Presentation
Several months right eye red, intermittent diplopia, chemosis, proptosis. decreasing vision.
Patient Data
Enlarged right superior ophthalmic vein (axial, coronal) with high signal on MRA suggesting high flow.
Additionally, the right cavernous sinus appears engorged with prominent flow voids. A similar appearance, albeit less marked, is seen on the left without, however, enlargement of the left superior ophthalmic vein. On the MRA there does appear to be elevated flow-induced signal in the left cavernous sinus, suggesting substantial abnormal flow here also.
Findings are suspicious for bilateral cavernous dural arteriovenous fistulas.
A cavernous dural arteriovenous fistula (dAVF) drains from a markedly enlarged right cavernous sinus (frontal, lateral) into a large right superior ophthalmic vein which drains via the angular vein to the right internal jugular. There is also a prominent inferior petrosal sinus.
In addition, however, there is drainage across the intercavernous connection to the left cavernous sinus, with drainage via cortical veins over the temporal pole and frontal lobe to the left transverse sinus.
Supply is minimal from the cavernous branches of the internal carotid artery. Most of the supply is from proximal branches of the occipital artery, the ascending pharyngeal artery, but predominantly the middle meningeal and distal branches from the maxillary artery.
Left side injection demonstrates a left side cavernous dural arteriovenous fistula, which opacifies the left cavernous sinus, which subsequently drains to the intracranial compartment over the left convexity.
There is also drainage across the previously demonstrated inter cavernous connections and via contralateral right inferior petrosal sinus.
It is not clear if a good caliber left inferior petrosal sinus is present.
Supply on this side is also predominately external with virtually no internal carotid meningeal supply.
In addition, left vertebral artery injections (not shown) outline large meningeal branches arising distally which also feed the left cavernous dural arteriovenous fistula.
Conclusion:
Symptomatic right-sided cavernous dAVF.
However, there are bilateral cavernous sinus dural arteriovenous fistulas, with predominant drainage on the right into superior ophthalmic vein and inferior petrosal sinus, but on the left with intracranial cortical venous reflux.
The former would explain the current symptoms and signs, the latter poses a risk of intracranial hemorrhage with treatment unless both cavernous sinuses are occluded.
Right internal jugular vein guide with microcatheter to the left cavernous sinus. Venogram showing extensive cortical venous reflux without reflux into the left superior ophthalmic vein or inferior petrosal sinus.
Multiple coils were then introduced into both cavernous sinuses. At the end of the procedure, no residual dAVF was able to be demonstrated on common carotid artery injections.
Case Discussion
This case illustrates the difference between symptomatic dAVF from orbital hypertension (right) and asymptomatic but dangerous cortical venous reflux, potentially resulting in subarachnoid hemorrhage.
If the right side is untreated, the patient risked becoming blind. However, if only the right side was treated then there was a high risk, potentially even higher post-treatment, of the left resulting in a hemorrhage. Conversely, if only the left side was treated then potentially the right-sided symptoms would be exacerbated.
Thus it was elected to treat both sides with coils. The procedure went well and the patient made an uneventful recovery.
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