21
Importance
Inadvertent injury to the skull base is more likely to occur if the maxillary to ethmoid
vertical height ratio is greater than 1:1
Risk for intracranial injury is positively correlated with higher Keros classification. It is
critical to note any asymmetry of the skull base or areas of bony dehiscence
Arteries suspended below the skull base are more susceptible to injury during sinus
surgery. Damage to the artery can result in hemorrhage, CSF leak, or orbital hematoma
e sphenoid sinus is helpful in identifying the anterior skull base
ere is an increased risk of optic nerve injury if an Onodi cell or bony dehiscence is
present
Risk of carotid artery injury increases if there is an insertion of an intersinus septation or
overlying bony dehiscence
Inadvertent injury to the skull base is more likely in the presence of an asymmetric skull
base or areas of bony dehiscence. Similarly, injury to the orbit, carotid artery, and optic
nerve is increased with areas of bony dehiscence/abnormalities
