Current aesthetic use of abobotulinumtoxinA in clinical practice: an evidence-based consensus review

Cosmetic Treatment Using Botulinum Toxin in the Oral and Maxillofacial Area: A Narrative Review of Esthetic Techniques

Botulinum toxin (BoNT) is an anaerobic rod-shaped-neurotoxin produced by Clostridium botulinum, that has both therapeutic and lethal applications. BoNT injection is the most popular cosmetic procedure worldwide with various applications. Patients with dynamic wrinkles in areas such as the glabella, forehead, peri-orbital lines, nasal rhytides, and perioral rhytides are indicated. Excessive contraction of muscles or hyperactivity of specific muscles such as bulky masseters, cobble stone chins, gummy smiles, asymmetric smiles, and depressed mouth corners can achieve esthetic results by targeting the precise muscles. Patients with hypertrophic submandibular glands and parotid glands can also benefit esthetically. There are several FDA-approved BoNTs (obabotuli-numtoxinA, abobotulinumtoxinA, incobotulinumtoxinA, letibotulinumtoxinA, prabotulinumtox-inA, daxibotulinumtoxinA, rimbotulinumtoxinB) and novel BoNTs on the market. This paper is a narrative review of the consensus statements of expert practitioners and various literature on the injection points and techniques, highlighting both the Asian and Caucasian population separately. This paper can serve as a practical illustrative guide and reference for optimal, safe injection areas and effective doses for application of BoNT in the face and oral and maxillofacial area. The history of BoNT indications, contraindications, and complications, and the merits of ultrasonography (US)-assisted injections are also discussed.

An Update on the Cosmetic Use of Botulinum Toxin: The Pattern of Practice among Korean Dermatologists

The efficacy and safety of botulinum toxin injection have made it a popular aesthetic procedure worldwide. A cross-sectional survey was performed in order to determine the pattern of type A botulinum toxin injections in cosmetic practice, for which an 18-item questionnaire was distributed to dermatologists. A total of 469 Korean board-certified dermatologists participated in the survey, with the following results: the main candidates for type A botulinum toxin injection were individuals in their 40–50 years (46.1%), followed by those in their 20–30 years (33.4%), and people over 60 years of age (20.5%). Overall, the upper face (the glabella, forehead, and crow’s line, in decreasing order) was the most favored area of injection (51%). In contrast, body contouring (i.e., shoulder, calf) and treatment for benign masseter hypertrophy were significantly more popular in the 20–30 years age group than their older counterparts. For wrinkle effacement, the most preferred dilution was 100 units/2.5 mL with isotonic sodium chloride injection (51.2%), and the most often used interval was six months (43.6%). About half (46.3%) of the dermatologists reported the experience of clinical cases which were suspicious of botulinum toxin resistance. Despite this, regarding the choice of the product, type A botulinum toxin products with greater cost-effectiveness were favored over products with a lower risk of antibody formation. Other than its cosmetic usage, botulinum toxin is applied for a variety of skin conditions. Further studies are suggested in order to identify the practice pattern of type A botulinum toxin for therapeutic uses in dermatology, such as hyperhidrosis and rosacea.

Forehead Movement Discrepancies After Botulinum Toxin Injections: A Review of Etiology, Correction, and Prevention

BACKGROUND

Forehead rhytides are a popular target for botulinum toxin injections, but neuromodulation of the frontalis can be fraught with complications because of its anatomic complexity and integral role in brow position and expressivity.

OBJECTIVE

This article explores common forehead movement discrepancies that can occur after neuromodulation of the frontalis, as well as how to correct and prevent them.

METHODS

A review of the literature was conducted and combined with clinical experience to examine underlying forehead anatomy, etiology and correction of forehead movement discrepancies, and important factors to consider before injecting the frontalis with botulinum toxin.

RESULTS AND CONCLUSION

Variable anatomy from person to person necessitates an individualized treatment approach to achieve the best cosmetic results and prevent the occurrence of forehead movement discrepancies.

