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Encephaloduroarteriosynangiosis (EDAS)

What is encephaloduroarteriosynangiosis (EDAS)?

EDAS reroutes a section of an artery that is normally connected to the scalp onto the surface of the brain. New blood vessels grow from this artery into the brain itself. The goal of EDAS is to provide a new source of blood for an ischemic area of the brain.

When is this procedure performed?

EDAS is performed to treat a condition of progressively restricted blood flow to the brain known as moyamoya.

When moyamoya restricts blood flow, certain areas of the brain are deprived of the oxygen and glucose they need to function well. In an attempt to compensate, the body grows a network of thin, fragile blood vessels. As the restriction progresses, however, the compensatory vessels cannot provide enough blood flow.

EDAS revascularizes the brain by providing access to a healthy artery with a robust blood supply. Vessels grow like roots from this artery into the brain, restoring blood flow over the course of approximately three to six months.

EDAS is a member of a group of procedures in which the brain grows vessels from a new blood supply. These are termed indirect revascularization procedures. Pial synangiosis, a procedure closely related to EDAS, is another example of indirect revascularization.

Indirect revascularization procedures like EDAS are performed most often in children. In certain cases they may also be the procedures of choice in adults, though adults are more commonly treated with a form of direct revascularization called EC-IC bypass.

How is this procedure performed?

Usually, the patient is admitted to the hospital the night before the procedure for intensive hydration.

When it is time for the procedure, the patient receives general anesthesia. Hair is shaved at the surgery site, on the side of the head.

To perform most of the surgery, the surgeon uses an operating microscope and delicate instruments.

First the surgeon makes an incision in the scalp and exposes the target artery, usually the superior temporal artery (STA). As its name implies, this artery is in the region of the temple. Along a distance of several inches, the surgeon releases the vessel from its attachments to the scalp, leaving a ribbon of tendon-like material attached to the vessel.

Next the surgeon exposes the bone of the skull beneath the course of the artery. The surgeon makes two burr holes where the artery will enter and exit the skull and then temporarily removes a small window of bone through which to perform surgery.

Beneath the bone are the three snug layers of protective covering over the brain. The surgeon opens the top layer, called the dura. Using the ribbon of tendon-like material, the surgeon sutures the artery to the opened edges of the dura. The artery is now held against the two innermost layers of protective covering, the arachnoid and the pia.

Then the surgeon replaces the small window of bone, minus openings through which the artery now enters and exits the skull. The bone is secured with thin metal plates and screws to hold it in place as it heals. (The plates and screws can remain in place permanently, even after the bone has knit together.) Then the surgeon closes the incision.

How should I prepare for this procedure?

Make sure you understand the risks and goals of your/your child’s procedure. It may help to write down questions as you think of them and bring your list to your appointments.

Give your surgeon a complete list of your/your child’s medications and their schedule. Ask if the schedule should be changed in any way for surgery.

If you smoke or otherwise use tobacco products, quit. You may wish to ask your doctor for help quitting.

What should I expect after the procedure?

After surgery, the patient moves to the ICU for overnight monitoring, and then to the regular neuroscience floor for continued recovery.

The post-surgical period generally is not painful. Adequate pain control is achieved through medication. Young children may also receive sedation.

Pre- and post-surgical care for the emotional health of our young patients and their families is provided by the caring, dedicated staff at NewYork-Presbyterian/Morgan Stanley Children’s Hospital.

How long will I stay in the hospital?

Hospital stay is an average of four to five days.

Will I need to take any special medications?

No special medications are required after EDAS.

Will I need rehabilitation or physical therapy?

No rehabilitation is required. Patients usually return to school or work between two weeks and a month after surgery, with some restrictions on the types of activity in which they can safely engage. Physically demanding activities can usually be resumed by six months after surgery, as long as the doctor permits.

Will I have any long-term limitations due to EDAS?

There are no long-term limitations per se. It will always be important for the patient to stay well-hydrated and to protect the head from trauma. Discuss these recommendations with your neurosurgeon.

patient journey

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