Spinal Cord Stimulators

The Spinal Cord Stimulator (SCS), also known as a Dorsal Column Stimulator is the particular neurostimulator used directly on the spine for the treatment of severe chronic pain.  This device consists of a surgically implanted pulse generator producing low-level electrical impulses delivered directly to the spinal cord via leads surgically inserted in the epidural space.  These electrical impulses interfere with the direct transmission of any pain signals traveling along the spinal cord to the brain.  Painful stimulation is then replaced with a more pleasing tingling sensation in the areas where pain is usually felt. This sensation is referred to as parasthesia.

There are three types of SCS units:

• Conventional Implantable Pulse Generator (IPG) consists of a battery and control electronics. When the battery wears out, it is surgically replaced.

• Rechargeable Implantable Pulse Generator (IPG) consists of a rechargeable battery and control electronics. The battery is recharged by an external device worn for a few hours every two to three weeks.

• Radiofrequency device consists of an implanted receiver and a transmitter device worn like a cell phone. The transmitter sends RF energy to the receiver which in turn sends stimulation to the lead. RF units have traditionally been used for patients that require high-power settings that would quickly deplete a primary-cell IPG (conventional IPG).

    Manufacturers

There are three companies in the United States that currently market the Spinal Cord Stimulator, Advanced Bionics, Advanced Neuromodulation Systems, Inc. (a St. Jude Medical company) , and Medtronic. 

The major difference between these systems is, of course, the location of the battery.  Where as the internally-powered system uses a battery implanted beneath the skin, the externally-powered system uses a battery worn outside the body.

A Spinal Cord Stimulator company representative and the treating physician will assist the patient in selecting which of the two systems is better suited for the patient’s type of pain.  Generally, the internally-powered system (IPG) is the one to choose for simple pain patterns, which require less energy and therefore fewer battery replacements.  The externally-powered system is better suited for the more complex pain patterns, because the battery is contained in the external transmitter and can easily be recharged.
 

How Spinal Cord Stimulators Are Used

An important fact to note is that the implantation of the stimulator is a two-staged surgical process.  It involves a trial implantation of the spinal cord leads on a temporary basis to help determine if the therapy will be effective in the patient’s pain control.  A trial period may last anywhere from one to ten days.  If the trial proves to be successful (pain is decreased by 50 percent or more), the patient will return to the operating room to have the complete system permanently implanted.  Surgical pain from the incision site on the back will last for several days, but it heals quickly.  However, pain at the IPG or receiver site on the buttocks can last up to six weeks as scar tissue is formed.  Once the scar tissue is formed, this pain will disappear.

How Often Used

Based on Marketdata Enterprises' last major study of pain management programs, 51% of all pain treatment practitioners used spinal cord stimulators  to treat chronic pain in 2003, so this is a fairly common treatment method.

Cautions

With the public still reeling over the lethal side effects of Cox-2 inhibitors such as Vioxx, more people may be temptedt to try spinal cord stimulators.

Patients with SCS units are not able to have MRI procedures due to heating of the implanted electrodes which can cause spinal cord damage. Other medical scans such as ultrasound, CT  and plain X-ray can be performed.

People with SCS should avoid areas and performing tasks which are linked with strong electromagnetic interference, examples include electricity substations and activities such as arc welding.

  Benefits

   Spinal cord stimulators can work in those tough cases where other methods, although tried, have not brought relief.

   Spinal cord stimulators allow you to adjust the pain modulating current, which in turn allow you to be in control of the pain  relief you receive from it.

   The stimulator device is portable and therefore will enable activities of daily living to resume.