I've got the same thing, brought on by years of gripping overly large handfuls of letters and aggravated by guitar playing. I wore an immobilizing sprint for a while but it didn't really seem to improve things. At best it prevents you from doing things with your thumb which will hurt. Massage seems to help though, the more painful the better, of course. Hopefully your specialist can show you some techniques. Rolling a golfball between the balls of the thumbs is one. Don't let them hard-sell you an operation just because it's the only tool in their box.