Onabotulinumtoxin Type A Dosage for Upper Face Expression Lines in Males: A Systematic Review of Current Recommendations

BACKGROUND

Botulinum toxin injection is the most commonly performed minimally invasive aesthetic procedure in men. Despite various recommendations by experts on the use of onabotulinumtoxin type A in the literature, distinct guidelines for its use in males and females do not exist.

OBJECTIVES

The aim of this study was to delineate safe and effective doses for the use of onabotulinumtoxin type A in males for correction of upper facial expression lines.

METHODS

PubMed (MEDLINE), Embase, the Cochrane database, and Google Scholar were searched from 2002 to 2019 inclusive. Three researchers independently assessed trials for inclusion, extracted data, checked for accuracy, and assessed the evidence with AGREE II.

RESULTS

Average dosing recommended for the treatment of upper face expression lines was specific to glabellar frown lines, crow's feet, and horizontal forehead lines. Changing trends and gender variation was noted in each of the studies. Six of the 11 recommendations suggest the need to alter dosing in male patients, although do not give separate recommendations.

CONCLUSIONS

There is an urgent need for up-to-date recommendations for the use of onabotulinumtoxin type A in upper face expression lines of male patients.

Use of AbobotulinumtoxinA for Cosmetic Treatments in the Neck, and Middle and Lower Areas of the Face: A Systematic Review

AbobotulinumtoxinA (aboBoNT-A) has been used for various cosmetic purposes, including minimization of moderate to severe lines, or other cosmetic indications, in the face and neck. We carried out a systematic review to identify all relevant evidence on the treatment approaches and outcomes of aboBoNT-A as a cosmetic treatment of the middle and lower areas of the face, and the neck. Embase, MEDLINE, Cochrane Library, congress proceedings and review bibliographies were searched for relevant studies. Identified articles were screened against pre-specified eligibility criteria. Of 560 unique articles identified, 10 were included for data extraction (three observational studies, 1 randomized controlled trial [with two articles] and five non-randomized trials). The articles provided data on gummy/asymmetric smile (2), marionette lines (5), masseter muscle volume (2), nasal wrinkles (2), perioral wrinkles (3) and the platysma muscle (4). All articles reporting on efficacy of aboBoNT-A demonstrated positive results, including reduction of wrinkles (5), reduction of masseter muscle (2) and degree of gummy smile (1) compared with before treatment. No serious adverse events were reported and patient satisfaction was high. In conclusion, positive findings support further research of aboBoNT-A for the middle and lower areas of the face, and in the neck, which are largely unapproved indications.

The mechanisms of action and use of botulinum neurotoxin type A in aesthetics: Key Clinical Postulates II

BACKGROUND

The literature on botulinum neurotoxin type A (BoNT-A) is extensive, often contradictory, and confounded by a competitive market of products and research attempting to distinguish brand individuality.

METHODS

A comprehensive review of literature on the principles of BoNT-A in aesthetics as well as clinical examples.

RESULTS

In 2017, the Eight Key Clinical Postulates were formulated as a guide for the aesthetic practitioner in understanding BoNT-A pharmacodynamics and to compare different toxins. These are now updated to include (a) All type A toxins act identically; (b) The mathematical relationship between toxin and receptor is the basis of efficacy, and clinical efficacy is influenced by molecular potency and patient attributes including muscle mass, gender, age, and ethnicity; (c) Efficacy, onset, and duration are functions of "molecular potency" defined as the number of active 150 kDa molecules available for binding; (d) "Molecular potency" is difficult to objectively quantify for commercially available toxins; (e) Up to a point, increased molecular potency decreases time to onset and increases duration of effect, and the "Molecular Potency Quotient" is a construct for comparing molecular potency commercial cost; (f) The area of effect of a toxin injection is dependent upon molecular potency, diffusion (passive), and spread (active); (g) Differing reconstitution volumes; and (h) Increased number of injection sites can affect spread, onset, and duration of effect.

