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M. Shaw, L. Mitsumori, A. J. Amadi; Globe and Orbit Volumes as a Risk Factor for the Development of Orbital Blowout Fractures. Invest. Ophthalmol. Vis. Sci. 2008;49(13):2294. doi: https://doi.org/.
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Evaluation of the ratio of globe-to-orbit volumes as a risk factor for the development of orbital blowout fractures in patients sustaining blunt ocular trauma.
This is a retrospective chart review of patients at least 18 years of age with unilateral blunt ocular trauma. The globe and orbit volumes of ocular trauma patients resulting in blowout fractures were compared with control patients sustaining open globe injury without blowout fracture. Volumes of the uninjured eye were obtained using 3D image post processing of axial CT data sets with Vitrea software (Vital Images, Inc., Minnetonka, MN). Reliability of the volume measurements were confirmed by tracing the orbit volume of a model skull CT scan. Operator variability was determined by comparing dual orbit and globe tracings of ten random fracture patients. All tracings were completed by a single operator, eliminating interoperator variability.
Mean age was 51 years (19-81) for the control group and 35 years (18-75) for the fracture group. Gender distribution was 65% male and 35% female for the control group and 77% male and 23% female for the fracture group. Racial distribution was 75% Caucasian, 10% African American, and 5% Hispanic for the control group versus 63% Caucasian, 10% African American, and 10% Hispanic for the fracture group. In the fracture group, 50% had a floor fracture, 4% had a medial wall fracture, and 46% had both a floor and medial wall fracture. For mechanism of injury in the control group, 35% were fall injuries, 30% were assault injuries, and 35% had a blunt object to the eye. For the fracture group, 3.6% were fall injuries, 68% were assault injuries, 21% had a blunt object to the eye, and 7.1% were from motor vehicle accidents. Mean operator variability was 0.3cm3 (±0.2std, range 0.0-0.6) for globe tracings and 0.6cm3 (±0.5std, range 0.1-1.5) for orbit tracings. Mean globe and orbit volumes in study patients were 8.7cm3 (±1.0std, range 7.5-11) and 26.2cm3(±2.38std, range 22-30), respectively. The globe to orbit ratio was 0.33 (0.25-0.46). For control patients, the mean globe and orbit volumes were 8.7cm3 (±0.87std, range 7.1-11) and 26.3cm3(±2.4std, range 22-31), respectively. The globe to orbit ratio was 0.33 (0.28 - 0.37). This data was calculated from preliminary data of 30 fracture and 20 control patients.
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