Spinal AVM information AVM (Arteriovenous Malformation) Dural Fistula Info - AVM Support, Stories, Links and general information.


?What is an AVM
?What is a Spinal AVM
?What is a Dural Fistula
?What are the symptoms
?What types of AVM's exist
?Why do AVM's occur
?How common are AVM's
?Do AVM's grow or change
?What causes an AVM to bleed
?What are the risks
?What should victims avoid
?How are AVM's diagnosed
?What treatments are available
?How do I get help/support
?Cant find what you're looking for? Maybe we can still help!
?Referenced Documentations

?AVM Community Forums
?AVM Stories & Testimonials

?Spinal AVM Info Donations - Your help is greatly appreciated. Thank you!

?Site Information


Information about this site:
The contents of this site are not guaranteed to be 100% accurate and are not a substitute for seeking medical advice from a licensed physician/neurologist.

This information was personally written by myself and is not legal/licensed documentation and is not intended to be used as such.

Information is added to this site as often as possible. The more information found/discovered/learned, the more information that is added.

The information provided here has been gathered from the American Stroke Association, American Society of Neuroradiology, several random Internet sources (some are listed in the links section) and personal experiences with my AVM and the neurologists I have spoken to at University of Michigan in Ann Arbor & Mid-Michigan Medical Center in Midland, Michigan.

Thank you also to: John Ratliff, MD and Edward Connolly, MD of the Department of Neurosurgery; Louisiana State University Medical Center and Ochsner Clinic. New Orleans, Louisiana

Referenced Documentations
1)Neurophysiologic Monitoring and Pharmacologic Provocative Testing for Ebolization of Spinal Cord Arteriovenous Malformations.

Univiersity of Michigan References

Ewen Nicol - Interventional Neuroradiologist PA (No longer with UofM)

Dheeraj Gandhi - Interventional Neuroradiologist (No longer with UofM)

Joseph Gemmete - Interventional Neuroradiologist

B. Gregory Thompson - Neurosurgeon


What is an AVM?

1) A congenital disorder (one present at birth) of blood vessels in the brain, brainstem, or spinal cord that is characterized by a complex, tangled web of abnormal arteries and veins connected by one or more fistulas (abnormal communications).

2) An abnormal communication between an artery and vein that may be present at birth or may result from injury or infection. Blood may flow directly from the artery to the vein, bypassing the small vessels where oxygen and tissue nutrients are exchanged. These unusual malformations are often found in the brain and spinal cord, but may occur anywhere in the body.

Normally, arteries carry blood containing oxygen from the heart to the brain, and veins carry blood with less oxygen away from the brain and back to the heart. When an arteriovenous malformation (AVM) occurs, a tangle of blood vessels directly diverts blood from the arteries to the veins.

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What is a Spinal AVM?

A Spinal AVM is an Arteriovenous Malformation that is located within, on or around the spinal cord.

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What is a Dural Fistula?

An abnormal direct connection (fistula) between a meningeal artery and a meningeal vein or dural venous sinus. (Also known as an arteriovenous fistula)

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What are the symptoms of a Spinal AVM?

Symptoms of a Spinal AVM can be almost anything. The most common symptoms that occur are: numbness, weakness, sensation irregularity, problems with balance, burning or hot sensations, paralysis, headaches and random pains throughout the body. Symptoms can range greatly and can affect your body in ways that you wouldn't think possible. For example, a Spinal AVM can also affect your bowel movements, urination habits & abilities, concentration and many other systems within your body.

The fact is... Spinal AVM's can cause so many different symptoms that it would be impossible and illogical to list them all. The severity of your symptoms also depend on the size, location and type of AVM.

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What types of AVM's exist?

Type 1 Spinal AVM: Dural Arteriovenous Fistula
Dural arteriovenous fistulas are the most common variety of spinal cord AVMs, comprising 80-85% of spinal AVMs. These lesions show a male predominance (80-90%) and generally present in late adulthood, ages 40-60. Presentation is generally with radiculomyelopathy, followed by slow but progressive neurological deterioration. Subarachnoid hemorrhage is very uncommon in dural AV fistulas, and acute deterioration in neurologic function is unlikely.

