Moyamoya Disease Treatment

Understanding Moyamoya Disease

Moyamoya disease is a rare, progressive condition in which the large arteries at the base of the brain, primarily the internal carotid arteries and their main branches, slowly narrow and close. In response, the brain grows a fragile network of tiny collateral vessels to compensate. On an angiogram these vessels look like a hazy cloud, which is where the name comes from: moyamoya is Japanese for "puff of smoke."

Because those collaterals are small and fragile, they cannot keep up with the brain's demand for blood. Children with moyamoya most often present with transient ischemic attacks or strokes, sometimes brought on by crying, hyperventilating, or exertion. Adults present with stroke as well, but are also at risk of hemorrhage when the overworked collateral vessels rupture. Untreated, moyamoya tends to progress, and the risk of a disabling stroke accumulates over time.

Moyamoya syndrome refers to the same pattern of arterial narrowing when it occurs alongside another condition, such as sickle cell disease, neurofibromatosis, Down syndrome, or prior radiation to the head. The surgical treatment is the same.

My Approach to Moyamoya

There is no medication that halts moyamoya. Aspirin can reduce the risk of small strokes, but the definitive treatment is surgical revascularization: bringing a new blood supply to the brain from outside the skull. I perform both direct and indirect bypass, and I choose between them, or combine them, based on each patient's anatomy, age, symptoms, and the pattern of blood flow on their imaging.

I trained in cerebrovascular and skull base surgery at UCSF, one of the highest-volume moyamoya centers in the country, and cerebrovascular bypass is a core part of my practice at Santa Barbara Cottage Hospital. Patients who have been told that their moyamoya is being watched, or that surgery is not an option, are welcome to seek a second opinion.

Treatment Options

Direct Bypass (STA-MCA)

In a direct bypass, a scalp artery (the superficial temporal artery) is connected directly to a branch of the middle cerebral artery on the surface of the brain using sutures finer than a human hair. Blood flow improves immediately, which makes direct bypass especially valuable for adults and for anyone with ongoing symptoms who cannot afford to wait months for new vessels to grow. This is technically demanding microsurgery, and outcomes depend heavily on the surgeon's experience with the procedure.

Indirect Revascularization

Indirect procedures, such as encephaloduroarteriosynangiosis (EDAS), lay a scalp artery and its surrounding tissue directly onto the surface of the brain without a sutured connection. Over the following months, the brain grows new vessels into that tissue. Indirect surgery is the standard approach in young children, whose vessels are too small for a direct connection, and is also used in adults when anatomy favors it.

Combined Bypass

Many adult patients benefit from both approaches in a single operation: the immediate flow of a direct bypass plus the long-term growth of an indirect procedure. Because I perform both techniques, I can tailor the operation rather than fit the patient to a single method.

Medical Management and Surveillance

Not every patient needs surgery immediately. For patients with mild, stable disease, I use perfusion imaging to measure how well the brain is compensating and follow them closely, with a clear plan for when surgery becomes necessary.

Symptoms of Moyamoya

• Transient weakness, numbness, or speech difficulty, often lasting minutes
• Stroke, sometimes at a young age
• Headaches, particularly migraine-like headaches
• Seizures
• Cognitive changes or decline in school or work performance
• Sudden severe headache or neurologic decline from hemorrhage in adults

If you experience sudden weakness, difficulty speaking, or a severe headache, call 911 immediately.

Why Choose Dr. Walcott for Moyamoya Treatment?

• Both Direct and Indirect Bypass: The full range of revascularization techniques, chosen and combined for each patient
• UCSF Fellowship Training: Cerebrovascular and skull base training at one of the country's leading moyamoya and bypass centers
• Harvard and MGH Residency: Neurosurgical training at Massachusetts General Hospital and Harvard Medical School
• Comprehensive Stroke Center: Surgery and neurocritical care at Santa Barbara Cottage Hospital
• Academic Excellence: Author of over 160 peer-reviewed publications in cerebrovascular disease