Presentation # : eP-128 A Novel Imaging Measurement Identifying Patients with Orbital Floor Fracture Requiring Surgical Repair Taheri, MR1; Rudolph, M2; Brown, D3; Mansour, T4 1: Department of Radiology, George Washington University, Washington, DC 2. Medical Student, George Washington University, Washington, DC 3. Department of Biostatistics, George Washington University, Washington, DC 4. Department of Ophthalmology, George Washington University, Washington, DC

Disclosure None

Background Patients with orbital fractures make up a significant percentage of those evaluated in the Emergency Department for facial trauma. In our experience, only a fraction of these patients will likely require immediate Ophthalmological consultation for possible surgical correction. Decreasing time elapsed between patient presentation and surgical intervention can improve the long-term outcome as scarring has yet to fully develop.   CT findings suggestive of orbital floor fractures spanning greater than fifty percent of the orbital floor (BOF > 50%) is considered the most predictive imaging sign that could help identify those patients whom surgical correction is required in the adult population group. Clinically, many patients with the CT finding of BOF > 50% do not have a clinical presentation that would require them to undergo surgical correction.

Hypothesis / Purpose The goal of this project is to identify an accurate and reproducible tool that may be used in the Emergency Department to identify those patients who require timely Ophthalmological evaluation. We tested the hypothesis that Cranio-Caudal Discrepancy (CCD) is a reliable predictor of those patients with orbital floor fracture that require emergent surgical management. This novel measurement was defined as the difference between the cranial-caudal dimension, measured just posterior to the globe, of the fractured orbit minus the normal side.

Methods / Material – Selection In this retrospective IRB approved study, we reviewed ninety-nine (99) patients older than 18 years with orbital fractures treated in a level I trauma center during 2011-2015. Thirty-three (33) patients met the inclusion criteria of having an isolated orbital floor fractures with or without a minimally displaced medial wall fracture.

Methods / Material – CT Measurements 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 three questions: Extent of the fracture fragment; greater than or less than 50%? Involvement of the infra-medial strut (IMS)? CCD of the orbits. Please see next slide for more details.

Methods / Material – CCD of the Orbit IR IR IOC IOC The posterior aspect of the globe in the coronal plane (A) defines the level at which the caudal cranial dimension of the globe is measured in the sagittal plane (B). Arrow labelled IOC points to the inferior orbital canal. Arrow labelled IR points to the inferior rectus muscle. CT scan of the orbit in bone algorithm in sagittal plane (B) at the level of the inferior rectus shown in (A) shows the belly of the IR and the course of the IOC. In this view, a globe line is drawn perpendicular to the axis of the globe (thin white line). A line perpendicular to globe line is drawn such that it intersects the posterior aspect of the globe (thick white arrow). The difference between this cranial-caudal dimension of the orbit with an acute floor fracture from the normal side defines CCD.

Methods / Material – Clinical Outcome Electronic medical record (EMR) 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 – CCD >0.8 is Defined as a Positive Test B 3.75cm 3.28cm The orbital fracture of this patients measures greater than 50% of the floor, which typically would require surgical repair. After a physical exam by an Ophthalmologist, a surgical repair was deemed unnecessary. Application of the CCD, which is obtained by calculating the difference between the caudal-cranial dimension of the orbit with the floor fracture (3.75) (A) from the normal side (3.28) (B), measures 0.47 cm that is below a threshold needed for surgical repair (set at 0.8cm).

Results – Accuracy of BOF >50% was 48%

Results – Accuracy of IMS Involvement was 74% : (IMS not inv.)

Results – Accuracy of CCD was 94%

Results – R.T. CCD Test Predictiveness of Surgery. Kappa Agreement Between The Two Readers Was 0.93 : (CCD > 0.8) : (CCD < 0.8)

Results – T.M. CCD Test Predictiveness of Surgery. Kappa Agreement Between The Two Readers Was 0.93 : (CCD > 0.8) : (CCD < 0.8)

Conclusion We introduce a new CT measurement, called CCD. CCD greater than 0.8 cm is predictive of the development of diplopia and/or enophthalmos that will require surgical correction. BOF greater than 50% and IMS involvement were much less accurate in making similar predictions. CCD should be used by the Radiologists and 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.

Please direct your comments and questions to Reza Taheri : rtaheri@mfa.gwu.edu Thank you