Spinal Cord Stimulation Treatment

What is Spinal Cord Stimulation Therapy?

A Spinal Cord Stimulator (SCS) device is surgically placed under your skin and sends a mild electrical current to your spinal cord. Thin wires carry current from a pulse generator to the nerve fibers of the spinal cord. When opened, the SCS stimulates the nerves in the area where your pain is felt. The pain is reduced because the electrical pulses change and block the pain signal from reaching your brain.

Some SCS devices use a low-frequency current to replace the sensation of pain with a slight tingling sensation called paresthesia. Other SCS devices use high-frequency or sudden pulses to mask pain without a tingling sensation. On most devices, the paresthesia-free setting is an option.

Stimulation does not remove the source of the pain. It just changes the way your brain perceives it. As a result, the amount of pain relief varies from person to person. The goal for SCS is to achieve a 50% to 70% reduction in pain. However, it is also important if it helps you carry out your daily activities and reduces the amount of pain medication you take. SCS does not increase muscle strength.

There are several types of SCS device systems. However, they all have three main parts:

• A battery-powered pulse generator that generates electrical pulses.
• A lead wire containing a series of electrodes (8-32) that transmit electrical signals to the spinal cord.
• A hand control that turns the device on and off and adjusts the settings.

Systems with non-rechargeable batteries need to be surgically replaced every 2 to 5 years, depending on frequency of use. Rechargeable battery systems can last 8 to 10 years or more, but you should remember to charge the system every day.

The signal generator has programmable settings. Some SCS devices can detect a change in body position (sitting or lying down) and adapt the stimulation level to your activity. Other systems have independently programmable tips to cover multiple pain areas. Some send an electrical signal without tingling. Your doctor will choose the best system type for you.

Who is an SCS Candidate?

Evaluation of your physical condition, medication regimen, and pain history will determine whether your pain management goals are appropriate for SCS. Your doctor will review all previous treatments and surgeries.

Patients selected for SCS usually have chronic pain in the lower back, leg (sciatica), or arm for more than 3 months.

You Can Be A Candidate For SCS If:

• If conservative treatments have failed,
• If you have not benefited from additional surgery,
• If the pain is caused by a correctable problem,
• If you do not want further surgery due to risks or long recovery time,
• Unless you have a contraindicated medical condition for SCS.
• The SCS functions better in the early stages of a chronic condition, before a pain-disability cycle is established.

SCS Indications Are:

• Chronic leg (sciatica) or arm pain: Ongoing chronic pain caused by arthritis, spinal stenosis, or nerve damage.
• Diabetic Neuropathy: Diabetic condition that can cause burning or burning pain, usually in the legs or feet.
• Failed Back Surgery: One or more surgeries fail 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 typically experience persistent, chronic burning pain in the foot or hand.
• Arachnoiditis: Painful inflammation and scarring of the protective membrane of the spinal nerves.
• Other: Root pain, peripheral vascular disease, multiple sclerosis or spinal cord injury.

How is the Surgical Decision Made?

Determining whether a spinal cord stimulator would be a good option for you is a two-step process. First, you should go through a trial to see if the device reduces your pain level.

1. Step 2: Trial “test stimulation”

Trial stimulation is a “test stimulation” to determine if an SCS works for the type, location, and severity of your pain. It is carried out in the outpatient clinic.

If you are on blood thinners, you must stop the drug 3 to 7 days before the study.

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 cable is placed over certain nerves and positioned. The wires are connected to an external generator attached to a belt. You will be sent home with instructions on how to use the trial stimulator and care for your incision site. A written record of the stimulation settings and level of pain relief is kept during different activities. After 4 to 7 days, you should meet with your doctor to discuss permanent implantation of the stimulator or removal of trial electrodes.

If the trial is successful and you feel more than 50% improvement in pain, surgery may be scheduled to insert the SCS device into your body.

2. Step: Operation

It usually takes 1 to 2 hours. The electrode tips are placed with the help of fluoroscopy (a type of X-ray). A small skin incision is made in the middle of your back and the bony vertebrae are exposed. Part of the bony arch is removed (laminotomy) to provide room to place the electrodes. Electrodes are placed in the epidural space above the spinal cord and secured with sutures. The electrodes do not directly touch your spinal cord.

3. Step 2: Testing the Stimulation

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 electrodes can be positioned according to the anatomy or electrical condition of the nerves. The settings from the trial are used to program the pulse generator at the end of surgery, so your feedback is important to determine the best pain reliever and stimulation.

4. Step: Fixing the Electrodes

After the lead electrodes are placed, the wire is passed under the skin from the spine to the hip, where the generator is implanted.

