The Buffalo Score (AVM)

The Buffalo Score is a new grading system for the endovascular treatment of cerebral AVMs.  It is a 5-point system, and higher scores is associated with higher complication rates.  This new score was created because components of the Spetzler Martin Grading scale, while useful for determining suitability of surgical treatment of cerebral AVMs, may not be relevant in determining suitability for endovascular treatment.

For example, the diameter and number of arterial pedicles supplying the AVM nidus is an important factors to consider in endovascular intervention, since smaller vessels are more prone to injury with catheterization, and a greater number of arterial pedicles produces more risk with each embolization.  The actual size of the AVM nidus and venous drainage pattern is important when considering surgical resection, but is less important during endovascular embolization.

Points for Buffalo Score:

  • number of arterial pedicles
    • 1 point for 1–2 pedicles
    • 2 points for 3–4
    • 3 points greater than 5
  • arterial pedicle diameter
    • 1 point for less than 1 mm
    • 0 points for more than 1 mm
  • eloquence of the location
    • 1 point for eloquent location
    • 0 point for non-eloquent location




Buffalo System Vs. Spetzler Martin Grading System:


*arterial pedicles for Buffalo and draining veins for Spetzler Martin (black lines); nidus (black shading);  deep drainage (dashed lines)

  • Buffalo system = # arterial pedicles (N), diameter of pedicles (D), and eloquence (E)
  • Spetzler–Martin system = venous drainage (V), size (S), eloquence (E)



  1. Measurement of arterial pedicle diameter is made at a distal segment of the arterial pedicle, within 1 cm of the AVM nidus.
  2. Eloquent location is determined based on the nidus location and is defined according to the grading system of Spetzler-Martin.
  3. Any portion of AVM nidus located within motor or sensory cortex, language and vision, and deep eloquent areas (hypothalamus, thalamus, brainstem, cerebellar peduncles) is considered eloquent in location.
  4. This system has not been applied or validated yet.



Levy, EladI et al. “A Proposed Grading System For Endovascular Treatment Of Cerebral Arteriovenous Malformations: Buffalo Score”. Surgical Neurology International 6.1 (2015): 3.


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s