Treat the supply. Give the collection a chance to heal.

What MMA embolization is

These membranes can contribute to continued leakage and recurrence. Reducing their blood supply can help the hematoma resolve over time.

MMAE does not remove the blood immediately. Surgical drainage and embolization address different parts of the problem and are often used together.

Who may benefit?

Your specialist considers your symptoms, CT or MRI, prior treatments, other illnesses, medications, and the anatomy of the arteries.

• Patients having surgical drainage: adding MMAE can lower the chance of recurrence requiring another intervention.
• Selected patients at higher surgical risk: standalone MMAE may be reasonable when the collection and symptoms allow time for gradual resolution.
• Patients with a recurrent chronic collection: the team may consider MMAE as part of a plan to reduce further recurrence.

The strongest guideline recommendation is for MMAE alongside surgical drainage. The 2026 SNIS guideline separately considers standalone MMAE reasonable in selected circumstances, such as high surgical risk or a bleeding disorder.

What happens during the procedure?

1. Planning and preparation. The team reviews your scan, blood tests, medications, kidney function, and contrast allergy history. You receive instructions about fasting and medicines.
2. Arterial access. A small catheter enters an artery, usually at the wrist or groin. Sedation or general anesthesia is selected for the individual case.
3. Mapping the vessels. Contrast and X-rays show the middle meningeal artery and any connections that could make embolization unsafe.
4. Embolization. The specialist delivers embolic material into appropriate branches to reduce blood flow to the membranes.
5. Observation and follow-up. The team checks neurologic function and the access site. Repeat brain imaging tracks the collection over time.

The embolization itself does not require opening the skull. Some patients also need a separate drainage operation.

What are the potential benefits?

The main demonstrated benefit is a lower risk of recurrence, progression, or another intervention in appropriately selected patients. It is not a guarantee of faster recovery, complete resolution, or avoiding all future surgery.

In EMBOLISE, repeat surgery for recurrence or progression by 90 days occurred in 4.1% with MMAE plus surgery and 11.3% with surgery alone. Those findings apply to the studied population with an indication for surgical evacuation.

What are the risks?

MMAE is minimally invasive, but it is not risk-free. Risks include stroke, bleeding or injury to an artery, an access-site hematoma, contrast reaction, kidney injury, and anesthesia complications. Unintended embolization can affect vessels supplying the eye or cranial nerves, potentially causing vision loss or nerve injury.

The collection may persist, grow, or recur, and drainage or another procedure may still be needed. Serious complications can be disabling or life-threatening.

In EMBOLISE, serious events attributed to embolization occurred in 2.0% of the MMAE group by 30 days, including two disabling strokes. A trial percentage does not define your personal risk.

Your operator should explain the anticipated benefit, alternatives, and risks for your anatomy and condition.

What does recovery involve?

Monitoring and hospital stay depend on the symptoms, procedure, other illnesses, and whether drainage was also performed. The collection usually resolves gradually rather than immediately.

Your team sets the scan schedule, activity restrictions, and blood-thinner plan. Do not change prescribed medication based on general online information. Continue in the recovery guide.