A spinal cord stimulator (SCS) is an implanted device that sends low levels of electricity directly into the spinal cord to relieve pain. It masks pain signals before they reach the brain, and helps people better manage their chronic pain and reduce their use of opioid medications.
Spinal cord stimulators consist of thin wires (electrodes) and a small, pacemaker-like battery pack (generator). The electrodes are placed between the spinal cord and the vertebrae (the epidural space). The generator may be implanted or external. An implanted generator is placed under the skin, usually near the buttocks or abdomen. Alternatively, an external generator is device that can be worn on the clothes near the site of the wires.
Spinal cord stimulators allow patients to send the electrical impulses using a remote control when they feel pain. Both the remote control and its antenna are outside the body. Stimulation does not eliminate the source of pain, it simply interferes with the signal to the brain, and so the amount of pain relief varies for each person.
Some SCS devices use a low-frequency current to replace the pain sensation with a mild tingling feeling called paresthesia. Other SCS devices use high-frequency or burst pulses to mask the pain without a tingling feeling, or parasthesia-free. A paresthesiafree setting is an option on most devices.
Spinal cord stimulation is used most often after other pain treatment options have failed to provide sufficient relief. Spinal cord stimulators may be used to treat or manage different types of chronic pain, including:
• Back pain, especially back pain that continues even after surgery (failed back surgery syndrome, post-laminectomy syndrome)
• Post-surgical pain
• Arachnoiditis (painful inflammation of the arachnoid, a thin membrane that covers the brain and spinal cord)
• Heart pain (angina) untreatable by other means
• Injuries to the spinal cord
• Nerve-related pain (such as severe diabetic neuropathy and cancer-related neuropathy from radiation, surgery or chemotherapy)
• Peripheral vascular disease
• Complex regional pain syndrome
• Pain after an amputation
• Visceral abdominal pain and perineal pain
Spinal cord stimulation can improve overall quality of life and sleep, and reduce the need for pain medicines. It is typically used along with other pain management treatments, including medications, exercise, physical therapy and relaxation methods.
You will want to make sure spinal cord stimulation is right for you — and that it is likely to provide significant relief from your chronic pain. To make this recommendation requires imaging tests and psychological screening. In addition, most insurance companies require a psychological screening to ensure disorders like depression or anxiety aren’t worsening your pain.
Each patient is different, but generally, people who benefit the most from spinal cord stimulation are those who:
• Have not experienced sufficient pain relief with medications, less-invasive therapies or prior surgeries
• Do not have psychiatric disorders that would decrease the effectiveness of the procedure
• Do not have untreated drug addiction; this should be treated prior to having the procedure.
Spinal Cord Stimulation works better in the earlier stages of a chronic condition, before a cycle of pain-suffering-disability-pain is established.
Spinal cord stimulators come in three main types:
1. Conventional implantable pulse generator (IPG) is a battery-operated spinal code stimulator. A battery is placed under the skin during an operation. When it runs out, usually after 5 to 10 years, the battery must be replaced with another surgery. This device can be a good choice for people with pain in just one body part because it has a lower electrical output.
2. Rechargeable IPG works similarly to the conventional device, with the difference that the battery can be recharged without another surgery. Because the energy source is rechargeable, these stimulators can put out more electricity. This may be a better choice for people with pain in the lower back or in one or both legs, as the electrical signal can reach further.
3. External generator uses a battery that’s outside the body. It has rechargeable batteries, and can be replaced by simply exchanging it for another generator. Not further surgery is required. It may also be a good choice for those who do not want a battery implanted under their skin.
Your surgeon will explain how to operate the device and adjust the intensity of the electrical signal, which all three types of stimulators support. Different body positions may require different stimulator settings, such as one setting that works better for sitting and another for walking. To help you easily access the most used settings, most devices save two or three preset programs. Some newer devices feature several waveforms for electricity delivery, including high frequency, burst and high-density stimulation.
Spinal cord stimulators require two procedures to test and implant the device: the trial and the implantation.
Stimulation does not work for everyone. Some people may find the sensation unpleasant. Other people may not get relief over the entire pain area. For these reasons a trial stimulation allows you to try it for a week. If it doesn't work for you, the trial wires can be removed, leaving no damage to the spinal cord or nerves.
