A review of spinal cord stimulation systems for chronic pain.

Spinal cord stimulation (SCS) applications and technologies are fast advancing. New SCS technologies are being used increasingly in the clinical environment, but often there is a lag period between the clinical application and the publishing of high-quality evidence on safety and efficacy. Recent developments will undoubtedly expand the applicability of SCS, allowing more effective and individualized treatment for patients, and may have the potential to salvage patients who have previously failed neuromodulation. Already, high-level evidence exists for the safety, efficacy, and cost-effectiveness (Level I-II) of traditional SCS therapies in the treatment of chronic refractory low back with predominant limb pain (regardless of surgical history). More than half of all patients with chronic painful conditions experience sustained and significant levels of pain reduction following SCS treatment. Although only limited evidence exists for burst stimulation, there is now Level I evidence for both dorsal root ganglion SCS and high-frequency SCS that demonstrates compelling results compared with traditional therapies. The body of evidence built on traditional SCS research may be redundant, with newer iterations of SCS therapies such as dorsal root ganglion SCS, high-frequency SCS, and burst SCS. A number of variables have been identified that can affect SCS efficacy: implanter experience, appropriate patient selection, etiologies of patient pain, existence of comorbidities, including psychiatric illness, smoking status, and delay to SCS implant following pain onset. Overall, scientific literature demonstrates SCS to be a safe, effective, and drug-free treatment option for many chronic pain etiologies.