Unilateral hypoglossal nerve palsy following orthognathic surgery: A case report and literature review

INTRODUCTION: Hypoglossal nerve palsy (HNP) can be caused by nerve damage from the central nerve to a peripheral nerve, and individuals with multiple factors could be predisposed to HNP. We report a case of isolated unilateral HNP after orthognathic surgery. CASE PRESENTATION: A 56-year-old Japanese woman complained of jaw distortion and malocclusion. She had undergone a Le Fort I osteotomy and bilateral sagittal split ramus osteotomy (BSSRO) under general anesthesia in August 2021. On postoperative day 3, she experienced tongue motility, and when the tongue protruded forward, the tongue tip shifted to the right, and swelling of the right lateral pharyngeal wall was observed. An additional blood test revealed increased antibody titer levels (40×), cytomegalovirus IgG EIA titer (16.9 U/mL), HSV-IgG EIA titer (40 U/mL), and EBV-viral capsid antigen (VCA) IgG EIA titer (1.4 U/mL). We administered valacyclovir hydrochloride 1000 mg/day for 7 days, prednisolone (PSL) 60 mg/day, mecobalamin 1500 μg/day, and adenosine triphosphate (ATP) disodium hydrate 300 mg/day. A neurological examination revealed no central lesions, and we continued the patient's tongue-function training and oral hygiene guidance. The tongue apex deviation was resolved approx. 3 months postoperatively. DISCUSSION: There are no major reports on the etiology of HNP after orthognathic surgery. The possibility of HNP triggered by endotracheal intubation or through packing gauze under general anesthesia and viral infection cannot be ruled out. CONCLUSION: Clinicians should be aware of the possibility of unilateral HNP following orthognathic surgery.