A Consistent, Reliable Landmark to Assist in Placement of Orbital Floor Reconstruction Plates After Blowout Fractures.

OBJECTIVE: To define a reliable and consistent landmark, the superior posterior wall of the maxillary sinus, and to describe how this landmark can be used when repairing orbital floor fractures.

METHODS: Retrospective chart review. Patients >18 years old diagnosed with unilateral orbital floor and/or zygomaticomaxillary complex fractures.

MAIN OUTCOMES: The distance from the inferior orbital rim to the superior posterior wall of the maxillary sinus (landmark distance), and the distance from the landmark to the entrance of the optic canal were reported.

RESULTS: Eighty patients were included in the study. Each had unilateral isolated orbital floor fractures (n = 46) or unilateral zygomaticomaxillary complex fractures with an orbital floor component (n = 34). The contralateral eye in all patients was uninjured, and was used as an internal control. In orbital floor fractures, the mean landmark distance was 38.8 ± 1.4 mm, with a mean distance on the normal side of 38.8 ± 1.6 mm (P = 0.49). Distance to the optic canal on the injured side in isolated orbital floor fracture patients was 9.0 ± 0.8 mm with the same measurement on the normal side being 8.8 ± 0.7 (P = 0.21). In the setting of zygomaticomaxillary complex fracture, the orbital floor length was 38.2 ± 1.3 mm with a mean normal floor length of 37.8 ± 1.1 mm (P = 0.18). The mean distance from the superior posterior wall to optic canal in zygomaticomaxillary complex fractured orbits was 9.2 ± 1.1 mm with a normal side mean length of 9.5 ± 1.0 mm (P = 0.23). No significant difference was found between the measured distances in the fractured orbit and its normal counterpart for both fracture groups.

CONCLUSIONS AND RELEVANCE: The superior posterior wall of the maxillary sinus is a reliable landmark that can be used to assist in placement of an orbital floor reconstructive plate. The landmark is unchanged despite the presence of an orbital floor or zygomaticomaxillary sinus fracture.