@jfsherley
Hi Again!
A TENS unit is NOT planted right under the skin.
As I previously explained, there are these pads (like a cardiogram) that to put on your skin.
The other end is attached to the machine.
You turn on the united to a comfortable intensity for a period of time.
When it is done, it will shut off.
What Jannix59 is talking about is a SPINAL STIMULATOR.
A spinal stimulator IS placed right under the skin.
Ronnie (GRANDMAr)

PS I'll see if I can find info on it an post it.
https://i.pinimg.com/736x/11/fc/1c/11fc1c11e17b9d717e159f7348cb103f--spinal-cord-stimulator-implant.jpg