FAVd: the dural arteriovenous fistula
Written by:Dr.. Enrico Cotroneo, an expert in Radiology in Rome , explains the difference between cranial and medullary fistulas, how to recognize them and how to treat them
What is a dural fistula?
The dural arteriovenous fistula (FAVd) is an arteriovenous malformation acquired that occurs with greater frequency from the fourth to sixth decade of life and which is expressed both in intracranial level spinal. A very rare type is instead the FAVd with a giant epidural venous discharge that occurs instead in the pediatric age. The dural fistulae represent about 10-15% of all the arteriovenous malformations of the Nervous System. For inflammatory and / or thrombotic phenomena there is an anomalous communication between arteries and veins at the dura mater level, one of the three sheets that cover the brain or the medulla. Venous discharge usually occurs using normal brain or marrow veins, but increased blood flow leads to increased flow and pressure in veins that is expressed by suffering from the medullary or encephalic parenchyma.. This suffering causes neurological symptoms.
How do I recognize a medullary fistula?
FAVd medullary, much less frequently percentages than intracranial FAVd, has a subtle pathology. Begin with disturbance of sensitivity or strength to a lower limb and over time also involves the contralateral. It is associated over time with disorders of urination. If not diagnosed and treated, loss of strength can lead to paraplegia of the lower limbs. The initial diagnostic test is a Magnetic Resonance (MR) study of the medulla with contrast agent administration. If the presence of FAVd is identified, the golden standard is the selective angiographic study of the arteries afferent to the spinal cord to identify the exact point of the dura where the pathological has arteriovenous.
Is it possible to treat the medullary fistula?
There is no medical therapy, treatment must be of endovascular embolization or neurosurgery. The collaboration between the specialist neuroradiologist interventionist and the neurosurgeon allows the resolution of the pathology. A diagnosis and treatment as early as possible is essential because a delay, even after the eradication of FAVd, may not result in clinical recovery.
Cranial fistula
The cranial FAVd, more frequent than the medullary one, has the same acquired inflammatory or thrombotic genesis, same decade of onset, prevalence of the female sex, with an afferent affirmation of the dura mater by dural arteries and discharge in the superficial cerebral venous system or deep. There are different types depending on the type of venous discharge. There are many symptoms, in fact there are extremely benign forms that do not require treatment, but also more serious forms that put the patient's brain function at risk.. The affected subject may present synchronous tinnitus with the wrist, oculomotor disorders and, less frequently, cerebral hemorrhages.
Diagnosis and treatment of the cranial fistula
The suspected diagnosis must be confirmed with an MRI study of the brain with administration of contrast medium and, subsequently, with a selective angiographic study. The treatment of choice is the endovascular embolization in a specialized environment, in some cases it is possible to resort to stereotaxic radiosurgery or to neurosurgery.
PUBLICATIONSNeurosurgery. 2012 Jan; 70 (1): 141-9; Endovascular treatment of cervical giant perimedullary arteriovenous fistulasCasasco A1, Guimaraens L, Senturk C, Cotroneo E, Gigli R, Theron J.
NATIONAL CONGRESSESEmbolization of the arterial and venous route of intracranial dural fistulasIS. Cotroneo; R. Gigli; TO. Casasco° XIX AINR CONGRESSVERONA 15-18 MAY 2003
Editor: Marta Buonomano