Conditions + Treatments

Moyamoya Disease | Treatments

LIke ThisLIke ThisLIke ThisLIke ThisLIke This

Contact the Moyamoya Disease Program


While surgery is the only viable treatment for Moyamoya disease in the long term, your doctor may also recommend medication to manage some of your child's symptoms. 

Anti-clotting drugs (aspirin)
Since the slowing of blood flow within the brain's narrowed arteries can cause transient ischemic attacks (TIAs) (“mini-strokes”) and strokes in children with Moyamoya disease, medicines that prevent the formation of blood clots are vital. Aspirin is the most commonly prescribed anti-clotting drug, and Boston Children's Moyamoya Disease Program clinicians recommend that all children with Moyamoya take aspirin throughout their lives.

Calcium channel blockers
Calcium channel blockers, such as verapamil, are also often prescribed for children with Moyamoya disease. These drugs stop calcium from entering the cells of the heart and blood vessel walls, lowering blood pressure. The decrease in blood pressure can help reduce the severe headaches and TIAs experienced by many children with Moyamoya. 

However, these medications should be used with caution, as too low of a blood pressure can be dangerous. Always speak to your treating clinician for guidelines and precautions involved in taking medication.

Medication manages symptoms, but is not a cure
Parents often ask whether steroids or other anti-inflammatory medications can be helpful in treating Moyamoya disease. However, Boston Children's Moyamoya Disease Program does not recommend these drugs: There is no evidence to suggest that any inflammation process occurs in the blood, arteries or cerebrospinal fluid of children with Moyamoya.

Again, it's important to emphasize that no medication can stop either the progression of narrowing in the brain's blood vessels or the development of the thin, fragile vessels that characterize Moyamoya disease. Surgery is the mainstay of treatment for Moyamoya.


Several surgical treatments for Moyamoya disease have been very effective at bypassing narrowed arteries and creating a new blood supply for the affected areas of the brain, decreasing the likelihood of a stroke.

Every potential surgery involves many technical considerations, as well as possible advantages and disadvantages. You should always discuss your questions and concerns about surgery with your child's treating clinician. Ask the neurosurgeon why a particular procedure is recommended, and what the results have been for patients who have undergone that type of operation. 

Indirect procedures

Some procedures for Moyamoya disease are considered indirect surgeries, meaning that they encourage and introduce new blood vessel growth to the brain over time.

Examples of these procedures are:

  • EDAS (encephaloduroarteriosynangiosis), in which the superficial temporal arteryin the child's brain is laid over an opening in the cortex. The artery is then sewed to the dura (the firm layer of tissue that covers the brain). Over time, small new arterial vessels begin to develop.
  • EMS (encephalomyosynangiosis), in which small portions of temporalis musclea major muscle in the jaw that allows it to closeare attached in a parallel direction to the surface of the child's brain. The transplanted muscle gradually generates new blood vessels, forming a supplementary source of blood flow to the brain.
  • omental transposition/transfer, in which the child's omentum—the blood-rich lining that surrounds the organs in the abdomen—is laid over the surface of the brain. New vessels eventually develop and grow into the brain.
  • dural inversion, in which neurosurgeons invert (reverse the position of) the flaps of fibrous dural tissue on the child's meningeal vessel, a large artery within the skull. This places the outer dural surface, which has plentiful blood vessels, in direct contact with the parts of the brain that were previously deprived of essential blood flow. 

Direct arterial bypass

The direct arterial bypass surgery is also known as superficial temporal to middle cerebral artery anastomosis or STA-MCA bypass. During this procedure, neurosurgeons join a blood vessel from the child's scalp directly to a vessel in the brain. Blood flow throughout the brain should improve over the next several months.


Pial synangiosis

Pial synangiosis is the mainstay of surgical treatment in Boston Children's Moyamoya Disease Program. Our neurosurgeon, R. Michael Scott, MD, developed the procedure, and both Dr. Scott and Edward Smith, MD, have been performing this surgery—with excellent results—for years. 

How does the surgery work? What happens during the operation?
Pial synangiosis is designed to take advantage of the tendency of the brains of children with Moyamoya disease to attract new blood vessels from any source that is made available by the surgeon. During the procedure, the neurosurgeon:

During the procedure, the neurosurgeon makes an incision in the child's scalp, exposing a healthy blood vessel in the scalp.

The neurosurgeon then separates the scalp vessel from the surrounding tissue while ensuring that blood continues to flow through it.

Moyamoya Surgery
A window of bone is opened beneath the artery. Using a microscope to carefully open each of the brain's coverings, the surface of the brain is eventually exposed.

moyamoya surgery children
The neurosurgeon then places the scalp artery directly onto the brain and sews the tissues surrounding the artery's walls to the surface of the brain using tiny sutures. This keeps the transplanted artery in direct contact with the brain. The neurosurgeon then replaces the window of bone and closes the incision in the skin.

How long does the surgery take?
The procedure usually takes three to four hours (longer if both sides of the brain require surgery). 

Why does pial synangiosis work?
Pial synangiosis works because:

  • It stimulates the development of new blood vessels that grow from the donor scalp artery, providing a vital source of blood to the brain beneath.
  • The new blood vessels emerge not only from the transplanted scalp artery, but also from blood vessels sprouting from the coverings of the brain around the opening in the skull.

It's still not fully understood why these new blood vessels emerge and flourish. Boston Children's researchers have discovered that the cerebrospinal fluid that flows over the brains of children with Moyamoya disease may have certain growth factors that prompt new blood vessel development.

Learn more about our ongoing research, and watch an actual pial synangiosis procedure at Boston Children's.

