Walsh & Hoyt: Pathogenesis

Direct CCFs most often result from head trauma. The most frequent settings are motor vehicle accidents, fights, and falls. The injury may be penetrating or nonpenetrating, and it may be associated with basal or facial skull fracture. The injury may be so severe that the patient requires hospitalization, or it may seem quite trivial, requiring no treatment until symptoms and signs of the fistula develop. Dandy emphasized that the carotid artery may tear or be perforated by a bone fragment during impact from a sudden deformation or fracture through the carotid canal. Orbitocranial perforating injury is another cause of traumatic CCF. We have seen several patients in whom such a fistula was caused by a stab wound. In all cases, the object (knife, umbrella tip, pencil) passed through the superior orbital fissure and lacerated the internal carotid artery within the cavernous sinus. Direct CCFs may become symptomatic directly after injury, or they may not become evident until several days to weeks later.