What is the efficacy and safety of standalone Middle Meningeal Artery (MMA) embolization for chronic subdural hematoma (CSDH)?

Middle Meningeal Artery Embolization for Chronic Subdural Hematoma

Standalone middle meningeal artery (MMA) embolization appears to be a safe and effective minimally invasive treatment option for chronic subdural hematoma (CSDH), particularly for refractory cases or patients at high risk of recurrence after conventional surgery. 1

Current Evidence on MMA Embolization for CSDH

Efficacy Data

• In a multi-center study of 154 consecutive MMA embolizations, only 6.5% of patients required additional surgical treatment within 90 days 1
• 70.8% of patients showed >50% reduction in hematoma thickness on follow-up imaging 1
• Clinical improvement was observed in 31.9% of patients 1
• The procedure demonstrates high technical success rates (97.4%) 1

Patient Selection

MMA embolization has shown particular benefit in:

• Refractory CSDH cases with repeated recurrence after conventional surgery 2, 3
• Patients at high risk for recurrence (elderly, on antiplatelet/anticoagulation therapy) 3
• Patients with severe brain atrophy and bilateral hematomas 3

Procedural Considerations

• Both particle embolization (70.2%) and liquid embolic agents (25.3%) have been used with no significant outcome differences 1
• The procedure can be performed under general anesthesia (46.1%) or conscious sedation 1
• Technical approach involves advancing a microcatheter through the MMA as peripherally as possible 2
• Common embolic materials include:
  • Polyvinyl alcohol particles (200 μm) 2, 3, 4
  • n-butyl-2-cyanoacrylate (15-20%) 2

Safety Profile

• Complication rate is relatively low (16 complications in 154 procedures) 1
• Most common complication is continued hematoma expansion (6.5%) 1
• Mortality rate of 4.4% was reported, mostly unrelated to the procedure but due to underlying comorbidities 1

Comparison with Conventional Surgical Treatment

MMA embolization offers several advantages over conventional surgical approaches:

• Less invasive than burr hole drainage or craniotomy
• Associated with early brain re-expansion and lesser hematoma recurrence compared to conventional surgery 3
• Particularly beneficial for patients with multiple health issues who may not tolerate surgery 5
• Can be used as either primary treatment or for recurrence after conventional surgery 1

Clinical Algorithm for MMA Embolization in CSDH

1. Primary candidates:

   • Refractory CSDH with repeated recurrences after conventional surgery
   • Elderly patients with high surgical risk
   • Patients on antiplatelet/anticoagulation therapy
   • Patients with severe brain atrophy and bilateral hematomas

2. Timing options:

   • As primary treatment (66.7% of cases in the multi-center study) 1
   • After burr hole drainage when signs of recurrence appear 2
   • Before surgical evacuation in high-risk patients 2

3. Expected outcomes:

   • Reduction in hematoma size (median 71% thickness reduction) 1
   • Low rate of requiring additional treatment (6.5%) 1
   • Resolution of symptoms in most patients 4

Limitations and Considerations

• Current evidence is based primarily on case series and retrospective studies
• Lack of large multicenter randomized controlled trials comparing MMA embolization to conventional surgical approaches 5
• Optimal patient selection criteria and most suitable embolic agents are still being determined 5
• Long-term outcomes beyond 90 days require further investigation

MMA embolization represents a promising treatment option for CSDH, particularly for refractory cases or patients at high risk for recurrence after conventional surgery. The procedure demonstrates high technical success rates with relatively low complication rates and good clinical outcomes.