Validation of a New Anesthesia Technique for Invasive Treatment in the Forehead and Temple: A Split-Face Randomized Study

Abstract

Background:Administering local anesthesia to the zygomaticotemporal nerve (ZTN) involves a deep insertion 1.5 cm lateral to the lateral canthus of the zygomatic bone, which may cause substantial pain. Use of a superficially located ZTN can cause less pain and fewer complications during injection. This study was performed to compare the conventional anesthesia method with the novel injection method by comparing the anesthesia area and degree, pain intensity using the visual analog scale (VAS), and muscle morphologic anatomy through ultrasonography. Methods:A split-face randomized study was conducted on 24 adult patients with no general medical conditions. The zygomaticotemporal fossa and nerve were marked, and their depths were calculated using ultrasonography. A total of 0.9 mL of the dental ample of 2% lidocaine mixed with epinephrine was injected using the conventional injection technique, and another 0.9 mL was injected using the novel injection technique. VAS scores, skin temperature, anesthesia area, and the efficacy of block anesthesia on the related fibers (cold, pressure, and pain) were assessed. Results:Nineteen women and 5 men (average age, 29.3 +/- 3.7 years) were enrolled in this study. The average VAS scores for the novel injection technique (2.4 +/- 1.1) were significantly lower than those for the conventional method (3.7 +/- 1.1) (P < 0.01). Touch sensation and skin temperature showed statistically significant differences between the injection groups (P < 0.05). Conclusions:The novel technique for superficially located ZTN injection results in a significantly lower pain level during injection and similar effects compared with the conventional technique. This novel technique can be considered for aesthetic procedures requiring anesthesia in the temporal area.