Does maxillary sinus size affect the risk for zygomatic complex fractures?

The purpose of the study was to measure the maxillary sinus sizes in patients with and without zygomatic bone fractures. In this cross-sectional study computed tomography data of a case group of consecutive treated patients with displaced zygomatic bone fractures were compared to a control group with mandibular fractures. Maxillary sinus sizes were measured in width, height, depth, and volume. We compared sinus sizes between the case and control group, followed by a subgroup analysis of slightly and severely displaced fractures using T-tests. We identified 89 cases, thereof 46 with slightly and 43 with severely displaced fractures. The control group consisted of 110 patients. The mean sinus volume of the case group (19,313 mm³  ± 5237) was significantly larger than in the control group (17,645 mm³  ± 4760; p = 0.02). Subgroup analyses revealed that this difference in volume was more pronounced between patients with severely displaced fractures (20,354 mm³  ± 5416; p = 0.003) and the control group. In two-dimensional measures, only sinus height was significantly greater in the case group (37.41 mm ± 4.25 vs. 35.33 mm ± 4.88; p = 0.002). The same holds for the subgroup with severely displaced fractures (38.27 mm ± 3.91; p = 0.001). Sinus width and depth showed no significant differences between the groups. A maxillary sinus volume larger than 20,000 mm³ is a predictive risk factor for a displaced zygomatic bone fracture. Greater sinus height indicates a larger surface area of the zygomaticomaxillary buttress that decreases the resistance to facial trauma.