Computed tomography of orbital trauma

Post-traumatic orbital cellulitis

Orbital cellulitis is uncommon. It may arise as a sequel to eyelid infection, or from direct spread of infection from the paranasal sinuses; it may be of odontogenic origin and has been reported after meningitis and after nasoorbital fractures with pre-existing sinusitis. Clinically, orbital cellulitis is of great importance, as it is a severe disease with potentially disastrous consequences. It may lead to optic neuritis, optic atrophy, blindness, cavernous sinus thrombosis, superior orbital fissure syndrome, meningitis, subdural empyema, and even death. We report two cases of severe post-traumatic orbital cellulitis with subperiosteal abscesses. These were managed surgically and vision was preserved. We describe the anatomy, a classification of orbital infection, and the importance of multidisciplinary management of these cases.

Traumatic transconjunctival orbital emphysema

Orbital emphysema can be produced by trans-conjunctival migration of air from a high pressure airgun. In an industrial accident an 8 mm conjunctival laceration was produced in the superior fornix which acted as a portal of entry for air into the subconjunctival, subcutaneous, and retrobulbar spaces. Computed tomography revealed no evidence of orbital fracture and showed that traumatic orbital emphysema occurred without a broken orbital bone.

Optic nerve trauma: clinical, electrophysiological and histological remarks

18 patients with post-traumatic visual disease of the optic nerve are presented. In the post-traumatic stage, visual evoked potentials were monitored. In amaurosis there was a high incidence of midface or frontobasal fractures. The severity of the trauma is not correlated with the severity of visual deficits. Flash evoked potential (FEP) findings were different: In most cases there was a correlation of clinical and FEP findings. In some we found false positive potentials in the acute stage. In smaller visual field deficits the alterations of FEP could not be correlated with the clinical disorders. FEP alterations depended on time. The pathophysiological mechanisms are discussed in regard to the pathological findings in 51 unselected autopsies with an investigation of the visual pathway from the intraorbital optic nerve to the visual cortex. Because of the different morphological alterations the clinical, neurological and ophthalmological examination should be followed by standard CT scanning to evaluate intracranial haematomas and by CT scanning with thin slices of the optic nerves and the soft tissue of the orbit. Visual evoked potentials (VEP) and in the unconscious patient, flash evoked potentials (FEP) do not give much more security for therapeutic decisions in comparison with former times. The histological findings do not support the hypothesis that operative decompression is successful.