Update on Botulinum Toxin

Botulinum Toxin in Aesthetic Medicine: A Bibliometric Analysis of Research Trends and Methodological Quality of the Top 100 Cited Publications

Background

Botulinum toxin is widely used in aesthetic medicine, with numerous studies examining its efficacy and safety.

Objectives

This bibliometric analysis aims to describe research trends and assess the methodological quality of the highest-impact botulinum toxin research in aesthetic applications.

Methods

The authors of this study identified the 100 most-cited publications on botulinum toxin in aesthetics using Web of Science, covering all available journal years (from inception to October 2024). The Oxford Centre for Evidence-Based Medicine Level of Evidence (LOE) was used to assess the methodological quality of each study.

Results

The authors identified 1728 articles on the aesthetic uses of botulinum toxin, with the top 100 most-cited articles spanning from 1994 to 2021. The United States dominated the research landscape with 50 articles, followed by Canada (15). The University of California (United States) and the University of British Columbia (Canada) emerged as the top contributing institutions. Among journals, Dermatologic Surgery led in publication count, followed by Plastic and Reconstructive Surgery and Aesthetics Surgery Journal. Notably, Professors Jean Carruthers and Alastair Carruthers from Canada were the leading researchers, topping both publication count and citation metrics. Notably, more than half of the studies were classified as LOE 5 (Expert Opinion/Narrative Review).

Conclusions

This bibliometric analysis reveals a paucity of high-quality studies in the field of botulinum toxin in aesthetic medicine, with research predominantly concentrated in western countries. These findings highlight the need for more rigorous, evidence-based studies and increased global collaboration to advance the understanding and application of botulinum toxin in aesthetics.

Level of Evidence 4 Therapeutic

Consensus Recommendations for Treatment of the Upper Face With LetibotulinumtoxinA

One of the authors (K-H. Y.) convened a panel of seven aesthetic experts from South Korea and Australia to create guidelines for treating facial lines of the upper face with letibotulinumtoxinA. The panel members provided recommendations for injection sites, dosage, and injection techniques for using letibotulinumtoxinA and also considered relevant anatomy, patient assessment and selection, and individual variations to evaluate clinical strategies for minimizing complications. The panelists provided recommendations for treating forehead horizontal lines, glabellar frown lines, and lateral canthal lines. The guidelines developed by the panel will support clinical practitioners of all skill levels in providing safe and effective aesthetic treatments of the forehead, glabellar complex, and lateral canthal lines with letibotulinumtoxinA.

Effects of Botulinum Toxin Injection on Reducing Myogenic Artifacts during Video-EEG Monitoring: A Longitudinal Study

Medically refractory seizures affect one-third of patients with epilepsy (PwE), for whom epilepsy surgery is considered. Video electroencephalography (vEEG) monitoring is a fundamental tool for pre-operative seizure localization. Facial and cranial myogenic artifacts can obscure vEEG findings, thus interfering with seizure localization. Studies have shown the beneficial effects of botulinum toxin type A (BTX-A) injection into cranial muscles for reducing myogenic artifacts. This longitudinal study aimed to assess the effects of BTX-A injection on these artifacts. Twenty-two patients with medically refractory hypermotor seizures with daily seizure frequency and undetermined epilepsy localization were included in this study and underwent Dysport® injection (200 units) into the frontotemporal region. vEEG recordings were performed at baseline (one week before the injection), and at three days and six days post-injection. Before and after the injection, the amplitudes of myogenic artifacts were compared during various states (ictal, blinking, chewing, bruxism, head lateralization, scowling, talking, and yawning). BTX-A injection significantly reduced the amplitudes of EEG myogenic artifacts, except during blinking (day three) and talking (days three and six). On day six, significant reduction in EEG myogenic artifacts were noted during blinking, chewing, and bruxism for the greatest number of patients (95.5%, 90.9%, 81.8%), while significant reductions in EEG myogenic artifacts during talking, head lateralization, and ictal phase were associated with the least number of patients (22.7%, 36.3%, and 40.9%). Therefore, BTX-A injection could be a convenient method for filtering myogenic contamination, improving EEG interpretation, and facilitating seizure localization in patients with medically refractory seizures.

