Middle Meningeal Artery (MMA) Embolization
Fellowship-trained cerebrovascular and endovascular neurosurgeons • 12 hospital affiliations across New JerseyMiddle meningeal artery (MMA) embolization is a minimally invasive endovascular procedure used to treat chronic subdural hematoma by sealing the small arterial branches that feed the fragile membranes responsible for ongoing bleeding and fluid buildup. Unlike surgical drainage, which removes the existing blood collection, MMA embolization targets the blood supply that can cause the hematoma to recur. It may be performed alone for selected patients or combined with burr hole drainage, SEPS drainage, or craniotomy when the hematoma is larger or causing significant pressure on the brain.
Key takeaways
- Chronic subdural hematoma is a blood collection between the brain and its outer covering that can enlarge over days to weeks, especially in older adults and patients on blood thinners.
- MMA embolization treats the vascular source of chronic subdural hematoma by closing the small middle meningeal artery branches that supply the hematoma membranes.
- The procedure is performed through a small wrist or groin artery puncture, with no skull incision required.
- MMA embolization may be used alone for selected smaller hematomas or combined with surgical drainage for larger hematomas causing brain compression.
- Recent randomized trials show that MMA embolization can significantly reduce recurrence and repeat surgery rates when added to standard treatment for chronic subdural hematoma.
| Condition treated | Chronic subdural hematoma |
| Procedure type | Endovascular embolization of middle meningeal artery branches supplying the hematoma membranes |
| Approach | Small radial or femoral artery puncture with microcatheter navigation under X-ray guidance |
| Anesthesia | Conscious sedation or general anesthesia, depending on patient factors |
| Procedure time | Approximately 1 to 2 hours |
| Hospital stay | Same-day discharge or overnight observation for selected patients; longer if combined with surgical drainage |
| Embolic agents | n-BCA glue, Onyx, SQUID, PHIL, microparticles, or coils depending on anatomy and surgeon preference |
| Used alone or combined | May be performed alone for selected patients or combined with burr hole drainage, SEPS drainage, or craniotomy |
What Is a Chronic Subdural Hematoma?
Chronic subdural hematoma is a collection of blood and fluid that forms between the brain and the dura, the brain’s tough outer protective covering. It often develops slowly after minor head trauma, especially in older adults, because the brain naturally shrinks with age and the small bridging veins become more vulnerable to tearing.
Over time, fragile inflammatory membranes can form around the hematoma. These membranes are supplied by small branches of the middle meningeal artery and may continue to leak blood or fluid, causing the collection to persist, enlarge, or recur after drainage.
Symptoms may include headache, confusion, weakness on one side of the body, speech difficulty, imbalance, falls, or changes in alertness. Treatment depends on the size of the hematoma, the degree of pressure on the brain, symptoms, age, blood thinner use, and overall medical condition.
How MMA Embolization Works
During MMA embolization, a neurosurgeon inserts a catheter through a small puncture in the wrist or groin and navigates it through the blood vessels to the middle meningeal artery. A smaller microcatheter is then advanced into the branches supplying the hematoma membranes.
Once the catheter is positioned safely, embolic material is injected to close the abnormal blood supply. By sealing these vessels, MMA embolization helps stop ongoing leakage into the hematoma membranes and allows the body to gradually reabsorb the collection.
MMA embolization does not immediately remove the existing blood collection. Instead, it treats the source of ongoing bleeding that allows chronic subdural hematomas to persist or recur. For patients with significant brain compression or neurological symptoms, surgical drainage may still be needed to relieve pressure quickly. In those cases, embolization can be performed before or after drainage to reduce the risk of recurrence.
MMA Embolization Alone vs. Surgery Plus Embolization
Some patients with smaller, stable chronic subdural hematomas may be candidates for MMA embolization alone, especially when the goal is to prevent progression or avoid open surgery.
