Orbital blowout fracture with persistent mobility deficit due to fibrosis of the inferior rectus muscle and perimuscular tissue.

A case of orbital blowout fracture accompanied by fibrosis of the inferior rectus muscle resulting in an irreversible orbital mobility deficit is reported. An 8-year-old girl with an orbital blowout fracture was treated with steroids for 10 days, as with other cases in our department. She exhibited a disturbance of vertical eye movement and a positive forced duction test result. Although surgery was performed on day 13, and on day 27 due to poor recovery after the first operation, almost no improvement of the ocular movement was noted. The results of a traction test, performed during the second operation, suggested that the inferior rectus muscle had adhered to the periosteum. Magnetic resonance imaging performed 3 days after the second operation revealed fibrosis of the inferior rectus muscle and perimuscular tissue, resulting in an irreversible disturbance of the vertical ocular movement. The present findings suggest that the need for and timing of surgery in patients with blowout fractures should be determined on an individual basis.