Spinal arteriovenous malformation are very rare. Spinal AVMs are an abnormal vessel or group of vessels forming a direct connection between arteries and veins which prevents the blood flowing through the normal structures; within the spine they can involve the spinal cord, the tissues around the spinal cord within the spinal canal, the bones of the spine, the tissues around the spine, or a combination of these. Some of these lesions are present at birth; others develop during life.

They usually present to medical attention in adult life.  They are a potientionally treatable cause of myelopathy (a term used for any disease or disorder of the spinal cord.  Myelopathies may cause any or all of the following symptoms:

• Weakness of the legs;
• Disturbance of sensation over the legs, buttocks or genital areas;
• Impairment of the bladder and or bowel function.

Symptoms can be caused by decreased blood supply to the spine and nerves, by pressure from the abnormal vessels, or by rupture of the vessels resulting in haemorrhage

Spinal AVMs usually involve the lower part of the spinal cord, called the thoracic cord which stretches from the neck to the small of the back.

Improvements in spinal cord imaging with Magnetic Resonance Imaging (MRI) have lead to quicker diagnosis.  However, spinal AVMs are notoriously difficult to detect and may require spinal catheter angiography (visualisation of the blood vessels after injection of a radiopaque substance) to be certain about the diagnosis.

Treatment of spinal AVMs is often difficult, and usually its objective is to limit further damage to the spinal cord, rather than to alleviate the problem caused. 

The two main forms of treatment are surgical excision and embolisation via catheter in the grion.  Embolisation is becoming the mainstay of treatment as technological advances in catheters and embolic glues are made.