Spetzler-Martin Grade
The Spetzler-Martin arteriovenous malformation (AVM) grading system was described as a method of estimating the mortality and morbidity of surgical resection to guide treatment recommendations. [1, 2, 3, 4] It allocates points for various features of intracranial AVMs, including size, eloquent location, and venous drainage. [5]
Size of nidus
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1 point = Small (< 3 cm)
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2 points = Medium (3-6 cm)
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3 points = Large (>6 cm)
Eloquence of adjacent brain
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0 points = Noneloquent (frontal and temporal lobe, cerebellar hemispheres)
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1 point = Eloquent (sensorimotor, language, visual cortex, hypothalamus, thalamus, brain stem, cerebellar nuclei, or regions directly adjacent to these structures)
Venous drainage
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0 points = Superficial only
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1 point = Deep
The Spetzler-Martin grade was originally validated in a study of 100 consecutive patients treated with microsurgical excision of AVMs. Morbidity rates were as follows:
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Grade 1: 0%
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Grade 2: 5% minor deficit, 0% major deficit
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Grade 3: 12% minor deficit, 4% major deficit
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Grade 4: 20% minor deficit, 7% major deficit
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Grade 5: 19% minor deficit, 12% major deficit
