Dural arteriovenous malformations (AVM) in the region of the transverse-sigmoid sinus are common, although they have been reported infrequently. Various questions concerning their etiology, pathophysiology and treatment remain unanswered and surgical treatments are not always successful.
Six Dural AVM patients ranging in age from 28-74 years were studied. There was no significant difference in sex. Clinical symptoms and signs were pulsatile tinnitus, convulsion, headache, sudden loss of consciousness, papilledema, and subarachnoid hemorrhage. Angiography revealed the dural lesion fed by one or more of the meningeal branches supplying the dura mater of the posterior fossa: the occipital artery, the posterior branches of the middle meningeal artery, the ascending pharyngeal artery, the meningohypophyseal trunk of the internal carotid artery and the meningeal branches of the vertebral artery. In all 6 patients, venous drainage was entirely via the transverse sinus which was irregular in all and occluded in 3 cases. In these cases, there was retrograde venous outflow through the cortical veins and Labbe's vein. In the venous phase of the angiogram, the transverse sinus at the involved side was not opacified in 4 of 5 cases, while the contralateral transverse sinus was filled from the superior sagittal sinus densely. This indicated that the involved transverse sinus drained venous flow from the Dural AVM alone and had no significant role in the outflow from the intracranial venous system.
Various surgical procedures were performed. Ligation or occlusion of the occipital artery or the external carotid artery (Cases 1, 2, 4, ) was insufficient. Isolation of the transverse sinus from all dural attachments (Case 4) resulted in disappearance of the pulsatile tinnitus, but postoperative angiography revealed that the tentorial artery continued to contribute to the dural lesion. Excision of the bilateral transverse sinuses, including the torcular, resulted in complete cure in Case 5. Cases 3 and 6 received no surgical interventions and were asymptomatic for 3 and less than 2 years after the diagnosis, respectively.
The most effective treatment was total removal of the involved dural sinus and the adjacent dura mater. Angiographical findings of the involved dural sinus in the arterial or venous phase suggested that the lesion, including the dural sinus, could be excised successfully.