What is a Dural fistula?
The dura is a leather-like covering that surrounds and protects the brain and lines the inner surface of the skull. It has its own blood supply from arteries that are separate to the ones that supply the brain itself.
A dural fistula is an abnormal direct communication between arteries that normally supply the dura and the veins over the surface of the brain. They are thought to develop in response to previous clot formation or insults to the veins.
This results in high-flow arterial blood draining directly into veins that are not used to that kind of flow/pressure. Depending on the location and strength of the draining veins, dural fistulae can burst – leading to bleeding in the brain. The high flow in the veins also leads to back pressure in the brain’s venous system that can cause seizures or even a reversible dementia. A common symptom for patients with a dural fistula is pulsatile tinnitus – a ‘whoosh’ sound in the ears that synchronizes with the heartbeat.
Dural fistulae can also occur in the spine leading to back pressure in the spinal cord, with swelling of the cord causing weakness in the legs. This is a potentially reversible cause of paraplegia.
Dr Bhatia has published and presented extensively on the diagnosis, treatment, and anatomy of dural fistulae (including two book chapters and a presentation at the illustrious LINNC Paris Conference) and was trained by world leading experts on the condition in Toronto, Canada.
A diagnosis of dural fistula may be suspected based on the symptoms (e.g. whoosh sound in the ears, bulging and redness of the eye etc.) and/or the CT and MRI appearances. However, to make the diagnosis with certainty and to map all the arteries involved and the venous drainage, digital subtraction angiography (DSA) is required. Taking detailed DSA images of the fistula is helpful for treatment planning and to avoid complications during treatment.
Cerebral Angiography (DSA)
A cerebral angiogram using digital subtraction angiography (DSA) uses a thin plastic tube inserted through the thigh or wrist artery to inject dye into the blood vessels of the brain. This provides us with the best quality imaging available for dural fistulae. Dr Bhatia is an expert in the diagnosis and management of dural fistulae and has published multiple articles on the subject. Here at Sydney AVM we will tailor your angiogram to ensure we get the highest level of detail.
The most effective and safest treatment for most dural fistulae is endovascular treatment (through the arteries and veins) performed by interventional neuroradiologists such as Dr Bhatia. This procedure is performed under general anaesthesia (asleep) and using thigh and/or wrist access to the blood vessels, a very fine tube is advanced up towards the abnormal communication point. This is then used to deliver a lava-like fluid (e.g. Onyx) that will block the abnormal blood vessels to slow down and cure the fistula. For some rare types of dural fistulae, open surgery may still be a good option and if we think this is the best option for you we will refer you a neurosurgeon with expertise in the procedure.