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.
Causes
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.
Symptoms
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.
When & How to Seek Medical Care
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.
Testing & Diagnosis
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.
Treatment
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.
Non-Surgical Treatments
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.
Surgery
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.
Who performs the procedure?
Neurosurgeons and doctors who specialize in pain management (an anesthesiologist or physiatrist) implant spinal cord stimulators.
The surgical decision
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 3 to 7 days prior to the trial.
A local anesthetic is given to numb the area in the lower back. Using X-ray fluoroscopy, 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 (Fig. 2).
You will be sent home with instructions on how to use the trial stimulator and care for your incision site. Keep a written log of the stimulation settings during different activities and the level of pain relief. After 4 to 7 days, you will return to the doctor’s office to discuss permanently implanting the stimulator or removing the trial leads.
During a Trial SCS, temporary leads are placed in the spinal canal and a stimulator is worn on a belt. For several days you will test the device to see if it relieves your pain during various activities.
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.
What happens before surgery?
In the doctor’s office, you will sign consent and other forms so that the surgeon knows your medical history (allergies, medicines/vitamins, bleeding history, anesthesia reactions, previous surgeries). Inform your healthcare provider about all the medications (over-the-counter, prescription, herbal supplements) that you are taking. Presurgical tests (e.g., blood test, electrocardiogram, chest X-ray) may need to be done several days before surgery. Consult your primary care physician about stopping certain medications and ensure you are cleared for surgery.
Continue taking the medications your surgeon recommends. Stop taking all non-steroidal anti-inflammatory medicines (ibuprofen, naproxen, etc.) and blood thinners (Coumadin, aspirin, Plavix, etc.) 7 days before surgery. Stop using nicotine and drinking alcohol 1 week before and 2 weeks after surgery to avoid bleeding and healing problems.
You may be asked to wash your skin with Hibiclens (CHG) or Dial soap before surgery. It kills bacteria and reduces surgical site infections. (Avoid getting CHG in eyes, ears, nose or genital areas.)
Morning of surgery
- Don’t eat or drink after midnight before surgery (unless the hospital tells you otherwise). You may take permitted medicines with a small sip of water.
- Shower using antibacterial soap. Dress in freshly washed, loose-fitting clothing.
- Wear flat-heeled shoes with closed backs.
- Remove make-up, hairpins, contacts, body piercings, nail polish, etc.
- Leave all valuables and jewelry at home (including wedding bands).
- Bring a list of medications (prescriptions, over-the-counter, and herbal supplements) with dosages and the times of day usually taken.
- Bring a list of allergies to medication or foods.
Arrive at the hospital 2 hours before your scheduled surgery time (1 hour before at the outpatient surgery center) 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.
What happens during surgery?
The surgery generally takes 1 to 2 hours.
Step 1: prepare the patient
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: place the leads
The electrode leads are inserted with the aid of fluoroscopy (a type of X-ray). A small skin incision is made in the middle of your back, and the bony vertebra is exposed.
A skin incision is made in the middle of your back for the leads and another is made in your buttock for the generator.
A portion of the bony arch is removed (laminotomy) to allow room to place the leads. The leads are positioned in the epidural space above the spinal cord and secured with sutures (Fig. 4). The leads do not directly touch your spinal cord.
A laminotomy is cut in the bone to make room to insert the leads into the spinal canal.
B. The leads are positioned in the epidural space above the spinal cord to deliver electrical current to the nerves.
Step 3: test stimulation (optional)
Depending on the SCS device being implanted, you may be awakened to help the doctor test how well the stimulation covers your pain areas. However, modern SCS device leads can be positioned based on anatomy or electric monitoring of the nerves. Settings from the trial will be used to program the pulse generator at the end of surgery, so your feedback is important to ensure the best pain relief.
In some cases, if the leads implanted during the trial are positioned perfectly, there is no need to reposition or insert new leads.
Step 4. tunnel the wire
Once the lead elecrodes are in place, the wire is passed under the skin from the spine to the buttock, where the generator will be implanted.
Step 5. place the pulse generator
A small skin incision is made below the waistline. The surgeon creates a pocket 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.
The SCS generator pocket is created below the waist, under the skin of the buttock.
Step 6. close the incisions
The incisions are closed with sutures and skin glue. A dressing is applied.
What happens after surgery?
You will wake up in the recovery area. Your blood pressure, heart rate, and respiration will be monitored, and your pain will be addressed. Most patients are discharged home the same day or the following morning. The pulse generator will be programmed before you leave. You will be given written instructions to follow when you go home.
Follow the surgeon’s home care instructions for 2 weeks after surgery or until your follow-up appointment. In general, you can expect:
Restrictions
Do not bend, lift, twist your back or reach overhead for the next 6 weeks. This is to prevent the leads from moving out of place until it heals.
- Don’t lift anything heavier than 5 pounds.
- No strenuous activity including yard work, housework and sex.
- Don’t drive until your follow-up appointment.
- Don’t drink alcohol. It thins the blood and increases the risk of bleeding. Also, don’t mix alcohol with pain medicines.
Incision Care
- Wash your hands thoroughly before and after cleaning your incision to prevent infection.
- You may shower the day after surgery.