Site of pathology in these lesions is within the dural root sleeve, where a direct arteriovenous fistula develops, generally with a single dural artery feeder vessel. Additional small feeding vessels from adjacent levels may also penetrate the dural and contribute to venous outflow. Hence these lesions are not true AVMs but instead AV fistulas. Venous drainage of the AV fistula is by a high-pressure, low-flow arterialized vein intradurally. Venous dilatation may extend rostrally and caudally from the fistula site. Eventual drainage is to the coronal venous plexus. Increased pressure in the coronal venous plexus yields spinal cord dysfunction, via chronic venous hypertension and loss of autoregulatory tone. Increased venous pressure yields chronic spinal cord ischemia, cell loss, and cord atrophy. Impaired autoregulation yields direct transmission of changes in systemic arterial pressure to the spinal cord without the normal dampening effect of the venous plexus.

Goal of treatment is isolation and obliteration of the fistula and draining veins, which normalizes venous pressure and corrects venous hypertension. Two different therapeutic modalities are possible: embolization of the feeding vessel, via endovascular techniques, and direct surgical ligation, through laminectomy and direct intradural exposure of the fistula. Fistula obliteration yields correction of the lesion; resection of arterialized veins is not necessary and may actually be traumatic to the spinal cord. Embolization in well chosen cases is a safe and effective therapy for dural AV fistulas. In cases where the site of origin of the AV fistula is a large radicular artery and embolization may be difficult or dangerous, direct surgical exposure is preferred.

Type 2 Spinal AVM: Intramedullary AVM
This is a true intramedullary arteriovenous malformation of the spinal cord. These lesions are characterized by a compact intramedullary nidus, with feeding vessels arising from the anterior or posterior spinal arteries, or both, and drainage into an arterialized coronal venous plexus. In contradistinction to spinal AV fistulas, flow within these lesions is high pressure and low flow, with rapid filling on angiogram and early venous drainage.

Intramedullary AVMs have equal incidence distribution between men and women, and generally present at a much earlier age (average age of presentation: 24). The clinical course of these lesions is marked by progressive and fluctuating myelopathy, often overlaid by periods of acute neurologic deterioration secondary to hemorrhage within the AVM. Sudden apoplectic presentation, often with profound neurologic impairment and possible transverse myelopathy, is common in spinal AVMs. SAH (hemorrhage?) often occurs in these lesions, occurring in 50% of cases. While dural AV fistulas are more commonly found in the lower thoracic and lumbar spine, true intramedullary AVMs occur throughout the cord, and hence presentation with upper extremity symptoms is possible.

Treatment of intramedullary spinal AVMs involves initial embolization of feeding vessels using particulate matter. Immediate clinical improvement is often noted after embolization, through reduction in arterial steal and improved cord perfusion; however, recanalization may occur over time, with continued risk of hemorrhage. Hence, surgical resection of residual nidus after embolization is generally considered.

Type 3 Spinal AVM: Juvenile AVM
Juvenile spinal AVMs are extremely rare lesions. These lesions are again true AVMs, with an intramedullary nidus which may occupy the entire spinal canal at the involved level. Cord tissue is present within the AVM interspaces. Extramedullary and even extraspinal extension of the lesion is possible

Juvenile AVMs are large and complex lesions, with multiple arterial feeding vessels often arising from different cord levels. Hemodynamically, this lesion manifests both high flow and high pressure, often yielding an auscultatable spinal bruit over involved levels. They occur most commonly in adolescents and young adults. Presentation and treatment are similar to type II AVMs; however, prognosis for these lesions, considering their size and vascular complexity, is understandably very poor.

