Surgical Treatments for Moyamoya

The goal of offering surgery to patients with moyamoya disease is to prevent neurologic deterioration from strokes.  There are several different options offered at the Moyamoya Center at Stanford University Medical Center which are described below: 

Direct bypass graft (STA-MCA bypass)

This procedure benefits patients by providing an immediate improvement in blood supply to the brain by redirecting blood from the scalp into the brain.  It's also known as an extracranial to intracranial bypass graft (EC-IC bypass). By virtue of doing the STA-MCA bypass, an indirect revascularization is achieved as well, and 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 percent 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 presurgery activities.This procedure is our first line recommendation in patients who are eligible. Children under 5 often don't have arteries large enough to bypass, and may not be candidates for this surgery.

A branch of a main scalp artery (superficial temporal artery, or STA) is sewn to a branch of a brain artery (middle cerebral artery, or MCA) lying on the brain's surface in order to provide an immediate improvement in blood flow. 

This is the procedure most often recommended for adults because it offers an immediate improvement in blood flow that will help reduce the risk of stroke and other symptoms associated with moyamoya.

EDAS (encephalo-duro-arterio-synangiosis)

This is an indirect method of providing more blood flow for moyamoya patients. A branch of the superficial temporal artery is laid onto the surface of the brain, with the expectation that it will eventually grow into the brain and therefore provide more blood flow. This is a less technically challenging procedure than a direct bypass graft; however, it has not been shown in any large series of patients to be effective in preventing strokes related to moyamoya. 

One of the drawbacks to doing this procedure is that it will most likely prohibit a direct bypass graft being done in the future if it's ineffective and more surgery is needed. The reason for this is that the superficial temporal artery is sacrificed and can't be used for a direct bypass. This surgery is done at The Moyamoya Center at Stanford only when a direct bypass graft is not feasible. Children tend to have better results with this procedure than adults.

EMS (encephalo-myo-synangiosis)

This 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, 6-8 weeks are required for a new blood supply to develop from the transposed muscle.

Omental transposition

This is a surgical procedure that involves taking some omentum (lining surrounding organs in abdomen), which is very rich in blood supply, and placing it on the surface of the brain with the expectation that vessels will eventually grow into the brain and improve blood supply.  This is used only when a direct bypass graft and EDAS is not feasible. 

Stanford Medicine Resources:

Footer Links: