Which dr to contact, spine or hand surgeon? having sporadic spasms at the base of thumb, seized & couldn't move my thumb, it was drawn into my hand. have foraminal stenosis c5 and had cmc arthroplasty and 3 level acdf. what causes it?

If you're not experiencing hand or thumb symptoms in between episodes of spasms, you could start with an evaluation by a neurologist or neurosurgeon in view of your neck surgery. However since you had a thumb arthroplasty the hand surgeon can also be consulted to reassure you that the surgical site is not a problem.

I would see your hand surgeon given that you’ve already had a cmc arthroplasty. This could represent a trigger finger which is also common amongst those in the age that develop cmc arthritis. If it is not a hand problem, then your hand surgeon will direct you to your neurosurgeon or spine doctor.