of avoiding complications [5].

Third, it is important to keep in mind that doses are much smaller for perioral treatments versus upper facial applications, as the lower facial muscles (in particular, those supporting the oral complex) respond more strongly to the same BTX-A dose [5,13]. A related dosing issue is that, especially when clinicians first begin to administer BTX-A injections into the lower face, a conservative approach (eg, lower dosing followed by touch-ups) is recommended, as lower doses are associated with fewer AEs than higher doses [3,5], and complications are often caused by “overenthusiastic” use of BTX-A in large doses [5].

Finally, as most AEs are the result of unwanted diffusion into nontargeted muscles, concentrated doses (dilutions of 1 to 3.3 mL) are recommended [2,5,14,15]. In addition, as different types of botulinum toxins are associated with different migration patterns [9,10], we recommend exercising caution with dosing and placement when using other BTX-A products.

When utilizing BTX-A for lower facial applications, it is important to establish reasonable patient expectations (eg, during pretreatment counseling), thereby ensuring greater satisfaction for both patient and physician. <>

Fillers in combination with BTX-A

As briefly mentioned in our review of anatomical sites, the simultaneous use of BTX-A and fillers for lower facial applications is not an “either-or” proposition; rather, their conjunctive use is encouraged and it is where usage trends appear to be headed [2,3,9,12,13,17]. Specific areas in which BTX-A and fillers are commonly administered include the perioral lip line, oral commissures, and nasolabial folds [3,12,17].

Frequently, we use BTX-A in combination with fillers when treating lower facial areas. For example, we utilize BTX-A with hyaluronic acid fillers (eg, Restylane [Medicis Aesthetics Holdings, Inc., Scottsdale, Ariz.]) for the lip body; collagen (eg, Cosmoderm [Allergan, Inc., Irvine, Calif.]) for the fine lines associated with the lips; and BTX-A with Restylane or a calcium hydroxylapatite filler (eg, Radiesse [BioForm Medical, Inc., San Mateo, Calif.]) when treating the oral commissures and nasolabial folds. Initial experience with Juvéderm (Allergan, Inc., Irvine, Calif.), a family of new hyaluronic acid fillers recently approved by the US Food and Drug Administration, has been promising in these areas as well.

Summary

The use of BTX-A is evolving beyond upper facial applications, with a wide variety of procedures now being successfully performed in the lower face and neck. In this region, BOTOX is the BTX-A most studied and has been shown to be safe and effective in a number of applications. One of the desirable characteristics of BOTOX that allows it to work so well is its distribution within the injected tissue, with minimal migration outside of the target area. In the hands of an experienced injector, this allows for precise effect. An understanding of functional facial anatomy, the importance of precise injections, and correct dosing all are critical to obtaining positive outcomes.
References

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Figure Legends

Fig. 1. Muscles involved in the BTX-A treatment of the perioral lip line and recommended injection sites. Areas in circles represent optional injection points. Adapted from Sommer B, Sattler G, eds. Botulinum Toxin in Aesthetic Medicine. Boston: Blackwell Science, Ltd.; 2001, with permission.

Fig. 2. The muscle involved in the treatment of the oral commissures and recommended injection sites. Adapted from Sommer B, Sattler G, eds. Botulinum Toxin in Aesthetic Medicine. Boston: Blackwell Science, Ltd.; 2001, with permission.

Fig. 3. Recommended injection sites for the treatment of a dimpled chin (into the mentalis). Adapted from Sommer B, Sattler G, eds. Botulinum Toxin in Aesthetic Medicine. Boston: Blackwell Science, Ltd.; 2001, with permission.

Fig. 4. The platysmal muscle can be successfully treated with BTX-A injections. Adapted from Sommer B, Sattler G, eds. Botulinum Toxin in Aesthetic Medicine. Boston: Blackwell Science, Ltd.; 2001, with permission.

Fig. 5. The masseter muscle can be reduced via BTX-A injection; the procedure is performed on both sides of the face. Masseter muscle reduction is most commonly requested by patients of Asian ethnicity. Adapted from Sommer B, Sattler G, eds. Botulinum Toxin in Aesthetic Medicine. Boston: Blackwell Science, Ltd.; 2001, with permission.