Editing Cerebral arteriovenous malformation (section)

=== Spetzler-Martin (SM) Grade ===

A common method of grading cerebral AVMs is the Spetzler-Martin (SM) grade.<ref>{{cite journal|last=Spetzler|first=R|author2=Martin N|s2cid=21796375|journal=J Neurosurg|year=1986|volume=65|pages=476–83|pmid=3760956|doi=10.3171/jns.1986.65.4.0476|title=A proposed grading system for arteriovenous malformations|issue=4|doi-access=}}</ref>  This system was designed to assess the patient's risk of neurological deficit after open surgical resection (surgical morbidity), based on characteristics of the AVM itself. Based on this system, AVMs may be classified as grades 1–5. This system was not intended to characterize risk of hemorrhage.<ref>{{Cite web |title=Spetzler Martin Grading Scale |url=https://www.bmc.org/spetzler-martin-grading-scale#:~:text=The%20Spetzler%20Martin%20Grading%20Scale,and%20low%20risk%20for%20surgery. |access-date=2022-04-23 |website=[[Boston Medical Center]]}}</ref>
{| class="wikitable"
|-
! AVM size !! Adjacent eloquent cortex !! Draining veins
|-
| < 3&nbsp;cm = 1 || Non-eloquent = 0 || Superficial only = 0
|-
| 3 – 6&nbsp;cm = 2 || Eloquent* = 1|| Deep veins = 1
|-
| > 6&nbsp;cm = 3 ||  ||
|}

"[[Eloquent cortex|Eloquent]]" is defined as areas within the brain that, if removed will result in loss of sensory processing or linguistic ability, minor paralysis, or paralysis.  These include the basal ganglia, language cortices, sensorimotor regions, and white matter tracts.<ref>{{Cite journal |last1=Jakola |first1=Asgeir S. |last2=Unsgård |first2=Geirmund |last3=Myrmel |first3=Kristin S. |last4=Kloster |first4=Roar |last5=Torp |first5=Sverre H. |last6=Lindal |first6=Sigurd |last7=Solheim |first7=Ole |date=2012-12-10 |title=Low Grade Gliomas in Eloquent Locations – Implications for Surgical Strategy, Survival and Long Term Quality of Life |journal=[[PLOS One]] |language=en |volume=7 |issue=12 |pages=e51450 |doi=10.1371/journal.pone.0051450 |issn=1932-6203 |pmc=3519540 |pmid=23251537|bibcode=2012PLoSO...751450J |doi-access=free }}</ref> Importantly, eloquent areas are often defined differently across studies<ref>{{Cite journal |last1=Satoer |first1=Djaina |last2=Visch-Brink |first2=Evy |last3=Dirven |first3=Clemens |last4=Vincent |first4=Arnaud |date=2016-01-01 |title=Glioma surgery in eloquent areas: can we preserve cognition? |url=https://doi.org/10.1007/s00701-015-2601-7 |journal=Acta Neurochirurgica |language=en |volume=158 |issue=1 |pages=35–50 |doi=10.1007/s00701-015-2601-7 |issn=0942-0940 |pmc=4684586 |pmid=26566782}}</ref> where deep cerebellar nuclei, cerebral peduncles, thalamus, hypothalamus, internal capsule, brainstem, and the visual cortex could be included.

The risk of post-surgical neurological deficit (difficulty with language, motor weakness, vision loss) increases with increasing Spetzler-Martin grade.<ref>{{Cite web |title=Brain arteriovenous malformations |url=https://www.uptodate.com/contents/brain-arteriovenous-malformations |access-date=2022-04-22 |website=UpToDate |publisher=[[Wolters Kluwer]] |quote=A higher Spetzler-Martin grading scale score correlates with increased risk of surgical morbidity and neurologic deficits.}}</ref>