Overview of Spinal Cord Stimulator Implant
Spinal cord stimulators are devices that get implanted in your body to help manage chronic or long-time pain. They work by using electricity to provide relief from various types of pain. This treatment option doesn’t involve taking medicine and can be used for both nerve-related and low oxygen supply related pains.
These devices are usually recommended for patients who didn’t find relief from different types of conservative and medication-based treatments. After a trial period, where a temporary device is used, a permanent spinal cord stimulator can be installed. Many patients find lasting relief from their pain after this procedure.
There are a number of reasons to get a spinal cord stimulator, but the most common reason is after a back surgery hasn’t worked. There’s a low chance of serious complications after getting a spinal cord stimulator, but if they happen, they can be significant. There are different types of stimulators, as well as different types of electrical pulses they can use to provide pain relief.
More research is being done to see if one type of stimulator is better than another. It’s also important to note that many insurance companies need mental health screenings before approving the device. That’s because there can be worse results after getting the device for patients with mental health disorders. Regular check-ups are usually needed after getting the spinal cord stimulator. This can include adjusting the settings on the device and replacing the battery.
It’s also common to have to revise, or fix, the spinal cord stimulator due to the wires moving or breaking. In all, spinal cord stimulators can be a promising way to manage chronic pain for those who haven’t found relief other ways.
Anatomy and Physiology of Spinal Cord Stimulator Implant
The spinal cord stimulator leads, small devices used for pain management, are positioned within a space inside our backbone known as the epidural space. This space is sandwiched between the dura mater, a protective coating of the spinal cord at the front, and the back wall of the spine. This back wall is composed of blood vessels, lymph nodes, and fatty tissues. The epidural space is physically located within a protective sack, known as the dural sac, which holds nerve roots bathed in cerebrospinal fluid, a clear fluid found in the brain and spine.
The epidural space is at its widest point at a backbone level known as the L2 vertebra, and starts at the bottom of the skull at a hole called the foramen magnum. It continues down the spine until reaching the sacrum, a shield-shaped bone at the base of the spine. The leads of the spinal cord stimulator device can be implanted in various parts of the backbone, from the cervical to the thoracic and lumbar vertebrae, and even the sacrum. Once the device is installed, it sends out either continuous or pulsing electrical signals to the epidural space.
Spinal cord stimulators work by influencing a nerve pathway in the spinal cord called the spinothalamic tract that controls how we perceive pain. When a person has chronic pain, this pathway is said to be disrupted or dysregulated. A spinal cord stimulator calms the nerve cells within the rear part of the spinal cord, known as dynamic range neurons. Studies have shown that the device can be effective in lessening pain, not only by direct influence on the pathway locally, but indirectly by reducing pain through other descending pathways in the nervous system. Hence, the stimulators help manage the pain through both local and central methods.
Why do People Need Spinal Cord Stimulator Implant
If someone is living with debilitating back pain due to diseases that limit blood flow, like peripheral vascular disease or intractable angina, it might be a good idea to consider spinal cord stimulation. This method could be particularly viable when these conditions can’t be managed surgically. Spinal cord stimulators are devices that send mild electrical pulses to the spine, which can help to improve the heart function, as classified by the New York Heart Association (NYHA), and boost a person’s overall quality of life.
Spinal cord stimulators are also often used for those who have gone through back surgery but are still experiencing persistent discomfort, a condition known as failed back surgery syndrome. In medical terms, spinal cord stimulators can help manage the ongoing pain caused by nerve irritation after surgery, known as radicular pain. This method could be highly effective and is frequently used.
In medical studies, it’s been found that spinal cord stimulators are more effective than medication at reducing chronic pain by more than half. They can be used for a variety of continual pain ailments, which might include diabetic neuropathy, which is a type of nerve damage caused by diabetes; chronic back pain; peripheral vascular pain, which is pain related to poor blood flow; failed back surgery syndrome; and complex regional pain, a chronic pain that usually affects an arm or a leg. Spinal cord stimulators have even been used to relieve nerve pain in patients with HIV, a condition known as HIV-related polyneuropathy.
When a Person Should Avoid Spinal Cord Stimulator Implant
Often, devices such as pacemakers and defibrillators can be safely used alongside spinal cord stimulator implants. However, if someone has previously had a pacemaker or cardiac defibrillator fitted, a heart doctor (cardiologist) must approve the spinal stimulator implant before the surgery can happen. Even though it’s usually possible, having a pacemaker or defibrillator is still seen as a bit risky when getting a stimulator implant. It’s crucial to monitor both devices closely after the implant is fitted.
