Spinal Cord Stimulation
Chronic pain develops when the body’s appropriate response to an injury lasts longer than it should. This pain no longer protects the body from injury but becomes harmful on its own. Chronic pain can lead to problems working, eating, exercising, or pursuing other activities of daily life. This can wear a person down leading to other chronic health problems such as depression, and weight gain, as well as issues related to medication overuse to manage the pain.
Nerve signals are being transmitted from the body to the brain constantly. This helps prevent injury by making a person aware that something is wrong. Unfortunately, when nerves are damaged, they can send pain signals to the brain even if an injury is not occurring. Spinal cord stimulation can be used to disrupt these signals so the brain doesn’t receive them.
Chronic pain can develop for many reasons. Nearly any injury to a nerve has the ability to become a chronic problem. Depending on the location of the nerve injury, this pain can feel differently. Trauma to the body, as well as other medical conditions or medications can cause injury to nerves. A pinched nerve in the back, uncontrolled diabetes, or a medical procedure are a few things that can result in chronic pain. A person’s mental health can also play a role in the perception of pain and the ability to manage it. With so many potential causes of chronic pain, the evaluation and treatment for one chronic pain patient may be very different from another similar patient.
It is important to understand that a person can experience periods of nearly constant acute pain related to muscle or joint injury, arthritis, and many other medical conditions. Chronic pain results when the pain continues even after the initial cause is no longer present. Spinal cord stimulation is most useful for injury to the nerve, which causes this type of chronic pain.
The symptoms of pain depend greatly on the cause. Chronic nerve pain can range from sharp, shooting pain to burning, throbbing pain. This pain lasts longer than usual and is usually out of proportion, meaning a light touch or rub hurts when it shouldn’t. This can lead to feeling tired, decreased energy, difficulty sleeping, and a depressed mood. It can make it hard to work, play, or simply manage normal activities of daily life.
Pain can have a negative impact on a patient’s overall health. Medical care is recommended when the pain interrupts someone’s usual activities and does not improve with rest. Primary care providers are the best option to initially evaluate ongoing pain. When pain lasts for more than 6 months, it may be considered chronic and referral to a pain specialist may be needed.
Some causes of pain may be easy to identify while others can be more difficult. A good history of the pain and a physical exam is needed to begin the evaluation. Combining this with laboratory testing, imaging studies, and some minor procedures will find most of the common causes of chronic pain. The ability to locate where the pain is coming from and why the injury happened in the first place are important for treating the pain.
Finding the most effective treatment option for a patient requires understanding the location where the pain is starting and the type of injury that has occurred. The source of the pain may be specific to one area or it may be wide spread. The best treatment is found by understanding the cause of the nerve injury and using therapy that will correct the problem or reduce its effect. There is not a single treatment plan that will work for all patients and many patients will need several different approaches.
In most situations, non-surgical treatments should be used first during the evaluation and treatment of chronic pain. Improving lifestyle factors, such as appropriate weight management, regular physical activity, good mental and emotional health, proper nutrition, and healthy sleep habits are often helpful in promoting recovery. The effects of chronic pain will typically make a healthy lifestyle more difficult and can lead to many of the negative effects already mentioned. Physical therapy is often used as a first line treatment for pain conditions. This promotes many of the good lifestyle factors listed above and does not have the risks that come with medication use and surgical treatment.
Several medications are available with different ways of improving pain. Anti-inflammatory drugs like ibuprofen are often used as the first option. When pain gets worse, prescription pain medication, including opioids such as oxycodone may be used to manage pain. Although effective for acute pain, these medications are less helpful for chronic pain. In addition, these types of prescription pain medications can lead to addiction, abuse, and potential harm. The risks of these problems increase when the medications are taken over the long term. Some medications are more or less effective for particular types of pain, so it is important to talk with your medical provider about any medications prior to use.
Several procedures are used to manage chronic pain. Some procedures will be used to help identify the cause and location of the pain, while others will help control the pain. Injections or nerve blocks are commonly used during this process and may use numbing medication and/or steroid medication to block inflammation to a specific area. Pain specialists can use procedures like this to manage pain without the need for a larger surgical procedure.
When there is a problem with the body, surgery can be done to correct it. A surgeon will use x-rays, CT scans, or MRI to look at the areas where the pain is located and see if a problem is found. When a problem can be identified and surgery can be done to correct it, this will usually be the best option. In neurosurgery, this will most often include removing bone from the spine or fusing parts of the spine together. If no defect can be found to explain why the patient has pain or correcting it is not likely to improve the pain, surgery to do so is not a good option.
Spinal cord stimulation (SCS) is a relatively new technology that can help manage chronic pain when the cause cannot be removed or the injury cannot be repaired. The device consists of a stimulating wire or “electrode” or connected to control unit or “generator.” By placing a stimulating electrode over the spinal cord, the pain signal cannot be sent up from the spine to the brain. After a patient has been evaluated and non-surgical treatments have been used, spinal cord stimulation is considered to help manage chronic pain. A patient will often undergo mental health testing and counseling so they understand how an implanted device will be managed. A trial is done by placing one or two wires into the space outside the spinal cord and controlling them from a unit outside of the patient’s body. This is usually kept in place for about a week and the patient is able to test how well stimulation through the wire helps their pain. The stimulation is a very mild electrical pulse that the patient usually does not feel. These electrical pulses mask the pain signal and can be adjusted over the course of the trial to get the greatest improvement in pain. Trials are considered successful if they can remove half of a patient’s pain.
A successful trial is then followed by surgery to place a permanent stimulator. This is usually done by making a small cut in the back and another near the waist. A small, flat electrode or wire is placed through the incision on the back to the space behind the spinal cord. The wire is then tunneled under the skin to the incision near the waist where it is connected to a small battery powered generator. The generator is placed under the skin at the waist incision. The system is tested and if all is found to be working properly, the incisions are closed and the surgery is finished. The stimulator is controlled with a small hand-held remote, which can be used to make adjustments as needed. Some generators’ batteries need to be recharged every few days and some don’t need to be recharged at all. Those that are not rechargeable usually need to be replaced about every 3-5 years while rechargeable batteries can last for more than 10-15 years.
The surgeon will usually see the patient within a month of surgery to make sure the incisions are healing well and to remove sutures if needed. Management or adjustment of the stimulator is usually done by a pain specialist or a representative from the medical device company. No further surgical intervention is needed until the battery needs to be replaced.
Patient Pages are authored by neurosurgical professionals, with the goal of providing useful information to the public.
Brian Anderson, MD
Chief Resident, Neurological Surgery
Penn State Hershey Medical Center and Penn State College of Medicine
Kevin M. Cockroft, MD, FAANS
Professor, Neurological Surgery, Radiology and Public Health Sciences
Penn State Hershey Medical Center and Penn State College of Medicine
The AANS does not endorse any treatments, procedures, products or physicians referenced in these patient fact sheets. This information is provided as an educational service and is not intended to serve as medical advice. Anyone seeking specific neurosurgical advice or assistance should consult his or her neurosurgeon, or locate one in your area through the AANS’ Find a Board-certified Neurosurgeon”online tool.