Defining the Zygomaticosphenoidal Angle as a Guide to Anatomic Zygomaticomaxillary Complex Fracture Reduction

Background:Alignment of the zygomaticosphenoid suture is fundamental to reduction of zygomaticomaxillary complex fractures. To prevent a rotational deformity, the correct angle of the zygoma relative to the cranial base must be restored. Clinically, this can be a challenge, especially when there is comminution of the zygomaticosphenoid suture. Defining a zygomaticosphenoidal angle would provide a reference for use with stereotactic navigation to achieve anatomic reduction.Methods:A single-center retrospective analysis of 100 patients was designed to determine normative zygomaticosphenoidal angle values. An angle subtended by the midline and a best-fit line through the zygomaticosphenoid suture on axial computed tomography was measured bilaterally in patients with isolated mandibular or nasal fractures. The mean of this measurement for 3 vertically adjacent cuts was calculated with position of central cut determined by the equator of the globe and trigone of the sphenoid. Multivariate regression was completed to identify changes in zygomaticosphenoidal angle with age, sex, and race.Results:The mean zygomaticosphenoidal angle was 47° (range 39°-55°). 97% of angles were within 2 standard deviations (8°) of mean. Regression analysis demonstrated no significant change in angle with age (P=0.74) or sex (P=0.89). For each angle, the variation across the 3 sample cuts was ≤4.5°. Patients demonstrated high fidelity in zygomaticosphenoidal angle bilaterally with mean difference of 3°.Conclusion:The zygomaticosphenoidal angle is a useful reference, in conjunction with stereotactic navigation, for reduction of zygomaticomaxillary complex fractures. Contralaterally obtained patient-specific data may be used to guide unilateral repair. Normative values may serve as reference in bilateral injury.