OnabotulinumtoxinA Treatment for Moderate to Severe Forehead Lines: A Review

Background:

With onabotulinumtoxinA approved for the treatment of glabellar and crow’s feet lines and, most recently, for forehead lines (FHL), it is possible to simultaneously treat multiple areas of the upper face that are of high concern and treatment priority for aesthetically oriented individuals. This review aims to present key insights on the use of onabotulinumtoxinA for the treatment of moderate to severe FHL.

Methods:

Double-blind, placebo-controlled registration trials of onabotulinumtoxinA for the treatment of FHL were included. Using findings from 3 such published studies, we discuss key concepts and clinical experience for the treatment of moderate to severe FHL with onabotulinumtoxinA (20 U in the frontalis and 20 U in the glabellar complex, with/without 24 U in crow’s feet lines), including injection pattern, dose selection, efficacy and safety data, and considerations for patient selection.

Results:

Across the 2 pivotal phase 3 studies, responder rates on investigator- and subject-assessed measures of appearance of FHL severity were significantly higher with onabotulinumtoxinA versus placebo for the treatment of FHL at day 30 (P < 0.0001), and results were maintained through 3 cycles of onabotulinumtoxinA.

Conclusions:

OnabotulinumtoxinA treatment also resulted in high patient satisfaction rates. The incidence of eyebrow and of eyelid ptosis was low, and no new safety signals were detected. OnabotulinumtoxinA is safe and effective and an appropriate option for patients with moderate to severe FHL encountered in clinical practice.

Nonsurgical Management of Facial Masculinization and Feminization

BACKGROUND

Transgender patients may seek nonsurgical methods for facial masculinization and feminization as an adjunct or alternative to undergoing surgical procedures.

OBJECTIVES

The authors reviewed the existing literature regarding this topic and provided an overview of nonsurgical techniques for facial masculinization and feminization.

METHODS

A comprehensive literature search of the PubMed and MedLine databases was conducted for studies published through December 2017 for techniques and outcomes of nonsurgical facial masculinization and feminization. Keywords were used in performing the search. Data on techniques, outcomes, complications, and patient satisfaction were collected.

RESULTS

Four articles fit our inclusion criteria. Given the lack of published literature describing facial injectables in transgender patients, data from the literature describing techniques in cisgender patients were utilized to supplement our review.

CONCLUSIONS

Facial feminization can be achieved through injectables such as neurotoxin and fillers for lateral brow elevation, lip augmentation, malar augmentation, and improvement of rhytids. Facial masculinization can be achieved with injectables used for genioplasty, jawline augmentation, and supraorbital ridge augmentation. One must develop best practices for these techniques in the transgender patient population and increase awareness regarding nonsurgical options.

LEVEL OF EVIDENCE: 4

Phase 3 Study of OnabotulinumtoxinA Distributed Between Frontalis, Glabellar Complex, and Lateral Canthal Areas for Treatment of Upper Facial Lines

BACKGROUND

Although commonly practiced, simultaneous onabotulinumtoxinA injections to multiple facial areas have not been investigated in prospective studies.

OBJECTIVE

Evaluate safety and efficacy of onabotulinumtoxinA for treatment of forehead lines (FHL) distributed between the frontalis (20 U) and glabellar complex (20 U), with or without simultaneous lateral canthal areas (crow's feet lines [CFL], 24 U) treatment.

METHODS

Subjects with moderate to severe FHL were randomized (2:2:1) to onabotulinumtoxinA 40 U, onabotulinumtoxinA 64 U, or placebo. After 180 days, subjects could receive up to 2 additional open-label onabotulinumtoxinA 64 U treatments.

RESULTS

The intent-to-treat (ITT) population comprised 787 subjects, and the modified ITT (mITT) population (subjects with psychological impact) comprised 568. After 30 days, onabotulinumtoxinA 40 U and 64 U significantly improved investigator- and subject-assessed FHL severity by at least 2 Facial Wrinkle Scale (FWS) grades in 45.6% and 53.0% of ITT subjects, respectively, versus 0.6% receiving placebo (both, p < .0001). Significantly more mITT subjects receiving onabotulinumtoxinA achieved investigator- and subject-assessed FWS ratings of none/mild versus placebo (p < .0001). OnabotulinumtoxinA was well tolerated.

CONCLUSION

OnabotulinumtoxinA distributed between the frontalis and glabellar complex, with or without additional CFL injections, was safe and effective for treatment of moderate to severe FHL.

