Spinal arteriovenous malformations
Spinal arteriovenous malformations (AVMs) are characterised by arteriovenous shunting with a true nidus. They represent ~25% of spinal vascular malformations.
Different types of spinal AVM (see below) have differing age of presentation, but overall 80% present between the age 20 and 60 years 3.
It is variable, ranging from the progressive myelopathy (Foix-Alajouanine syndrome), often with delayed diagnosis, to the catastrophic spinal subarachnoid haemorrhage (see: coup de poignard of Michon 3).
Spinal AVMs may be classified as intramedullary and extramedullary (80%) 1 and further divided into four angiographic types, with additional subtypes 2-3 (see: spinal AVM classification).
- myelopathy from venous congestion/hypertension
- haemorrhage: within the cord parenchyma or subarachnoid space 6
- high-flow AVMs may cause arterial steal from adjacent spinal cord segments 6
- myelopathy from large AVMs (rare) 6
Angiography remains the investigation of choice but requires meticulous technique. It is essential to remember that the site of arterial supply can be anywhere from the upper thoracic to sacral areas with little relationship to the clinical level, or visible nidus (if present).
- signal voids from high-velocity flow
- dilated perimedullary vessels indent/scallop the cord 1
- signal voids from high-velocity flow 1
- increased cord signal due to cytotoxic oedema or myelomalacia 1
Treatment and prognosis
Both surgery and angioembolisation have a role in the treatment of spinal AVMs 6.
- 1. Minami S, Sagoh T, Nishimura K et-al. Spinal arteriovenous malformation: MR imaging. Radiology. 1988;169 (1): 109-15. Radiology (abstract) - Pubmed citation
- 2. Doppman JL, Di chiro G, Oldfield EH. Origin of spinal arteriovenous malformation and normal cord vasculature from a common segmental artery: angiographic and therapeutic considerations. Radiology. 1985;154 (3): 687-9. Radiology (abstract) - Pubmed citation
- 3. Greenberg MS. Handbook of Neurosurgery. Thieme. (2010) ISBN:1604063262. Read it at Google Books - Find it at Amazon
- 4. Kim D. Surgery Of The Pediatric Spine. Thieme Medical Pub. (2008) ISBN:1588903427. Read it at Google Books - Find it at Amazon
- 5. Teng MM, Chang T, Lirng JF et-al. Spinal dural arteriovenous anomalies. J Vasc Interv Radiol. 1992;3 (2): 329-36. - Pubmed citation
- 6. Patsalides A, Knopman J, Santillan A et-al. Endovascular treatment of spinal arteriovenous lesions: beyond the dural fistula. AJNR Am J Neuroradiol. 2011;32 (5): 798-808. doi:10.3174/ajnr.A2190 - Pubmed citation