Degrees of Tolerance in Post-Traumatic Orbital Volume Correction: The Role of Prefabricated Mesh

Purpose

To identify factors influencing the volumetric correction of orbital fractures, and evaluate the use of prefabricated titanium mesh in their repair.

Materials and Methods

We included patients with unilateral orbital fractures and floor or medial-wall defects, subsequently reconstructed with titanium mesh, and subject to adequate follow-up with multislice, digitalized computed tomography (CT) images. Medical records were reviewed, and demographics, operative details, and postoperative course were recorded as prognostic variables. Moreover, orbital volume, apex-to-globe distance, and orbital rim area were measured using postoperative CT. Univariate analysis and a multiple-regression model were used to identify associated factors.

Results

A total of 32 patients fulfilled the inclusion criteria. Postoperative clinical evaluation and CT images were obtained in a mean ± SD of 12.3 ± 7.2 months after surgery. Clinically, 20 patients were considered normal (63%), and 12 manifested some ocular dystopia (37%). On postoperative CT, the mesh was in good position in 44% of cases, and in an insufficient position in 56% of cases. There was a significant difference between fractured and normal orbits in relation to orbital volume and apex-globe distance. Clinical evaluation significantly correlated with CT mesh placement, but there was no correlation between clinical evaluation and any of the variables measured on CT. The most important factors influencing postoperative orbital volume correction were type of fracture, affected walls, and use of prefabricated mesh.

Conclusion

Volumetric and lineal symmetry between fractured and normal orbits are very difficult to achieve. In this study, postoperative CT measurements did not correlate with subjective clinical assessment. The clinical-radiological disagreement may be explained by measurement accuracy problems, clinical bias, or normal differences between orbits. The most important identified modifiable factor was the use of prefabricated mesh.