What is a Spinal Cord Stimulation?
Spinal cord stimulation (SCS) delivers mild electrical stimulation to nerves along the spinal column, modifying or blocking nerve activity in a non-medicinal way to minimize the sensation of pain reaching the brain. Spinal cord stimulation was first used to treat pain in 1967.
How does it work?
A spinal cord stimulator (SCS) device is surgically placed under your skin and sends a mild electric current to your spinal cord. Thin wires carry current from a pulse generator to the nerve fibers of the spinal cord. When turned on, the SCS stimulates the nerves in the area where your pain is felt. Pain is reduced because the electrical pulses modify and mask the pain signal from reaching your brain.
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 with no tingling feeling. A paresthesia-free setting is an option on most devices.
The goal for spinal cord stimulation is a 50-70% reduction in pain. However, even a small amount of pain reduction can be significant if it helps you to perform your daily activities with less pain and reduces the amount of pain medication you take.
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 where only the leads are placed and the device is external during this time. If it doesn’t work for you, the trial wires can be removed, leaving no damage to the spinal cord or nerves.
What makes up a SCS device?
There are several types of SCS device systems. However, all have three main parts:
A hand-held remote control that turns the device on and off and adjusts the settings.
A lead wire with a number of electrodes (8-32) that delivers electrical pulses to the spinal cord.
A pulse generator with a battery that creates the electrical pulses.
Systems with a non-rechargeable battery need to be surgically replaced every 2 to 5 years, depending on the frequency of use. Rechargeable battery systems may last 8 to 10 years or longer, but you must remember to charge the system daily.
The pulse generator has programmable settings. Some SCS devices are able to sense a change in body position (sitting vs. lying down) and adapt the stimulation level to your activity. Other systems have leads that can be independently programmed to cover multiple pain areas. Some send a sub-perception pulse with no tingling. Your doctor will select the best type of system for you.
Why is it done?
An evaluation of your physical condition, medication regime, and pain history will determine whether your goals of pain management are appropriate for SCS. Usually a neurosurgeon, physiatrist, or pain specialist will review all previous treatments and surgeries. Because chronic pain also has emotional effects, a psychologist will also assess your condition to maximize the probability of a successful outcome.
Patients selected for SCS usually have had chronic debilitating pain for more than 3 months in the lower back, leg (sciatica), or arm. They also typically have had one or more spinal surgeries or may not be good candidates for spinal surgery.
You may be a candidate for SCS if :
Conservative therapies have failed.
You would not benefit from additional surgery.
The pain is caused by a correctable problem and should be fixed.
You do not want further surgery because of the risks or long recovery
Sometimes SCS may be chosen over a large, complex spine surgery.
You do not have untreated depression or drug addiction.
You have no medical conditions that would keep you from undergoing implantation.
You have had a successful SCS trial.
SCS works better in the earlier stages of a chronic condition, before a cycle of pain-suffering-disability-pain is established.
An SCS can help lessen chronic pain caused by:
Chronic leg (sciatica) or arm pain: ongoing, persistent pain caused by arthritis, spinal stenosis, or by nerve damage.
Failed back surgery syndrome: failure of one or more surgeries to relieve persistent arm or leg pain, but not a technical failure of the original procedure.
Complex regional pain syndrome: a progressive disease in which patients feel constant, chronic burning pain, typically in the foot or hand.
Arachnoiditis: painful inflammation and scarring of the protective lining of the spinal nerves.
Other: stump pain, angina, peripheral vascular disease, multiple sclerosis, or spinal cord injury.
What are the risks?
As with any interventional procedure, there is a small risk of infection and bleeding at the procedure sites. Specifically for SCS the risk is extremely minimal. The leads are very small wires that are placed under real-time x-ray (fluoroscopy) guidance and the pulse generator device is also small and is placed superficially, just under the skin. You are given IV antibiotics during the procedure to help further decrease the risk of infection.
In addition, there are some risks that are specific to the spinal cord stimulator. These may include:
Undesirable changes in stimulation (can possibly be related to cellular changes in tissue around electrodes, changes in electrode position, loose electrical connections, and/or lead failure)
Epidural hemorrhage, hematoma, infection, spinal cord compression, and/or paralysis (can be caused by placing a lead in the epidural space during a surgical procedure)
Battery failure and/or battery leakage
Cerebrospinal fluid leak
Persistent pain at the electrode or stimulator site
A pocket of clear fluid (seroma) at the implant site. Seromas usually disappear by themselves, but may require a drain.