During the trial, a temporary device is placed in your spine for you to test out. Guided by a specific type of X-ray called fluoroscopy, electrodes will be carefully inserted into the epidural space of the spine. The location of your pain affects where these electrodes will be placed along the spine. Your feedback will be required during the procedure to best position the electrodes.
This trial procedure typically requires only one or two needle insertions to place the electrodes. No incisions are required. The generator/battery will be secured outside of your body.
For about a week, you will evaluate how well the device reduces your pain. The trial is considered a success if you experience a 50% or greater reduction in pain level.
At the end of the trial, the wires are easily removed in the clinic without damage to the spinal cord or nerves. If successful, surgery is scheduled to permanently implant the device.
During the permanent implantation procedure, the generator is placed underneath the skin and the trial electrodes are replaced with sterile electrodes. Unlike the trial electrodes, these will be anchored by sutures to minimize movement.
The implantation can take about 1-2 hours and is typically performed as an outpatient procedure.
After the local anesthesia has been administered, your surgeon will make one incision (typically along your lower back or buttocks) to hold the generator and another incision (along your spine) to insert the permanent electrodes. The incisions are generally less than the length of a driver’s license. As in the trial procedure, fluoroscopy is used to determine where the electrodes are placed.
Once the electrodes and generator are connected and running, your surgeon will close the incisions. You will be provided sedation during the procedure to keep you comfortable, but as with the trial, your feedback will be required toward the end of the procedure to best position the electrodes
Most patients leave the same day as their procedure. For several days after surgery, your incisions may be painful. Try not to stretch, twist or reach, which could pull at the incisions. Dressings will be placed over the incision sites, which can be removed after about 3 days. In most cases, incisions heal within about 2-4 weeks after surgery.
Once you have been approved for regular activity, you can return to work and drive again (with the stimulator turned off). This is typically 1-2 weeks after surgery
Complications of spinal cord stimulator surgery are rare, but no procedure is without risk. A small percentage of patients may experience:
• Infection, which may occur in the first 2-8 weeks.
• Device migration (i.e., the electrodes move from their original location and the stimulator doesn’t block pain as effectively). This often requires a follow-up surgery to put the electrodes back in the proper spot.
• Device damage (e.g., a fall or intense physical activity breaks the stimulator).
• Dural puncture. The dura mater surrounds the spinal cord. Spinal cord stimulators are inserted in the epidural space, the area just outside the dura mater. If a needle or electrode goes too deep and pierces it, cerebrospinal fluid may leak out. These punctures can cause severe headaches.
• Spinal cord trauma. Although extremely rare, spinal cord stimulator insertion can cause nerve injury and paralysis.
Generally, the pain relief provided by spinal cord stimulators allows patients to do much more than they could before surgery, but there are certain restrictions to be mindful of.
Stimulation does not cure the condition that is causing pain. Rather, it helps patients manage the pain. SCS is considered successful if pain is reduced by at least 50%.
X-rays and CT scans are generally safe. Most stimulators are MRI compatible. Before undergoing any scan, always let your doctor, nurse or technician know you have a spinal cord stimulator.
MRIs are not always safe for those with spinal cord stimulation devices; however, most newer devices are compatible with MRI. If your device is not MRI compatible, MRIs can cause serious injury.
Communicate with your pain specialist beforehand so that he or she can weigh in on whether a procedure will interfere with or harm your stimulator model.
The spinal cord stimulator can be detected by airport and department store security gates. Be sure to carry your Implanted Device Identification card when flying, since the device is detected at airport security gates. Security gates or theft detectors may cause an increase or decrease in stimulation when you pass through the gate. This sensation is temporary and should not harm your system. However, as a precaution, you should turn off your system before passing through security gates.
No, you should power off your stimulator when you’re driving or operating heavy machinery, as sudden changes in stimulation levels could cause distraction.
Swimming is fine with a permanent, implanted generator, but you cannot get your temporary stimulator wet. You will need to avoid baths and showers during that short trial period. If you have a model with an external generator, you must first take the generator off before going into the water.
SCS therapy is reversible. If a patient decides at any time to discontinue, the electrode wires and generator can all be removed.