Classification:
Neoplastic vascular lesions:
- Hemangioblastoma
- Cavernous hemangioma
Spinal aneurysms, rare
Spinal Arteriovenous fistula, AVF
- Extradural
- Intradural: a.k.a. Foix-Alajouanine
- Ventral intradural:
- A. Small shunt
- B. Medium shunt
- C. Large shunt
- Ventral intradural:
- Dorsal intradural:
- A. single feeder
- B. multiple feeders
Spinal Arteriovenous malformation AVM:
- Extradural-intradural
- Intradural:
- Intramedullary:
- Compact
- Diffuse
- Conus medullaris
Spinal Arteriovenous Fistula, spinal-AVF:
Spinal extradural arteriovenous fistula AVF, rare:
Diagnosis:
Catheter angiography: Fistula point is entirely external to the dura
Spinal dural arteriovenous fistula SDAVF, a subtype Foix-Alajouanine, rare:
Pathology:
A fistula between an extradural artery and vein, high flow, leads to enlargement of the extradural venous plexus and compression of the spinal cord or vascular steal.
Spinal intradural arterivenous fistulas:
Classification:
Ventral:
- A: Small, B: Medium, C: Large
Dorsal:
- A: Single arterial feeder, B: Multiple arterial feeders
Diagnosis:
Catheter angiography
Pathology:
Ventral type: A fistula between the anterior spinal artery and enlarged venous system, high flow.
Dorsal type: A fistula between radicular artery and corresponding radicular vein within the dural root sleeve, low flow. Usually thoracolumbar
Enlarged Veins outside the spinal cord. Thickened intima and media. Widened lumen. Infarction/necrosis of the lower spinal cord grey>white matter. Secondary long tract degeneration.
Clinically:
Middle age men >women, lower limb ascending motor or sensory lower motor neuron symptoms, then spinal cord symptoms regardless of the level. This is because congestion of the cord affects the lower segements first.
Findings on investigations:
Catheter angiography: demonstrates fistula, arterial feeders and venous drainage
MRI: Cord Swelling. T2: hyperintensity within the cord over 5-7 segments. Flow void (hypointensity) dorsal to the cord: tortuous veins. T1: hypointensity. Contrast enhancement especially 40-45 min post injection.
MRA: Serpentine perimedullary structures. False positives occur.
Myelography: dilated lumbar veins =’postage stamp’ appearance of lumbar roots,
Treatment of spinal intradural arteriovenous fistula:
Consider:
- Endovascular therapy
- Surgical closure of the fistula
Related articles:
References:
- Spetzler, R.F., et al., Modified classification of spinal cord vascular lesions. J Neurosurg, 2002. 96(2 Suppl): p. 145-56