What is the anatomy involved in the embolization of a superior petrosal Dural Arteriovenous Fistula (DAVF)?

Anatomy Involved in Superior Petrosal Dural Arteriovenous Fistula Embolization

The embolization of superior petrosal dural arteriovenous fistulas (DAVFs) requires detailed understanding of the complex vascular anatomy of the petroclival region, with special attention to the arterial feeders from the meningohypophyseal trunk of the internal carotid artery, which is the dominant supply in most cases requiring surgical intervention.

Vascular Anatomy of Superior Petrosal DAVFs

Arterial Supply

• Dominant arterial feeders:
  • Meningohypophyseal trunk (MHT) from the internal carotid artery - primary supply in most challenging cases 1
  • Middle meningeal artery branches from the external carotid artery
  • Tentorial branches from the meningohypophyseal trunk
  • Petrosal branches from the middle meningeal artery

Venous Drainage

• Superior petrosal sinus (primary drainage pathway)
• Petrosal vein
• Potential dangerous cortical venous drainage (Borden Grade II or III) that increases hemorrhage risk 2
• Dilated venous structures that may compress adjacent cranial nerves 3

Technical Considerations for Embolization

Access Routes

• Transarterial approach:

  • Common femoral artery access (preferred route) 4
  • Selective catheterization of feeding arteries using 4F or micro-catheters
  • Less effective for lesions with dominant internal carotid artery supply via MHT 1

• Transvenous approach:

  • Superior success rate compared to transarterial approach for anterior cranial fossa DAVFs 5
  • May be technically challenging for superior petrosal location

Embolization Materials

• Liquid embolic agents (Onyx, NBCA) for permanent occlusion
• Coils for larger fistulous connections
• Temporary embolic materials when appropriate

Procedural Considerations

Pre-procedural Imaging

• Digital subtraction angiography to delineate:
  • Exact location of the fistula
  • All arterial feeders
  • Venous drainage pattern
  • Proximity to critical structures

Anesthetic Management

• Either general endotracheal anesthesia or deep intravenous sedation 4
• Direct arterial pressure monitoring via femoral sheath 4
• Normotensive and euvolemic conditions maintained 4

Technical Approach

1. Initial aortography to identify all feeding vessels
2. Selective catheterization of internal and external carotid arteries
3. Super-selective catheterization of dominant feeders
4. Careful embolization with appropriate agent
5. Post-embolization angiography to confirm occlusion

Success Rates and Challenges

• Superior petrosal DAVFs with dominant MHT supply have lower rates of successful endovascular occlusion (40%) 1
• Cases with significant external carotid artery supply have higher endovascular success rates 1
• Surgical intervention may be necessary after failed embolization attempts
• Combined approaches (endovascular followed by surgical) may be required for complex cases

Potential Complications

• Hemorrhagic complications (2-4.7%) 4
• Cranial nerve palsies, particularly facial nerve 3
• Thromboembolic events
• Inadvertent embolization of normal vasculature
• Migration of embolic material to internal carotid or vertebral arteries 6

Post-Procedure Management

• Neurological intensive care monitoring for at least 24 hours 4
• Blood pressure monitoring with arterial catheter
• Urine output monitoring with indwelling catheter
• Maintenance of normotensive and euvolemic conditions 4
• Follow-up angiography to confirm complete occlusion

Understanding this complex anatomy is critical for successful embolization of superior petrosal DAVFs, with recognition that cases with dominant internal carotid artery supply via the meningohypophyseal trunk may ultimately require surgical intervention for definitive treatment.