Having severely low platelet count, known as severe thrombocytopenia, or a condition that makes it hard to control bleeding, called uncontrolled coagulopathy, makes spinal stimulator implant more dangerous due to the increased danger of bleeding around the spinal cord, which is known as a spinal epidural hematoma.
An active infection should absolutely prevent the implantation of a spinal stimulator because of the dangers it could pose. There’s not a lot of information about the safety of getting an implant while pregnant. However, because the surgery needs the use of fluoroscopy (a type of imaging that shows a continuous X-ray image), it’s typically held off until after the baby is born.
Equipment used for Spinal Cord Stimulator Implant
When a doctor performs a procedure to implant a spinal cord stimulator, they use several equipment pieces. These include stimulation leads (which are essentially wires that distribute electrical signals), a cable to connect these leads to a generator, and a pulse generator, which produces electrical impulses. The electrical signals from the pulse generator can be adjusted, offering relief for the patient’s pain.
The generators used in this procedure come in different types. Some are called paresthesia-based generators, and others are known as paresthesia-free generators (which can either be high frequency or burst stimulators). The term “paresthesia” refers to abnormal sensations in the body; some patients prefer to feel these sensations in areas where they have pain (those would use a paresthesia-based generator), while others don’t (and would use a paresthesia-free generator).
The anesthetic bupivacaine is also used in the procedure to reduce discomfort, and it’s administered via a spinal needle. The doctor often uses a particular type of leads known as cylindrical leads for implanting the stimulator when the procedure is done through the skin (a process called percutaneous implantation).
After the procedure, the patient is given a programmer for their spinal cord stimulator. This programmer has multiple settings options that were established during the procedure, and these can be adjusted later during follow-up meetings with the doctor.
Who is needed to perform Spinal Cord Stimulator Implant?
Your main doctor, also known as your primary care provider, will be involved in your care. There’s also a specialist on the team who specifically treats pain. During the procedure to place a device in your spinal cord, another health professional will help out. This is known as the first assistant for the spinal cord implantation. You’ll also have a team of nurses looking after you. An anesthesiologist, a doctor who helps you sleep during the surgery, will also be present to ensure you don’t feel any pain during the procedure.
Preparing for Spinal Cord Stimulator Implant
When dealing with medications that prevent blood clots, it is crucial to have a conversation with your doctor before any form of treatment begins. If you’re taking these blood-thinning drugs, you may be at a higher risk of developing blood clots in the spine.
Before permanently inserting a spinal cord stimulator – a device used to help manage chronic pain – you need to try it out for a while first. The goal: to see how well the device meets your needs and how comfortable you are with it. This trial run is typically done as an outpatient procedure, meaning you won’t have to stay at the hospital overnight.
The doctors use a method called “fluoroscopy” to make sure the stimulator leads (parts of the device that deliver electricity) are placed in just the right position in your spine. In this procedure, they numb the area with a local anesthetic, resembling how a dentist numbs your mouth before filling a cavity.
If the trial proves successful, we move on to permanent implantation. This procedure usually needs expert anesthesia care, meaning stronger drugs to prevent pain and discomfort. The aim here is to minimize your pain but not eradicate it completely. This way, the doctors can confirm the device is in the right place during the implantation. The standard trial period for the stimulator usually ranges from three to seven days.
How is Spinal Cord Stimulator Implant performed
There are two main types of stimulators used in the medical field: those that cause a tingling sensation, known as paraesthesia, and those that don’t. These stimulators can function in different ways – some are always active, while others use high frequency or burst modes. The type of electrical impulses used can determine either a continuous or a rhythmic delivery of stimulation.
A particular kind of stimulator uses an internal system (or algorithm) to decide the frequency and strength of impulses. This means it constantly changes its settings based on nerve signals it receives. Stimulators can either come with a rechargeable battery or a non-rechargeable one. Plus, there are even some wireless models being developed. However, we still need more research to understand how well these wireless ones work. Rechargeable models can be charged through the skin, while non-rechargeable ones tend to have a shorter lifespan (four to seven years compared to ten years for rechargeable).
Most current spinal cord stimulators are safe to use with MRI scans. However, if you have an older model, you should check if it’s safe before having an MRI.
No matter the type of stimulator, the installation process is usually the same. When the device is implanted, this is typically done with a local anesthetic to numb the area. Even with this numbness, we can still check how well the stimulator is functioning. If needed, we can use general anesthesia to put you to sleep. Although, this carries a higher risk of injury.
