Arteriovenous Malformation Treatment

Understanding Arteriovenous Malformations

An arteriovenous malformation (AVM) is an abnormal tangle of blood vessels connecting arteries and veins in the brain. Normally, arteries carry oxygen-rich blood from the heart to the brain through progressively smaller vessels, eventually reaching tiny capillaries where oxygen is delivered to brain tissue. In an AVM, arteries connect directly to veins without this normal capillary network, creating a high-pressure shunt that can damage surrounding brain tissue and carry a risk of bleeding.

AVMs are relatively rare, affecting less than 1% of the population. It is possible that many AVMs are present at birth, although it is known that some develop later in life. They may not cause symptoms until adulthood. The annual risk of hemorrhage from an AVM is approximately 2-4%, and this risk accumulates over a lifetime.

Symptoms of Brain AVMs

Many AVMs cause no symptoms and are discovered incidentally. When symptoms occur, they may include:

• Seizures (the most common presenting symptom)
• Headaches
• Progressive neurological deficits
• Bleeding (hemorrhage) into the brain
• Pulsatile tinnitus (whooshing sound in the ear)

Comprehensive AVM Treatment Options

My training at both UCSF (open cerebrovascular surgery) and USC (endovascular techniques) allows me to offer the full spectrum of AVM treatment options. The best approach depends on the AVM's size, location, and angioarchitecture.

Observation

Not all AVMs require immediate treatment. For some patients, particularly those with AVMs in critical brain locations or those who are asymptomatic, careful observation with periodic imaging may be the safest approach.

Endovascular Embolization

This minimally invasive procedure uses catheters to deliver specialized materials (liquid embolic agents) directly into the AVM to block abnormal blood flow. Embolization may be used as a standalone treatment for small AVMs or as a preparatory step before surgery or radiosurgery.

Microsurgical Resection

Complete surgical removal offers the highest cure rate for appropriately selected AVMs. My fellowship training in cerebrovascular and skull base surgery at UCSF provides the expertise needed for safe resection of complex AVMs. Surgery is often the preferred treatment for accessible AVMs that have bled or are at high risk of bleeding.

Stereotactic Radiosurgery

Radiosurgery uses precisely focused radiation beams to cause gradual closure of the AVM over 2-3 years. Radiosurgery is particularly useful for small, deep AVMs that would be difficult to access surgically.

Combined Treatment

Many AVMs benefit from a multimodal approach, combining embolization with surgery or radiosurgery. This staged approach can reduce surgical risk and improve overall outcomes.

AVM Grading Systems

The Spetzler-Martin Grading System

AVMs are traditionally graded using the Spetzler-Martin scale, which considers size, location relative to eloquent brain areas, and venous drainage pattern. This grading helps predict surgical risk and guides treatment decisions.

The Lawton-Young Supplementary Grading Scale

The Lawton-Young scale provides additional prognostic information beyond the Spetzler-Martin grade, incorporating patient-specific factors that influence surgical outcomes. This supplementary scale has been shown to improve prediction of outcomes, particularly for higher-grade AVMs.

The Lawton-Young Scale is calculated as follows:

• Patient Age: <20 years (1 point), 20-40 years (2 points), >40 years (3 points)
• Hemorrhagic Presentation: Yes (0 points), No (1 point)
• Nidus Diffuseness: Compact (0 points), Diffuse (1 point)

The supplementary grade (1-5 points) is added to the Spetzler-Martin grade (1-5 points) to create a combined Spetzler-Martin-Lawton-Young grade (2-10 points). Higher combined scores indicate greater surgical complexity and risk.

I carefully review all imaging and discuss the implications of your specific AVM grade during consultation, using both grading systems to provide a comprehensive assessment of treatment options and expected outcomes.

Why Choose Dr. Walcott for AVM Treatment?

• Comprehensive Training: Fellowship-trained in both open microsurgery (UCSF) and endovascular techniques (USC)
• Harvard Foundation: Residency at Massachusetts General Hospital/Harvard Medical School
• Multimodal Expertise: Able to offer surgery, embolization, and radiosurgery coordination
• Research Background: Published extensively on cerebrovascular conditions
• Collaborative Approach: Work closely with radiation oncology and neurology colleagues