The neurosurgeons and interventional neuroradiologists at Houston Methodist Hospital Neurological Institute Cerebrovascular Center diagnose and treat many kinds of cerebrovascular conditions, including cranial and spinal dural fistulas.
Cranial dural fistulas, also called cranial dural arteriovenous fistulas (dAVFs), are abnormal connections between arteries, the outermost layer of the brain (dura), and a draining vein. They are very rare, and can form as a result of venous sinus blood clots or traumatic head injury.
Depending on the location and size, cranial dural fistula symptoms may include:
Untreated, they can cause hydrocephalus (excess fluid in the ventricles of the brain, sometimes called “water on the brain”) and potentially life-threatening brain hemorrhage (bleeding).
Cerebral angiography is usually the best way to diagnose and evaluate a cranial dural fistula. This procedure uses a contrast (dye), along with X-rays to see how blood flows through the brain.
A neurosurgeon or interventional neuroradiologist inserts a thin catheter into an artery in the groin, then carefully guides it to an artery in the neck. The contrast fluid goes through the catheter and X-rays are taken to show how it flows through the brain. The dye helps show blockages or abnormal flow. Sometimes magnetic resonance imaging (MRI) or computed tomography (CT) scan may also be used to diagnose a cranial dural fistula.
Treatment options for cranial dural fistulas depend on each patient, the location of the fistula, and the symptoms associated with it. Treatment may include endovascular embolization, microsurgical resection (microsurgery), and focused stereotactic radiation. Some patients may need multiple treatments or a combination of treatments to completely eliminate the fistula.
Neurosurgeons and interventional neuroradiologists at Houston Methodist Neurological Institute Cerebrovascular Program use today’s most advanced technology to treat cranial dural fistulas that would have previously been considered untreatable.
During an endovascular embolization, a neurosurgeon inserts a tiny catheter into an artery in your groin, then guides it up to the fistula to block the blood flow between the artery and vein. Platinum coils or other materials, such as surgical glue (Onyx), may be used to block the blood flow.
Surgery is a better treatment option for some patients. To treat a cranial dural fistula microsurgically, the neurosurgeon performs a craniotomy, removing a piece of bone from the skull to access the brain. A high-resolution, high-magnification microscope helps the surgeon find and treat the fistula. The surgeon places tiny metal clamps on the artery that supplies blood to the fistula to seal off the abnormal blood flow between artery and vein. The bone flap is replaced at the end of the surgery.
During stereotactic radiosurgery, a neurosurgeon or interventional neuroradiologist uses precisely focused beams of radiation to stop the abnormal connection between the affected artery and vein.
A spinal dural fistula is an abnormal connection between a spinal artery and a draining vein near the spinal cord covering (dura). It is usually found in the lower thoracic or lumbar spine (middle to lower back). Spinal dural fisutlas cause blood congestion and higher pressure in the spinal cord, which can cause swelling and dysfunction in the spinal cord, including irreversible vein damage and possible paralysis.
There is no known cause for most spinal dural fistulas, although some may be caused by previous surgeries or trauma to the area. Anyone can develop a spinal dural fistula, but they are most common in men ages 50 and older.
Fistulas may not cause any symptoms until they enlarge or cause swelling in the spinal cord. Symptoms of spinal dural fistula may include:
Spinal angiography is usually the best way to diagnosis and evaluate a spinal dural fistula. Each vessel supplying the spinal cord is selectively catheterized and imaged, offering an extremely precise assessment of both the arteries and veins. This procedure often takes several hours.
Sometimes magnetic resonance imaging (MRI) or computed tomography (CT) scans may also be used.
Treatment options include both transarterial and transvenous embolization and microsurgical resection (microsurgery). Some patients may need a combination of treatments to repair the fistula and preserve motor function.
Many cranial and spinal dural fistulas can be cured and do not recur. Sometimes, additional treatment is needed. The specific recovery and rehabilitation period depends on each patient, and the location and severity of the fistula.