Although a number authors have published articles suggesting the need to target specific periorbital muscles for desired effect, there remains a great variability in the injection type, location, and dosage.2–4 Moreover, there can be significant variability in muscle anatomy between individuals.5,6 As such, we do not believe that it is critical to target a specific muscle, especially given the diffusion radius of the toxin; rather, the injection should be aimed at restoring balance along the 24-hour clock. For example, if a patient presents with left Mona Lisa (zygomatic) smile because of overactive levator anguli oris and zygomaticus minor, injections are given along the 4- and 5-o’clock positions rather than aiming for the specific muscles (Table 1). Since 2006, the senior author of this article has successfully used the 24-hour clock concept to achieve favorable and predictable outcome in botulinum toxin injection to the lower face and minimize complications.
None of the authors has a financial interest to declare in relation to the content of this article.
Nam Ho Kim, M.D.
Tae Joo Ahn, M.D.
Ro Hyuk Park, M.D.
Kyun Tae Kim, M.D.
Edward Ilho Lee, M.D.
Edward I. Lee Plastic Surgery
1. Janis JE, Rohrich RJThorne CHRhinoplasty.In: Grabb & Smith’s Plastic Surgery20076th edPhiladelphiaLippincott517–532
2. Sucupira E, Abramovitz AA simplified method for smile enhancement: Botulinum toxin injection for gummy smile.Plast Reconstr Surg2012130726–728
3. Suber JS, Dinh TP, Prince MD, Smith PDOnabotulinumtoxinA for the treatment of a “gummy smile”.Aesthet Surg J201434432–437
4. Hwang WS, Hur MS, Hu KS, et alSurface anatomy of the lip elevator muscles for the treatment of gummy smile using botulinum toxin.Angle Orthod20097970–77
5. Kane MAThe effect of botulinum toxin injections on the nasolabial fold.Plast Reconstr Surg200311266S–72S
6. Pessa JE, Zadoo VP, Adrian EK Jr, Yuan CH, Aydelotte J, Garza JRVariability of the midfacial muscles: Analysis of 50 hemifacial cadaver dissections.Plast Reconstr Surg19981021888–1893
Viewpoints, pertaining to issues of general interest, are welcome, even if they are not related to items previously published. Viewpoints may present unique techniques, brief technology updates, technical notes, and so on. Viewpoints will be published on a space-available basis because they are typically less timesensitive than Letters and other types of articles. Please note the following criteria:
- Text—maximum of 500 words (not including references)
- References—maximum of five
- Authors—no more than five
- Figures/Tables—no more than two figures and/or one table
Authors will be listed in the order in which they appear in the submission. Viewpoints should be submitted electronically via PRS’ enkwell, at www.editorialmanager.com/prs/. We strongly encourage authors to submit figures in color.
We reserve the right to edit Viewpoints to meet requirements of space and format. Any financial interests relevant to the content must be disclosed. Submission of a Viewpoint constitutes permission for the American Society of Plastic Surgeons and its licensees and assignees to publish it in the Journal and in any other form or medium.
The views, opinions, and conclusions expressed in the Viewpoints represent the personal opinions of the individual writers and not those of the publisher, the Editorial Board, or the sponsors of the Journal. Any stated views, opinions, and conclusions do not reflect the policy of any of the sponsoring organizations or of the institutions with which the writer is affiliated, and the publisher, the Editorial Board, and the sponsoring organizations assume no responsibility for the content of such correspondence.