Symptoms

•Loss of function of cranial nerves III, IV, VI

•Damage of the optic nerve (N. II) with loss of visual acuity

Clivus Syndrome

Intracranial bleeding can lead to a compression and interruption of the oculomotor nerve at the clivus prior to its point of entrance into the superior orbital fissure. The clinical consequence is a mydriasis on the affected side.

6.1.2.3  Vascular Injuries in Skull Base Trauma

Particularly endangered in frontal skull base injuries are the cavernous sinus and the sagittal sinus. There is potential injury to the internal carotid artery by fractures in the sphenoid region, especially in the pyramidal apex. Carotid-cavernous sinus fistulas are more common than isolated injuries to the internal carotid artery.

Cavernous Sinus Syndrome

In severe craniofacial trauma with fractures of the sphenoid and/or petrous bone, there may also be an injury to the internal carotid artery on its course through the cavernous sinus (Takenoshita et al. 1990). As a consequence of arterial damage, arterial blood flow into the venous circulatory system occurs (cavernous arterio-venous fistula), producing a back-flow in the orbital veins (superior ophthalmic vein) (Hasso et al. 1979; Harris et al. 1984).

Clinically, this results in a massive unilateral (occasionally bilateral and seldomly contralateral) pulsating, progressive exophthalmus (exophthalmus pulsans)

and leads to an extreme conjunctival reddening through intense dilatation and congestion of the conjunctival and episcleral veins. There is additional chemosis and lid swelling.

This results in a pulse synchronic sound above the eye and beside the temple and cerebral nerve damage (abducent nerve, oculomotor nerve, trochlear nerve, first, and second trigeminal branches) due to their course within the cavernous sinus wall as well as reduction in visual acuity and visual field. Further risks arise from raised intraocular pressure.

The reduction of vision may end in a complete amaurosis. Vascular fistulas can be detected by MRI examination as well as by angiography (Schaller 2002) (Fig. 6.22).

Symptoms

•Internal ophthalmoplegia

•Exophthalmus (pulsating)

•Ptosis

•Conjunctival injections

•Pulse synchronic sound

Thrombosis of the Superior Ophthalmic Vein

Fractures in the region of the orbital roof can lead to a thrombosis of the superior ophthalmic vein, resulting in a mild exophthalmus and damage to the external branch of the oculomotor nerve. Ptosis and reduced motility are clinical signs.

Craniofacial injuries can also lead to disruptions of the ophthalmic and the anterior cerebral arteries as well as the anterior and posterior ethmoidal arteries. In frontal skull base injuries the cavernous sinus and the sagittal sinus are particularly susceptible to lacerations. Thrombi, hemorrhage, and air embolism are possible consequences (Fig. 6.23).