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Orbital floor fracture |
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Orbital blow-out fracture Smith and Regan, 1957, showed that when an object of slightly greater diameter than the orbital rim struck the protruding incompressible eyeball, the rapid increased intra-orbital pressure resulted in fracture of the weak part of the orbital floor.
Bone fragment displaced downwards into the antral cavity, remaining attached to the orbital periosteum. Periorbital fat tends to herniated through the defect, interfering with the inferior rectus and inferior oblique muscles which are contained within the same fascial sheath. This prevents upward movement and outward rotation of the eye and the patient experiences diplopia on upward gaze.
Oedema and ecchymosis masks the signs and symptoms and takes 5—7 days to resolve. Diplopia should be tested for on review.
Radiology Opacity of the maxillary sinus +/- ethmoidal sinuses, due to extravasations of blood and herniation of fat into them via a fracture of overlying bone. PA tomography, lateral tomography and CT scanning may be required for imaging.
Should symptoms persist surgical intervention may be required to return the orbital contents to their correct position, a graft placed on the orbital floor helps retain the integrity of the fractured bone. Permacol can be used, or it the fracture is more severe a titanium mesh may be required.
Complications of grafting the orbital floor: ¨ Persistent enophthalmos ¨ Depression of the globe ¨ Persistent diplopia in vertical gaze ¨ Extrusion of the implant ¨ Infection and chronic fistula ¨ Lower eyelid retraction and ectropion ¨ Intra-oral haemorrhage ¨ Persistent oedema of lower eye-lid ¨ Tissue reaction to implant ¨ Dacryocystitis ¨ Blindness
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