5. Step: Placing the Pulse Generator

A small skin incision is made below the waistline. A pocket for the generator is created under the surgeon’s skin. The lead wire is connected to the pulse generator. The generator is then accurately positioned within the skin pocket.

6. Step: Closing
   

The incisions are closed with sutures and skin glue and a dressing is applied. After surgery, most patients are discharged home the same day or the next morning. The pulse generator will be programmed before you leave. You will be given written instructions to follow when you get home. Heavy activities should be avoided for 6 weeks after surgery. You can take a shower the day after the surgery. Skin care should be done. Pain relievers should be continued as directed by your surgeon.

When Should You Call Your Doctor?

• Fever over 38°C.
  Nausea or vomiting that does not go away.
  Severe pain that does not go away.
  Signs of infection at the incision site.
  Redness or itching at the incision site (allergy to Dermabond skin adhesive).
  Swelling and tenderness in the calf (a sign of blood clots).
  New onset tingling, numbness, or weakness in the arms or legs.
  Dizziness, confusion, nausea or excessive sleepiness.
  Fluid accumulation under the skin around the electrodes or device.
  Sudden severe back pain, sudden onset of leg weakness and spasm, loss of bladder and/or bowel function. -this is an emergency-

Visit your doctor 7-10 days after the operation to check the incision. The controller of your device and the product box should be brought to the control appointment with the surgeon. If the pulse generator needs to be programmed, it can be set at this time. It is important to work with your doctor to adjust your medications and program the stimulator.

What are the Results?

The results of SCS depend on careful patient selection, successful trial stimulation, appropriate surgical technique, and patient education. Stimulation does not improve the condition causing the pain. Rather, it helps patients manage pain. SCS is considered successful if the pain is reduced by at least half.

Published studies of spinal cord stimulation show long-term improvement in 50 to 80% of patients suffering from chronic pain. One study reports that 24% of patients recover enough to return to work with their warning alone or with the addition of pain medication.

SCS treatment is reversible. If a patient decides not to continue at any time, the leads and the entire generator may be removed.

What are the risks?

No surgery is risk-free. Common complications of any surgery include bleeding, infection, blood clots, and anesthesia reactions. Specific complications related to SCS may include:

• Undesirable changes in stimulation (Possibly related to cellular changes in tissue around the electrodes, changes in electrode position, loose electrical connections, and/or lead failure.)
  Epidural bleeding, hematoma, infection, spinal cord compression and/or paralysis (can result from insertion of a lead into the epidural space during a surgical procedure)
  Battery failure and/or battery leakage
  Cerebrospinal fluid leak
  Persistent pain at the electrode or stimulator site
  There may be clear fluid accumulation at the implant site, which usually goes away on its own but may require drainage.
  Lead migration, which can cause changes in stimulation and reduced pain relief
  Allergic reaction to implant materials
  Generator pass and/or local skin erosion
  Paralysis, weakness, clumsiness, numbness, or pain below the implantation level
  Conditions that may require additional surgery include lead movement, lead or extension wire breakage, or (in rare cases) mechanical failure of the device. Reasons for device removal include infection and failure to relieve pain.
  Sometimes scar tissue develops around the electrode and can make stimulation less effective.

Living with a Stimulator

Once the SCS is programmed, you are sent home with instructions to regulate the stimulation, controlling the strength and duration of each stimulation period. If necessary, your doctor may change the pulse width, amplitude, and frequencies at follow-up visits.

SCS has programmable settings:

• Frequency (rate): the number of times the stimulation is delivered per second.
  Stimulation amplitude: the area that the stimulation will cover.
  Pulse amplitude: determines the pain perception threshold.
  The portable programmer allows you to turn the stimulator on and off, select programs and adjust the strength of the stimulation. Most people are given more than one schedule to get the best possible pain relief at any time of the day or during certain activities. If necessary, you can use your spinal cord stimulator around the clock.

Sometimes, differences in stimulation intensity can be felt depending on their position (eg sitting versus standing). This is due to changes in the dissipation of electricity as the position changes and is normal.

Various SCS systems have different restrictions on their use with magnetic resonance imaging, ultrasound, defibrillator, electrocautery, diathermy, and pacemakers.

Just like a pacemaker, your stimulator is immune to devices such as cell phones, pagers, microwave ovens, security doors, and anti-theft sensors. As the device is detected at airport security gates, you should have your implanted device ID card with you when you fly. Large department store and airport security gates or burglary detectors can cause increased or decreased stimulation when you walk through the door. This feeling is temporary and will not harm your system. However, as a precaution, you should turn off your system before going through the security gates.