Facial nerve palsy (FNP) following sagittal split ramus osteotomy (SSRO) is rare, but once it occurs, it can be a source of mental and social distress because of functional and cosmetic disturbances. Here, we report a case of peripheral FNP that developed after SSRO for mandibular advancement and was treated by us. The patient was a 22-year-old woman. She had a clinical history of right FNP that occurred when she underwent extraction of her right wisdom tooth before preoperative correction. She underwent bilateral SSRO via a modified version of the Obwegeser technique to correct mandibular retrognathism. The intraoperative course was uneventful. Right FNP developed immediately after the operation. Pharmacotherapy (steroids, vitamin B12, ATP, antiviral drugs) and stellate ganglion blocks (SGB) were administered to reduce the swelling around the facial nerve and promote healing of the facial nerve damage. The symptoms exacerbated 2 days after the operation, but improved from about 7 days after the operation. Given her clinical history of FNP, we thought that she had a high risk of FNP because of hematoma, edema, and local anesthesia around the mandibular ramus. We thought that facial nerve injury was probably caused by compression by the hematoma and edema formation during or immediately after the operation, direct or delayed nerve paralysis caused by the anesthetic solution, and reactivation of herpes simplex virus type 1 (HSV-1) or varicella zoster virus (VZV). The symptoms resolved completely 2 months after the operation, and treatment was completed.
