You want to find a NUCCA trained chiropractor (nucca.org) if you can. They treat C-1 and C-2 much differently than most other chiros. The twist and pop neck adjustment will not cause a concussion but it may be too aggressive for your neck condition.

A Physical Therapist may be OK if he/she can do some light traction and gentle manipulation. Some PT clinics have specialized training in gentle neck work for whiplash and such. Just use good sense before you let them get aggressive.

My best to you.