Spinal Arteriovenous Metameric Syndrome: Clinical Manifestations and Endovascular Management

Case 1. A, Right vertebral artery angiogram before the first treatment demonstrates an intramedullary nidus at the C5 level (arrow) and paravertebral/vertebral fistulas at the C2 and C3 levels. B, Left vertebral artery angiogram demonstrates paravertebral/vertebral fistulas at the C2 and C3 levels. The distal right vertebral artery is opacified in a retrograde fashion due to steal phenomenon. C, Left dorsocervical artery angiogram at the time of the second treatment demonstrates a radiculomedullary artery opacifying the C5 level nidus (short arrow) as well as a second discrete nidus at the C2 and C3 levels (long arrow). There is anastomotic visualization of the right vertebral artery (arrowheads) (compare with A). D, Series of angiographic appearances of the spinal cord AVMs in the lateral view. Right: At the time of the second treatment (lateral view of C) showing 2 discrete nidi. There is a small ASA aneurysm (arrow). Middle: Right vertebral artery injection 21 months later showing enlargement of the ASA aneurysm (arrow). Left: Right vertebral artery angiogram 18 months later from the middle when the patient developed acute left-sided weakness showing further enlargement of the ASA aneurysm (arrow). The distal right vertebral artery is occluded by previous Onyx embolization. E, Right vertebral artery angiogram after the last (eighth) embolization shows minimal residual paravertebral/vertebral fistulas. Spinal cord AVMs are persistently opacified. F, Left vertebral artery angiogram after the last (eighth) embolization shows residual paravertebral/vertebral fistulas. G, Serial T2-weighted sagittal MR images of the cervical spine. Left: After the fourth n-BCA embolization showing resolution of T2 signal abnormality seen before the treatment (not shown). Middle: Before the seventh embolization after development of acute left-sided weakness. There is increased T2 high-signal abnormality involving the upper cervical cord and medulla surrounding the aneurysm (arrow). Signal voids obscuring the C2 and C3 vertebral bodies are due to Onyx. Left: Three months after n-BCA embolization of the anterior spinal artery aneurysm, showing disappearance of the aneurysm and resolution of the T2 high-signal abnormality. ASA indicates anterior spinal artery.