First up, a primer on what the heck a Spinal Cord Stimulator even is and how it works.
Spinal Cord Stimulators (SCSs) are an electrical device that is implanted into the epidural space in the spine. The body of the device, often referred to as the "brains" or the "battery", as it serves both functions, is about 1.5" across, and is generally somewhere in the middle of a rounded square and a true circle. These days, these batteries are only 1/3-1/2" thick and are curved to help them fit the contours of the abdomen. From the top of the titanium battery pack sticks out 1-2 pairs of wires. The wires are only a foot long and the last few inches have no insulation and multiple metal contacts on them.
The Boston Scientific brand Precision Spectra model, sans wires (this is the brand I plan to have implanted):
The brain/battery is implanted in the buttcheek, side of the abdomen, or back, generally into a "well padded" area, right below the skin. The wires, or leads, stick out the top of battery/brains (you can see 4 little round white ports on the right side top on the above picture- those are where the leads connect to it) and go up your back, under your skin. The last few inches, which have contacts on them, are fed between vertebrae into the epidural space of the spine, allowing for current fed through these wires to interact with the portions of the spine that feed pain sensations to the brain.
The SCS works to control pain through what's known as the "Gate Theory" of Pain Management. This is basically that if the "gate", or spinal cord, is wide open/unblocked, pain signals can reach the brain uninterrupted. But if you close the gate by somehow interfering with the signals on their way up the spine into the brain, then the brain can not feel the pain signals as intensely, or sometimes at all. The SCS closes the gate using an electric current to confuse the nerves. Instead of the pain signals reaching the brain, the brain feels paresthesia, or a non-sensation that many people describe as a light buzzing similar to having a cell phone on vibrate ring in their pocket. If the SCS is implanted for back or leg pain, this feeling extends from the bra band (T8) to the toes. They can also be implanted in the neck to control upper back and arm pain and the sensation of paresthesia extends from the neck down and fades out by the low back in most patients.
The sensation of paresthesia does not interfere with normal sensation. Some spine injury patients actually find they regain normal sensation afterwards. This is because before, the brain was completely overwhelmed by pain signals. Once the paresthesia kicks in, the brain is dedicating a lot fewer resources to the feelings from that region and thus has the resources left over to notice normal feelings like the sensation of warm water flowing over your skin or a breeze on your leg.
This freeing up of brain resources also means that the SCS treats other symptoms aside from the pain. Memory and concentration improve, many people regulate their weight better as they can feed themselves better and exercise more, and for CRPS patients, there tend to be fewer issues from a malfunctioning Sympathetic Nervous System.
Upcoming: the personal story of my journey through the SCS process, and more info on CRPS treatments and coping techniques.