Pam
There is a guide to AVM size & grading here:
If your AVM is in your dura mater, a different method is used, which often indicates “leave alone”. The other factor which indicates it may be best left alone is if it is in “eloquent” areas of the brain, in other words areas with lots of critical function, deep in the brain, and more likely to do damage trying to do surgery on it than come out with a better situation. So, you need to understand where your AVM is in your brain as to whether it is definitely better to leave alone or to have some treatment.
A lot will have changed since your first diagnosis, so what can be achieved today may not have been a viable option all those years ago.
Very best wishes,
Richard