Spinal cord stimulation delivers low voltage electrical stimulation to the spinal cord to block the sensation of pain. It may be the appropriate treatment for the management of certain chronic pain conditions. Chronic pain is considered a distinct disease entity, which may or may not be related to some underlying cause. It is irreversible and oftentimes progressive. Chronic pain conditions that respond to SCS include: failed back treatment syndrome (FBTS), complex regional pain syndrome type I (CRPS), and arachnoiditis.
Medtronic engineers and a physician, C. Norman Shealy, M.D., developed the first spinal cord stimulation system in the 1960s. Since the first system was implanted in 1967, SCS technology has undergone significant advancements, including refinements in patient selection criteria, equipment design, flexibility, reliability, and lifespan. Medtronic’s SCS systems have helped thousands of chronic pain patients lead more comfortable and productive lives.
Benefits of Spinal Cord Stimulation
The goal of SCS therapy is to reduce rather than eliminate pain. When used on carefully selected chronic pain patients, SCS may:
- Improve pain relief (60 to 70 percent of patients may experience a 50 to 70 percent reduction in pain)
- Increase activity levels
- Reduce use of narcotic medication
These results may also lead to reduced hospitalizations and surgical procedures, reduced health care costs, greater independence, and improved quality of life. Although spinal cord stimulation may reduce pain, it does not eliminate pain.
SCS System Components and Implantation
There are two types of spinal cord stimulator systems. In one type of SCS system, the power source (battery) is surgically implanted. In the other type of system, a radio-frequency receiver is implanted, and the power source is worn externally with an antenna over the receiver.
The spinal cord stimulation system consists of:
- A lead which delivers electrical stimulation to the spinal cord
- An extension wire which conducts electrical stimulation from the power source to the lead
- A power source which generates the electrical stimulation
The SCS system is typically implanted in a two-stage procedure, separated by a trial screening period lasting 5 to 10 days. Stage 1 involves implantation of a lead for trial screening, and Stage 2 involves implantation of the complete SCS system (either the totally implantable system or the radio-frequency system).
How Spinal Cord Stimulation Controls Pain
Most pain is caused by actual or potential tissue damage. When pain occurs, the affected person reacts to remove the source of pain. In this way, pain acts as a protective mechanism. Chronic pain, however, continues after the tissue damage has healed. Chronic pain often produces various harmful psychosocial effects including fear, anxiety, interference with work, decreased self-esteem, and problem relationships. The physical effects of pain include increased heart rate and blood pressure, increased blood sugar, decreased digestive activity, and reduced blood flow.
Pain theories suggest how SCS reduces pain. One theory, the gate control theory of pain developed by researchers Ronald Melzack and Patrick Wall, proposes that SCS activates the body’s pain inhibitory system. According to this theory, there is a gate in the spinal cord that controls the flow of noxious pain signals to the brain. The theory suggests that the body can inhibit these pain signals or “close the gate” by activating certain non-noxious nerve fibers in the dorsal horn of the spinal cord. The spinal cord stimulation system, implanted near the dorsal column of the spinal cord, stimulates these pain-inhibiting nerve fibers, masking the sensation of pain with a tingling sensation (paresthesia).