To report a case of acute orbital abscess after Medpor^® implantation for orbital floor fracture repair.

A 15-year-old boy who was punched in the right orbit visited our clinic because of diplopia. An orbital CT scan demonstrated a fracture of the right orbital floor. At surgery, a Medpor sheet was placed over the orbital floor defect. Over the first three days, clinical improvement was gradual, but at four days postoperatively, depression of the right eye was restricted, and lower lid edema and proptosis was present in the right eye. At eight days postoperatively, the orbital CT scan showed a large cystic mass surrounding the Medpor sheet and fine needle aspiration cytology showed a number of inflammatory cells. Because systemic antibiotics were ineffective, the Medpo^® sheet and the cystic mass were removed through a transconjunctival approach to the orbit. A culture of the removed Medpor^® sheet grew Staphylococcus aureus and signs of inflammatory cells in the tissue were present. After removal of the abscess, most clinical symptoms showed improvement except for the remaining depression of the right eye.

Symptoms of eye movement restriction, lower lid edema, and proptosis may be uncommon after orbital floor fracture repair but can occur. We should also consider the possibility of abscess formation due to infection of the implant and emphasize the importance of prompt diagnosis and treatment of such a case.