To report the clinical manifestations and computed tomography (CT) findings of patients with a trapdoor type medial orbital wall blowout fracture. Methods

From March 2009 to October 2016, the clinical records and computed tomography findings of patients who underwent surgical treatment for a trapdoor type medial orbital wall blowout fracture were retrospectively analyzed. Results

A total of eight patients (six males and two females) were enrolled with a combined mean age of 14.4 years. Clinical manifestations were eyeball movement limitation (abduction and adduction) and ocular motility pain (eight patients, 100%), diplopia (seven patients, 87.5%), and nausea and vomiting (four patients, 50%). On CT, the distance from the orbital apex to the fracture site was an average of 22.0 mm and occurred in the middle position of the entire wall. Two patients had missed rectus completely dislocated into the ethmoid sinus through the fracture gap and six patients had definite involvement in the fracture gap and edema of the medial rectus muscle. The medial rectus muscle cross-sectional area was 47.7 mm² which was edematous compared to the contralateral eye (40.1 mm²). Orbital wall reconstruction was performed an average of 4.1 days after the injury. In all patients with oculocardiac reflex-like nausea and vomiting immediately improved after surgery. Six out of eight patients who had eyeball movement limitations (abduction and adduction) preoperatively showed adduction limitation after surgery. The eyeball movement limitation and diplopia disappeared 11.7 days and 46.7 days after surgery, respectively. Conclusions

Patients with trapdoor type medial wall blowout fracture showed characteristic computed tomographic findings and clinical manifestations such as eyeball movement limitation, ocular motility pain, diplopia, and oculocardiac reflex. An understanding of clinical findings and quick surgical treatment are therefore required. The type of eyeball movement limitation was abduction and adduction limitation preoperatively and adduction limitation postoperatively.