Keywords:
Interventional vascular, Neuroradiology brain, Catheter arteriography, Catheter venography, Shunts, Embolisation, Arteriovenous malformations
Authors:
T. Dotsu1, H. Kiyosue1, Y. Hori1, S. Tanoue1, J. Kashiwagi1, R. Shimada2, Y. Sagara1, M. Okahara1, H. Mori1; 1Oita/JP, 2Yufu city/JP
DOI:
10.1594/ecr2013/C-1939
Conclusion
Halbach(2) et al.
reported that SSS-DAVFs are relatively rare (11 % in their series),
and are highly associated with head trauma and sinus thrombosis.
Thrombus formation due to several causes such as operation and trauma can cause proliferation of vessels at the venous sinus wall and arteriovenous shunts.
However,
sinus thrombosis was observed less frequently in histopathologic examinations(5).
A histopathologic study by Nishijima et al.(6) showed that arteriovenous fistulas were located in the dural sinus wall and/or the adjacent dura mater.
Restrictive changes in the sinuses were mainly due to the intimal thickening of sinuses and the development of abnormal vascular networks within the sinus walls.
Terada et al.(7) showed venous hypertension can cause DAVFs in an animal model.
A few studies(8-9) suggested that angiogenic factors contribute to the cause and progression of DAVFs.
In our cases,
2 cases had previous open head surgery and trauma,
2 cases showed coexistence of DAVFs in other locations,
and 1 patient had a history of transvenous embolization of the bilateral TSS-DAVFs.
This would suggest that SSS-DAVFs can by caused by angiogenesis promoted by venous hypertension and/or traumatic events.
Bavinzski(4),
et al.
reported that SSS-DAVFs were supplied by the middle meningeal artery,
the occipital artery,
the superficial temporal artery,
and the anterior falx artery,
which is in line with our cases.
Some studies(4) reported that SSS-DAVFs were also supplied by the middle cerebral artery in addition to the branches of the external carotid artery.
Careful attention should be paid to transarterial embolization in cases where DAVFs are supplied by the cortical branch of internal carotid artery because embolic materials injected from the external carotid artery may migrate into the cortical branches.
Regarding the shunted pouches,
some authors(10-12) described cases of selective transvenous embolization of shunted pouches for the treatment of DAVFs including SSS-DAVF.
Piske et al.(13) demonstrated a dural sinus compartment (shunted pouches) in 12 of 40 cases (30%) of DAVFs.
In our 6 cases,
at least one shunted pouch can be identified,
and 1 case could be successfully treated by selective transvenous embolization of the shunted venous pouch combined with transarterial embolization with NBCA.
Normal cerebral venous drainage is important to determine whether the affected sinus can be sacrificed.
It is generally thought that occlusion of the affected sinus with coils or liquid embolic materials can be acceptable for cases of DAVF involving an isolated sinus (Borden type-3) because the isolated sinus does not work as a drainage route for normal cerebral venous blood in most cases.
However,
2 cases in our series showed that cerebral venous blood from the brain partially drained via the isolated SSS into the epidural veins and/or emissary vein.
Sinus packing for these cases may cause disturbance of normal cerebral venous return resulting in venous infarction even if they are Borden type-3 DAVFs.
Therefore,
selective transvenous embolization or transarterial embolization of the shunted pouch with liquid embolic materials while preserving the main sinus lumen would be more preferable for the treatment of such cases.
In conclusion,
SSS-DAVFs are highly associated with the coexistence of DAVFs in other locations.
Borden type-3 SSS-DAVFs could be successfully treated by endovascular techniques selected based on angioarchitecture and hemodynamics.