A prospective and randomized study comparing ultrasound-guided real time injection to conventional blind injection of botulinum neurotoxin for glabellar wrinkles.

BACKGROUND: Botulinum neurotoxin injections are the most frequently performed cosmetic procedures, but conventional blind injection for glabellar wrinkles remains to have some limitations. AIMS: We intend to directly inject botulinum neurotoxin into the glabella complex guided by real time ultrasound. We aim to propose a more efficient and safer botulinum neurotoxin injection strategy for glabellar wrinkles. METHODS: A total of 40 subjects with moderate to severe glabellar lines were enrolled in this study to receive botulinum neurotoxin injection, either through ultrasound-guided real time injection or conventional blind injection. Facial Wrinkle Scale (ranging from 0 = none to 3 = severe) and inter-brow distance (from 3D scanned face images) were used to evaluate the glabellar wrinkles improvement. Paired t test and two-sample t test were performed to analyze the within-group and between-group differences. RESULTS: The wrinkle score reduction was significant (p < 0.0001) immediately after the injection in ultrasound-guided injection group, but not in blind injection group (p = 0.163). Ultrasound-guided injection also showed a higher performance of wrinkle score reduction and more effective inter-brow distance increase over blind injection at Day 0 (p < 0.0001), Day 1 (p < 0.0001), Day 21 (p < 0.01) and Day 35 (p < 0.01) after initial treatment. CONCLUSIONS: The results of the study confirmed that botulinum neurotoxin injection for glabellar wrinkles under ultrasound guidance achieves quicker onset of action and better final outcomes compared to conventional blind injection.