Epidural stimulators are devices that send electrical currents to the nerve roots that are causing your pain. They can work, but they are invasive treatments. You will need surgery to permanently place electrodes in the sleeve of the nerve roots. Most of the time, doctors will have you try a temporary stimulator to make sure it helps you before placing a permanent device.
Epidural stimulators work by the “gate theory” of pain. The principle of the gate theory is that if you can make the nerve recognize a sensation other than pain–such as heat, rubbing, or electrical current–your central nervous system “closes the gate” on any other sensations. This means the pain doesn’t register. Electrical currents get to the spinal column much faster than pain impulses, so they are pretty effective at closing that gate.