Injection with botulinum neurotoxin type A (BoNT-A) is one of the most widely performed non-invasive cosmetic procedures. BoNT-A blocks the release of the neurotransmitter acetylcholine, which is essential for neuromuscular transmission.1 Therefore, injection of BoNT-A can help to smooth wrinkles caused by muscular activities and may improve patient’s quality of life.2
Several commercial preparations of BoNT-A products are currently available for aesthetic usages. Azzalure/Dysport and Vistabel/Botox, the two most widely used products, are produced from different strains of bacteria, purified using different methods and therefore have distinct properties.1,3 The units of Azzalure/Dysport and Vistabel/Botox are not interchangeable, as different bioassays were employed for measuring their activities.4,5 Azzalure and Dysport are quantified in Speywood Units (s.U) and are therefore collectively referred to as BoNT-A (Speywood Unit).
Dysport is available in two different quantities (500 s.U and 300 s.U). Dysport (500 s.U) has a 20-year history of product consistency and safety in both therapeutic and aesthetic usages.6–9 Dysport (300 s.U) is approved in the U.S as abobotulinumtoxin A for the treatment of glabellar lines. Azzalure (125 s.U) is specifically designed for aesthetic usages and recently received European approvals. The efficacy and safety of glabellar line treatment with BoNT-A (Speywood Unit) were demonstrated in clinical studies involving more than 4000 patients.3,6,10–18
Although treatment in the glabellar region is the only labelled aesthetic indication for BoNT-A products, it is common for physicians to treat wrinkles in other areas.6,19–21 A full understanding of both BoNT-A properties and related anatomy is essential to ensure optimal treatment results and should be acquired through proper trainings. As there are only a few clinical studies and regional guidelines on the off-label indications,21–28 international consensus recommendations should be helpful in providing a general guideline for efficacious and safe injection of BoNT-A (Speywood Unit). Consensus recommendations on the upper face treatments with BoNT-A (Speywood Unit) have already been established.29 In the present article, we provide consensus recommendations on the treatment of the middle and lower face, neck and chest region with BoNT-A (Speywood Unit).