CONCLUSIONS

The principles of BoNT-A use in aesthetics are complex yet understandable as outlined in the framework of the updated Eight Key Clinical Postulates and serves as a useful tool for providing the most effective treatment and interpreting research on present and future toxin formulations.

Myomodulation with Injectable Fillers: An Innovative Approach to Addressing Facial Muscle Movement

Consideration of facial muscle dynamics is underappreciated among clinicians who provide injectable filler treatment. Injectable fillers are customarily used to fill static wrinkles, folds, and localized areas of volume loss, whereas neuromodulators are used to address excessive muscle movement. However, a more comprehensive understanding of the role of muscle function in facial appearance, taking into account biomechanical concepts such as the balance of activity among synergistic and antagonistic muscle groups, is critical to restoring facial appearance to that of a typical youthful individual with facial esthetic treatments. Failure to fully understand the effects of loss of support (due to aging or congenital structural deficiency) on muscle stability and interaction can result in inadequate or inappropriate treatment, producing an unnatural appearance. This article outlines these concepts to provide an innovative framework for an understanding of the role of muscle movement on facial appearance and presents cases that illustrate how modulation of muscle movement with injectable fillers can address structural deficiencies, rebalance abnormal muscle activity, and restore facial appearance.Level of Evidence V This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Global Trends of Botulinum Toxin Literature: A Bibliometric Analysis of Botulinum Toxin Publications Between 1975 and 2017

BACKGROUND

Botulinum toxin has been effectively used cosmetically and therapeutically for the last decades in a wide range of medical conditions. Although bibliometrics has been a popular and growing study area in recent years, medical literature lacks studies evaluating published botulinum toxin literature.

OBJECTIVE

The goal of our study was to evaluate bibliometric features and to perform a detailed trend analysis in the medical literature related to botulinum toxin.

MATERIALS AND METHODS

We analyzed all the published documents including the keywords "botulinum toxin" and "botulinum neurotoxin" and commercial brand names of botulinum toxin products between 1975 and 2017. We performed a detailed bibliometric and scientometric assessment in this field.

RESULTS

A total of 24,948 articles were retrieved from four databases provided by Web of Science, and most of which were original articles (76.19%). The United States ranked first and dominated literature with 8,729 documents (34.29%) followed by the United Kingdom, Germany, and Italy (14.61%, 11.18%, and 5.5%, respectively). The United Kingdom was detected to be the most productive country with the highest productivity (55.09) followed Switzerland, Denmark, and Germany (47.7, 34.01, and 33.98, respectively). The most studied area was neurology (56.1%) and University of California System was the most productive institution. We noted no correlation between publication number and citations by year.

CONCLUSION

We found that all top 10 authors and institutions were from developed countries. Physician from developing and the least-developed countries should be supported to carry out novel studies on botulinum toxin.

Muscle Insertion and Strength of the Muscle Contraction as Guidelines to Enhance Duration of the Botulinum Toxin Effect in the Upper Face

BACKGROUND

In this series of patients the cutaneous insertion and strength of voluntary contraction of the muscles in the upper third of the face were used as guidelines for botulinum toxin application named "BTA Codes."

METHOD

Anatomical dissection of fresh cadavers identified the shape and cutaneous insertions of the muscles in the upper third of the face. Patient voluntary contraction of the muscles in the upper third of the face created different patterns of skin lines classified by the 4-grade Facial Wrinkle Scale. For botulinum toxin application injections points followed the muscle cutaneous insertion and dose the 4-grade Facial Wrinkle Scale.

RESULTS

Injection points ranged from 3 to 23 points per patient, average of 9.4 points. Dose per point varied from 2.5 to 7.5 U, ranging from 12.5 to 72.5 U per patient, average of 33.82 U. Skin lines resulting from the voluntary contraction of the muscle prior to toxin application were stated as baseline 1. The absence of skin lines and muscle activity on day fifteen after toxin application defined baseline 2. Skin lines resulting from the recovered voluntary contraction of the muscle after toxin application like those of baseline 1 established baseline 3. The botulinum toxin effect was the time elapsed between baselines 2 and 3, ranging from 171 to 204 days, average of 183.72 days, greater than the 3 or 4 months reported in the literature.

