What is Spinal Cord Stimulation?

Spinal cord stimulation, also called Dorsal Column stimulation, is an advanced FDA approved reversible method of pain control. It can be used to treat a number of conditions including failed back surgery syndrome, Complex Regional Pain Syndrom, Post Lamenctomy syndrome and other forms of chronic neuropathic pain. In the United States, it is more commonly used to treat pain in the low back and lower extremities. In other countries, it is also used to treat peripheral vascular disease. Spinal cord stimulation was first used to treat pain over twenty years ago. Since its introduction, thousands of patients with severe chronic painful conditions have received relief with spinal cord stimulation.

To understand how it works it is helpful to understand the components of a typical Spinal Cord Stimulation system. A spinal cord stimulation system is composed of three basic parts, the pulse generator, the lead and the wire that connects the pulse generator to the leads. The system itself resembles and works quite similar to a Pace Maker, In fact some patients refer to Spinal Cord Stimulation systems as “Pain Pacemakers”.

The pulse generator is the “brain” of the system and contains the power supply and computer that instructs the rest of the system on what to do. Implantable Pulse Generators come in various sizes; some are rechargeable while others are not. Up until recently, all of the Implantable Pulse Generators were non rechargeable and had a finite battery life. The batteries needed to be replaced every 3-5 years depending on how much the stimulator was used and how much power was used as well. Now, rechargeable systems are available and it is thought that this technology will allow for longer time intervals between the need to replace the implantable pulse generator. Some of the rechargeable IPG’s are expected to last 9 years or more. There are advantages and disadvantages of each and the choice should be individualized to each patient.

The second and third components of the spinal cord stimulation system are the wire and the lead. The wire and lead are essentially the same component. The wire attaches to the IPG and at the end of the wire is an array of small electrical leads. There are 4-16 leads at the end of the wire depending on which system component is chosen. The leads are told to be active or in active by the Implantable Pulse Generator. The IPG has the capability of choosing various leads to be active. By selecting certain leads to be on or off the electrical stimulation pattern is shaped. The shape of the electrical field (or pattern) will determine the area of the body that feels the stimulation and thus has pain relief. When the lead is on or active, low intensity electrical impulses trigger nerve fibers selectively along the spinal cord. When theses fibers are stimulated, they diminish or block the pain message traveling to the brain. When this happens, the painful sensation is replaced with a soothing tingling sensation.

The lead is the part of the system that is placed in the epidural space. This is a space in the body that is near the outside covering of the spinal cord. The wire is then tunneled under the skin and is attached to the IPG. The pulse generator is implanted under the skin and located in a comfortable convenient, discrete location for the patient. The patient is then able to activate the system with a small remote control device that is small enough to carry in a pocket or purse. If the patient happens to have a rechargeable system, they use a small recharger that is held over the IPG and recharges the system through the skin.

A simple office based procedure is available to determine if a patient would benefit from spinal cord stimulation as a therapy option. Using a needle and local anesthetic, a temporary stimulator lead is placed and attached to a battery supply. The patient is then released to home and allowed to essentially do their normal activities. They try the device for 5-7 days essentially like a week long test drive of the device. After the trial period is over, the wire and the lead are removed. After the initial trial period, the patient is then re-evaluated by the physician. If the patient responds favorably to the screening test (had good pain relief) and liked the way the device made them feel, they are good candidates to have the permanent stimulator implanted via a minor surgical procedure. Once it is permanently implanted, the device itself is contained under the skin similar to a pacemaker.

Again, this system is FDA approved and covered by most insurances including Medicare.

Ben Wall, MD, MSPH, FAAPM&R obtained his Bachelor of Science Degree from Wake Forest University, a Masters of Science in Public Health from the University of North Carolina at Chapel Hill and his Doctor of Medicine Degree from the Bowman-Gray School of Medicine of Wake Forest University. He completed his specialty training at the Medical College of Virginia. He is board certified in PM&R and PAIN. Dr. Wall is a member of the International Spinal Injection Society and has special interests in fluoroscopic pain management. 2005 President North Carolina Society of Physical Medicine and Rehabilitation President-Elect the New Hanover-Pender County Medical Society.