The stainless steel implant
there is no use worrying about some things we cannot change. At least that's always worked for me.
if it brings you any measure of comfort... my aunt once told me (and I have since tried it
) if the mass is greater than the medal the microwave won't cause any sparking or any thing. So if I am thinking this correctly your body may be "the mass" and your implant "the medal" I would be surprised if any thing would be a problem. Like I said before ... ask your doctor and maybe you might want to Google for more info.