CONCLUSION

"BTA Codes" is a set of rules to apply botulinum toxin supported by muscle anatomy and degree of voluntary contraction to enhance the duration of its effect.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Myomodulation with Injectable Fillers: An Innovative Approach to Addressing Facial Muscle Movement

Consideration of facial muscle dynamics is underappreciated among clinicians who provide injectable filler treatment. Injectable fillers are customarily used to fill static wrinkles, folds, and localized areas of volume loss, whereas neuromodulators are used to address excessive muscle movement. However, a more comprehensive understanding of the role of muscle function in facial appearance, taking into account biomechanical concepts such as the balance of activity among synergistic and antagonistic muscle groups, is critical to restoring facial appearance to that of a typical youthful individual with facial esthetic treatments. Failure to fully understand the effects of loss of support (due to aging or congenital structural deficiency) on muscle stability and interaction can result in inadequate or inappropriate treatment, producing an unnatural appearance. This article outlines these concepts to provide an innovative framework for an understanding of the role of muscle movement on facial appearance and presents cases that illustrate how modulation of muscle movement with injectable fillers can address structural deficiencies, rebalance abnormal muscle activity, and restore facial appearance.

LEVEL OF EVIDENCE V

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Botulinum Toxin in Aesthetic Medicine: Myths and Realities

Several formulations of Botulinum toxin serotype A (BoNT-A) for aesthetic indications are available, with numbers likely to increase. Preparations are not interchangeable, based on dose unit comparisons.

The Use of Botulinum Neurotoxin Type A in Aesthetics: Key Clinical Postulates

BACKGROUND

The most common aesthetic procedure performed worldwide is the injection of botulinum neurotoxin Type A (BoNT-A). Aesthetic providers must fully comprehend the objective scientific data, theoretical mechanisms of action, and differences between brands of BoNT-A.

OBJECTIVE

To determine and review the relevant clinical postulates for the use of botulinum toxin in aesthetics.

MATERIALS AND METHODS

The BoNT-A clinical postulates presented here discuss how each brand of BoNT-A acts identically, how the molecular potency may vary between the different products, how patient age, gender, genetics, and muscle mass cause variation in toxin receptor number and density, and how both practitioner and patient can affect toxin distribution.

RESULTS

A total of 8 clinical postulates have been identified that are key to understanding the use of botulinum toxin in aesthetics and to obtaining the best clinical results.

CONCLUSION

All of these factors affect the potential efficacy of the injected toxin and hence the aesthetic results obtained.

[Conversion ratio between different botulinum neuroprotein product in neurological practice]

Despite nearly 30 years of experience in the application of botulinum toxin type A (BTA) in clinical practice, many fundamental questions of therapy remain valid. There are 5 botulinum toxin type A used for neurological indications in the Russian Federation in 2017. They contain different number of active neuroprotein (150 kDa) in a therapeutic dose of the drug that may have a potential impact on the efficacy and duration of action. The current SmPC of each BTA stated that the unit of activity is unique and can not be compared with any other BTA. In scientific publications one can find many details concerning the equivalence doses of onabotulinumtoxin A (botox) and abobotulinumtoxin A (dysport) and the ratio of units varies from 1:1 to 1:11. However, according to clinical guidelines, systematic reviews and high quality research evidence of recent years, the ratio of units of abobotulinumtoxin A (dysport) and onabotulinumtoxin A (botox) is 3(2,5):1. Use of a fixed ratio of units is possible only when switching from one drug to another or in case of limiting access to specific drug. Botulinum toxin type A is the first line of therapy in the treatment of several neurological diseases. The most commonly used drugs of botulinum toxin type A (botox, dysport, xeomin) have a significant evidence base that confirms their efficacy and optimal safety profile. The main difference between botulinum toxin type A is their potential activity of action, i.e., activity units and total therapeutic dose.

