Do Moyamoya Disease Surgeries Require Craniotomy?

Understanding Moyamoya Disease and the Need for Craniotomy

Moyamoya disease is a rare, progressive cerebrovascular disorder that leads to the narrowing or blockage of arteries in the brain. As blood flow becomes increasingly restricted, patients face a higher risk of strokes and transient ischemic attacks (TIAs). To restore adequate circulation and prevent neurological damage, surgical intervention is often necessary. A common question among patients and families is whether these procedures require opening the skull—known as a craniotomy. The answer is typically yes, as most effective revascularization techniques involve direct access to the brain's vascular network.

Types of Surgical Procedures Involving Craniotomy

Surgical treatment for moyamoya disease focuses on improving cerebral blood flow through revascularization. This is generally achieved via one or more of the following craniotomy-based approaches:

1. Direct Vascular Bypass Surgery

In this procedure, neurosurgeons create a direct connection between an extracranial (outside the skull) artery and an intracranial (inside the brain) vessel. The most common technique involves harvesting the superficial temporal artery (STA) from the scalp and connecting it directly to a branch of the middle cerebral artery (MCA) on the brain's surface. This immediate rerouting of blood helps alleviate ischemia right after surgery. When the STA is too small or unsuitable, alternative donor vessels such as the occipital artery or posterior auricular artery may be used to bypass into the MCA or posterior cerebral artery (PCA), depending on anatomical feasibility.

2. Indirect Revascularization Techniques

Unlike direct bypass, indirect methods do not involve microsurgical anastomosis. Instead, tissues rich in blood vessels—such as the superficial temporal artery, galea, dura mater, or even muscle flaps—are placed onto the surface of the brain. Over time, new collateral vessels grow from these tissues into the brain parenchyma, enhancing blood supply gradually. Common indirect procedures include encephaloduroarteriosynangiosis (EDAS), encephalomyosynangiosis (EMS), and multiple burr holes. While these don't provide instant results, they are especially beneficial in pediatric patients whose brains have a greater capacity for angiogenesis.

3. Combined Direct and Indirect Bypass Approaches

Many surgeons opt for a hybrid strategy, combining both direct and indirect techniques during the same operation. This dual approach offers the best of both worlds: immediate improvement in perfusion from the direct bypass, along with long-term vascular growth stimulated by the indirect method. Studies suggest that combined procedures lead to superior outcomes in terms of stroke prevention and improved cerebral hemodynamics, particularly in adult patients with advanced disease.

Why Craniotomy Remains Essential

Craniotomy allows precise access to the cerebral vasculature, which is critical for both direct anastomosis and optimal placement of vascularized tissues in indirect procedures. Although minimally invasive alternatives are being explored, current standards of care rely on open surgery to ensure durable and effective revascularization. Modern techniques utilize advanced imaging, intraoperative monitoring, and microsurgical tools to minimize risks and enhance recovery.

Recovery and Long-Term Outlook

Post-surgery, patients typically remain in the hospital for several days for close neurological monitoring. Recovery varies but most individuals resume normal activities within 4 to 6 weeks. Long-term success depends on early diagnosis, surgical timing, and comprehensive follow-up care including antiplatelet therapy and lifestyle modifications. With proper treatment, many patients experience significant symptom relief and a reduced risk of future strokes.

Conclusion

While the idea of brain surgery can be daunting, craniotomy-based interventions for moyamoya disease are well-established, safe, and highly effective. Whether through direct bypass, indirect revascularization, or a combination of both, these procedures offer life-changing benefits by restoring blood flow and protecting cognitive function. Patients should consult with experienced cerebrovascular neurosurgeons to determine the most appropriate surgical plan based on their individual condition.