Lead migration, which can result in changes in stimulation and reduction in pain relief
Allergic response to implant materials
Generator migration and/or local skin erosion
Paralysis, weakness, clumsiness, numbness, or pain below the level of implantation
Sometimes scar tissue develops around the electrode and can make the stimulation less effective.
How do I know the spinal stimulator will work?
Determining whether a spinal cord stimulator will be a good option for you is a two-step process. First, you must undergo a temporary trial to see if the device decreases your level of pain.
Stage 1. Trial “test drive”
Trial stimulation is a “test drive” to determine if an SCS will work for the type, location, and severity of your pain. It is performed at an outpatient center.
If you take blood-thinners, you are required to stop the medication for a few days (depending on the type of blood thinner you are on).
A local anesthetic is given to numb the area in the lower back. Using X-ray (fluoroscopy) guidance, a hollow needle is inserted through the skin into the epidural space between the bone and spinal cord. The trial lead is inserted and positioned over specific nerves. The wires are attached to an external generator worn on a belt.
You will be taught on how to use the trial stimulator and care for your small puncture site. Keep a written log of the stimulation settings during different activities and the level of pain relief. After 1 week, you will return for a follow-up visit to discuss if SCS was successful for you. If successful, the trial leads will be removed and you will need to heal for 2 weeks prior to scheduling permanent implantation of the stimulator.
Stage 2. Surgical implant
If the trial is successful and you felt greater than 50% improvement in pain, surgery can be scheduled to implant the SCS device in your body.
How do I prepare for the procedure?
You may be scheduled for pre-surgical tests (e.g., blood test, electrocardiogram, chest X-ray) several days before surgery.
Stop taking all non-steroidal anti-inflammatory medicines (Naprosyn, Advil, Motrin, Nuprin, Aleve, etc.) and blood thinners (Coumadin, Xarelto, Eliquis, Plavix, etc.) 1 to 2 weeks before surgery as directed by your physician. In addition, stop smoking, chewing tobacco, and drinking alcohol 1 week before and 2 weeks after surgery, because these activities can cause bleeding problems and may increase risk for infection. No food or drink is permitted past midnight the night before surgery.
Morning of surgery
Shower using antibacterial soap. Dress in freshly washed, loose-fitting clothing. Wear flat-heeled shoes with closed backs.
If you have instructions to take regular medication the morning of surgery, do so with small sips of water.
Remove make-up, hairpins, contacts, body piercings, nail polish, etc.
Leave all valuables and jewelry at home (including wedding bands). Anything brought to the hospital can get lost or damaged.
Bring your list of medications (prescriptions, over-the-counter, and herbal supplements) with dosages and the times of day usually taken.
Bring your list of allergies to medication or foods.
Arrive at the hospital 2 hours before your scheduled surgery time to complete the necessary paperwork and pre-procedure work-ups. An anesthesiologist will talk with you and explain the effects of anesthesia and its risks. An intravenous (IV) line will be placed in your arm.
How is the procedure done?
The procedure generally takes 1 hour.
Step 1: Prep
You will lie on your stomach on the table and be given light anesthesia. Next, the areas of your back and buttock are prepped where the leads and generator are to be placed.
Step 2: Placement of the leads
The electrode leads are inserted with the aid of fluoroscopy (a type of X-ray). A small skin puncture is made in the middle of your back and a needle is inserted to the epidural space. The needle is replaced with a sheath that allows access for the leads to be placed into the epidural space. Real-time fluoroscopy is used again to localize the precise positioning of the leads.
Step 4. Tunnel the wire
Once the lead electrodes are in place, the wire is passed under the skin from the spine to the left or right low back, where the pulse generator will be implanted.
Step 5. Place the pulse generator
A small skin incision is made at the low back where the pulse generator will be placed. A small pocket is then created for the generator beneath the skin. The lead wire is attached to the pulse generator. The generator is then correctly positioned within the skin pocket.
Step 6. close the incisions
The incisions are closed with sutures and skin glue. A dressing is applied.
What you can expect after the procedure?
After the procedure you will go to the post surgical area at El Camino Hospital (unit 2B). There we will be able to monitor your blood pressure, heart rate, oxygen saturation, procedure site and pain level. The pulse generator will be programmed before you leave. You will be given written instructions to follow when you go home. In general, you will be there for about 1-2 hours to recover (depending if you got the device implanted or just the trial).. You will be able to eat and drink after the procedure and see your family members soon after the procedure while in recovery (2B).
