0
We're unable to sign you in at this time. Please try again in a few minutes.
Retry
We were able to sign you in, but your subscription(s) could not be found. Please try again in a few minutes.
Retry
There may be a problem with your account. Please contact the AMA Service Center to resolve this issue.
Contact the AMA Service Center:
Telephone: 1 (800) 262-2350 or 1 (312) 670-7827  *   Email: subscriptions@jamanetwork.com
Error Message ......
Original Article |

Electromyographic Differences Between Normal Upper and Lower Facial Muscles and the Influence of Onabotulinum Toxin A

Bryan J. Winn, MD; Bryan S. Sires, MD, PhD
JAMA Facial Plast Surg. 2013;15(3):211-217. doi:10.1001/jamafacial.2013.692.
Text Size: A A A
Published online

Importance Empirically determined doses of onabotulinum toxin A for aesthetic treatments are as much as 5 times higher for the upper than for the lower facial muscles.

Objective To use electromyography (EMG) to determine objectively whether the disparity between doses is due to intrinsic differences between the muscle groups' responses to onabotulinum toxin A or to variable amounts of paralysis required to achieve the desired aesthetic outcomes.

Design We collected EMG data before and at 2 to 4 weeks and 3 months after 8- and 2-U onabotulinum toxin A injections to the corrugator and depressor anguli oris muscles, respectively.

Setting A private oculofacial plastic surgery practice.

Participants Twenty-six subjects recruited from February 1 through April 1, 2009.

Interventions Electromyography recordings and cosmetic onabotulinum toxin A injections.

Main Outcome Measures Mean motor unit (MU) durations and maximal amplitudes at baseline and 2 to 4 weeks and 3 months after injection.

Results Baseline mean MU amplitudes were similar for the corrugator and depressor anguli oris muscles. At 2 to 4 weeks after injection, 78% MU and 64% maximal amplitude reduction for the corrugator muscle were detected, but only 54% MU and 18% maximal amplitude reduction for the depressor anguli oris (P = 2.7 × 10−8 and P = 1.3 × 10−14, respectively). At 3 months, function was partially recovered for both muscle groups.

Conclusions and Relevance Onabotulinum toxin A causes a similar dose-dependent reduction in MU and maximal voluntary amplitudes for muscles of the upper and lower face. The dose disparity appears to result from differences in the amount of paralysis required to achieve desirable aesthetic results.

Level of Evidence 2.

Figures in this Article

Sign in

Create a free personal account to sign up for alerts, share articles, and more.

Purchase Options

• Buy this article
• Subscribe to the journal

Figures

Place holder to copy figure label and caption
Graphic Jump Location

Figure 1. Standard electromyography tracings used for grading (1-10) maximal voluntary corrugator and depressor anguli oris muscle amplitudes.

Place holder to copy figure label and caption
Graphic Jump Location

Figure 2. Injection sites for the glabella and depressor anguli oris muscles. Circles and triangles represent 4 and 2 U each of onabotulinum toxin A, respectively.

Place holder to copy figure label and caption
Graphic Jump Location

Figure 3. Mean motor unit (MU) amplitude (A) and mean normalized MU amplitude (B) by time from onabotulinum toxin A injection for corrugator and depressor anguli oris (DAO) muscles. Error bars represent 95% confidence intervals.

Place holder to copy figure label and caption
Graphic Jump Location

Figure 4. Mean maximal (max) amplitude (A) and mean normalized max amplitude (B) by time from onabotulinum toxin A injection for corrugator and depressor anguli oris (DAO) muscles. Error bars represent 95% confidence intervals.

Place holder to copy figure label and caption
Graphic Jump Location

Figure 5. Mean motor unit (MU) duration by time from onabotulinum toxin A injection for corrugator and depressor anguli oris (DAO) muscles. Error bars represent 95% confidence intervals.

Tables

References

Correspondence

CME
Meets CME requirements for:
Browse CME for all U.S. States
Accreditation Information
The American Medical Association is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The AMA designates this journal-based CME activity for a maximum of 1 AMA PRA Category 1 CreditTM per course. Physicians should claim only the credit commensurate with the extent of their participation in the activity. Physicians who complete the CME course and score at least 80% correct on the quiz are eligible for AMA PRA Category 1 CreditTM.
Note: You must get at least of the answers correct to pass this quiz.
You have not filled in all the answers to complete this quiz
The following questions were not answered:
Sorry, you have unsuccessfully completed this CME quiz with a score of
The following questions were not answered correctly:
Commitment to Change (optional):
Indicate what change(s) you will implement in your practice, if any, based on this CME course.
Your quiz results:
The filled radio buttons indicate your responses. The preferred responses are highlighted
For CME Course: A Proposed Model for Initial Assessment and Management of Acute Heart Failure Syndromes
Indicate what changes(s) you will implement in your practice, if any, based on this CME course.
NOTE:
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).
Submit a Comment

Multimedia

Some tools below are only available to our subscribers or users with an online account.

Sign in

Create a free personal account to sign up for alerts, share articles, and more.

Purchase Options

• Buy this article
• Subscribe to the journal

Related Content

Customize your page view by dragging & repositioning the boxes below.

Articles Related By Topic
Related Topics
PubMed Articles
Jobs
brightcove.createExperiences();