Key Parameters for the Use of AbobotulinumtoxinA in Aesthetics: Onset and Duration

Time to onset of response and duration of response are key measures of botulinum toxin efficacy that have a considerable influence on patient satisfaction with aesthetic treatment. However, there is no overall accepted definition of efficacy for aesthetic uses of botulinumtoxinA (BoNT-A). Mechanical methods of assessment do not lend themselves to clinical practice and clinicians rely instead on assessment scales such as the Frontalis Activity Measurement Standard, Frontalis Rating Scale, Wrinkle Severity Scale, and Subject Global Assessment Scale, but not all of these have been fully validated. Onset of activity is typically seen within 5 days of injection, but has also been recorded within 12 hours with abobotulinumtoxinA. Duration of effect is more variable, and is influenced by parameters such as muscle mass (including the effects of age and sex) and type of product used. Even when larger muscles are treated with higher doses of BoNT-A, the duration of effect is still shorter than that for smaller muscles. Muscle injection technique, including dilution of the toxin, the volume of solution injected, and the positioning of the injections, can also have an important influence on onset and duration of activity. Comparison of the efficacy of different forms of BoNT-A must be made with the full understanding that the dosing units are not equivalent. Range of equivalence studies for abobotulinumtoxinA (Azzalure; Ipsen Limited, Slough UK/Galderma, Lausanne CH/Dysport, Ipsen Biopharm Limited, Wrexham UK/Galderma LP, Fort Worth, TX) and onabotulinumtoxinA (Botox; Allergan, Parsippany, NJ) have been conducted, and results indicate that the number of units of abobotulinumtoxinA needs to be approximately twice as high as that of onabotulinumtoxinA to achieve the same effect. An appreciation of the potential influence of all of the parameters that influence onset and duration of activity of BoNT-A, along with a thorough understanding of the anatomy of the face and potency of doses, are essential to tailoring treatment to individual patient needs and expectations.

The Practical Use of AbobotulinumtoxinA in Aesthetics

Botulinum toxin (BoNT) has been approved for aesthetic use since 2002. Since then, clinical studies and expert use have informed our understanding of how BoNT exerts its clinical effect and the practical use of this product across a number of aesthetic applications. This review discusses the clinical properties and characteristics of abobotulinumtoxinA, which patients are suitable for its use, and how it can be utilized to treat facial rhytides.

Safety and Patient Satisfaction of AbobotulinumtoxinA for Aesthetic Use: A Systematic Review

A systematic review of the published literature (from January 2000 to January 2016) to ascertain the safety of, and patient satisfaction with, the aesthetic use of abobotulinumtoxinA was conducted. In addition to the licensed indications, other special populations were considered for discussion. The potential impact of neutralizing antibodies and systemic toxicity were also addressed. A total of 364 papers were screened and 86 were found to be relevant to the population, intervention(s), and outcomes stipulated in the protocol. The safety and patient satisfaction data from these publications are discussed in this review.

Comparison of different consensuses of BTXA in different countries

The most international dosing guidelines on the use of botulinum toxin type A (BTXA) drugs support a 1:1 dose relationship between OnaBTXA and IncoBTXA and 1:2.5 between OnaBTXA and AboBTXA. However, different facial zones demonstrate different doses conversion ratios. The comparative analysis of nine consensuses on the use of Abo-, Ona-, and IncoBTXA in the United States, Russia, and Europe has been performed. We conducted a review of publications adopting the key words "botulinum toxin consensus," "botulinum toxin guideline." Information search has been carried out primarily in specialized databases (DB). To find the relevant RCTs and guidelines/consensuses, the following databases were used: PubMed and Medline that were screened up to May 2008. Results regarding dose ratios for OnaBTXA:AboBTXA and IncoBTXA:AboBTXA showed that in most cases it is characterized both by increase and by decrease compared to the ratio of 1:2.5. The mean value of dose ratios OnaBTXA:AboBTXA adopted in the United States is 1:2.8. The ratio IncoBTXA:AboBTXA according to international and Russian data is 1:1.9. There are some differences in clinical approach of BTXA use in certain countries. In Russia, low doses are recommended for "crow's feet" and forehead. The US consensus recommends a higher dosage to correct perioral wrinkles. Despite many years of experience in using BTXA, there is no strict international uniformity of clinical guidelines. The recommended doses for the individual areas of the face may differ in different countries. Therefore, physicians in their practice should be guided not by international consensuses, but prefer a national guidelines.

