Common Post-Surgical Complications of Moyamoya Disease and What Patients Should Know

Patients undergoing surgery for moyamoya disease face a range of potential complications, both in the acute and chronic phases following the procedure. While surgical intervention—such as revascularization or bypass procedures—is often necessary to restore cerebral blood flow, it also carries inherent risks. In the immediate postoperative period, one of the most critical concerns is ischemic stroke due to unintended vascular injury during the bypass surgery. This can lead to new or worsened neurological deficits, including hemiparesis (partial paralysis on one side of the body), aphasia (difficulty with speech or language comprehension), sensory disturbances, and in some cases, homonymous hemianopia (loss of vision in half of the visual field).

Acute Phase Risks: Infection and Rebleeding

During the early recovery stage, patients are particularly vulnerable to infections. Due to the invasive nature of craniotomy and temporary immune suppression, bacterial infections such as meningitis or wound infections may occur. Additionally, patients might develop respiratory tract infections like pneumonia, especially if they remain bedridden for extended periods. Urinary tract infections are also common, particularly in individuals requiring catheterization after surgery.

Another serious concern in the acute phase is the risk of rebleeding. Although surgeons take meticulous precautions to control hemorrhage during the operation, fluctuations in blood pressure post-surgery can compromise healing tissues. Sudden spikes in blood pressure may cause previously stabilized vessels to rupture again, leading to intracranial hemorrhage. In severe cases, emergency reoperation may be required to evacuate hematoma and relieve pressure on the brain.

Long-Term and Procedure-Specific Complications

Revascularization Failure and Neurological Outcomes

One of the key goals of moyamoya surgery is to improve cerebral perfusion through direct or indirect bypass techniques. However, if the graft fails to establish adequate blood flow—or if collateral circulation does not develop properly—patients may experience no improvement in neurological function. In some instances, symptoms may even deteriorate over time. This underscores the importance of close monitoring using imaging studies such as MRI, CT angiography, or cerebral blood flow assessments during follow-up.

Complications Related to Indirect Revascularization Techniques

Indirect methods, such as encephalomyosynangiosis (EMS) where temporal muscle is grafted onto the brain surface, come with their own set of challenges. The procedure requires a craniotomy that leaves a bone defect, which can affect skull integrity and increase sensitivity at the surgical site. Some patients report persistent numbness, tingling, or discomfort along the scalp due to nerve irritation or damage during muscle dissection and placement.

Moreover, many individuals continue to experience headaches or dizziness long after surgery. These symptoms may result from altered cerebral hemodynamics, inflammation around the surgical area, or psychological factors related to prolonged recovery. While these issues often diminish over months, they can significantly impact quality of life and require multidisciplinary management involving neurologists, pain specialists, and rehabilitation therapists.

While surgical treatment offers hope for improved outcomes in moyamoya disease, patients and caregivers must remain aware of the possible complications. From early risks like infection and rebleeding to longer-term issues such as failed revascularization and sensory disturbances, understanding these challenges enables better preparation and proactive care. Regular follow-ups, strict blood pressure control, and prompt reporting of new symptoms are essential for optimizing recovery and minimizing adverse events.