Clinical trials are research studies that evaluate a new medical approach, device, drug, or other treatment. As a Stanford Health Care patient, you have access to the latest, advanced clinical trials.
Open trials refer to studies currently accepting participants. Closed trials are not currently enrolling, but may open in the future.
One the rarest forms of occlusive cerebrovascular disorders encountered in neurosurgery is moyamoya disease. Fragile blood vessels proliferate around a blocked artery in an attempt to bypass an occlusion and their appearance on a cerebral angiogram resembles a "puff of smoke" or "moyamoya," a term coined by a Japanese team who first described the disease. It can affect both children and adults usually with symptoms of transient ischemic attacks, strokes, headaches and seizures.
There is currently no drug treatment that is effective for moyamoya disease and surgery is aimed at bypassing the blockage with another artery to restore normal blood flow. Dr. Steinberg has performed more than 1,000 of these revascularization procedures for moyamoya, making his case experience with this disease one of the largest in the world.
Symptoms of Moyamoya
Common symptoms of Moyamoya include:
- Weakness or numbness in an arm or leg
- Difficulty speaking or understanding language
- Visual abnormalities
- Problems with balance
- Transient ischemic attacks, or TIA's (temporary stroke-like symptoms that don't last long)
Children can experience temporary weakness in one or more of their extremities during strenuous physical activity or when crying. Adults can also present with brain hemorrhage (from the fragile moyamoya vessels or from aneurysms) causing neurologic symptoms in addition to nonhemorrhagic strokes, TIA's and headaches.
Moyamoya sometimes occurs along with other disorders such as Down Syndrome, brain AVM's (arteriovenous malformations), neurofibromatosis, sickle cell disease and prior radiation for brain tumors.
Although initially thought to be limited to the Asian population, Moyamoya is now known to affect people from all races and ethnicities. The pie chart below shows data of patients treated at the Stanford Moyamoya Center.
Based on the patients' symptoms and history, the physician may order one or all of these tests before making a decision about treatment.
- Magnetic resonance imaging (MRI)
- Cerebral angiogram
- Xenon CT scans
- Neuropsychological assessment—As part of the presurgical diagnostic process, an evaluation of mental abilities (such as memory) is performed. These abilities can be affected by moyamoya disease. The evaluation, which consists of paper and pencil tests and questions, provides a baseline and provides the team information about how the brain is functioning.
Magnetic Resonance Imaging (MRI)
This allows physicians to examine brain structures and detect any strokes that might have occurred.
This is the definitive test that confirms the diagnosis of moyamoya. "Contrast" (or dye) is injected into arteries to reveal the anatomy of the arteries of the brain and scalp. This is a minimally invasive test that requires patients to stay at the hospital for several hours. This test assesses the severity of moyamoya and its results guide treatment options, which are determined by how severe the disease is and what the external (scalp) blood supply is.
MRI/ Nova scans are a new technique useful for determining the quantitative volume of blood flowing through brain arteries. This information aids physicians in determining if areas of the brain are getting too much or too little flow. It is used during the pre op MRI and at the post op MR outpatient appointments.
Xenon CT Scans
This test reveals blood flow to regions of the brain to determine if enough blood is reaching all areas. Patients breathe xenon (an odorless, colorless gas), which acts as a contrast agent to show regions of low and high blood flow.
Surgical Treatments for Moyamoya
Surgery for moyamoya disease is offered to prevent neurologic deterioration from strokes. Two types of surgical approaches are offered for patients with moyamoya: direct and indirect revascularization.
Learn more about preparing for your surgery.
Direct revascularization (STA-MCA bypass) involves use of a branch of a scalp artery (STA) for direct anastomosis (connection) to a branch of the brain artery (MCA) on the outer surface of the brain. This procedure benefits patients by providing an immediate improvement in blood supply to the brain. It's also known as an extracranial to intracranial bypass graft (EC-IC bypass). By virtue of doing the STA-MCA bypass and laying the STA directly on the brain surface, an indirect revascularization is achieved as well. Through enlargement of the STA and increased indirect revascularization, blood flow is expected to continue improving over a period of several months.
In the series of patients who have had direct bypass grafts at The Moyamoya Center, results indicate a greater than 95 %graft patency with excellent long term outcomes. Patients are typically hospitalized for 3-5 days, with overall recovery taking between 2 - 6 weeks before returning to all pre-surgery activities. This procedure is our first line recommendation in patients who are eligible. Many children under 5 often don't have arteries large enough to bypass, and may not be candidates for this particular surgery.
There are various indirect surgical methods used for providing more blood flow to the brains of moyamoya patients.
