Hi and welcome to the Chiari forum.
It seems many of us have waited many years to finally get a DX of Chiari....I went to Drs while still in grade school and was not DX'd until I was 48.....keep in mind MRI's were not around then....and once they began to use them it was not for DXing like they do now and now that they do, they are finding things they just do not understand or consider to be an incidental finding.
First, what testing besides a Brain and cervical MRI have you had? You will want to have one of the thoracic and lumbar spine. Ask what related conditions the Dr will look for and rule out and why he/she feels it is important to do.Also a CINE MRI to check CSF flow.Then testing for related conditions should be done before any thought of surgery .
Educate yourself on the answers to the questions you ask,,,,get copies of ALL tests and the reports as this will make the next phase easier on you.
How is your Chiari affecting you and your overall health?
What symptoms do you have?