You may also want to post on the -
Medications & Treatments /with a sub forum - SCS & Pain Pumps
http://neurotalk.psychcentral.com/forum118.html
If your main question is about the implant & welding, you might use that in the next title.
I wonder if a welding specific site might have information you are looking for.
But I'm thinking because of the electricity/power used in welding , that it may affect the electronics of the implanted device in a bad way...