Spinal Cord Stimulation

People whose back or neck pain has not been relieved by back surgery or other treatments may have another option to consider: spinal cord stimulation.

Typically two thin, flexible wires are placed in the epidural space above the spinal cord. These are then connected to a device also implanted underneath the skin that sends an electrical signal to the nerves in the spinal cord.

The electrical signal will control or decrease the feelings of pain by, in a sense, blocking or diluting the signals from the pain nerves to the brain. This means the patient doesn’t feel their pain as much or at all. Think of the pain as a loudspeaker and the spinal cord stimulator as the knob that turns down the volume.

One of the specialized interventional pain management doctors at Semmes Murphey Clinic can implant the transmitter device through minimally invasive surgery. Physicians who have specific training in neuromodulation techniques have reduced complications and adverse events associated with this procedure. For this reason, it is vital that patients carefully choose a board-certified pain specialist with expertise in neuromodulation before committing to any therapy.

Each year approximately 14,000 patients around the world receive spinal cord stimulator implants.

Spinal cord stimulation was approved by the Food and Drug Administration (FDA) in 1989 to relieve pain from nerve damage in the trunk, arms, or legs, and now accounts for about 90 percent of all neuromodulation treatments. That number is expected to grow to help manage chronic disease states as the population ages and as spinal cord stimulation is expanded to treat other diseases.

This device is typically used in patients who are still in pain after trying physical therapy, medications, nerve blocks, and even surgery.

A general condition known as failed back surgery syndrome is one of the most common reasons spinal cord stimulation is used. The term describes chronic pain after one or more back or neck surgeries fails to alleviate persistent low back pain, leg pain (sciatica or lumbar radiculopathy) or arm pain (cervical radiculopathy).

Spinal cord stimulation is also an option for patients who are not surgical candidates because of a medical condition or because there isn’t a surgery that will help with their pain.

Spinal cord stimulation is recommended for an increasing number of painful health problems. While this is not a comprehensive list, some of the conditions which the therapy may help includes:

• Arachnoiditis — painful inflammation and scarring of the meninges (protective layers) of the spinal nerves
• Chronic back pain with or without leg pain
• Chronic neck pain with or without arm pain
• Complex regional pain syndrome — a chronic progressive disease characterized by severe pain and swelling
• Peripheral neuropathy — a constant burning pain of the legs caused by the dying off of the distant nerves
• Refractory angina — which causes chest pain, shortness of breath, and fatigue
• Cervical and lumbar radiculitis — a painful condition resulting from the compression of the spinal nerves

Patients who have spinal cord stimulators can often reduce or even eliminate the medications they use for pain.

Before any patient receives the trial spinal cord stimulation therapy, he or she must go through a thorough screening process. This includes:

• In-depth history and physical examination to assess for medical conditions that increase the risk that the treatment will either fail or create complications
• Routine laboratory evaluation as determined by the patient’s medical history and the type of anesthesia that will be used during the implantation procedure
• Relevant spine imaging studies (for example, X-ray films, CT and MRI scans)
• Psychological screening (often required by insurance companies for approval of payment)
• For patients with cardiac issues, a consultation with a cardiologist as well as a compatibility test is necessary

Despite this careful selection process, spinal cord stimulation may not provide optimal pain relief some patients. Most often, this is due to factors such as lifestyle (for example, preexisting tobacco or drug use), age or a lengthy delay between the first appearance of pain symptoms and device implantation.

A valuable feature to spinal cord stimulators is the ability to try out the device before committing to a surgical implant.

After being medically cleared for the procedure, the patient can begin the first phase which is call a trial. Here, one of our pain physicians uses a needle to access the epidural space. Then a wire is inserted through the needle and placed at the appropriate level of the spine above the spinal cord in the epidural space.

This procedure is similar to a nerve block, except once the wires are in place, the device is turned on while the patient is still in the operating room. The patient is able to feel the stimulation as a light buzzing sensation.

The system is adjusted to cover the patient’s specific area of pain, making adjustments in the operating room as needed. After that, the needles are removed, but the flexible wires stay in the patient’s back, connected to a small external stimulator device usually worn on a belt.

The patient spends a week with the system going about his or her normal routine to see if the implant will work for them.

At the end of the trial, the patient returns to the clinic where the wires are painlessly removed. The physician will also discuss the trial week to determine if the patient should and would like to proceed with the implant procedure.

If the stimulator provided the patient relief from their pain, they often chose to have the system implanted.

This is a minor, outpatient surgical procedure similar to the trial procedure. Two small incisions are made so both the wires and the stimulator, or pulse generator, can be implanted underneath the skin.

What does the stimulator feel like? People experience the stimulation in two ways:

• Traditional stimulation feels like a light buzzing sensation.
• A newer option is a silent or high frequency program where the patient doesn't feel any light buzzing at all.

The systems are customizable to each individual patient.

Will I still be able to feel normal sensations once the device is in place? Yes, the stimulator only affects pain nerves, so your sensory and motor nerves are unaffected. Also, if you have a new painful sensation, like dropping a hammer on your foot, you will still feel that normally. This device reduces the constant background chronic pain.

What is the recovery time after the implant? The incisions and pulse generator site may cause moderate discomfort for a few days. The wires can take about six to eight weeks until they “scar down”which means that as the tissue around the implant heals, its scarring secures it in place within your body.

During the six to eight week period after implanting, severe and excessive movement should be avoided as it can cause the wires to move. Normal activities should not be a problem.

If the wires move too much, the system may need to be reprogramed. This reprogramming can be done simply and wirelessly. In very rare instances, if the migration is severe, the patient may have to undergo a revision surgery to put the wires back in place.

How long does the battery last? Like cell phones, these implants will need to be regularly charged. The patient will simply place a charger over their pulse generator site. The device will charge through their skin.

Charging times and frequency varies depending upon use of the device and personal preference. Some patients charge it for 10 to15 minutes every day, and others prefer to charge it for about an hour once per week.

The battery inside the pulse generator has a typical lifespan of about seven to ten years, at which point they must be replaced. This is a minor surgical procedure where the pulse generator is simply removed and a new one is implanted. The wires are not affected.

What are my limitations? Once the system is in place and the leads have had time to scar into place, there are very few limitations. With the system self-contained inside the body, patients can swim, play golf, work out, ride a bike, work in the yard, or do any of the things that they enjoy. The idea behind the spinal cord stimulator system is to reduce or eliminate chronic pain so that it is no longer a part of your life.

This information was provided by the specialists at Semmes Murphey Clinic. Readers are encouraged to research trustworthy organizations for information. Please talk with your physician for websites and sources that will enhance your knowledge and understanding of this issue and its treatments.