Spinal dural fistula
A spinal dural arteriovenous fistula is the commonest vascular malformation of the spine and one of the most missed. It slowly congests the spinal cord and causes leg weakness that is wrongly blamed on the back. Closing it stops the decline.
What it is
A small artery in the lining of a spinal nerve root connects directly to a vein on the surface of the cord. The vein carries arterial pressure it cannot drain, the cord swells and over months the legs weaken, sensation changes, and the bladder and bowel are affected. It mostly affects men in later life. Symptoms often worsen with exercise or standing. Sudden loss of bowel or bladder control with leg numbness is an emergency: call 999.
How it is found
MRI shows a swollen cord and enlarged veins on its surface, findings that are easy to overlook. Spinal angiography is the definitive test and the map for treatment: I catheterise the segmental arteries level by level to find the single feeding vessel, and I identify the artery supplying the cord so it can be protected.
How I treat it
Embolisation closes the fistula from inside: a microcatheter is placed in the feeding artery and a liquid embolic agent is injected to seal the connection and the first part of the draining vein. Where the feeding artery also supplies the cord, embolisation is not safe and the fistula is closed surgically instead, which I arrange with spinal neurosurgical colleagues. Either way the aim is the same: stop the shunt, let the cord decongest.
What to expect
One night in hospital. Symptoms often improve over the following weeks and months, though recovery is gradual.
Risks and follow-up
The main specific risk is injury to the spinal cord from embolic agent reaching a cord vessel; careful mapping keeps it low. Bleeding and infection are rare. Follow-up MRI shows the cord swelling settling, and angiography confirms the fistula has stayed closed.
Common questions about spinal dural fistula
I have had back scans and injections that did not help. Could this be the cause?
Possibly. Progressive leg weakness with bladder symptoms and a cord that looks swollen on MRI should prompt a search for a fistula.
Will I walk normally again?
Most patients stabilise and many improve. The longer the cord has been congested, the less complete the recovery, which is why prompt diagnosis matters.
Have another question?
Ask a question and the AI assistant will answer from Dr Makalanda’s published information. It cannot give personal medical advice, so please do not share personal or medical details. For emergencies, call 999.
