Orbital Apex Syndrome Secondary to a Dental Implant Infection Caused by Staphylococcus lugdunensis

Orbital apex syndrome (OAS) is a rare complication of odontogenic maxillary sinusitis. An 87-year-old woman with gingivitis caused by a dental implant infection developed diplopia, followed by a rapid visual deterioration and limited extraocular movement in her left eye. Imaging revealed penetration of the upper left first molar into the maxillary sinus and inflammation involving the extraocular muscles and the orbital apex. Staphylococcus lugdunensis (S. lugdunensis) was cultured from the patient's sinus. Steroid pulse therapy, antimicrobial treatment, tooth extraction, and sinus irrigation partially improved her visual acuity, while extraocular movement was fully recovered. This report presents a rare case of OAS caused by S. lugdunensis.