Barrow classification of caroticocavernous fistulae

Barrow caroticocavernous fistula classification divides caroticocavernous fistulas into direct (type A) or indirect (types B-D). This classification was proposed by Barrow et al. in 1985 ¹ and at the time of writing (mid-2016) remains the most widely used system for describing caroticocavernous fistulas. Indirect fistulae are further subdivided according to whether the supply is from the internal carotid artery, external carotid artery, or both. 

Classification

• type A (most common ²): a direct connection between the...
  • intracavernous internal carotid artery, and the...
  • cavernous sinus
• type B: dural shunt (indirect) between the...
  • meningeal branches of the intracavernous internal carotid artery, and the...
  • cavernous sinus
• type C: dural shunt  (indirect) between...
  • meningeal branches of the external carotid artery, and the... 
  • cavernous sinus
• type D: dural shunt  (indirect) between both...
  • meningeal branches of the intracavernous internal carotid artery (type B), and the...
  • meningeal branches of the external carotid artery (type C), and the... 
  • cavernous sinus

Alternative classifications

In 2015 Thomas et al. proposed an alternative classification system based on venous drainage ³.

Tomsick et al. have also proposed further dividing type D into D1 (unilateral supply) and D2 (bilateral supply) ⁴.