Preparing for pial synangiosis surgery

Most children undergoing pial synangiosis are admitted to Boston Children's the night before surgery. They receive intravenous (IV) fluids to ensure that the volume of fluid within their body's blood vessels remains sufficient. 

Care and follow-up after surgery 

The night after pial synangiosis surgery, a child stays in the Intensive Care Unit (ICU) at Boston Children's. She is then be transferred to a patient floor for three to four days.

There are no restrictions on airplane travel after pial synangiosis, so children and their families can usually return home a week after surgery. The sutures in the child's skin will dissolve on their own, and don't require removal.

Long-term care and follow-up

If distance permits, patients are asked to come back to Boston Children's four to six weeks after undergoing surgery. Many families, however, live too far away for an office visit in Boston to be practical, so a visit to the child's local neurologist can serve as a substitute.

We ask all of our patients to have a follow-up cerebral angiogram a year after surgery—ideally, here at Boston Children's. This evaluates how well the surgery has been working and establish a baseline for the child's treatment going forward. Your child will also likely have another MRI and MRA, and your neurosurgeon will discuss next steps with you.

Restrictions on activities

Once your child has had surgery for Moyamoya disease, her exercise should be restricted until new blood vessels have begun to grow in the brain. Your treatment team will carefully explain this to you, but as a basic guideline:

  • Kids can usually return to school and regular activities within two to four weeks after surgery, but cannot participate in gym class, sports or other strenuous activities for three months.
  • Under careful medical supervision, kids can gradually return to physical activities over a three- to six-month period.
  • The area of the surgical incision on the head must always be protected against trauma during any activity—for example, by wearing a helmet for bike riding and baseball. “Heading” the ball in soccer is not permitted until six months after surgery and clearance by the medical team. 

Even after returning to normal activities, a child's fluid intake should always be monitored to prevent dehydration. Read more about keeping your child properly hydrated (Adobe Acrobat required). 

Help for kids dealing with the stress of an illness

The Behavioral Medicine Clinic at Boston Children's helps kids and families deal with anxiety, sadness and fears about their illness, medical and surgical procedures and long-term care. Call 617-355-6688 to learn more.

Coping and support 

When your child has a serious condition like Moyamoya disease, your family is dealing with many different concerns and worries. Not only are you focused on meeting all of your child's medical needs; you are also grappling with a significant emotional and psychological toll that affects every member of your family.

In addition to the clinical information offered on this page, Boston Children's has several other resources designed to give your family comfort, support and guidance. 

Resources at Boston Children's Hospital

  • Boston Children's Center for Families is dedicated to helping families locate the information and resources they need to better understand their child's particular condition and take part in their care. All patients, families and health professionals are welcome to use the center's services at no extra cost. The Center for Families is open Monday through Friday from 8 a.m. to 7 p.m., and on Saturdays from 9 a.m. to 1 p.m. Please call 617-355-6279 for more information.
  • The hospital's Complex Care Services provides care for children with complex medical conditions in both inpatient and outpatient settings. CCS partners with the child's family, primary care physician and treatment team specialists to ensure comprehensive, coordinated and centralized medical care. Please call 617-355-6162 for more information.
  • Boston Children's Behavioral Medicine Clinic helps children who are being treated on an outpatient basis at the hospital—as well as their families—understand and cope with their feelings about:
    • being sick
    • facing uncomfortable procedures
    • handling pain
    • taking medication
    • preparing for surgery
    • changes in friendships and family relationships
    • managing school while dealing with an illness
  • For children and families affected by life-threatening illness, our Pediatric Advanced Care Team (PACT) is available to provide supportive treatments intended to optimize the quality of life and promote healing and comfort. In addition, PACT can provide emotional support and help arrange end-of-life care when necessary. Please call 617-632-5042 for more information.
  • The Experience Journal was designed by Boston Children's psychiatrist-in-chief, David DeMaso, MD, and members of his team. This online collection features thoughts, reflections and advice from kids and caregivers about living with a variety of medical conditions, the “befores” and “afters” of surgery and going through many other medical experiences.
  • Boston Children's Psychiatry Consultation Service provides several services, including:
    • short-term therapy for children admitted to one of the hospital's inpatient units
    • parent and sibling consultations
    • teaching healthy coping skills for the whole family
    • educating members of the medical treatment team about the relationship between physical illness and psychological distress
  • Boston Children's Department of Psychiatry offers a free booklet, “Helping Your Child with Medical Experiences: A Practical Parent Guide.” (Adobe Acrobat required to view and download) Topics in the booklet include:
    • talking to your child about her condition
    • preparing for surgery and hospitalization
    • supporting siblings
    • taking care of yourself during your child's illness
    • adjusting to life after treatment
  • The Boston Children's chaplaincy is a source of spiritual support for parents and family members. Our program includes nearly a dozen clergy members—representing Episcopal, Jewish, Lutheran, Muslim, Roman Catholic, Unitarian and United Church of Christ traditions—who will listen to you, pray with you and help you observe your own faith practices during your child's treatment.
  • Boston Children's International Center is a resource for patients and families from countries outside the United States. The center can provide assistance with everything from reviewing medical records to setting up appointments and locating lodging. Contact the center by phone at 01-617-355-5209 or via e-mail at


Boston Children’s is so much more than a hospital—it’s a community of researchers, clinicians, administrators, support staff, innovators, teachers, patients and families, all working together to make the impossible possible. ”
- Sandra L. Fenwick, President and CEO

Boston Children's Hospital
300 Longwood Avenue, Boston, MA 02115
For Patients: 617-355-6000
For Referring Providers: 844-BCH-PEDS | 844-224-7337