Split-face Study: Cosmetic Botulinum Toxin Type A Injection Under Electromyography-guidance Versus Conventional Palpation Technique

The study was conducted on 15 healthy-looking female subjects with visible glabellar rhytids when frowning. All participants were recruited from the outpatient clinic of Dermatology Department, Main University Hospital, Faculty of Medicine, Alexandria University. The mean age was 46.27 ± 6.31 with a range from 33 to 59 years. All 15 subjects completed the study.

Each subject provided a right and left corrugator supercilii muscles to the study. Each muscle was divided into a body and a tail, each part injected separately (n=60).

Neurotoxin injection into the corrugator body and tail by palpation method on one side and under EMG-guidance on the other.

Photographs were taken both at rest, and while frowning at each visit: pre-operatively, after 2 weeks and after 3 months.

Clinical grading according to static and dynamic Merz glabellar frown line scales and EMG analysis was done at each visit: pre-operatively, after 2 weeks and after 3 months.

Inclusion criteria

• Consent.
• Patients within age range of 25 - 60 years.
• Visible corrugator muscle rhytids when frowning by examination.

Exclusion criteria

• Patients with no, or minimal wrinkles on the studied area.
• Previous use of botulinum toxin in the previous 6 months.
• Patients on regular or very occasional antispasmodics.
• Patients with any neuromuscular disorders, infections or skin problems at the injection site.
• Patients with any known neurological disease.
• Patients who undergone surgery involving the glabellar area.