Efficacy and Safety of OnabotulinumtoxinA Treatment of Forehead Lines: A Multicenter, Randomized, Dose-Ranging Controlled Trial

BACKGROUND

Various onabotulinumtoxinA doses are effective in treating forehead lines (FHL), with a trend toward lower doses.

OBJECTIVE

To evaluate efficacy and safety of onabotulinumtoxinA dose-ranging treatment of FHL when the frontalis area and glabellar complex are treated together.

MATERIALS AND METHODS

Adults with moderate-to-severe FHL received onabotulinumtoxinA 40 U (FHL, 20 U; glabellar lines [GL], 20 U), 30 U (FHL, 10 U; GL, 20 U), or placebo. Response was assessed at weeks 1, 2, day 30, and monthly to day 180. Coprimary efficacy end points were investigator- and subject-assessed Facial Wrinkle Scale scores of none or mild (day 30). Patient-reported outcomes, onset/duration of effect, and adverse events (AEs) were evaluated.

RESULTS

Responder rates (investigator/subject, respectively) were 40-U group, 91.2%/89.5%; 30-U group, 86.4%/81.4%; placebo, 1.7%/5.1%. OnabotulinumtoxinA resulted in significantly greater responder rates than placebo (p < .001). Adverse events were mild to moderate and similar between groups (most common AEs: nasopharyngitis [4.6%] and headache [4.0%]).

CONCLUSION

Treatment of FHL with onabotulinumtoxinA 40 and 30 U (in frontalis and glabellar complex muscles) was tolerable, effective, and sustained. Both doses significantly reduced FHL severity; however, the 40-U dose demonstrated a trend toward greater sustained benefit and longer duration of effect versus the 30-U dose, with similar AE rates.

Patient Perceived Benefit in Facial Aesthetic Procedures: FACE-Q as a Tool to Study Botulinum Toxin Injection Outcomes

BACKGROUND

There are numerous methods of assessing patient satisfaction with botulinum toxin type A neuromodulation of the glabellar rhytids. As the use of aesthetic neuromodulation increases both in breadth and number of procedures, there is a need for more comprehensive tools to evaluate patient-reported outcomes. The FACE-Q is a recently validated patient-reported outcome instrument that can be used to measure patient perceptions of botulinum toxin type A neuromodulation.

OBJECTIVES

This study used the FACE-Q to assess patient satisfaction following botulinum toxin type A neuromodulation of the glabellar rhytids.

METHODS

57 female patients completed the FACE-Q, a survey that evaluates patients' satisfaction with their facial appearance. After this baseline survey, the patients received injections of one of onabotulinumtoxinA (Botox, Allergan, Dublin, Ireland), abobotulinumtoxinA (Dysport, Galderma, Lausanne, Switzerland), or incobotulinumtoxinA (Xeomin, Merz Pharmaceuticals, Frankfurt am Main, Germany) in the glabella. Two weeks post-injection, the patients completed the FACE-Q again. The percentage changes in patient responses were tabulated to determine how neuromodulation affects patient satisfaction with their facial appearance. The percentage changes for each of the neurotoxin groups were compared to determine if patient satisfaction with neuromodulation varies with the type of neurotoxin.

RESULTS

Patient satisfaction with their overall facial appearance increased by 28% following neuromodulation. Patients stated that they believe they look an average of 5.6 years younger post-neuromodulation. There were no significant differences among the treatment groups.

CONCLUSIONS

The FACE-Q demonstrates that patients are more satisfied by their overall facial appearance and age appearance following neuromodulation of their glabellar rhytids. Patients are equally satisfied with the improvement of their facial appearance regardless of which neurotoxin they received. LEVEL OF EVIDENCE 2: Therapeutic.

Selection and preference for botulinum toxins in the management of photoaging and facial lines: patient and physician considerations

Various noninvasive to minimally invasive techniques can be used for the improvement of cutaneous changes seen with photoaging. These include dermabrasion, chemical peels, ablative and nonablative lasers, and filler agents such as hyaluronic acid. However, the most common nonsurgical cosmetic procedure performed in the treatment of rhytides is injection with botulinum toxin. Its extensive safety history and relative ease of use by the practitioner has led to high satisfaction in millions of patients. Nonetheless, proper training of the fundamentals in injection technique, the choice of the appropriate candidate, and knowledge of potential adverse events are imperative to ensure a satisfactory and safe outcome.

