The role of computed tomography (CT) in predicting diplopia in orbital blowout fractures (BOFs).

Abstract

The management of orbital blowout fractures (BOFs) is controversial: the evaluation of diplopia is the most important criterion for planning whether to undertake surgery. Our aim was to determine CT findings that may suggest the presence of diplopia when patients with BOFs cannot be adequately examined to plan an orbital repair. We retrospectively evaluated CT of all patients presented to our Emergency Department for blunt craniofacial trauma (N=3334) from January 2014 to March 2016, selecting patients with CT-demonstrated BOFs. The following CT variables were assessed: fracture location, fracture multifocality, bone fragments displacement, extraocular muscles (EOM) thickening, EOM entrapment, EOM displacement, EOM hooking, intraconal and extraconal emphysema, intraconal and extraconal hematoma, and fat herniation. All patients underwent Hess-Lancaster test, to establish the presence of diplopia. After performing group comparison with Pearson χ2 test, we derived our prediction model by using logistic regression, with diplopia as the prediction and CT variables as predictors. We observed 299 patients with BOFs, 46 (15.4%) with a Hess Lancaster test-proven diplopia. The CT variables with statistically significant difference between the group with diplopia and the group without diplopia were as follows: floor fracture (p=.014), bone fragments displacement (p=.001), multifocality (p=.005), EOM thickening (p=.001), EOM entrapment (p<.001), EOM displacement (p<.001), fat herniation (p=.003). The CT variables with significance as predictors of diplopia at multivariate analysis were as follows: orbital floor fracture (p value 0.015; odds ratio 2.871, 95% confidence interval of odds ratio 0.223-6.738), EOM displacement (p value 0.001; odds ratio 10.693, 95% confidence interval of odds ratio 3.761-30.401), EOM entrapment (p value 0.001; odds ratio 11.510, 95% confidence interval of odds ratio 3.059-43.306). The presence of diplopia can be suggested on the basis of CT findings after an orbital trauma.