Isolated trapdoor-type medial blowout fracture in an adult presenting horizontal diplopia treated by endoscopic endonasal approach.

Orbital blowout fracture frequently occurs along the floor or medial aspect of the orbital wall, which are the two thinnest areas of the bony orbit. True trapdoor injury of the orbit is less common and is rare as an isolated medial wall injury, because the medial orbital wall has several bony septa within the ethmoid sinus that provide support and decrease the risk of a trapdoor fracture. Additionally, the incidence of trapdoor-type blowout fracture in adults is lower than in children. In a trapdoor-type blowout fracture with restricted ocular movement, prompt diagnosis and early intervention are associated with better clinical outcomes. We encountered a case of trap door-type medial blowout fracture with horizontal eye ball movement limitation in an adult. She underwent endonasal endoscopic reduction surgery for the medial blowout fractures. Here we report this case, and suggest early diagnosis and prompt surgical exploration.