EDAS (encephalo-duro-arterio-synangiosis) uses a branch of the superficial temporal artery which is laid directly on the surface of the brain without doing a direct anastomosis. The expectation is that it will eventually grow new arteries into the brain and therefore provide more blood flow. This surgery is done at Stanford only when a direct bypass graft is not feasible. In our experience, children tend to have better results with this procedure than adults. Once used for an indirect bypass, the STA branch cannot be used again for direct bypass, even if the indirect bypass is not successful. It usually requires at least 3-6 months for new blood supply to develop from this procedure.
EMS (encephalo-myo-synangiosis) is another indirect bypass operation. The temporalis muscle, which is in the temple region of the forehead, is dissected. Then, through an opening in the skull, the muscle is placed on the surface of the brain. Like the EDAS, 3-6 months are required for a new blood supply to develop from the transposed muscle.
Omentum is a rich source of blood flow from the lining in the abdomen. Transferring this to the brain can provide an alternative source of flow to patients, when other bypass procedures are not possible or have not been effective enough. Dr. Steinberg has had very good success in providing improved blood flow for some of his moyamoya patients, using omentum for bypass procedures.
Each of the surgical procedures requires approximately three days of hospitalization. The first night after surgery is spent in the intensive care unit. The day after surgery, patients are encouraged to get out of bed and ambulate several times a day. Food is generally offered the day after surgery, starting with liquids and advancing to a regular diet as tolerated.
Post-operatively, patients experience some minor scalp pain from the incision, and some patients may get headaches. Pain medication is routinely prescribed.
The incision is closed with staples or sutures. In adults, these are removed one week after surgery when patients return to clinic. In children, dissolvable sutures are used to minimize procedures that might increase their anxiety. A return visit to our clinic is still scheduled for children even if there are no sutures to remove.
Patients with moyamoya will have minimal restrictions after surgery. They usually don't have their "normal" energy level for a few weeks after surgery. Activities are generally left up to the patients. We recommend that contact sports not be played for several weeks.
Patients take an oral anti-platelet agent, such as daily aspirin, after surgery and for the rest of their lives. This is recommended because it thins the blood, which promotes flow through the grafts. Patients who have stomach problems should use coated aspirin and take it with food. If it's still not tolerated, another drug will generally be prescribed. Birth control pills may put patients at a higher risk of having blood clotting problems, and we recommend that patients with moyamoya not use them. Alternative methods of birth control are fine.
Patients with moyamoya are not restricted from becoming pregnant after surgical treatment. Aspirin is still recommended throughout the pregnancy. The method of delivery is up to the patient and the obstetrician, and we are always happy to communicate with the obstetrician at your request.
- Blood pressure management
The general range for blood pressure should be 110-130 over 70-90. If you are diagnosed with high blood pressure, please put your physician in touch with us before starting treatment so that the plans and goals for blood pressure treatment can be discussed and agreed upon.
Headaches may or may not be related to moyamoya. Patients can be diagnosed after their physician refers them for an MRI due to headaches, but the headaches may not actually be due to moyamoya. If the characteristics of your headaches change after surgery, we should be contacted. However, long-term pain management may be recommended if you have persistent headaches after surgery.
- Non-constrictive devices
Patients who have direct or indirect bypass grafts have a risk of compressing their grafts if they wear eyeglasses or other devices that fit too closely to their heads around the temple area. We will discuss this with you after surgery.
- Long-term follow up
Follow up tests including an angiogram, MRI, blood flow studies and neuropsychological testing are performed at 6 months, 3 years, 10 years and 20 years following surgery. This is to ensure that blood flow is adequate. Unless patients have further symptoms, no other routine follow up studies are usually needed for patients who have had bilateral surgeries.
For patients who have unilateral moyamoya, we recommend an annual CT angiogram or MRI/MRA to look for progression of moyamoya on the other side. However, we like our patients to contact us with an update of their progress at least once a year. If symptoms persist or recur, we want to be contacted as soon a possible.
- Other considerations and restrictions
Patients should always stay well hydrated, drinking between 2-3 liters of non-caffeinated beverages each day.
Frequently Asked Questions
Frequently asked questions and answers for moyamoya patients and families treated at Stanford Health Care:
General Moyamoya Questions
Moyamoya is a progressive disease that does not improve without treatment. While moyamoya itself is not curable, surgery to provide alternative blood flow to the brain prevents the symptoms related to moyamoya and can provide an excellent long term outcome with significant stroke risk reduction.
Moyamoya disease runs in families in approximately 8-10% of the time in Dr. Steinberg's series. We recommend that if more than one family member has moyamoya, others be tested for the disease, especially if there are symptoms. Screening tests for family members might include an MRI/MRA head scan.
