Dural arteriovenous fistula of the sphenobasilar s

Authors: LiangFu Zhou Liang Chen DongLei Song YuXiang Gu Bing Leng

Publish Date: 2007/05/05

Volume: 30, Issue: 3, Pages: 269-274

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Abstract

Dural arteriovenous fistula of the sphenobasilar sinus is a true but rare lesion that connects the meningeal arteries from both the external and internal carotid arteries to the superficial middle cerebral vein SMCV and dural sinus It must be distinguished from other dural arteriovenous fistulas DAVFs of the middle cranial fossa such as cavernous DAVFs and sphenoparietal sinus DAVF because of differences in the treatment and outcome between these DAVFs Two patients with sphenobasilar sinus DAVFs reported in the literature have been identified but they did not simultaneously harbor intracranial meningiomas To the best of the authors’ knowledge the patient described here is the first case that concomitantly harbors a sphenobasilar sinus DAVF and intracranial meningioma A 42yearold man presented with acute subarachnoid hemorrhage Angiography demonstrated a DAVF of the sphenobasilar sinus with a giant venous aneurysm of the SMCV After transarterial embolization the fistula was successfully obliterated and the giant venous aneurysm was resected microsurgically A fortuitous small meningioma at the anterior clinoid was found and removed during the operation The patient recovered excellently and resumed his normal activities The relevant literature is reviewed and discussedIt is generally considered that the superficial middle cerebral vein SMCV can either join the sphenoparietal sinus or drain directly into the cavernous sinus However according to a recent study of San Millán Ruíz et al the SMCV never drains into the sphenoparietal sinus There are three basic drainage pathways of the SMCV 1 it may continue as a paracavernous sinus coursing laterally over the middle cranial fossa 2 as a lateral cavernous sinus enclosed within the lateral wall of the cavernous sinus CS 3 or may terminate into the anterosuperior aspect of the CSIn patients with a sphenoparietal DAVF arterialized blood does not drain into the SMCV Sphenoparietal sinus DAVFs reported in the literature always presented with mild clinical manifestations without subarachnoid hemorrhage or intracranial venous hypertension and their outcomes were always favorable All such fistulas reported but two belonged to Borden type ITwo patients with a sphenobasilar sinus DAVF were reported in the literature This manuscript presents the third case The SMCV was involved in all three cases The retrograde arterialized blood drained into the SMCV to the superior cerebral veins and the superior sagittal sinus These Borden type III lesions require aggressive and definite treatmentIn this case an accidental small meningioma was also found at the operation it was not diagnosed preoperatively It is not rare that a DAVF and a meningioma occur in one patient The meningioma was small in size and far from the sinus to be able to directly mechanically provoke an increase in the resistance of venous outflow and be responsible for the genesis of the DAVFThe authors’ suggestion that the meningioma might have provoked the development of the DAVF is interesting This concept has been based on the studies of Shin et al and Berkman et al that vascular endothelial growth factor VEGF plays an important role in the promotion of development of the DAVF and that meningiomas often express a high level of VEGF However this case history does not confirm the notion of the authors that “VEGF may play an important role for the concomitant occurrence of these two entities” it remains only an interesting theoryThe authors report treatment of a patient with a dural arteriovenous fistula DAVF of the sphenobasilar sinus and concomitant meningioma Embolization of the feeding arteries which reduced but did not eliminate the arterial flow to the fistula was performed prior to surgery During the attempted exposure of the fistula a dilated aneurysmal draining vein ruptured and the subsequent bleeding was controlled by compression and coagulation After coagulation the dural fistula was easily accessible and was disconnected from the draining vein A small anterior clinoid meningioma was identified and removedImportant aspects are addressed in this case report 1 Prior to therapy the angioarchitecture has to be fully understood to differentiate between DAVFs which involve a dural sinus and DAVFs with direct leptomeningeal venous drainage Sometimes digital subtraction angiography alone is not sufficient to disclose the angioarchitecture which can be better visualized with CT and/or MR angiography 2 Dural AVFs with direct leptomeningeal venous drainage are aggressive fistulas requiring therapy There is growing evidence that cure can be achieved best by microsurgical interruption of the arterialized vein just at its dural origin I routinely use neuronavigation for this step to tailor the trephination and to open the dura precisely in close vicinity to the fistula The benefit of preoperative embolization of DAVFs with direct leptomeningeal venous drainage is debatable 1 3 The pathogenesis of a DAVF is still incompletely understood There are increasing clinical and experimental data showing that tumors trauma thromboses and previous operative interventions can result in sinus obstruction and elevated venous pressure leading to opening of arteriovenous dural shunts 2 Vascular endothelial growth factor might play a role in the development of DAVFs but further studies are required to support this assumption of Zhou et al

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