Surgery is the preferred way to treat moyamoya. The goal of surgery is to go around the blockage and allow new blood vessels to develop to bring blood and oxygen to the brain.
The moyamoya blood vessels and the areas of the brain they affect are sensitive. They can be affected by changes in blood pressure, the amount of blood flow and the amount of carbon dioxide in the blood. Under anesthesia it can be hard to control all these factors, especially in children.
Children undergoing treatment for moyamoya need a different type of anesthesia for this surgery than is given for almost any other type of neurosurgical procedure.
With trained, experienced neurovascular surgeons, the risks of this surgery are generally low. The long-term outlook for children who have been treated for moyamoya is good.
Medicines that prevent clots from forming can be helpful. This includes aspirin. Sometimes a calcium channel blocker such as verapamil is prescribed for people with moyamoya. Verapamil helps with the headache that some patients with moyamoya get. The drug needs to be given under the supervision of a neurologist. No drug, however, can prevent the arteries to the brain from narrowing.
Surgical Approaches for Moyamoya
Surgery for moyamoya uses the idea that a brain starved for blood and oxygen will reach out to grasp and develop new and more efficient means of bringing blood to the brain. The brain does this by bypassing the areas of blockage.
Encephaloduroarteriosynangiosis (EDAS) - This procedure requires freeing up, without severing, a scalp artery over a course of several inches and then making a small temporary opening in the skull directly beneath the artery. The artery is then sutured to the surface of the brain and the bone replaced.
Encephalomyosynangiosis (EMS) operation - In this procesure a muscle from the temple region of the forehead is freed from some attachments. A hole is then made in the skull through which this muscle is directed and then placed onto the surface of the brain.
Superficial temporal artery-middle cerebral artery (STA-MCA) - This procedure directly sutures a scalp artery to a brain surface artery.
Multiple small holes (burr holes) are placed in the skull to allow for growth of new vessels into the brain from the scalp.
Recovery from Surgery for Moyamoya
While symptoms may seem to improve almost immediately after surgery, it will usually takes six to 12 months before new vessels can develop sufficiently.
If a patient has had major bleeding into the tissues of the brain from moyamoya, the damage is usually permanent. Prompt treatment is important to prevent a permanent loss of function as much as possible.