Type 4 Spinal AVM: Perimedullary Arteriovenous Fistula
These rare lesions are similar to type I spinal AVMs, in that they are not true AVMs but instead arteriovenous fistulas. The fistulous connection in this lesion is intradural but extramedullary, with feeding vessel or vessels arising from the anterior spinal artery. Venous drainage is via an enlarged coronal venous plexus. No small vessel network or glomus is evident connecting arterial and venous halves of the circuit. These lesions were first described by Djindjian, and then classified as a type IV spinal AVMs by Heros et al.

These lesions may present in young adults, but presentation in the third to sixth decade is more likely. SAH is possible with intradural AV fistulas, with subsequent acute neurologic deterioration. A gradual but progressive neurologic deterioration is common. Three subcategories of intradural spinal AV fistulas have been recognized, with different treatment options appropriate for each. The simplest of these, the type IVa, features a single feeding vessel, often the artery of Adamkiewicz, with low flow through the arteriovenous shunt and moderate venous enlargement. Endovascular techniques are difficult with these lesions, due to the small size of feeding vessels. Surgical excision is therefore often mandated. Type IVb AV fistulas are intermediate in size, often with multiple feeding vessels, and more marked venous enlargement. Venous ectasia may develop at the site of shunting. Embolization in these lesions is easier, due to the increased size of feeding vessels. In cases of incomplete shunt obliteration with an endovascular approach, direct surgical excision may be necessary. The largest of the intradural AV fistulas are the type IVc, which feature giant, multipediculated fistulas, high blood flow, and large, tortous draining veins. Spinal ischemia may develop in these lesions secondary to vascular steal. Due to the size of these lesions, surgery is technically difficult and may jeopardize the spinal cord. Treatment is hence through combination of endovascular ablation, followed by surgical excision of retained elements.

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Why do AVM's occur?

It is unknown why AVM's occur. They're usually congenital, meaning someone is born with one. However, they usually are not hereditary. People probably do not inherit an AVM from their parents, and they probably will not pass an AVM on to their children.

AVM's have also been known to be a result of an injury that did not heal properly. This is not very common from what I've gathered.

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How common are AVM's?

The popularity of an AVM is far more common then most might realize. It is estimated that one in 200-500 people may have an AVM. Brain and Spinal AVM's, on the other hand, are much less common. A brain AVM is found in less then 1% of the general population. A spinal AVM is even more rare. They're so rare in fact, that there is not a known census to determine how common they really are.

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Do AVM's grow or change?

Most AVM's do not grow or significantly change although the vessels involved may dilate. There are some reported cases of AVM's shrinking or enlarging, but this may be due to clots in parts of an AVM causing it to shrink, or to redirect to adjacent blood vessels toward an AVM.

In my personal experience, an AVM can generate an aneurysm which can continually grow over a period of time. The longer blood flows through weakened veins, the bigger they may expand. This is not always true, but in my case, it is.

It is also true that the prolonged irregular oxygen distribution and/or pressure on the spinal cord can slowly increase nerve damage.

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What causes an AVM to bleed?

An AVM contains abnormal and, therefore, "weakened" blood vessels that direct blood away from the normal tissues. These abnormal and weak blood vessels dilate over time and may eventually burst from high pressure of blood flow from the arteries causing bleeding.

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What are the risks of having an AVM?

The biggest risk of an AVM is the possibility of a stroke. In order to have a stroke, the AVM must hemorrhage. The chance of an AVM bleed averages between 1 and 3 percent each year. Over a 15 year period, there is a 25% chance that an AVM will bleed causing damage and stroke. The more bleeds that occur, the higher the risks are that another bleed will follow at any time.

The average risk of a bleed over 10 years from diagnosis is approximately 30%. If the AVM shows signs of "wear & tear" such as aneurysms, it is more likely to bleed (like 50% or more). Over 30 years from diagnosis the risk of a bleed averages 66% but may be as high as 90%.

In the case of a Spinal AVM, the biggest risk is a stroke of the spinal cord. Depending on the location of the AVM it is almost most certainly going to cause some kind of neurological damage or even paralysis. If the AVM is high enough, and large enough, it may also go into the lower portion of the brain and cause an additional brain stroke. Each time a bleed occurs, normal tissue is damaged. This results in a loss of normal function, which may be temporary or permanent.

