Input age, hemorrhage status, and nidus compactness to calculate the supplementary Lawton-Young AVM grade.
Guidelines & Evidence
Clinical Details
Section 1
When to Use
When to Use
Refining the surgical risk profile of brain AVMs beyond anatomical descriptors.
Particularly useful for Spetzler-Martin Grade 3 AVMs to decide between observation and surgery.
Predicting long-term functional outcomes in younger vs. older patients.
Section 2
Literature
Development
Michael Lawton and colleagues at UCSF developed this supplemental scale in 2010 to address the "grey area" of AVM grading. By adding Age, Hemorrhage status, and Nidus Compactness, the scale significantly increases the predictive power for surgical outcomes, especially for unruptured AVMs.
Section 3
Pearls/Pitfalls
The ARUBA Effect
Since the ARUBA trial (2014), the Lawton-Young scale has become critical for justifying treatment for unruptured AVMs. Unruptured AVMs (Hemorrhage = 1 point) in diffuse niduses (Compactness = 1 point) have significantly higher surgical risk, often making conservative management or stereotactic radiosurgery the safer path.
Section 4
Evidence Appraisal
Primary Reference
A supplementary grading scale for resection of brain arteriovenous malformations
Lawton MT et al. • Neurosurgery. 2010;66(4):702-13
