Internal fixation in trapdoor-type orbital blowout fracture

The most common orbital blowout fracture is a trapdoor type. In many cases of trapdoor fracture, the bony segment has a stable hinge consisting of a greenstick fracture and the sinus mucoperiosteum that is attached to the intact orbital wall. If the displaced bony segment opposite the hinge is reduced into the original position and fixed on the unaffected bone, the orbital fracture may be reconstructed by internal fixation of the bony segment itself rather than requiring substitution with alloplastic implants or a bone graft.

In 20 cases of orbital blowout fracture of a trapdoor type, internal fixation was performed using a cantilever fixation technique (with a piece of titanium micromesh or a titanium microplate plus a microscrew) or a ledge fixation technique (with a piece of micromesh).

In all cases, the orbital wall was accurately reconstructed in its normal anatomical position. The associated ocular problems disappeared except for mild diplopia in one patient and there were no surgical complications associated with the internal fixation.

The advantages of internal fixation include anatomical reconstruction of the orbital wall; preservation of the original orbital bone and the mucoperiosteum of the sinus as an osteomucoperiosteal flap resulting in rapid wound healing and normal mucus drainage function of the sinus; the simplicity of the procedure; and consequently, the absence of surgery-related complications. This technique is presented as one of the preferred treatments for trapdoor-type orbital blowout fractures.