superior orbital fissure syndrome Flashcards
Superior orbital fissure (SOF)
lies at the back of the orbit between the lesser and greater wing of the sphenoid bone. It contains the SOV and IOV, superior and inferior branches of CN III, IV, VI, V1 and its branches including lacrimal, frontal, supraorbital, supratrochlear and nasociliary nerves
SOFS why?
Superior orbital fissure syndrome (SOFS)- Inflammatory:
* SOFS is a symptom complex caused by compression of structures which exist in SOF just before the orbital apex (VA not affected)
* The main difference of SOFS from OAS is no optic nerve involvement in SOFS
* It is known that the most common cause of SOFS is trauma (craniomaxillofacial injury) including RTA’s, zygomatic and orbital fractures.
* Tumours including lymphoma and rhabdomyosarcoma, infectious diseases including syphilis (syphilitic periostitis), meningitis, sinusitis, herpes zoster, ischemic, vasculitic or inflammatory diseases including THS, sarcoidosis, systemic lupus or temporal arteritis and vascular events including carotid-cavernous fistulas (CCF), retro-orbital haematoma and carotid aneurysm. However, it may also be idiopathic.
SOFS features
CN VI is most commonly damaged because of its location within the central SOF and close to the greater wing.
* CN IV is the least commonly involved CN because of its protection by the common tendinous ring
Features:
* Ophthalmoplegia due to damage to CN III, IV and VI
* Ptosis due to CN III injury and loss of sympathetic input
* Proptosis due to decreased tension in the EOMs with loss of innervation
* Fixed dilated pupil due to loss of parasympathetic innervation of the pupil by the CN III
* Lacrimal hyposecretion and eyelid or forehead anaesthesia and decreased corneal sensation due to damage to CN V1
* Chemosis and bruits caused by vascular congestion and occasionally visual loss due to mechanical compression of CN II.
* The proptosis, eyelid swelling, and chemosis indicate significant orbital masses.
