Atypical telencephalic reflux pattern in a cavernous sinus dural AV fistula related to an anatomical variation of the basal vein of Rosenthal

Abstract

Cavernous sinus dural arteriovenous fistula can cause cerebral edema and hemorrhage due to cortical venous reflux and congestion. Understanding complex venous reflux and drainage routes is crucial for treatment planning. Here, we present a case of a cavernous sinus dural arteriovenous fistula with cortical venous reflux via two separate terminations of the telencephalic veins caused by an aplastic basal vein of Rosenthal. The patient presented with diplopia and eye redness and was diagnosed with a Cognard type IIa + b cavernous sinus dural arteriovenous fistula. The shunt was supplied by the dural branches of the internal and external carotid arteries. Multiple shunt points involving the intercavernous sinus and the medial aspect of the left cavernous sinus were identified, with drainage into the supraorbital and intracranial veins, including two separate terminations of the telencephalic veins, one leading to the laterocavernous sinus via the superficial middle cerebral vein and the other to the cavernous sinus via the uncal vein, resulting in basal ganglia venous congestion in the absence of the basal vein of Rosenthal. During transvenous embolization, the intracranial veins, cavernous sinus, and intercavernous sinus were obliterated using a double-catheter technique with a combination of coils and liquid embolics. Telencephalic venous variations can lead to cavernous sinus drainage into the basal ganglia and orbitofrontal brain. This unique drainage pattern underscores the importance of recognizing anatomical variations when managing cavernous sinus dural arteriovenous fistula.

Keywords: Dural arteriovenous fistula; anatomy; basal vein of Rosenthal; cavernous sinus; embryology; telencephalon.

Figure 1.

Pre-procedural head computed tomography angiogram showing early contrast opacification of the left cavernous sinus and left superficial middle cerebral vein (single arrow) connected to the laterocavernous sinus (single arrowhead) (A). Multidirectional drainage routes including the superior ophthalmic vein (B, single asterisk), olfactory vein (C, double arrowhead), orbitofrontal vein (C, double asterisk), and inferior striate vein (D, double arrow) can be observed.

Figure 2.

Antero-posterior and lateral views of the right common carotid angiography (A and B: Arterial phase), left common carotid angiography (C and D: Arterial phase, E and F: Venous phase) are shown. The right internal carotid artery (meningo-hypophyseal trunk), left internal carotid artery (inferolateral trunk), and bilateral external carotid artery (petrosal branch of the middle cerebral artery, artery of foramen rotundum, and ascending pharyngeal artery) can be observed to feed into this shunt with a diffuse shunt point extending from the intercavernous sinus to the medial aspect of the cavernous sinus. There was no reflux to the inferior petrosal sinus and basal vein of Rosenthal (BVR). The BVR could not be observed even in the venous phase, and the BVR was thus considered hypoplastic or aplastic.

Figure 3.

The patient's stepwise treatment course is shown, with the results of digital subtraction angiography and digital angiography. Antero-posterior images of the right external carotid angiography (A: pre-procedure, B: after embolization of the SMCV, and C: after embolization of the UV) showing the progression of gradual embolization of the SMCV and UV (D, arrow and arrowhead, respectively). After embolization of the SMCV (B), as obvious reflux to the orbitofrontal vein (OFV, single asterisk) and UV (double asterisk) could be observed. Following embolization of the SMCV and UV, reflux of the OFV originating from the proximal part of the SMCV can be seen. The double catheter technique (E) was used for complete obliteration. Initially, the superior ophthalmic vein, sphenoparietal sinus, and CS were tightly packed with coils, and the shunt was completely blocked with ONYX from the catheter placed in the medial part of the CS (F). Finally, the complete obliteration was confirmed with bilateral common carotid angiography (G and H). UV: uncal vein; OFV: orbitofrontal vein; SMCV: superior middle cerebral vein; CS: cavernous sinus.

Figure 4.

Reflux and termination of telencephalic veins are shown in the axial image of the maximum intensity projection (A), anteroposterior image of right external carotid angiography (B), and an illustration (C). Obvious dilated veins (inferior striate vein (single arrowhead), insula vein (single arrow), olfactory vein (double arrowhead), and orbitofrontal vein (double arrow)) are shown (A). Termination to the cavernous sinus via the uncal vein (thin blue dotted line) and to the superficial middle cerebral vein (dark blue dotted line) is evident in the pre-procedural imaging. The venous terminations, in this case are illustrated (1: cavernous sinus, 2: latero-cavernous sinus, 3: superficial middle cerebral vein, 4: uncal vein, 5: basal vein of Rosenthal, 6: deep middle cerebral vein, 7: insular vein, 8: anterior cerebral vein, 9: olfactory vein, 10: orbitofrontal vein, 11: inferior striate vein).