Correlation between Orbital Computed Tomography Scan Measurements and Clinical Enophthalmos in Acute Isolated Orbital Floor Fractures.

Purpose: To analyze the correlation between orbital computed tomography (CT) scan measurements including the fracture area (FA), the fracture location, the soft-tissue herniation volume (HV), the fractured orbital volume ratio (OVR) to the normal orbit, and the clinical enophthalmos in acute isolated orbital floor fractures.

Methods: We enrolled 100 patients with acute isolated unilateral orbital floor fractures from May 2017 to January 2021. Based on the CT scan findings, we measured the FA, HV, OVR, and fracture site. We assessed enophthalmos using both clinical (CE) and radiographic (RE) measurements. Additionally, we investigated the correlation between CE and the measured parameters, along with the relationship between the pattern of diplopia and the fracture site.

Results: We identified enophthalmos in 81% and diplopia in 78% of the patients with an acute blowout orbital floor fracture. CE was moderately correlated with the FA (R ² = 0.4341, P < 0.001). CE was weakly correlated with the HV (R ² = 0.2861, P = 0.04). Anterior fractures caused diplopia in both vertical gazes, but posterior fractures were mostly associated with diplopia in the up gaze. OVR was strongly associated with RE (R ² = 0.663, P < 0.0001) and moderately associated with CE (R ² = 0.4378, P < 0.0001). The univariate regression analysis also showed that OVR could significantly predict CE and RE.

Conclusions: OVR surpasses other CT scan measurements such as FA and HV in the prediction of clinical enophthalmos. Thus, OVR could be utilized to estimate clinical enophthalmos at the time of presentation, especially when the acute clinical setting prohibits the proper clinical evaluation.