Arteriovenous Malformations (AVMs)
The Spetzler Martin Grading Scale estimates the risk of open neurosurgery for a patient with AVM, by evaluating AVM size, pattern of venous drainage, and eloquence of brain location. A Grade 1 AVM would be considered as small, superficial, and located in non-eloquent brain, and low risk for surgery. Grade 4 or 5 AVM are large, deep, and adjacent to eloquent brain. Grade 6 AVM is considered not operable.
Note however, that this scale does not necessarily correlate with risk of treatment by embolization or radiosurgery.
Spetzler Martin Grading Scale
Size of AVM
Spetzler RF, Martin NA. A proposed grading system for arteriovenous malformations. J Neurosurg 1986;65:476-83.
Iancu-Gontard D, Weill A, Guilbert F, Nguyen T, Raymond J, Roy D. Inter- and intraobserver variability in the assessment of brain arteriovenous malformation angioarchitecture and endovascular treatment results. Am J Neuroradiol 2007;28(3):524-7.