Stimulators that don’t cause tingling don’t require the patient’s feedback during the procedure. The frequencies of stimulation can be adjusted on the device during its installation. However, high-frequency stimulators use more power and may need their batteries replaced more often.
The install procedure uses a type of imaging called fluoroscopy to make sure the stimulator leads (the part that delivers the electrical impulses) are in the correct place. Where we put these leads depends on where you feel pain. For instance, for chronic lower back pain, we’d typically put the leads at the upper-middle part of your spine. For neck pain, we’d position the leads a bit higher.
Before we install a permanent stimulator, we usually do a trial run for three to seven days with temporary leads connected to an external power source. If this trial is successful, we’ll move to a permanent implant typically within one to two weeks.
When the leads are inserted and we confirm they’re in the right spot, we secure them in place. The leads should cover around 80 percent of your pain area for the implant to be successful. We create a “tunnel” under your skin to connect the generator (the part that produces the electric impulses) to the leads. The leads are connected to the generator using an extension cable, and the generator is placed under your skin through a separate small cut.
Possible Complications of Spinal Cord Stimulator Implant
Having a spinal cord stimulator implanted can cause a few problems in some cases, with a rate of complications between 5.3% to 40%. Most of these issues are due to the device itself not working properly, like the leads (the wires that carry electricity from the stimulator to the spine) moving out of place. When this happens, it might suddenly stop helping with pain relief because the location of one or both leads has changed. When the leads move, they are usually fixed in place again. Special devices have been made to help stop these leads from moving. For those with the stimulator implanted in the cervical vertebra (spinal bones of the neck), this might happen more often due to the neck’s wide range of movement.
Lead fractures, wherein the leads break, can happen in almost 10% of cases. This is often caused by intense physical activities. After the surgery, there can be fluid-filled lumps, known as seromas, but most of these clear up on their own. If they don’t, a small surgical cut might be needed to drain them. Between 2% to 12% of patients may experience infections in the year after having the device implanted.
In rare cases, the spinal cord covering, or dura, could be accidentally punctured during the lead placement causing a cerebrospinal fluid leak, which could result in intense headaches in up to 70% of these unique cases. Those who don’t readily overcome these headaches might need a treatment called a blood patch. The occurrence of a hematoma (a collection of blood) in the epidural space (the area around the spinal cord) is very rare, but when it does occur, is a medical emergency requiring surgery, as it needs to be treated immediately to prevent damage to the spinal cord.
In terms of effectiveness, for 20% to 40% of patients, the spinal cord stimulator might become less effective over time. As a result, an estimated 8% of these stimulators end up being removed, mostly because they don’t manage to provide enough relief from pain.
What Else Should I Know About Spinal Cord Stimulator Implant?
Stimulators, like those used in spinal cord stimulation treatments, can help to relieve pain. This relief may last for several weeks even after the device is turned off. They work by lowering the pain threshold, or the point at which you start to feel pain. There’s evidence on both brain scans and tests of the body’s response to touch and pressure that this is true.
However, it’s important to note that not all stimulators work the same way. For instance, high-frequency spinal cord stimulators don’t work through a central mechanism, or action in the brain’s processing centers.
People who have these devices implanted often experience an improvement in blood flow, which can help to relieve pain, especially pain due to reduced blood supply to a part of the body. They work by dilating blood vessels and activating the sympathetic nervous system, which controls your body’s response to stress, among other things. High-frequency and burst spinal cord stimulators have been shown to effectively reduce pain compared to traditional stimulators.
While not often used for general back pain, research is being conducted into the use of stimulators for this purpose. They might also help in cases of diabetes-related nerve pain and persistent pain in the area around the genitals and anus. If a spinal cord stimulator is implanted within two years of the onset of pain, it can be effective in up to 85% of cases.
However, these devices might not be as effective in people who have a 15-year history of chronic pain, providing relief in only nine percent of cases. Some stimulators are able to relieve back pain without causing a tingly feeling, known as paresthesia.
In terms of treating neuropathic pain, a type of pain caused by damage to the nerves, paresthesia-free stimulators are more effective than standard stimulators that induce paresthesia. Moreover, at a one-year follow-up, over 70 percent of patients preferred paresthesia-free stimulators to conventional ones.
It’s also important to note that over 80 percent of people will likely need an MRI scan within five years of having a spinal cord stimulator implanted. This is typically due to lead migration, or the movement of the device’s electrical leads within the body. This is very common in the early period after the procedure.