Transient Unilateral Forehead Paralysis Following Mohs Micrographic Surgery

Kim, Tae Wook; Mun, Je Ho; Kim, Hoon Soo; Ko, Hyun Chang; Kim, Byung Soo; Kim, Moon Bum; Song, Margaret

Abstract

Unilateral forehead paralysis is a well-documented symptom which follows the superficial temporal branch of the facial nerve injury. The temporal branch holds the highest risk of injury during head and neck surgery among facial nerve branches because it runs superficially above the level of the zygomatic arch, and is not protected by the galea-parietotemporal fascia. Injury to the nerves prior to its innervations into the frontalis muscles will result in unilateral frontalis paralysis which leads to a flattened forehead, eyebrow ptosis and an inability to raise the eyebrow. However, the postoperative forehead paralysis does not always leave permanent sequale. The restorations for motor functions of the nerves sometimes occur without any interventions from several days to several months after the injury. This transient forehead paralysis may result from inhibitory effects for local anesthetics of motor nerve function, neural edema, or direct nerve injury during the operation. Therefore, it is important to predict clinical courses and take appropriate management of postoperative facial nerve paralysis through the understanding neuroanatomy for temporal branch of facial nerves and sophisticated surgical techniques. Herein, we report a case of transient unilateral forehead paralysis which follows Mohs' micrographical surgery for basal cell carcinoma of left temple regions where the superficial temporal branch of the facial nerve runs.