Numbers
- It accounts for 3.5% (n=21) surgical series
Location
- It is located on the basal frontal surface along the anterior cranial fossa floor.
- This subtype resides in the gyrus rectus or orbital gyri (medial or lateral).
- Unlike the medial and sylvian frontal subtypes, the basal frontal AVM remains outside of the interhemispheric and sylvian fissures.
Vascular Supply (Dual Arterial Input)
- Dual arterial supply from
- MCA branches
- ACA branches
- It is defined by three distinct arterial fronts:
- Posterolateral Front: Supplied by MCA branches, specifically the Orbitofrontal Artery (OrbFrA) and Prefrontal Artery (PreFrA), which exit the sylvian fissure,.
- Anteromedial Front: Supplied by A2 ACA feeders, primarily the OrbFrA and Frontopolar Artery (FrPolA), which exit the interhemispheric fissure,.
- Posteromedial Front: Supplied by unnamed A1 segment ACA branches, which course over the olfactory tract along the medial orbital gyrus,.
Venous Drainage
- Superficial: anterior Orbitofrontal Vein (OrbFrV) OR FrPolV → Superior Sagittal Sinus (SSS)
- Deep: Olfactory Vein (OlfV) or posterior OrbFrV → Basal Vein of Rosenthal (BVR)
Eloquence
- Non-eloquent for AVM grading, but careful dissection is critical to preserve the olfactory apparatus and its blood supply, as damage to these structures can impact patient satisfaction.
Surgical Strategy
Craniotomy and Approach:
- The AVM is exposed using an orbital-pterional craniotomy.
- Taking down the orbit allows ease of visualisation of the frontal basal area without retraction of the frontal lobe
- Release CSF though the slyvian and optico-carotid triangle
- The surgical approach is subfrontal and uses a perpendicular angle of attack
- Identify both feeders likely branches from the fronto-polar and Orbitofrontal artery
Dissection
- Resection involves interrupting the posterolateral and anteromedial arterial fronts.
- The deepest dissection plane targets the A1 ACA feeders along the posteromedial border, lateral to the olfactory tract.
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