Background: Botulinum-derived neurotoxins have become a substantial tool in dermatologists' armamentarium for facial/neck rejuvenation. Current literature discusses anatomical "danger zones" to avoid during neurotoxin injection to prevent brow ptosis, blepharoptosis, and lower facial ptosis.
Objective: The aim of this study was to determine whether lidocaine 1% local anesthetic can be used to predict botulinum toxin treatment outcomes and prevent adverse effects of unwanted paralysis.
Materials and methods: One percent lidocaine was drawn up using BD ultra-fine 31 G (5/16″), 0.5-mL insulin syringes in the same quantity that would be drawn up for neurotoxin placement. The patient's face was cleansed and mapped; 0.1 mL of 1% lidocaine was injected × 5 sites in the glabella; and 3 sites were injected with 0.05 mL in the frontalis. The patient was assessed after 10 minutes.
Results: Improvement in frontalis and glabellar rhytides was appreciated, with noted "spocking" of the lateral brows. This technique allowed the authors to visualize the need for placement of toxin more laterally with eventual successful predictive placement for neurotoxin.
Conclusion: This technique of using local 1% lidocaine allows the practitioner to devise a neurotoxin distribution map tailored for each patient to limit unwanted paralysis from improper neurotoxin placement.