The basic design of the SCS unit is an implantable, programmable pulse generator (IPPG) that is tucked inside the abdomen or buttocks. Tiny, thin electrodes connected to the IPPG are inserted into the spinal canal where they can come in contact with the spinal cord. The electric impulses serve to interrupt or stop any pain signals that might be sent from the spinal cord to the brain.

The companies who have designed the SCS systems have tested these devices in animals and on humans. They are safe but not always effective. The rate of adverse events is one-third to one-half of all patients. Most of these problems aren't serious or life-threatening.