Spinal Cord Stimulation

Overview

Spinal cord stimulation (neurostimulation) is a procedure in which an electrical current is used to alleviate chronic back pain. It involves the implantation of a small pulse generator that transmits electrical impulses to the spinal cord, which in turn blocks the nerve signals to the brain responsible for the pain.

Spinal Cord Stimulation

Neurostimulation delivers low-voltage electrical stimulation to the spinal cord or targeted peripheral nerve to block the sensation of pain.

One theory on how this technology works, the Gate Control Theory of pain developed by researchers Ronald Melzack and Patrick Wall, proposes that neurostimulation activates the body's pain inhibitory system. According to this theory, there is a gate in the spinal cord that controls the flow of noxious pain signals to the brain. The theory suggests that the body can inhibit these pain signals or "close the gate" by activating certain non-noxious nerve fibers in the dorsal horn of the spinal cord. The neurostimulation system, implanted in the epidural space (the space outside the dura, or covering of the spinal cord, through which the spinal nerves extend into the rest of the body), stimulates these pain-inhibiting nerve fibers, masking the sensation of pain with a tingling sensation (paresthesia).1,2

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Conditions Treated

Spinal cord stimulation may be appropriate for the management of severe, chronic back pain. Spinal cord stimulation typically is recommended for patients for whom:

  • Conservative therapies have failed
  • Spine surgery has failed (failed back syndrome)
  • An observable pathology exists that is concordant with the pain complaint
  • Further surgical intervention is not indicated
  • No serious untreated drug habituation exists
  • Psychological evaluation and clearance for implantation has been obtained
  • No contraindications to implantation exist
  • A screening test has been successful

Published studies of the therapy have shown that when used on carefully selected chronic pain patients, spinal cord stimulation may:

  • Improve pain relief (a majority of patients may experience at least 50% reduction in pain)1,2,3
  • Increase activity levels1,2,3,4
  • Reduce use of narcotic medications2,3,4

These results may also lead to reduced hospitalizations and surgical procedures, reduced health care costs, greater independence, and improved quality of life.2,3,4

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How it Works

There are two types of neurostimulation systems: one that is completely internal (surgically implanted) and one with both internal and external components. Each neurostimulation system consists of:

  • One or two leads which deliver electrical stimulation to the spinal cord or targeted peripheral nerve
  • An extension wire which conducts electrical stimulation from the power source to the lead
  • A power source which generates the electrical stimulation

Both the power source (battery) and leads are surgically implanted for an internal system. A system with both internal and external components typically consists of a radiofrequency receiver and leads that are implanted and a power source that is worn externally. Batteries typically must be replaced every two to five years.

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Procedure

The neurostimulation system is typically implanted in a two-stage procedure. Stage 1 involves the implantation of a lead for trial screening. Stage 2 involves the implantation of the complete neurostimulation system.

Published studies of the therapy have shown that when used on carefully selected chronic pain patients, neurostimulation may:

  • Improve pain relief (a majority of patients may experience at least 50 percent reduction in pain)3,4,5
  • Increase activity levels3,4,5,6
  • Reduce use of narcotic medications4,5,6

These results may also lead to reduced hospitalizations and surgical procedures, reduced health care costs, greater independence, and improved quality of life.4,5,6

 

References:
1. Melzack R, Wall PD. Pain mechanisms: A new theory. Science. 1965;150(699):971-9.
2. Shealy CN, Mortimer JT, Reswick JB. Electrical inhibition of pain by stimulation of the dorsal columns: Preliminary clinical report. Anesth Analg. 1967;46(4):489-91.
3. Burchiel K, et al. Prospective, multicenter study of spinal cord stimulation for relief of chronic back and extremity pain. Spine. 1996; 21(23):2786-2794.
4. North R, et al. Failed back surgery syndrome: Five-year follow-up after spinal cord stimulator implantation. J Neurosurg. 1991;28(5):692-699.
5. North R, et al. Spinal cord stimulation for chronic, intractable pain: experience over two decades. J Neurosurg. 1993;32(3):384-395.
6. Racz G, et al. Percutaneous dorsal column stimulator for chronic pain control. Spine. 1989;14(1):1-4.

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