Intraoperative Findings of Extraocular Muscle Necrosis in Linear Orbital Trapdoor Fractures

Orbital trapdoor fractures can constitute a relative surgical emergency. The reason for poor surgical outcomes in ocular motility disturbances and diplopia is not apparent in these fractures. The purpose of this retrospective study was to analyze the possibility of ischemic necrosis of the orbital contents in linear trapdoor fracture of the orbital floor and to evaluate the recovery period of trapdoor fractures.

The study included 11 patients with linear trapdoor fracture of the orbital floor over 5 years with minimum 1-year follow-up. Patients with associated facial bone fractures were excluded. Demographic, etiologic, and radiologic characteristics, interval from trauma to surgery, and surgical techniques were recorded.

Patients' age range was 9 to 29 years (mean, 16.3 yr). Mean time to surgical intervention from time of injury was 3.9 days (range, 0 to 11 days). Intraoperatively, macroscopic segmental necrosis of the entrapped inferior rectus muscle was observed in 3 patients. Postoperative review was conducted for a minimum of 12 months at 1-week and 1-, 3-, 6-, and 12-month intervals. At the end of the follow-up period, incomplete recovery was observed in 5 patients, including the 3 patients with intraoperative necrosed muscle, and the other 2 patients were operated on at days 7 and 8 from time of injury.

This study showed that segmental necrosis of the entrapped inferior rectus muscle is possible in linear trapdoor fracture of the orbital floor. In addition, incomplete recovery correlated with clinical evidence of inferior rectus muscle necrosis and late surgical intervention.