At home, we recommend that you take it slow. Do not drive or operate heavy machinery, consume alcohol or make any important decisions for 24 hours if you received sedation. You can shower when you return home as your procedure site is sealed with skin glue. This glue should fall off on its own in about 1-2 weeks. You do not need to apply any bandages on the procedure sites.
You will be contacted to schedule a follow-up in about 1 week to check your procedure sites.
I have a spinal stimulator, now what?
Once the SCS has been programmed, you are sent home with instructions for regulating the stimulation by controlling the strength and the duration of each stimulation period. Your doctor may alter the pulse width, amplitude, and frequencies on follow-up visits if necessary.
The pulse generator has programmable settings:
Frequency (rate): number of times stimulation is delivered per second. Too few pulses results in no sensation. Too many results in a washboard or bumpy effect.
Pulse width: the area the stimulation will cover.
Pulse amplitude: determines threshold of perception to pain.
The handheld programmer lets you turn the stimulator on and off, select programs, and adjust the strength of the stimulation. Most people are given multiple programs to achieve the best possible pain relief at any point throughout the day or during specific activities. You can use your spinal cord stimulator around the clock if necessary.
Some people feel differences in stimulation intensity depending on their position (e.g., sitting versus standing). This is caused by variations in the spread of electricity as you change positions and is normal.
Just like a cardiac pacemaker, your stimulator cannot be damaged by devices such as cellular phones, pagers, microwaves, security doors, and anti-theft sensors. Be sure to carry your Implanted Device Identification card when flying, since the device is detected at airport security gates. Department store and airport 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.
The various SCS systems have different restrictions to their use with MRI, ultrasound, defibrillator, electrocautery, diathermy, and cardiac pacemakers. Be sure to know the limitations of your specific SCS device. Also, chiropractic manipulation may cause the lead to move. Consult your doctor first.
What are the results?
The results of SCS depend on careful patient selection, successful trial stimulation, proper procedural technique, and patient education. 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%.
Published studies of SCS show good to excellent long-term relief in 50 to 80% of patients suffering from chronic pain. One study reports that 24% of patients improved sufficiently to return to gainful employment or housework with stimulation alone or with the addition of occasional oral pain medication .
SCS therapy is reversible. If a patient decides at any time to discontinue, the electrode wires and generator can all be removed.
What should I watch for?
Procedural site pain and soreness is considered normal. This pain should subside over the next 2-3 days following the procedure. Worsening of pain, redness, warmth or discharge at the site of the procedure may be signs of infection.
If pain continues, worsens or signs of an infection are present please call our office immediately at (650) 404-8445 and seek immediate medical attention.
Do you have any additional questions?
Please let us know if you have any additional questions that we can answer for you prior to your procedure. Please do not hesitate to call our office at 650-404-8445, we look forward to serving you.
If you received sedation, you should not drive, consume alcohol, operate heavy machinery or make any important decisions for the remainder of the day.
You may resume your regular activities as tolerated (including driving) after 24 hours, unless you have been restricted for another reason.
No exercising, lifting heavy objects or strenuous activity for the next two weeks or until you have had your follow-up with us at our Interventional Radiology clinic.
You may shower 24 hours after the procedure.
You may use over the counter medication such as Acetaminophen (Tylenol) or Ibuprofen (Advil /Motrin) for minor discomfort, unless you are restricted from taking these medications.
If you feel that Tylenol or Advil are not enough to control your pain, please contact the Vascular and Interventional Radiology Clinic at 650-404-8445.
You can resume your normal diet. Some patients may develop nausea after the sedation. Therefore light meals are recommended until you know that you can eat without problems.
Make sure you drink enough fluids.
You can take a shower tonight. You should not soak the procedure site in water (eg. bath and swimming pool) for 1 week.
When should you call your physician?
Fever over 101.5° F (unrelieved by Tylenol)
Unrelieved nausea or vomiting.
Severe unrelieved pain.
Signs of incision infection.
Rash or itching at the incision (allergy to Dermabond skin glue).
Swelling and tenderness in the calf of one leg (sign of a blood clot).
New onset of tingling, numbness, or weakness in the arms or legs.
Dizziness, confusion, nausea or excessive sleepiness.
Fluid may accumulate under the skin around the leads or the device, creating a visible swelling (seroma). Call the doctor if this occurs.
Sudden severe back pain, sudden onset of leg weakness and spasm, loss of bladder and/or bowel function – this is an emergency – go to a hospital and call your surgeon.
You can reach your Interventional radiologist at (650) 404-8446