Intracranial dural arteriovenous fistulae with perimedullary venous drainage. Anatomical, clinical and therapeutic considerations

We report five cases of intracranial dural arteriovenous fistula (DAVF) wit h perimedullary venous drainage. All the patients presented with rapidly pr ogressive myelopathy and three had autonomic disorders. The DAVF were on th e tentorium cerebelli (two cases), sigmoid (one), superior petrosal (one), and cavernous sinus (one). Slow venous drainage was directed through dilate d perimedullary cervical veins. The transverse sinus was occluded in two ca ses. MRI, performed in four cases, demonstrated high signal on T2-weighted spin-echo sequences in the medulla oblongata and upper cervical spinal cord consistent with oedema, which signal resolved after complete cure of the D AVF in three cases. Embolisation was performed in all cases. It was followe d by clinical deterioration in two cases and in the dramatic improvement in the other three, with complete clinical cure in two. Extensive venous thro mbosis may explain the deterioration observed in one case.