Hi Rachel, 

As I am going through the question I see mine must have submitted early so I will clarify.  You never want to needle around implantable devices that have wires as unless you know exactly where they are you avoid the areas.  With an always "on" electrical device i.e. pacemaker/defibrillator I would not include ENS in your treatment- that comes from cardiologist that I spoke with.  Now with a hypoglossal unit that is on or off I think you have more leeway on including ENS in other areas like lumbar and below does not have the same concern but speaking to the neurologist or pain doc is never a bad idea and a way for you to explain how you can help patients with DN/ENS - never a bad time to educate!