Current Aesthetic Use of AbobotulinumtoxinA in Clinical Practice: An Evidence-Based Consensus Review

Abstract

The amount and complexity of scientific and clinical evidence for aesthetic use of botulinum neurotoxin type A (BoNT-A) has expanded rapidly in recent years, especially for abobotulinumtoxinA, necessitating reassessment of current knowledge about aesthetic use of abobotulinumtoxinA and other BoNT-A preparations. A committee of 13 plastic surgeons, facial plastic surgeons, and dermatologists engaged in a live discussion of information from a systematic literature review and an Internet-based survey of their beliefs and practices. The committee achieved consensus on most issues. It was concluded that doses of different BoNT-A preparations cannot be interconverted with a fixed ratio. The size of the "field of effect" is difficult to measure, and comparisons between preparations have yielded equivocal results. Nonresponse due to neutralizing antibodies appears exceedingly rare with currently available BoNT-A preparations and of little concern clinically. BoNT-A dose, injection depth, and injection technique should be adjusted according to the anatomic area being treated and each patient's individual characteristics and goals. Aesthetic use of BoNT-A has a good safety profile. Most adverse events are minor and related to the trauma of injection, although special care is needed in certain anatomic areas. Detailed recommendations for treatment of different anatomic areas are presented. BoNT-A products are often used in conjunction with other treatment modalities (eg, fillers and resurfacing), but little agreement was reached on best practices. The findings reported in this consensus document may serve as a practical guide for aesthetic practitioners as they apply the latest knowledge about BoNT-A in providing their patients with optimal care.

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

“…If the zygomaticus major has reduced lifting power due to a lack of underlying structural support, the relative role of the risorius muscle increases and produces a more horizontal smile. If zygomaticus major lifting capacity is further diminished, the depressor anguli oris (DAO) muscle predominates, and a “DAO smile,” with the corners of the mouth downturned, is observed [11, 26]. The lack of underlying structure leading to DAO smile may result from changes over time in aging, or it may occur in youth due to structural deficiency.…”

“…At the same time, any mechanical advantage of the lever effect over the lateral SOOF is reduced as SOOF volume is depleted. Consequently, the zygomaticus major can no longer adequately counterbalance the downward gravitational pull and the contracting force of the DAO [11, 26].

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

“…21 A regulatory definition of efficacy comes from draft Guidance to Industry issued by the United States Food and Drug Administration (FDA), which makes recommendations regarding the design of clinical trials for botulinum toxin drug products. The FDA recommends that: “Measurements at maximum contraction should be used to assess the efficacy of botulinum toxin drug products to demonstrate the paralytic effect” and that: “Success should be defined as … a two-grade improvement from the baseline, on both the [investigator’s assessment] and the [subject’s self-assessment] scales concurrently, to ensure clinical significance.” 23 …”

“…One reason for this recommendation is the theoretical risk that benzyl alcohol, when used as a preservative in so-called “preserved” saline, will denature the protein and reduce the potency of the injected solution. 21 As benzyl alcohol is also a mild analgesic, a number of split-face studies have compared BoNT-A solutions in preserved and unpreserved saline to investigate whether this ingredient can improve comfort for patients without compromising efficacy. 61-63 All of the studies found that using preserved saline significantly ( P ≤ .001) reduced pain scores without affecting the activity of the toxin.…”

“…Disagreements on how to define and measure doses or improvements in efficacy (eg, what scales to use, how to measure the scale effects [live or by photographs], the timing of those measurements, and the subjective nature of many of the scales) mean that there is very little standardization in clinical studies. However, during a consensus meeting on the recommendations for treatment with abobotulinumtoxinA (ABO; Dysport; Ipsen Biopharm Limited, Wrexham UK/Galderma LP, Fort Worth, TX), Maas noted that: “Aspects of BoNT-A use were consistent across anatomic areas…suggesting that these personal preferences…are not critical for treatment success.” 21 However, the actual concept of “treatment success” is not a constant, and adjusting the dose of BoNT-A based on observed muscle action, mass, facial symmetry, and desired result is considered to be important for nearly all anatomic areas. 21 The original concept of “frozen” muscle has generally, but not exclusively, been replaced with a desire for the “natural look.” However, adjusting the dosing to achieve a natural look will directly affect onset and duration.…”