Spetzler-Martin grade calculator or intracranial AV malformations

Notes

Original Spetzler-Martin grade
  • Points are assigned in the following manner:
    • Size of nidus
      • <3 cm: 1
      • 3-6 cm: 2
      • >6 cm: 3
    • + 1 point if the adjacent brain is eloquent
      • Eloquent areas are:
        • sensory, motor, visual, or language cortical areas
        • internal capsule
        • thalamus and hypothalamus
        • brainstem
        • cerebellar peduncles
        • deep cerebellar nuclei
    • +1 point if there is deep venous drainage
      • any drainage to the deep cerebral veins and most cerebellar hemispheric veins (unless they drain directly into the straight or transverse sinus)
  • In the original system a grade I-V can be assigned based on the points
  • A separate “grade VI” was reserved for diffuse nidus arteriovenous malformations, which were considered largely inoperable at the time when the original system was published
  • This entity is now referred as cerebral proliferative angiopathy
Supplemented Spetzler-Martin (SM-Supp) grade
  • Th supplemented system was proposed to facilitate selection of candidates with good surgical and neurologic outcome
  • Further points are assigned as follows:
    • Age at resection
      • <20: 1
      • 20-40: 2
      • >40: 3
    • Bleeding prior to resection
      • ruptured: 0
      • unruptured: 1
    • +1 point if the nidus is diffuse
  • A supplemented Spetzler-Martin grade ≤6 represents lower sugical risk and potentially better long term neurologic outcome
Further reading

Last updated: 2022-01-17