Please explain exactly what is a tens nerve stimulator and also what is the sprint nerve stimulator? do both of these units you wear a pump on the outside or is it just implanted inside?

TENS delivers electrical currents to the affected nerve through electrodes that adhere to the skin. With Sprint peripheral nerve stimulator (Sprint PNS), a thin wire is placed inside the body right at the site of the nerve so the electrical pulses are delivered as close as possible to the nerve causing pain. TENS is external, it is likely not as effective as Sprint PNS therapy. Good luck.