What Is Dural Arteriovenous Malformation?

Dural arteriovenous malformation (DAVM) is arteriovenous communication or arteriovenous fistula in the dura mater. It is supplied by the dura mater or dura mater of the intracranial artery and returns to the venous sinus or arterialized meningeal vein. It is essentially based on one or more arteriovenous fistulas of the dura mater, so it was also called "dural arteriovenous fistula" in the past. However, most of the arteriovenous fistulas are acquired lesions. The use of the term "dural arteriovenous malformation" can better reflect the characteristics of some congenital origins.

Basic Information

nickname: Dural arteriovenous fistula
Visiting department: neurosurgery

Common locations: Dura mater
Common symptoms: Intracranial murmur, headache, increased intracranial pressure, etc.

Clinical manifestations of dural arteriovenous malformations

Common symptoms and signs of dural arteriovenous malformations are:

Intracranial murmur

The most common clinical manifestations. It is roaring and persistent, becoming the patient's most unbearable symptom. The degree of intracranial murmur is related to the blood flow and location of the dura mater. If the vertebral artery is not involved in blood supply, the carotid murmur that oppresses the affected side can be weakened or disappeared.

Headache

The reasons are:

(1) Dura mater arteriovenous malformation "stealing blood" is serious, resulting in ischemia of the dura mater.

(2) Increased intracranial pressure.

(3) Intracranial hemorrhage.

(4) Stimulation of dura mater by dilated malformed blood vessels.

(5) Persistent intracranial vascular murmurs cause nervousness, poor rest, and headaches.

3. Increased intracranial pressure

The causes of increased intracranial pressure caused by dural arteriovenous malformations are:

(1) Increased cerebral blood flow and dural sinus pressure, accompanied by decreased cerebrospinal fluid absorption and increased cerebrospinal fluid pressure.

(2) The intracranial and external arteries communicate directly with the sinuses. A large amount of arterial blood directly enters the sinuses, which increases the pressure of the sinuses. Due to the increased pressure of the sinuses, the cortical veins return to the wall and cerebral congestion.

(3) The dural arteriovenous malformation returns directly to the cortical vein and causes cerebral congestion.

(4) Secondary sinus thrombosis.

(5) Occupation effect caused by giant subdural venous lake, or placental effect of arteriovenous malformation in posterior cranial fossa causes cerebrospinal fluid circulation disorder and forms obstructive hydrocephalus.

4. Intracranial hemorrhage

Another common manifestation of dural arteriovenous malformations. Patients with subarachnoid hemorrhage as the first symptom, mainly cortical drainage vein rupture. This is due to the lack of capillaries in the dural arteriovenous malformation. Arterial pressure directly flows into the dural drainage vein. When the pressure exceeds the load on the vein wall Rupture and bleeding. The incidence of intracranial hemorrhage varies from site to site.

5. Other

A few can occur epilepsy, tinnitus, hemiplegia, aphasia and so on. Cavernous sinus dura mater arteriovenous malformations may include frontal orbital or retrobulbar pain, exophthalmos, decreased vision, diplopia, and dyskinesia.

Dural arteriovenous malformation

Cerebral angiography

The most important means of diagnosis and typing can clearly show the performance of the malformed blood vessels from the automatic pulse phase to the venous phase, which is helpful for the classification of lesions and to understand the relationship between angiographic changes and clinical manifestations and prognosis. The direction of venous sinus embolism and venous return plays a decisive role in the design of the treatment plan.

2. Magnetic resonance angiography / venography (MRA / MRV)

Magnetic resonance angiography / venography is a non-invasive examination that can show the anatomical structure of the dural arteries and veins. However, the resolution is poor and cannot meet the clinical diagnosis requirements. Only as a means of screening and follow-up DAVM.

3.CT scan

CT scans can help detect lesions and intracranial hemorrhage. It can be the following abnormal changes: worm-like or patch-like contrast enhancement; local occupancy effect; dilatation of the large venous sinus; enlargement of the ventricle, mainly due to cerebrospinal fluid malabsorption or posterior cranial fossa dural arteriovenous malformation Caused by hydrocephalus; The density of white matter in the brain is significantly reduced, mainly due to venous infarction of the cerebral parenchymal vein infarction, edema, etc .; the blood vessels in the cranial bone plate appear enlarged; patients with intracranial hemorrhage can see subarachnoid High-density shadows in the cavity or brain. Three-dimensional computerized tomography reconstruction (3D-CTA) uses spiral CT to obtain enhanced intracranial blood vessel information, reconstruct blood vessel types, and can clearly show the three-dimensional spatial structure of deformed blood vessels. It has important reference value for the choice of treatment options and surgical approaches.

4. Magnetic resonance imaging (MRI)

On MRI, most of the blood vessels are tortuous clusters without signal, which are grape-shaped or honeycomb-shaped black shadows, and can clearly show the blood supply arteries and drainage veins. Can show the thickness of the dura at the lesion and the thrombus in the sinus, but this type of examination cannot show the dynamic change of blood flow in DAVM.

Diagnosis of dural arteriovenous malformations

Diagnosis can be made based on the patient's clinical manifestations and imaging, especially cerebral angiography.

Differential diagnosis of dural arteriovenous malformations

Should be distinguished from cerebral arteriovenous malformations. Sudden subarachnoid hemorrhage under the age of 40 years, history of epilepsy or hemiplegia, aphasia, headache before bleeding, and no significant increase in intracranial pressure, should be highly suspected of cerebral arteriovenous malformations, cerebral angiography can be used Identification.

Dural arteriovenous malformations

Some patients with mixed dural arteriovenous malformations may develop scalp blood vessels that are distorted, distorted, and even form blood vessel masses. When the dural arteriovenous malformation of the posterior cranial fossa drains into the spinal vein, it can cause venous hypertension in the spinal canal, resulting in spinal cord ischemia and spinal cord damage. High blood flow can also be accompanied by enlarged heart and heart failure.

Treatment of dural arteriovenous malformations

Medical treatment

Symptoms can be treated symptomatically, such as taking non-steroidal anti-inflammatory drugs, carbamazepine, or short-term hormone therapy, which has a certain effect on the relief of pain and pulsating murmurs. However, for the pain in the trigeminal nerve distribution area, percutaneous puncture can not be used to damage the nerve root, so as not to puncture the deformed blood vessels and cause major bleeding.

2. Non-medical treatment

Including transarterial or intravenous endovascular treatment and surgery and stereotactic radiosurgery. Individualized treatment options should be selected and formulated based on the patient's clinical manifestations, current status, and cerebral angiographic findings.