Grading of brain arteriovenous malformations to predict the risk of surgical resection.
The Spetzler-Martin scale grades cerebral arteriovenous malformations from I to V by summing points for nidus size, eloquence of adjacent brain, and pattern of venous drainage, predicting the risk of neurological morbidity from microsurgical resection.
Deep venous drainage (any drainage through deep veins): +1 point.
Grade = sum of the three components, ranging from 1 to 5.
📊 Interpreting the Result
Grade I–II — low surgical risk; generally favourable for microsurgical resection.
Grade III — intermediate risk; management is individualised.
Grade IV–V — high surgical morbidity; often managed conservatively or with staged/multimodal therapy.
A separate grade VI denotes an inoperable lesion in some schemes.
⚠️ Limitations & Pitfalls
Predicts microsurgical risk, not rupture risk or radiosurgery outcome.
Does not include patient age, diffuseness or prior haemorrhage (addressed by the supplemented Lawton-Young grade).
Eloquence is defined categorically and can be subjective at borders.
📚 References
Spetzler RF, Martin NA. A proposed grading system for arteriovenous malformations. J Neurosurg. 1986;65(4):476-483.
Lawton MT, Kim H, McCulloch CE, Mikhak B, Young WL. A supplementary grading scale for selecting patients with brain arteriovenous malformations for surgery. Neurosurgery. 2010;66(4):702-713.
⚕️ For clinical decision support only. Always verify calculations and apply clinical judgment.