Spinal cord stimulation (SCS) is a minimally invasive and reversible therapy for many types of chronic pain. Indications include failed back syndrome (FBS), radicular pain syndrome or radiculopathies secondary to FBS or a herniated disk, post-laminectomy pain, degenerative disk disease, arachnoiditis, and complex regional pain syndrome (CRPS). The therapy is based on the “gate-control” theory for segmental pain suppression, first articulated by Melzack and Wall in 1965. According to the theory, the body can inhibit pain signals or “close the gate” by activating the large diameter afferent fibers in the dorsal column of the spinal cord. SCS delivers low-amplitude electrical stimulation to the spinal cord to block the sensation of pain.