A modified radiosurgery-based arteriovenous malformation grading scale and its correlation with outcomes

Area of Science:

• Neurosurgery
• Radiation Oncology
• Radiology

Background:

• The Pittsburgh radiosurgery-based arteriovenous malformation (AVM) grading scale was developed to predict outcomes after radiosurgery.
• A modified scale incorporating a two-tiered location variable (deep vs. other) was introduced.

Purpose of the Study:

• To validate the modified radiosurgery-based AVM grading scale in an independent cohort of AVM patients treated with radiosurgery.
• To assess the scale's correlation with treatment outcomes.

Main Methods:

• The modified AVM score calculation includes volume, age, and a two-tiered location variable.
• The scale was tested on 293 patients who underwent AVM radiosurgery between 1992 and 2004.
• Dose planning utilized stereotactic angiography and MRI.

Main Results:

• The modified AVM scale showed a significant correlation with the rate of AVM obliteration without new neurological deficits (p = 0.001).
• Higher scores on the modified scale were associated with lower obliteration rates.
• Prescribed radiation dose to the AVM margin also correlated significantly with patient outcomes (p < 0.001).

Conclusions:

• The modified radiosurgery-based AVM grading scale, utilizing a two-tiered location variable, is a validated tool for predicting outcomes in AVM patients.
• This grading system can assist clinicians in choosing between observation, endovascular, surgical, or radiosurgical management for AVMs.