Orbital blowout fractures: a novel CT measurement that can predict the likelihood of surgical management.

OBJECTIVE

The purpose of this study is to identify an accurate and reliable computed tomographic (CT) measurement that can identify those patients presenting to the emergency department (ED) with orbital floor fracture (BOF) who require surgical repair to prevent ensuing visually debilitating diplopia and/or enophthalmos.

METHODS

In this retrospective institutional review board-approved study, we reviewed 99 patients older than 18 years with orbital fractures treated in a level I trauma center from 2011 through 2015. Thirty-three patients met the inclusion criteria of having an isolated BOFs with or without a minimally displaced medial wall fracture. The maxillofacial CT of these patients, which included axial, coronal, and sagittal reconstruction of the face in both soft tissue and bone algorithm, were independently reviewed by a neuroradiologist and an oculoplastic surgeon. Each reviewer analyzed the images to answer the following 3 questions: (1) extent of the fracture fragment; greater than or less than 50%? (2) involvement of the inframedial strut (IMS)? and (3) cranial-caudal discrepancy of the orbits. This novel measurement was defined as the difference between the cranial-caudal dimension (CCD), measured just posterior to the globe, of the fractured orbit minus the CCD of the normal side. Electronic medical record was reviewed to determine the course of recovery, ophthalmologist assessment of the globe, motility, diplopia, and the need for operative repair. Statistical analysis was performed to determine the accuracy of the measured CT parameters for the prediction of those who would ultimately require surgical repair.

RESULTS

Of the 33 patients included in the study, 8 patients required surgical correction of their BOFs. Others were managed conservatively. The accuracy of BOF > 50% for predicting those requiring surgical repair was 48%. The accuracy of IMS involvement was 74%. Using a threshold CCD value of 0.8 cm, the accuracy of CCD was 94%. Cranial-caudal discrepancy had a sensitivity of 100% and specificity of 92%. κ Agreement between the 2 readers evaluating the CT images was 0.93.

CONCLUSION

Initial maxillofacial CT studies obtained in the ED for those with BOF is used to predict which patients may need urgent surgical repair. In this report, we introduce a new CT measurement, called CCD. Cranial-caudal discrepancy greater than 0.8 cm is predictive of the development of diplopia and/or enophthalmos that will require surgical correction. Orbital floor fracture greater than 50% and IMS involvement were much less accurate in making similar predictions. Cranial-caudal discrepancy should be used by the ED physicians to identify those patients who should be referred sooner than later to an oculoplastic surgeon for surgical evaluation and intervention. Correct and timely triaging can prevent the complications of delayed correction including scarring, difficult surgical repair, and/or poor functional and aesthetic outcomes.