3-Dimensional Volumetric Analysis of Relationship Between the Orbital Volume Ratio and Enophthalmos in Unoperated Blowout Fractures

Purpose: Blowout fractures are common in midfacial trauma and often involve other parts of facial bones. Sometimes, patients have complications caused by inadequate management. Surgical indications, such as clinical symptoms, can be inaccurate owing to post-traumatic swelling or hematoma formation. Previous studies on the prediction of enophthalmos used the orbital volume ratio (OVR) or only the volume of herniated tissue. This study examined which of these values is more predictive of the degree of enophthalmos. In addition, the predictive values for a 2-mm enophthalmos in unoperated blowout fractures were assessed. Patients and Methods: A total of 191 patients underwent nonoperative treatment for blowout fractures at our institution; they were divided into 2 groups according to the degree of enophthalmos (>2 mm vs 0 to 2 mm) and were further divided into 3 subgroups according to the location of the fracture (inferior, medial, or inferomedial). Multifactor logistic regression analysis was performed to determine the relationship between the degree of enophthalmos and these values. Results: We observed a correlation between the OVR and the degree of enophthalmos, as well as a correlation between the volume of herniated tissue and the degree of enophthalmos. Regarding the anatomic location of herniation, the orbital floor was found to be more correlated with the amount of enophthalmos. Conclusions: The OVR is a more reliable predictor than measurement of the volume of herniated tissue. The relationship found between radiologic examination findings and the degree of enophthalmos can be used as a surgical indication in addition to consideration of the anatomic location.