Overview of Botulinum Toxins for Aesthetic Uses

Botulinum toxin type A (BTA) can be used for facial aesthetics. The 3 currently available BTA types include onabotulinumtoxinA (Botox; Botox Cosmetic, Allergan, Irvine, CA), abobotulinumtoxinA (Dysport; Ipsen, Ltd, Berkshire, UK), and incobotulinumtoxinA (Xeomin; Merz Pharmaceuticals, Frankfurt, Germany). The mechanism of action and clinical uses for treatment of dynamic lines of the forehead, brow, glabella, lateral orbit, nose, and lips are presented, as well as treatment of masseter hypertrophy, platysmal bands, and improvements of the perioral region. Specific BTA injection sites and suggested doses are presented.

Preliminary Report on an Objective, Fast, and Reproducible Method to Measure the Effectiveness of Botulinum Toxin Type A

BACKGROUND

The injection of botulinum toxin type A for cosmetic proposes is a popular procedure, although the interpretation of its effectiveness still poses a challenge. In fact, although the methods that evaluate the efficacy of the treatment are validated and reliable, they are usually based on subjective scales, while an objective and quantitative scale is still needed.

OBJECTIVES

I propose an objective, fast, and reproducible method to evaluate the severity of wrinkles with a three-dimensional imaging and texture analysis.

METHODS

Digital Analysis of the Cutaneous Surface (DACS) is employed to analyze cutaneous texture. Measures are performed in the glabellar area before and one month after infiltration of 15 units of onabotulinumtoxin-A.

RESULTS

Eight women were included in this study. DACS was able to detect improvements in all cases. On average, static lines decreased by 12.4% and dynamic lines by 41.2%.

CONCLUSIONS

DACS provides an objective, direct, fast, and reproducible method to measure the results of botulinum toxin type A usage. It avoids the use of subjective scores, gives a direct measure of the wrinkles, is simple to perform, and allows the operator to analyze only the desired area.

LEVEL OF EVIDENCE

4 Therapeutic.

Understanding the functional anatomy of the frontalis and glabellar complex for optimal aesthetic botulinum toxin type A therapy

BACKGROUND

Botulinum neurotoxin type A (BoNTA) is approved for the treatment of glabellar lines and also is commonly injected in an off-label fashion in the frontalis (i.e., frontalis epicranius) muscle to improve the appearance of horizontal forehead lines. This study aimed to review and discuss both the anatomy and physiology of the frontalis muscle and its relationship with antagonist muscles in the upper face and to provide a guide for the use of BoNTA to treat forehead rhytides while minimizing the occurrence of complications such as brow ptosis.

METHODS

A PubMed search was conducted to identify practitioner opinion and clinical publications on the efficacy and safety of BoNTA for aesthetic treatment of the upper face.

RESULTS

The use of BoNTA produces durable improvement in the appearance of moderate to severe horizontal forehead lines. Dose and injection technique must be adjusted and individualized based on the variable anatomy and function/mass of muscles in the forehead and upper face as well as on patient goals. Optimal aesthetic outcomes can be achieved by skillfully balancing the opposing effects of the frontalis muscle and its intricate interactions with the procerus, corrugator supercilii, depressor supercilii, and orbicularis oculi muscles.

CONCLUSIONS

The use of BoNTA to improve the aesthetic appearance of horizontal forehead lines is optimized when clinicians take into account variations in frontalis muscle function and position, anatomy of the brow, and proper injection technique when they devise individualized treatment regimens.