In the case of a brain stroke, there is a 10-15% chance of death and a 20-30% chance of permanent brain damage.

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What should victims of an AVM avoid?

If you have an active AVM in your body, no matter where it may be... you should avoid straining... try not to lift, push or pull anything more then what feels comfortable to you. Do not push yourself. Try to keep your blood pressure from reaching high levels. Avoid smoking .(Smoking will raise your blood pressure, and weaken your veins over time and could increase the risk of a bleed.)

Avoid any medications or medicines that will thin your blood or increase your heart rate/blood pressure. Anything of this sort could increase your risk of a bleed and also make a bleed much worse should you have one.

If at all possible, keep your stress levels as low as possible. I know that it's very stressful if you have an AVM because it's like having a time bomb in your body that could go off at any moment.

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How are AVM's diagnosed?

Most AVM's go undiagnosed until a bleed occurs. Some AVM's are found by accident, meaning they're found during a test for some other medical condition. Most people find their AVM's between the ages of 20 and 50.. and if they're not found by 50, they will usually go unnoticed for the remainder of the persons life.

The best ways to determine the existence of an AVM is by either a CT scan or an MRI scan. These tests are very good at detecting AVM's. They also provide information about the location and size of the AVM and whether it may have bled.

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What treatments are available for an AVM?

Well first of all, it must be determined if the AVM can be treated at all. Some AVM's are untreatable. In general, an AVM may be considered for treatment if it has bled, if it is an area that can be easily treated and if it is not too large.

The best treatment depends upon what type it is, the symptoms it may be causing and its location and size.

There are currently only 3 real treatments available for AVM's that may lead to a resolution. All of which are invasive and dangerous.

1. Surgery - If an AVM has bled and/or is in an area that can be easily operated upon, then surgical removal may be recommended.

2. Stereotactic radiosurgery - An AVM that is not too large, but is in an area that is difficult to reach by regular surgery, may be treated by performing stereotactic radiosurgery. Focused-beam high energy sources are concentrated on the AVM to produce direct damage to the vessels that will cause a scar and allow the AVM to "clot off."

3. Interventional neuroradiology/endovascular neurosurgery - It may be possible to treat all or part of the AVM by placing a small tube (catheter) inside the blood vessels that supply the AVM and blocking off the abnormal blood vessels with a variety of different materials. These include liquid tissue adhesives (glues), micro-coils, particles and other materials used to stop blood flowing to the AVM.

When an AVM is completely taken out, the possibility of any further bleeding should be eliminated.

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How do I get help/support?

The first and most important way to get help and or support is to talk to your doctor! Make sure they know what you have and how serious it is. Make sure that all your questions are answered.

Your doctor may be able to provide you with a Social Worker should you need that kind of help as well.

If you're aware of your options and are looking for support groups, donations and maybe some other people to talk to about AVM's, then there are many websites available for this sort of thing. I've found that sharing my story with others and reading other peoples experiences has helped greatly. Even if you have shared your story in one location, it may not reach everyone. Share your story with as many people and places as possible. Help yourself by helping others.

If you want to share your AVM story, I'd be more then happy to hear it and to make it available for everyone to read in hopes that it may provide someone with help in some way shape or form!

You can also join our AVM Community Forums and communicate with others sharing your experiences.

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Can't find what you're looking for? Can we help you find something? Are we lacking information?

I've tried to make this site as useful as possible in many ways. I have gathered as much information as I could find (which unfortunately is not a lot when the condition is this rare). I have also created a place (AVM Stories & Testimonials) where people who have had AVM experiences may share their story with everyone.


I know that I can't think of everything... even though sometimes I try (laugh) But since I can't... I'm hoping that everyone else can fill in for me! Register an account at the AVM Community Forums and post your question(s) or tell us what you're looking for (Sorry but I cannot offer medical advice. That is best left to a doctor) and we'll do our best to make it available to you and everyone else! (Maybe something you want to know about AVM's that isn't here... or something about AVM's that you are looking for that you can't find)

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