- Gently wash the incision covered in Dermabond skin glue with soap and water every day. Don’t rub or pick at the glue. Pat dry.
- Don’t soak the incision in a bath or pool.
- Don’t apply lotion / ointment on the incision.
- If there is drainage, cover the incision with a dry gauze dressing. If drainage soaks through two or more dressings in a day, call the office.
- Some clear, pinkish drainage from the incision is normal. Watch for increased volume of drainage or spreading redness. An infected incision may have colored drainage and begin to separate.
Medications
- Take pain medication as directed by your surgeon. Reduce the amount and frequency as your pain subsides. If you don’t need the pain medicine, don’t take it.
- Narcotics can cause constipation. Drink lots of water and eat high-fiber foods. Stool softeners and laxatives can help move the bowels. Colace, Senokot, Dulcolax, and Miralax are over-the-counter options.
Activity
- Ice your incision 3-4 times per day for 15-20 minutes to reduce pain and swelling.
- Don’t sit or lie in one position longer than an hour unless you are sleeping. Stiffness leads to more pain.
- Spinal headaches may be caused by leakage of cerebrospinal fluid around the lead site. The leak often heals on it’s own. Lie flat and drink plenty of caffeinated non-carbonated fluids (tea, coffee).
- Get up and walk 5-10 minutes every 3-4 hours. Gradually increase walking, as you are able.
When to Call Your Doctor
- 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.
Recovery
Approximately 10 days after surgery you will come to the office to have the incision checked. Bring your device remote and product box to your follow-up appointment with the surgeon. Programming of the pulse generator can be adjusted at this time if needed. It is important to work with your doctor to adjust your medications and refine the programming of the stimulator.
Your pain specialist and device representative will work with you to fine-tune adjustments to the SCS.
What are the results?
The results of SCS depend on careful patient selection, successful trial stimulation, proper surgical 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 half.
Published studies of spinal cord stimulation show good to excellent long-term relief in 50 to 80% of patients suffering from chronic pain [1-6]. 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 [7].
SCS therapy is reversible. If a patient decides at any time to discontinue, the electrode wires and generator can all be removed.
What are the risks?
No surgery is without risks. General complications of any surgery include bleeding, infection, blood clots, and reactions to anesthesia. Specific complications related to SCS 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
Conditions for which you might need additional surgery include movement of the lead, breakage of the lead or extension wire, or (in rare cases) mechanical failure of the device. Reasons for removal of the device include infection and failure to relieve pain.
Sometimes scar tissue develops around the electrode and can make the stimulation less effective.
Living with a stimulator
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 surgeon first.
Sources & links
Sources
- Verrills P, Sinclair C, Barnard A. A review of spinal cord stimulation systems for chronic pain. J Pain Res 9:481-92, 2016
- De la cruz P, Fama C, Roth S, et al. Predictors of Spinal Cord Stimulation Success. Neuromodulation 18(7):599-602, 2015
- Grider J, Manchikanti L, Carayannopoulos A, et al. Effectiveness of Spinal Cord Stimulation in Chronic Spinal Pain: A Systematic Review. Pain Physician 19:E33-E54, 2016
- Deer TR, Skaribas IM, Haider N, et al. Effectiveness of cervical spinal cord stimulation for the management of chronic pain. Neuromodulation 17(3):265-71, 2014
- Deer TR, Mekhail N, Provenzano D, et al. The appropriate use of neurostimulation of the spinal cord and peripheral nervous system for the treatment of chronic pain and ischemic diseases: the Neuromodulation Appropriateness Consensus Committee. Neuromodulation 17(6):515-50, 2014
- Eldabe S, Buchser E, Duarte RV. Complications of Spinal Cord Stimulation and Peripheral Nerve Stimulation Techniques: A Review of the Literature. Pain Med 17(2):325-36, 2016
- Sundaraj SR, et al: Spinal cord stimulation: A seven-year audit. J Clin Neurosci 12:264-270, 2005
Links
Spine-health.com
Nevro.com
mayfieldclinic.com
Controlyourpain.com
Tamethepain.com
Poweroveryourpain.com
Glossary
laminotomy: surgical cutting of the laminae or vertebral arch of the vertebra.
lead: a small, silicone coated medical wire that has electrodes at one end. Electrical current passes from a battery, along the wire, to the electrodes. Two types: percutaneous and surgical leads.
fluoroscopy: an imaging device that uses x-ray or other radiation to view structures in the body in real time, or “live”. Also called a C-arm.
percutaneous: by way of the skin (e.g., injection).
peripheral nerve stimulation: a surgical treatment for pain in which specific nerves are stimulated rather than the general area of the spinal cord.
sciatic nerve: nerve located in the back of the leg which supplies the muscles of the back of the knee and lower leg and sensation to the back of the thigh, part of the lower leg, and the sole of the foot.
sciatica: pain that courses along the sciatic nerve in the buttocks and down the legs. Usually caused by compression of the 5th lumbar spinal nerve.
seroma: a mass formed by the collection of tissue fluids following a wound or surgery.
spinal hygroma: an accumulation of cerebrospinal fluid under the skin, which produces a visible swelling, caused by leakage around a catheter, drain, or shunt.
Follow-up
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.