Safe botulinum toxin type A injection in patients with history of eyelid ptosis

BACKGROUND

Ptosis is an important side effect of frown correction by botulinum toxin type A (BTX-A). The most likely reason of eyelid ptosis is the diffusion of the toxin to levator palpebrae superioris muscle through orbital septum while the toxin is injected into the corrugator muscle.

OBJECTIVES

In this pilot study, to prevent ptosis, we evaluated the efficacy of BTX-A injection at superior middle aspect of the corrugator muscle instead of the common injection site located above the medial eyebrow head.

METHODS

Fifteen patients were selected from those referred to our clinic with history of eyelid ptosis due to previous BTX-A (dysport; Ipsen) injection. They received three injections of BTX-A; 10 U into the procerus muscle and 20 U into the superior middle aspect of each corrugator muscle, instead of injecting into the belly of the corrugator muscles.

RESULTS

We observed excellent, good and moderate responses in 66.66%, 13.33% and 20% of our patients 2 weeks post-injection respectively. The outcomes were improved to excellent in the latter two groups by injecting 5 U of BTX-A (dysport; Ipsen) into the contractible corrugator in patients with good and 5 U in each corrugator (total of 10 U) in patients with moderate responses.

CONCLUSION

Employing this method a very satisfactory outcome was obtained while no ptosis was observed. Therefore, we recommend this safe technique for treating patients with a history of eyelid ptosis.

An open-label, randomized, 64-week study repeating 10- and 20-U doses of botulinum toxin type A for treatment of glabellar lines in Japanese subjects

BACKGROUND

Repeated botulinum toxin type A (BoNTA) treatment typifies clinical practice. The long-term safety and efficacy should be demonstrated in diverse populations.

OBJECTIVE

To evaluate the long-term efficacy and safety of repeated BoNTA treatments of glabellar lines in Japanese subjects.

METHODS

This randomized, multicenter, 64-week, open-label study of 363 subjects compared 10-U and 20-U of BoNTA for up to five treatments. The endpoints were the physician ratings of line severity and duration of efficacy, and subject ratings of line improvement and satisfaction. Safety assessments included adverse events, laboratory tests, and vital signs. Tests for neutralizing antibodies were conducted.

RESULTS

Peak response rates (> 90%, maximal contraction) were observed at week 1 (treatment 1) and week 4 (treatments 2-5). The duration did not change with repeated treatments and was longer in the 20-U than in the 10-U group (17.1 +/- 6.58 weeks vs. 14.8 +/- 5.38 weeks; P < 0.001). Subject-assessed improvement ratings, 4 weeks' post-treatment, were significantly higher ( P < or = 0.05) in the 20-U group. Overall satisfaction ratings were significantly higher in the 20-U group ( P < 0.001). No serious adverse events occurred. Neutralizing antibodies were not detected.

CONCLUSION

Repeated treatments of glabellar lines with 10 or 20 U of BoNTA provided long-term safety and efficacy in Japanese subjects. The 20-U dose provided longer duration, greater subject satisfaction, and greater subject-rated improvement. The 20-U dose was identified as optimal for improving glabellar lines in Japanese subjects. These results apply only to the formulation of BoNTA used in this study.

Injectables and fillers in male patients

Traditionally, in facial plastic surgery, male patients were known to focus on function over form. Men typically did not consider rejuvenation surgery until they had advanced changes associated with aging, and it was often coupled with a functional concern. However, over the last several years, the number of men seeking minimally invasive cosmetic products, such as dermal fillers and injectables, has increased significantly. Motives include the desire to be more competitive and youthful in the workforce, the growing social acceptability of cosmetic procedures, and increased awareness of nonsurgical options. The optimal use of these products and procedures requires appropriate patient selection, knowledge of the products, and a thorough understanding of the regional anatomy and clinical applications.

Neurologic uses of botulinum neurotoxin type A

This article reviews the current and most neurologic uses of botulinum neurotoxin type A (BoNT-A), beginning with relevant historical data, neurochemical mechanism at the neuromuscular junction. Current commercial preparations of BoNT-A are reviewed, as are immunologic issues relating to secondary failure of BoNT-A therapy. Clinical uses are summarized with an emphasis on controlled clinical trials (as appropriate), including facial movement disorders, focal neck and limb dystonias, spasticity, hypersecretory syndromes, and pain.