Neuropsychological assessment is an evaluation of your cognitive abilities or thinking skills. Examples of such abilities are memory, planning/organizing and language. Cognition may be changed by moyamoya disease. The assessment helps the team know if any of these abilities have been affected. It also provides documentation or a baseline of cognitive abilities before surgery. This can be compared to the results of a second assessment that is performed after surgery.
Patients most commonly present with strokes, mini-strokes (TIA's) and/or headaches. Stroke symptoms can include numbness or weakness in the extremities, visual changes and/or difficulty speaking or understanding words.
Surgery Related Questions
There is some incisional scalp pain and tenderness for about a week after surgery. In addition, some patients have headaches. Medication is provided to minimize the discomfort.
Patients are advised to stay on lifelong aspirin after bypass surgery for moyamoya. This is used to help keep optimal blood flow through the bypass. Patients who have side effects from the aspirin such as excessive bruising/bleeding or stomach upset should contact Dr. Steinberg's office. Other possible medications will be reviewed with patients on an individual basis during hospitalization or at each clinic visit.
Most patients are in the hospital for 2-4 days after each bypass surgery. The first night is in the ICU and the other nights are usually on the neurosurgery ward. However, each patient recovers at a different rate and may have different hospitalization needs.
We want you to be up and around starting the second day after surgery. Activity will be limited to walking, with distance and time increasing gradually over a month. After one month, most pre-operative activities can be resumed. Specific activity restrictions will be reviewed during your postoperative clinic visit.
Hydration is important to help keep your blood volume up and therefore keep adequate flow through the bypass grafts. IV hydration is maintained while you are in the hospital. After discharge, patients are advised to drink about 2 liters of fluids each day.
The scalp can be wet if the incision is covered with waterproof tape starting a few days after surgery. Hair can be washed without covering the incision starting one week after surgery.
Most adult patients have incisions closed with staples. It takes at least 7 full days for the incision to heal enough for staples to be removed. The incisions of pediatric patients are often closed with dissolvable suture material, which dissolves over a period of a couple of weeks.
Patients should wait until the incision is well healed before coloring or using processing agents on their hair. This generally takes at least 4 weeks, and sometimes a few weeks longer.
Recovery and Long Term Implications of Moyamoya
It is not uncommon for patients to have persistent symptoms for several weeks after surgery. It's very unusual for patients to have a stroke after surgery. We advise patients that most new post op symptoms will likely gradually improve after surgery, but to keep a log/diary of them and communicate them to our team. Deficits from previous strokes are unlikely to improve with surgery.
Headaches may or may not be related to moyamoya. Therefore, it's difficult to say if they will be improved with surgery. They may temporarily be worsened after surgery.
This can vary from patient to patient, but we recommend that most patients plan to take off approximately 4–6 weeks for surgical recovery.
This is also variable from patient to patient. Most patients experience a gradual recovery over the course of a several weeks. It's not unusual for patients to feel pretty good shortly after surgery, and then to over-exert themselves. This sometimes results in a feeling of low energy. Be patient with yourself and give your body adequate time to recover!
Avoiding excessive caffeinated drinks is important, as they will make you urinate a lot and actually lose fluids. However, this does not mean caffeine is prohibited. It's just recommended that it not be used excessively.
We recommend avoiding oral birth control pills or hormone replacement therapy. These medications have a higher risk of causing development of blood clots, which could potentially impair flow through the bypass graft. We recommend discussing alternative methods of birth control with your primary MD or gynecologist.
There are minimal lifestyle limitations after bypass surgery. Patients should avoid wearing anything tight around the area in front of the ears that might constrict the grafts. There are no other specific limitations, but if you have additional questions, please call our office at 650-723-5575.
There are no pregnancy restrictions after surgical revascularization to treat moyamoya. Patients are asked to stay on their aspirin, and to have their obstetrician work with our team to ensure open communication is maintained. There are no specific restrictions for labor and delivery. Normal vaginal delivery is fine when considering the history of moyamoya.
It is recommended that moyamoya patients do not donate blood. Blood donation can deplete the overall blood volume and potentially increase the risk of TIA or stroke.
Pediatric Frequently Asked Questions
Children generally recover from surgery very quickly. They can return to school as soon as they feel up to it, but usually will stay home for about a week after surgery. Once they return to school, activities such as contact sports and swimming need to be limited until 4 weeks after surgery to allow for the incisions to heal well.
Yes, it's important to allow children to return to as normal a life as possible after brain surgery for moyamoya. We recommend children avoid contact sports for about a month after surgery. After, they can gradually resume whatever sports they were doing before treatment. It's also important to wear protective head gear appropriate for each individual sport. If there is concern about constricting the graft site, contact Dr. Steinberg's office for advice.
Yes! We strongly recommend bicycle helmets be worn at all times when biking, skateboarding or riding a scooter.