Patients with larger hematomas, significant brain compression, or neurological deficits often require surgical drainage first. This may be performed through burr holes, SEPS drainage, or craniotomy depending on the thickness, complexity, and urgency of the hematoma.
In combined treatment, surgical drainage relieves pressure on the brain, while MMA embolization addresses the blood supply that contributes to recurrence. This combined approach is especially helpful for patients at higher risk of recurrence, including older adults, patients on blood thinners, and patients with recurrent chronic subdural hematoma.
Benefits and risks
Potential benefits
- No skull incision is required when MMA embolization is performed alone.
- Targets the source of ongoing bleeding that contributes to chronic subdural hematoma recurrence.
- May reduce recurrence and repeat surgery rates after chronic subdural hematoma treatment.
- Can be combined with surgical drainage for larger hematomas requiring immediate decompression.
- May be especially helpful for older adults or patients on blood thinners who are at higher risk of recurrence.
Possible risks
- Stroke from unintended embolization of normal blood vessels, rare with careful angiographic technique
- Bleeding, bruising, or injury at the wrist or groin access site
- Allergic reaction or kidney effects from contrast dye
- The hematoma may not shrink quickly enough if there is significant brain compression, requiring surgical drainage
- Recurrence can still occur, though the risk may be reduced compared with drainage alone
What recovery looks like
Recovery depends on whether MMA embolization is performed alone or combined with surgical drainage. Most patients recover quickly from the endovascular procedure itself, while the overall recovery timeline depends on the size of the hematoma, neurological symptoms, and whether additional surgery was required.
- Day of procedure Monitoring after the procedure with neurological checks and observation of the wrist or groin access site.
- Day 1 Many patients treated with embolization alone go home the same day or after overnight observation. Patients who also require drainage may remain hospitalized longer.
- Weeks 1 to 4 Gradual return to light activity. Follow-up imaging is used to monitor hematoma shrinkage and brain re-expansion.
- 1 to 3 months The hematoma often continues to reabsorb over time. Activity level, blood thinner management, and follow-up imaging are individualized based on recovery and recurrence risk.
Frequently asked questions
Does MMA embolization replace surgery for chronic subdural hematoma?
Not always. MMA embolization can be used alone for selected smaller or stable chronic subdural hematomas, but patients with larger hematomas, significant pressure on the brain, or neurological symptoms may still need surgical drainage. In those cases, embolization is often used as an added treatment to reduce the risk of recurrence.
How is MMA embolization different from burr hole drainage?
Burr hole drainage removes the existing blood collection to relieve pressure on the brain. MMA embolization treats the small arteries that supply the membranes responsible for continued leakage and recurrence. Many patients benefit from a combined approach: drainage to relieve pressure and embolization to reduce the chance that the hematoma comes back.
Is MMA embolization safe for patients on blood thinners?
Many patients with chronic subdural hematoma are taking blood thinners, which is one reason recurrence risk can be high. MMA embolization may be considered for these patients, but blood thinner management is individualized based on stroke risk, bleeding risk, the size of the hematoma, and the reason the medication is needed. Your neurosurgical team will coordinate the safest plan.
How long does it take for the hematoma to go away after MMA embolization?
The hematoma usually shrinks gradually over weeks to months as the body reabsorbs the blood and fluid. Follow-up CT scans are used to confirm that the collection is decreasing and that pressure on the brain is improving. If symptoms worsen or the hematoma enlarges, additional treatment may be needed.
This page is for general education and does not replace medical advice. Treatment decisions should be made with a qualified neurosurgeon based on your individual diagnosis and imaging. To discuss your options, call Atlantic Brain and Spine at 973.993.7100 or request a consultation.
Middle Meningeal Artery Embolization Specialists at Atlantic Brain and Spine
Your care is provided by Atlantic Brain and Spine’s multidisciplinary cerebrovascular team, including fellowship-trained cerebrovascular and endovascular neurosurgeons.
